G2Cdb::Gene report

Gene id
G00002000
Gene symbol
MYO5A (HGNC)
Species
Homo sapiens
Description
myosin VA (heavy chain 12, myoxin)
Orthologue
G00000751 (Mus musculus)

Databases (8)

Gene
ENSG00000197535 (Ensembl human gene)
4644 (Entrez Gene)
51 (G2Cdb plasticity & disease)
MYO5A (GeneCards)
Literature
160777 (OMIM)
Marker Symbol
HGNC:7602 (HGNC)
Protein Expression
1356 (human protein atlas)
Protein Sequence
Q9Y4I1 (UniProt)

Synonyms (3)

  • GS1
  • MYO5
  • MYR12

Diseases (10)

Disease Nervous effect Mutations Found Literature Mutations Type Genetic association?
D00000235: Hypertrophic cardiomyopathy N Y (1361491) Deletion (D) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (7796500) Microinsertion (MI) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (7796500) Nonsense (No) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (7848441) Microinsertion (MI) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (7959583) Microinsertion (MI) N
D00000236: Hypertrophic cardiomyopathy (familial) N Y (8254035) Microinsertion (MI) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (8282798) Microinsertion (MI) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (8343162) Single nucleotide polymorphism (SNP) Y
D00000093: Acute myeloid leukaemia N Y (8643682) Translocation fusion (with another gene) (TF) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (8655135) Microinsertion (MI) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (8825881) Deletion (D) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (8944596) Insertion/deletion (I/D) Y
D00000135: Griscelli syndrome N Y (9207796) Single nucleotide polymorphism (SNP) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (9822100) Microinsertion (MI) N
D00000236: Hypertrophic cardiomyopathy (familial) N Y (9829907) Deletion (D) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (9829907) Microinsertion (MI) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (10374350) Repeat polymorphism (RP) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (10521296) Microinsertion (MI) Y
D00000135: Griscelli syndrome N Y (10704277) Insertion (I) Y
D00000135: Griscelli syndrome N Y (10733681) Microinsertion (MI) N
D00000237: Idiopathic dilated cardiomyopathy N Y (11106718) Microinsertion (MI) Y
D00000208: Myopathy (autosomal dominant) N Y (11114175) Microinsertion (MI) Y
D00000236: Hypertrophic cardiomyopathy (familial) N Y (11133230) Microinsertion (MI) Y
D00000132: Macrothrombocytopenia (autosomal dominant) N Y (11159552) Microinsertion (MI) Y
D00000132: Macrothrombocytopenia (autosomal dominant) N Y (11159552) Nonsense (No) Y
D00000132: Macrothrombocytopenia (autosomal dominant) N Y (11159552) Deletion (D) Y
D00000135: Griscelli syndrome N Y (12058346) No mutation found (N) N
D00000135: Griscelli syndrome N Y (12148598) Unknown (?) Y
D00000136: Griscelli syndrome type 3 N Y (12897212) Deletion (D) Y
D00000166: Schizophrenia Y Y (16508936) Single nucleotide polymorphism (SNP) Y
D00000182: Encephalomyopathy N Y (16142472) Single nucleotide polymorphism (SNP) ?

References

  • Association of mitochondrial complex I subunit gene NDUFV2 at 18p11 with schizophrenia in the Japanese population.

    Washizuka S, Kametani M, Sasaki T, Tochigi M, Umekage T, Kohda K and Kato T

    Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Saitama, Japan.

    Schizophrenia and bipolar disorder share common genetic background. Several loci such as 18p11, 13q32, and 22q11-13 were commonly linked with these diseases. Since mitochondrial dysfunction has been suggested in both of these disorders, NDUFV2 at 18p11, encoding a subunit of the complex I, NADH ubiquinone oxidoreductase, is a candidate gene for these diseases. We previously reported that single nucleotide polymorphisms (SNPs) in the upstream region of NDUFV2 were associated with bipolar disorder in Japanese. The association of haplotype consisting of two SNPs, -3542G > A and -602G > A, with bipolar disorder was also seen both in Japanese and the National Institute of Mental Health Pedigrees trios. In this study, 2 polymorphisms, -3542G > A and -602G > A, were investigated in 229 schizophrenic patients as compared with controls. Individual genotypes were not associated with schizophrenia. However, the haplotype consisting of these two SNPs were significantly associated with schizophrenia. These results suggested that inter-individual variation of the genomic sequence of the promoter region of NDUFV2 might be a genetic risk factor common to bipolar disorder and schizophrenia.

    American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics 2006;141B;3;301-4

  • Sequence analysis of nuclear genes encoding functionally important complex I subunits in children with encephalomyopathy.

    Hinttala R, Uusimaa J, Remes AM, Rantala H, Hassinen IE and Majamaa K

    Department of Neurology, University of Oulu, Finland.

    Complex I has a vital role in the energy production of the cell, and the clinical spectrum of complex I deficiency varies from severe lactic acidosis in infants to muscle weakness in adults. It has been estimated that the cause of complex I deficiency, especially in children, is often a mutation in the nuclear-encoded genes and, more rarely, in the genes encoded by mitochondrial DNA. We sequenced nine complex I subunit coding genes, NDUFAB1, NDUFS1, NDUFS2, NDUFS3, NDUFS4, NDUFS7, NDUFS8, NDUFV1 and NDUFV2, in 13 children with defined complex I deficiency. Two novel substitutions were found: a synonymous replacement 201A>T in NDUFV2 and a non-synonymous base exchange 52C>T in NDUFS8. The 52C>T substitution produced the replacement Arg18Cys in the leading peptide of the TYKY subunit. This novel missense mutation was found as a heterozygote in one patient and her mother, but not among 202 healthy controls nor among 107 children with undefined encephalomyopathy. Bioinformatic analyses suggested that Arg18Cys could lead to marked changes in the physicochemical properties of the mitochondrial-targeting peptide of TYKY, but we could not see changes in the assembly or activity of complex I or in the transcription of NDUFS8 in the fibroblasts of our patient. We suggest that Arg18Cys in the leading peptide of the TYKY subunit is not solely pathogenic, and that other genetic factors contribute to the disease-causing potential of this mutation.

    Journal of molecular medicine (Berlin, Germany) 2005;83;10;786-94

  • Griscelli syndrome restricted to hypopigmentation results from a melanophilin defect (GS3) or a MYO5A F-exon deletion (GS1).

    Ménasché G, Ho CH, Sanal O, Feldmann J, Tezcan I, Ersoy F, Houdusse A, Fischer A and de Saint Basile G

    Unité de Recherhe sur le Développement Normal et Pathologique du Systéme Immunitaire, Hôpital Necker-Enfants Malades, Paris, France.

    Griscelli syndrome (GS) is a rare autosomal recessive disorder that associates hypopigmentation, characterized by a silver-gray sheen of the hair and the presence of large clusters of pigment in the hair shaft, and the occurrence of either a primary neurological impairment or a severe immune disorder. Two different genetic forms, GS1 and GS2, respectively, account for the mutually exclusive neurological and immunological phenotypes. Mutations in the gene encoding the molecular motor protein Myosin Va (MyoVa) cause GS1 and the dilute mutant in mice, whereas mutations in the gene encoding the small GTPase Rab27a are responsible for GS2 and the ashen mouse model. We herein present genetic and functional evidence that a third form of GS (GS3), whose expression is restricted to the characteristic hypopigmentation of GS, results from mutation in the gene that encodes melanophilin (Mlph), the ortholog of the gene mutated in leaden mice. We also show that an identical phenotype can result from the deletion of the MYO5A F-exon, an exon with a tissue-restricted expression pattern. This spectrum of GS conditions pinpoints the distinct molecular pathways used by melanocytes, neurons, and immune cells in secretory granule exocytosis, which in part remain to be unraveled.

    The Journal of clinical investigation 2003;112;3;450-6

  • Evidence that Griscelli syndrome with neurological involvement is caused by mutations in RAB27A, not MYO5A.

    Anikster Y, Huizing M, Anderson PD, Fitzpatrick DL, Klar A, Gross-Kieselstein E, Berkun Y, Shazberg G, Gahl WA and Hurvitz H

    Heritable Disorders Branch, National Institute of Child Health and Human Development, National Institutes of Health, Building 10, 10 Center Drive, Bethesda, MD 20892-1830, USA.

    Griscelli syndrome (GS), a rare autosomal recessive disorder, is characterized by partial albinism, along with immunologic abnormalities or severe neurological impairment or both. Mutations in one of two different genes on chromosome 15q can cause the different subtypes of GS. Most patients with GS display the hemophagocytic syndrome and have mutations in RAB27A, which codes for a small GTPase. Two patients with neurological involvement have mutations in MYO5A, which codes for an actin-based molecular motor. The RAB27A and MYO5A gene products interact with each other and function in vesicle trafficking. We report the molecular basis of GS in a Muslim Arab kindred whose members have extremely variable neurological involvement, along with the hemophagocytic syndrome and immunologic abnormalities. The patients have normal MYO5A genes but exhibit a homozygous 67.5-kb deletion that eliminates RAB27A mRNA and immunocytofluorescence-detectable protein. We also describe the molecular organization of RAB27A and a multiplex polymerase chain reaction assay for the founder deletion in this kindred. Finally, we propose that all patients with GS have RAB27A mutations and immunologic abnormalities that sometimes result in secondary neurological involvement. The two patients described elsewhere who have MYO5A mutations and neurological complications but no immunologic defects may not have GS but instead may have Elejalde syndrome, a condition characterized by mild hypopigmentation and severe, primary neurological abnormalities.

    American journal of human genetics 2002;71;2;407-14

  • Griscelli disease: genotype-phenotype correlation in an array of clinical heterogeneity.

    Sanal O, Ersoy F, Tezcan I, Metin A, Yel L, Ménasché G, Gürgey A, Berkel I and de Saint Basile G

    Hacettepe University, Ihsan Doğramaci Children's Hospital, Immunology Division, Ankara, Turkey.

    Griscelli disease is a rare autosomal recessive disorder characterized by diffuse pigmentary dilution and occurrence of acute phases of uncontrolled lymphocyte and macrophage activation, so-called "hemophagocytic syndrome" (HS) that leads to death. Recently, two closely linked genes located on human 15q21 region have been found to be responsible for the disease. We present clinical and laboratory findings of 13 unrelated patients with Griscelli disease as well as mutation analyses in an effort to define a genotype-phenotype correlation. Eight patients who showed RAB27A mutations presented with HS. In contrast, two patients who primarily presented with a neurological impairment in the absence of infection susceptibility or HS were found to have homozygous MYO5A mutations. No mutation in RAB27A could be detected in the other three patients. One of the latter developed HS at a rather late age, while the other two are free of HS at 12 and 15 years of age. Griscelli disease presents with a heterogeneous clinical picture that seems to reflect the involved gene defect. This genotype-phenotype correlation suggests that the natural course of the disease and outcome is dictated by the site and type of the genetic mutation.

    Journal of clinical immunology 2002;22;4;237-43

  • Mutations in the NMMHC-A gene cause autosomal dominant macrothrombocytopenia with leukocyte inclusions (May-Hegglin anomaly/Sebastian syndrome).

    Kunishima S, Kojima T, Matsushita T, Tanaka T, Tsurusawa M, Furukawa Y, Nakamura Y, Okamura T, Amemiya N, Nakayama T, Kamiya T and Saito H

    First Department of Internal Medicine, Nagoya University School of Medicine, Showa-ku, Nagoya, Japan.

    Macrothrombocytopenia with leukocyte inclusions is a rare autosomal dominant platelet disorder characterized by a triad of giant platelets, thrombocytopenia, and characteristic Döhle body-like leukocyte inclusions. A previous study mapped a locus for the disease on chromosome 22q12.3-q13.2 by genome-wide linkage analysis. In addition, the complete DNA sequence of human chromosome 22 allowed a positional candidate approach, and results here indicate that the gene encoding nonmuscle myosin heavy chain-A, NMMHC-A, is mutated in this disorder. Mutations were found in 6 of 7 Japanese families studied: 3 missense mutations, a nonsense mutation, and a one-base deletion resulting in a premature termination. Immunofluorescence studies revealed that NMMHC-A distribution in neutrophils appeared to mimic the inclusion bodies. These results provide evidence for the involvement of abnormal NMMHC-A in the formation of leukocyte inclusions and also in platelet morphogenesis.

    Blood 2001;97;4;1147-9

  • Beta-myosin heavy chain gene mutations and hypertrophic cardiomyopathy in Austrian children.

    Greber-Platzer S, Marx M, Fleischmann C, Suppan C, Dobner M and Wimmer M

    Department of Pediatrics, Division of Pediatric Cardiology, University of Vienna, Währinger Gürtel 18-20, Vienna, A-1090, Austria. Susanne.Greber-Platzer@akh-wien.ac.at

    Hypertrophic cardiomyopathy occurs in two variants, either as an autosomal dominant familial disorder or as a sporadic disease without familial involvement. Different genes coding sarcomeric proteins of the heart have been identified as causing hypertrophic cardiomyopathy. Missense mutations in the cardiac beta-myosin heavy chain gene are found in 30% of all cases of familial hypertrophic cardiomyopathy. We screened the beta-myosin heavy chain gene of children of nine Austrian families with hypertrophic cardiomyopathy (referred to as group A) and of seven children with sporadic hypertrophic cardiomyopathy (referred to as group B). We were able to find two previously described (V606M, R453C) and two unknown missense mutations (V406M, R663H) in group A. Additionally, in two children of group B we could identify one already known missense mutation, R249Q as well as one previously unknown missense mutation, M877K. The genetically affected children of group A developed no or only mild clinical symptoms, whereas the children of group B with genetically confirmed sporadic hypertrophic cardiomyopathy showed manifest left ventricular hypertrophy and clinical symptoms including chest pain and dyspnoea. Clinical symptoms among the adults of group A, suffering from familial hypertrophic cardiomyopathy, varied significantly. We therefore believe V406M to be a more malignant missense mutation, probably linked with sudden death in the affected family, than R663H, which seems to be more benign causing late-onset hypertrophic cardiomyopathy and mild clinical symptoms in the affected family members.

    Journal of molecular and cellular cardiology 2001;33;1;141-8

  • Autosomal dominant myopathy: missense mutation (Glu-706 --> Lys) in the myosin heavy chain IIa gene.

    Martinsson T, Oldfors A, Darin N, Berg K, Tajsharghi H, Kyllerman M and Wahlstrom J

    Departments of Clinical Genetics, Pathology, and Pediatrics, Göteborg University, Sahlgrenska University Hospital, S-41685 Göteborg, Sweden. Tommy.martinsson@clingen.gu.se

    We here report on a human myopathy associated with a mutation in a fast myosin heavy chain (MyHC) gene, and also the genetic defect in a hereditary inclusion body myopathy. The disorder has previously been described in a family with an "autosomal dominant myopathy, with joint contractures, ophthalmoplegia, and rimmed vacuoles." Linkage analysis and radiation hybrid mapping showed that the gene locus (Human Genome Map locus name: IBM3) is situated in a 2-Mb region of chromosome 17p13, where also a cluster of MyHC genes is located. These include the genes encoding embryonic, IIa, IIx/d, IIb, perinatal, and extraocular MyHCs. Morphological analysis of muscle biopsies from patients from the family indicated to us that the type 2A fibers frequently were abnormal, whereas other fiber types appeared normal. This observation prompted us to investigate the MyHC-IIa gene, since MyHC-IIa is the major isoform in type 2A fibers. The complete genomic sequence for this gene was deduced by using an "in silico" strategy. The gene, found to consist of 38 exons, was subjected to a complete mutation scan in patients and controls. We identified a missense mutation, Glu-706 --> Lys, which is located in a highly conserved region of the motor domain, the so-called SH1 helix region. By conformational changes this region communicates activity at the nucleotide-binding site to the neck region, resulting in the lever arm swing. The mutation in this region is likely to result in a dysfunctional myosin, compatible with the disorder in the family.

    Proceedings of the National Academy of Sciences of the United States of America 2000;97;26;14614-9

  • Mutations in sarcomere protein genes as a cause of dilated cardiomyopathy.

    Kamisago M, Sharma SD, DePalma SR, Solomon S, Sharma P, McDonough B, Smoot L, Mullen MP, Woolf PK, Wigle ED, Seidman JG and Seidman CE

    Cardiovascular Division, Brigham and Women's Hospital, and Harvard Medical School and Howard Hughes Medical Institute, Boston, MA, USA.

    Background: The molecular basis of idiopathic dilated cardiomyopathy, a primary myocardial disorder that results in reduced contractile function, is largely unknown. Some cases of familial dilated cardiomyopathy are caused by mutations in cardiac cytoskeletal proteins; this finding implicates defects in contractile-force transmission as one mechanism underlying this disorder. To elucidate this important cause of heart failure, we investigated other genetic causes of dilated cardiomyopathy.

    Methods: Clinical evaluations were performed in 21 kindreds with familial dilated cardiomyopathy. A genome-wide linkage study prompted a search of the genes encoding beta-myosin heavy chain, troponin T, troponin I, and alpha-tropomyosin for disease-causing mutations.

    Results: A genetic locus for mutations associated with dilated cardiomyopathy was identified at chromosome 14q11.2-13 (maximal lod score, 5.11; theta=0), where the gene for cardiac beta-myosin heavy chain is encoded. Analyses of this and other genes for sarcomere proteins identified disease-causing dominant mutations in four kindreds. Cardiac beta-myosin heavy-chain missense mutations (Ser532Pro and Phe764Leu) and a deletion in cardiac troponin T (deltaLys210) caused early-onset ventricular dilatation (average age at diagnosis, 24 years) and diminished contractile function and frequently resulted in heart failure. Affected persons had neither antecedent cardiac hypertrophy (average maximal left-ventricular-wall thickness, 8.5 mm) nor histopathological findings characteristic of hypertrophy.

    Conclusion: Mutations in sarcomere protein genes account for approximately 10 percent of cases of familial dilated cardiomyopathy and are particularly prevalent in families with early-onset ventricular dilatation and dysfunction. Because distinct mutations in sarcomere proteins cause either dilated or hypertrophic cardiomyopathy, the effects of mutant sarcomere proteins on muscle mechanics must trigger two different series of events that remodel the heart.

    The New England journal of medicine 2000;343;23;1688-96

  • arg-cys substitution at codon 1246 of the human myosin Va gene is not associated with Griscelli syndrome.

    Lambert J, Naeyaert JM, De Paepe A, Van Coster R, Ferster A, Song M and Messiaen L

    Department of Dermatology, University Hospital, Gent, Belgium. jo.lambert@rug.ac.be

    Myosin Va is an actin-associated motor protein involved in organelle transport such as melanosomes and neuron synaptic vesicles and has always been proposed as the candidate gene for the autosomal recessive Griscelli-Pruniéras syndrome, one of the silvery hair syndromes, which is a lethal disease combining immunodeficiency and neurologic and pigmentary abnormalities. Thus far, two mutations in the myosin Va gene have been described to be associated with this syndrome. One of these mutations was a homozygous mis-sense mutation causing an arginine to cysteine alteration at codon 1246. Because we also found this particular substitution after mutation analysis of a Griscelli patient, we checked its relevance in a control group of 124 unrelated healthy individuals and found it to be present, even in homozygous state, in normal unaffected individuals. It is clear that this arg1246cys substitution is a polymorphism occurring in the human population and not occurring in association with Griscelli syndrome. Distinguishing a polymorphism from a bona fide mutation is of utmost importance and has major ethical implications with regard to prenatal genetic counseling in affected families.

    The Journal of investigative dermatology 2000;114;4;731-3

  • Two genes are responsible for Griscelli syndrome at the same 15q21 locus.

    Pastural E, Ersoy F, Yalman N, Wulffraat N, Grillo E, Ozkinay F, Tezcan I, Gediköglu G, Philippe N, Fischer A and de Saint Basile G

    Unité de Recherches sur le développement normal et pathologique du système immunitaire, INSERM U429, Hôpital Necker Enfants Malades, 149 rue de Sèvres, Paris Cedex 15, 75743, France.

    Griscelli syndrome is a rare autosomal recessive disease characterized by pigment dilution, variable cellular immunodeficiency, and an acute phase of uncontrolled T lymphocyte and macrophage activation. We previously mapped the disease locus to 15q21 and showed that a MyoVa gene (HGMW-approved symbol MYO5A) defect leads to Griscelli syndrome. We report a second MyoVa mutation in a new patient, confirming this first finding. However, in four other Griscelli syndrome patients analyzed, the MYOVA protein is expressed, and no mutation can be detected in the MyoVa gene coding sequence, even in the alternatively spliced region for which exon-intron boundaries were characterized. Linkage analysis performed in 15 Griscelli families thus far studied confirms the first localization. However, fine haplotype analysis in three families strongly suggests the existence of a second gene at the same locus for Griscelli syndrome less than 7.3 cM distant from the MyoVa gene.

    Genomics 2000;63;3;299-306

  • The origins of hypertrophic cardiomyopathy-causing mutations in two South African subpopulations: a unique profile of both independent and founder events.

    Moolman-Smook JC, De Lange WJ, Bruwer EC, Brink PA and Corfield VA

    US/MRC Centre for Molecular and Cellular Biology, Department of Medical Biochemistry, University of Stellenbosch Medical School, Tygerberg, South Africa.

    Hypertrophic cardiomyopathy (HCM) is an autosomal dominantly inherited disease of the cardiac sarcomere, caused by numerous mutations in genes encoding protein components of this structure. Mutation carriers are at risk of sudden cardiac death, mostly as adolescents or young adults. The reproductive disadvantage incurred may explain both the global occurrence of diverse independent HCM-associated mutations and the rare reports of founder effects within populations. We have investigated whether this holds true for two South African subpopulations, one of mixed ancestry and one of northern-European descent. Previously, we had detected three novel mutations-Ala797Thr in the beta-myosin heavy-chain gene (betaMHC), Arg92Trp in the cardiac troponin T gene (cTnT), and Arg645His in the myosin-binding protein C gene (MyBPC)-and two documented betaMHC mutations (Arg403Trp and Arg249Gln). Here we report three additional novel mutations-Gln499Lys in betaMHC and Val896Met and Deltac756 in MyBPC-and the documented betaMHC Arg719Gln mutation. Seven of the nine HCM-causing mutations arose independently; no conclusions can be drawn for the remaining two. However, the betaMHC Arg403Trp and Ala797Thr and cTnT Arg92Trp mutations were detected in another one, eight, and four probands, respectively, and haplotype analysis in families carrying these recurring mutations inferred their origin from three common ancestors. The milder phenotype of the betaMHC mutations may account for the presence of these founder effects, whereas population dynamics alone may have overridden the reproductive disadvantage incurred by the more lethal, cTnT Arg92Trp mutation.

    American journal of human genetics 1999;65;5;1308-20

  • The cardiac beta-myosin heavy chain gene is not the predominant gene for hypertrophic cardiomyopathy in the Finnish population.

    Jääskeläinen P, Soranta M, Miettinen R, Saarinen L, Pihlajamäki J, Silvennoinen K, Tikanoja T, Laakso M and Kuusisto J

    Department of Medicine, University of Kuopio, Finland.

    Objectives: The aim of the study was to screen 36 unrelated patients with hypertrophic cardiomyopathy (HCM; 16 familial and 20 sporadic cases) from a genetically homogeneous area in eastern Finland for variants in the cardiac beta-myosin heavy chain (beta-MHC) and alpha-tropomyosin (alpha-TM) genes.

    Background: Mutations in the beta-MHC and alpha-TM genes have been reported to be responsible for 30% to 40% and less than 5% of familial HCM cases, respectively. However, most genetic studies have included patients from tertiary care centers and are subject to referral bias.

    Methods: Exons 3-26 and 40 of the beta-MHC gene and the nine exons of the alpha-TM gene were screened with the PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) method. Linkage analyses between familial HCM locus and two intragenic polymorphic markers (MYO I and MYO II) of the beta-MHC gene were performed in 16 familial HCM kindreds.

    Results: A previously reported Arg719Trp (arginine converted to tryptophan in codon 719) mutation of the beta-MHC gene was found in one proband and two relatives. In addition, a novel Asn696Ser (asparagine converted to serine in codon 696) substitution was found in one HCM patient. No linkage between familial HCM and the beta-MHC gene was observed in 16 familial kindreds. A previously reported Aspl75Asn (aspartic acid converted to asparagine in codon 175) mutation of the alpha-TM gene was found in four probands and 16 relatives. Mutations in the beta-MHC and alpha-TM genes accounted for 6% and 25% familial HCM cases and 3% and 11% of all cases, respectively.

    Conclusions: Our results indicate that the beta-MHC gene is not the predominant gene for HCM in the Finnish population, whereas HCM caused by the Aspl75Asn mutation of the a-TM gene is more common than previously reported.

    Journal of the American College of Cardiology 1998;32;6;1709-16

  • Genetic heterogeneity for familial hypertrophic cardiomyopathy in Chinese: analysis of six Chinese kindreds.

    Ko YL, Teng MS, Tang TK, Chen JJ, Lee YS, Wu CW, Lien WP and Liew CC

    First Cardiovascular Division, Chang Gung Memorial Hospital, Taipei, China.

    Objective: Familial hypertrophic cardiomyopathy (FHCM) is a primary myocardial disease characterized by unexplained ventricular hypertrophy. The application of the techniques of reverse genetics has identified at least five chromosomal loci as the major causes for FHCM in diverse ethnic populations, suggesting substantial genetic heterogeneity for FHCM. Recently, the defective gene loci of two Chinese families with FHCM have been mapped to chromosome 11 and 14q1, respectively. For further understanding of the molecular basis of FHCM in Chinese, we analyzed the linkage between four other Chinese kindreds and DNA markers from chromosome 14q1.

    Methods: Six unrelated Chinese families with FHCM, including two previously reported, were studied. Totally 90 family members were included for analysis. DNA from 80 individuals was extracted and polymerase chain reactions were performed using the primers designed according to the sequences derived from the alpha and beta myosin heavy chain gene. Totally four polymorphisms were studied, including three polymorphic microsatellite sequences and one single strand conformation polymorphism. Genetic linkage analysis were performed using the Linkage program.

    Results: In the six studied families, 39 of the 90 family members were found to be affected diagnosed either by echocardiography or by clinical evaluation. The pattern of inheritance in all six studied families was most consistent with an autosomal dominant trait with a high degree of penetrance. Genetic linkage analysis using polymorphisms on the alpha and beta MHC genes showed a combined maximal lod score of 6.2 for trinucleotide repeat polymorphism AMHC-I 15 at theta = 0.00 for three studied families without recombination. Exclusion of linkage to the chromosome 14q1 location was noted in two of three other families with the maximal lod score of -2 or less.

    Conclusions: These results provide further evidence that FHCM in Chinese is genetically heterogeneous. Chromosome 14q1 locus, probably the beta myosin heavy chain gene, is important as the molecular basis for FHCM in Chinese.

    Chinese medical journal 1998;111;5;416-21

  • Genotype-phenotype analysis in four families with mutations in beta-myosin heavy chain gene responsible for familial hypertrophic cardiomyopathy.

    Tesson F, Richard P, Charron P, Mathieu B, Cruaud C, Carrier L, Dubourg O, Lautié N, Desnos M, Millaire A, Isnard R, Hagege AA, Bouhour JB, Bennaceur M, Hainque B, Guicheney P, Schwartz K and Komajda M

    INSERM UR 153, Groupe Hospitalier Pitié-Salpétrière, Paris, France. tesson@infobiogen.fr

    Familial hypertrophic cardiomyopathy is a genetically heterogeneous disease in which one of the most frequently implicated gene is the gene encoding the beta-myosin heavy chain. To date, more than 40 distinct mutations have been found within this gene. In order to progress on the determination of genotype-phenotype relationship, we have screened the beta-myosin heavy chain gene for mutations in 18 probands from unrelated families. We identified the mutation implicated in the disease in four families. Two of them, the Glu930 codon deletion and the Ile263Thr mutation, are reported here for the first time. The two other mutations are the Arg723Cys mutation, that was previously described in a proband as a de novo mutation, and the Arg719Trp mutation. A poor prognosis was associated with the Glu930codon deletion (mean maximal wall thickness (MWT) = 19.5 mm +/- 5) and the Arg719Trp mutation (mean MWT = 15.3 mm +/- 7), whereas a good prognosis was associated with the Arg723Cys mutation (mean MWT = 20.1 mm +/- 7). The combination of clinical and genetic characteristics of each family member suggests that prognosis is related neither to the degree of left ventricular wall thickness nor to a change in the net electrical charge of the protein. Additional family studies are needed to confirm these findings and to contribute to stratify the prognosis according to the mutation involved.

    Human mutation 1998;12;6;385-92

  • Griscelli disease maps to chromosome 15q21 and is associated with mutations in the myosin-Va gene.

    Pastural E, Barrat FJ, Dufourcq-Lagelouse R, Certain S, Sanal O, Jabado N, Seger R, Griscelli C, Fischer A and de Saint Basile G

    Unité de Recherches sur le Dévelopement Normal et Pathologique de Systéme Immunitaire INSERM U429 Paris, France.

    Griscelli disease (OMIM 214450) is a rare autosomal recessive disorder characterized by pigmentary dilution, variable cellular immunodeficiency and onset of acute phases of uncontrolled lymphocyte and macrophage activation, leading to death in the absence of bone-marrow transplantation. The pigmentary dilution is characterized by a diffuse skin pigmentation, silvery hair, large clumps of pigments in the hair shafts (Fig. 1) and an accumulation of melanosomes in melanocytes, with abnormal transfer of the melanin granules to the keratinocytes. Immunological abnormalities are characterized by absent delayed-type cutaneous hypersensitivity and an impaired natural-killer cell function. A similar disorder has been described in the dilute lethal mouse--which, however, differs by the occurrence of a severe neurological disorder. The dilute locus encodes myosin-Va, a member of the unconventional myosin family. Myosins bind actin and produce mechanical force through ATP hydrolysis. Some members of this family are thought to participate in organelle-transport machinery. Because of the phenotype resulting in the dilute mouse and because of their potential role in intracellular transport, unconventional myosin-encoding genes were regarded as candidate genes for Griscelli disease. Here we report that the Griscelli disease locus co-localizes on chromosome 15q21 with the myosin-Va gene, MYO5a, and that mutations of this gene occur in two patients with the disease. Griscelli disease is therefore a human equivalent of dilute expression in the mouse.

    Nature genetics 1997;16;3;289-92

  • A previously undescribed de novo insertion-deletion mutation in the beta myosin heavy chain gene in a kindred with familial hypertrophic cardiomyopathy.

    Cuda G, Perrotti N, Perticone F and Mattioli PL

    Dipartimento di Medicina Sperimentale e Clinica, Università di Reggio Calabria, Catanzaro, Italy.

    A previously undescribed de novo insertion-deletion mutation in the beta cardiac myosin heavy chain gene was found in a kindred with familial hypertrophic cardiomyopathy. In the mutated allele there is an inserted-deleted guanine at nucleotides 8823 and 8850 of the beta myosin heavy chain gene, resulting in a dramatic change of the amino acid sequence (AA 395-404). such a mutation, detected in the proband and in his son but not in the proband's parents, is likely to produce major impairment of myosin function.

    Heart (British Cardiac Society) 1996;76;5;451-2

  • Malignant familial hypertrophic cardiomyopathy in a family with a 453Arg-->Cys mutation in the beta-myosin heavy chain gene: coexistence of sudden death and end-stage heart failure.

    Ko YL, Chen JJ, Tang TK, Cheng JJ, Lin SY, Liou YC, Kuan P, Wu CW, Lien WP and Liew CC

    Department of Internal Medicine, National Taiwan University Hospital, Taipei, Republic of China.

    Recent genotype-phenotype correlation studies in familial hypertrophic cardiomyopathy (FHC) have revealed that some mutations in the beta- myosin heavy chain (BMHC) gene may be associated with a high incidence of sudden death and a poor prognosis. Coexistence of sudden death and end-stage heart failure in several families with FHC has recently being reported; however, the genetic basis of such families has not been clearly demonstrated. A three-generation Chinese familial hypertrophic cardiomyopathy (FHC) family (family HLI) with two cases of end-stage heart failure and three cases of sudden death was analyzed. The average age of death in the affected members in this family was 34 years old. Genetic linkage analysis using polymorphisms in the (alpha- and beta-myosin heavy chain genes revealed that FHC in this family is significantly linked to the BMHC gene without recombinations. Single-strand conformation polymorphism analysis of exons 8, 9 and 13 to 23 in the BMHC gene showed a polymorphic band on exon 14 that is in complete linkage with the disease status in this family. DNA sequencing analysis in the affected members revealed an 453Arg-->Cys mutation in the BMHC gene. To our knowledge this is the first reported mutation of FHC in Chinese. Our data suggest that the 453Arg-->Cys mutation is associated with a malignant clinical course in FHC due not only to sudden death but also to end-stage heart failure.

    Human genetics 1996;97;5;585-90

  • Core binding factor beta-smooth muscle myosin heavy chain chimeric protein involved in acute myeloid leukemia forms unusual nuclear rod-like structures in transformed NIH 3T3 cells.

    Wijmenga C, Gregory PE, Hajra A, Schröck E, Ried T, Eils R, Liu PP and Collins FS

    Laboratory of Gene Transfer, National Center for Human Genome Research, Bethesda, MD 20892-4470, USA.

    Patients with the M4Eo subtype of acute myeloid leukemia almost invariably are found to have an inversion of chromosome 16 in their leukemic cells, which results in a gene fusion between the transcription factor called core binding factor beta (CBFbeta) on 16q and a smooth muscle myosin heavy chain (SMMHC) gene on 16p. Subcellular localizations of the wild-type CBFbeta and the CBFbeta-SMMHC fusion protein were determined by immunofluorescence of NIH 3T3 cells that overexpress wild-type or fusion protein. Normal CBFbeta showed an unexpected perinuclear pattern consistent with primary localization in the Golgi complex. The CBFbeta-SMMHC fusion protein had a very different pattern. Nuclear staining included rod-like crystalline structures as long as 11 microm. The heterodimeric partner of CBFbeta, CBFalpha, formed part of this complex. Cytoplasmic staining included stress fibers that colocalized with actin, probably as a consequence of the myosin heavy chain component of the fusion protein. Deletion of different regions of the CBFbeta portion of the fusion protein showed that binding to CBFalpha was not required for nuclear translocation. However, deletion of parts of the SMMHC domain of the fusion protein involved in myosin-mediated filament formation resulted in proteins that did not form rod-like structures. These observations confirm previous indirect evidence that the CBFbeta-SMMHC fusion protein is capable of forming macromolecular nuclear aggregates and suggests possible models for the mechanism of leukemic transformation.

    Proceedings of the National Academy of Sciences of the United States of America 1996;93;4;1630-5

  • A novel deletion mutation in the beta-myosin heavy chain gene found in Japanese patients with hypertrophic cardiomyopathy.

    Nakajima-Taniguchi C, Matsui H, Eguchi N, Nagata S, Kishimoto T and Yamauchi-Takihara K

    Department of Medicine III, Osaka University Medical School, Japan.

    Mutations in the cardiac beta-myosin heavy chain (MHC) gene of 50 Japanese patients with hypertrophic cardiomyopathy (HCM) were investigated by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. A novel deletion mutation was detected in exon 3 of the cardiac beta-MHC gene in a Japanese family with HCM. Sequencing analysis revealed a three nucleotide deletion at codon 10 leading to a deletion of a glycine residue, which has been conserved in the myosin gene from birds to humans. Because this deletion mutation was not detected in other healthy family members, it was suggested that this 10Gly deletion is the cause of HCM in this family. The same deletion mutation has been found in three other unrelated patients with HCM. This is the first report of a one codon deletion in the beta-MHC gene in patients with HCM.

    Journal of molecular and cellular cardiology 1995;27;12;2607-12

  • A myosin missense mutation, not a null allele, causes familial hypertrophic cardiomyopathy.

    Nishi H, Kimura A, Harada H, Koga Y, Adachi K, Matsuyama K, Koyanagi T, Yasunaga S, Imaizumi T, Toshima H et al.

    Third Department of Internal Medicine, Kurume University School of Medicine, Japan.

    Background: Hypertrophic cardiomyopathy (HCM) is characterized by myocardial hypertrophy of unknown etiology. Missense mutations of the cardiac beta-myosin-heavy-chain (beta-MHC) gene that may be responsible for cardiac hypertrophy have been detected in patients with HCM. On the other hand, gross structural abnormalities in the cardiac beta-MHC gene, ie, an alpha/beta hybrid gene and partial deletion of the gene, have also been reported. The direct correlation between gross abnormalities and development of HCM is not well understood.

    We analyzed the structure of the cardiac beta-MHC gene from patients with HCM by using polymerase chain reaction-DNA conformation polymorphism analysis and found two sequence variations in exons 3 and 22 in one patient. These sequence variations at codon 54 (exon 3; nonsense mutation) and codon 870 (exon 22; Arg-to-His mutation) were identified by direct sequencing and dot-blot hybridization with allele-specific oligonucleotide probes. Relatives of this patient were examined for the mutations. It was revealed that the missense mutation was inherited from the affected father and the nonsense mutation from the unaffected grandmother through the unaffected mother. In addition, the missense mutation was also found in seven other patients from two other unrelated multiplex HCM families.

    Conclusions: The Arg870His mutation was suggested to cause HCM. In contrast, the gene with the nonsense mutation would encode for a cardiac beta-MHC protein of only 53 amino acid residues, which may be too short to be incorporated into the thick filament assembly of cardiac myosin chains and showed no dominant phenotype of heart disease. This is the first report of a nonsense mutation in the human cardiac beta-MHC gene.

    Circulation 1995;91;12;2911-5

  • [Genetic heterogeneity of hypertrophic cardiomyopathy in Japanese].

    Machida M

    Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Sapporo, Japan.

    Familial hypertrophic cardiomyopathy (FHCM) is thought to be caused by missense mutations in cardiac beta-myosin heavy chain (beta-MHC) gene in 30-40% of affected Caucasian individuals. On the other hand, it has been reported that Japanese FHCM is closely linked to DNA marker PALB on chromosome 18q by linkage analysis. Therefore, in order to elucidate the etiological significance of missense mutations in beta-MHC gene in Japanese HCM patients, we have investigated the sequence variation in exon 3 to 25 of beta-MHC gene from 16 multiplex FHCM kindreds and 28 sporadic patients by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method. In this study we demonstrated one missense mutation (codon741: GlyGGG-->ArgAGG) in only one kindred among 16 multiplex Japanese kindreds with FHCM. Two synonymous mutations (codon715: TryTAC-->TryTAT, codon 989: IleATT-->IleATC) are demonstrated in another kindred. The same mutation in codon 989 is also detected in one sporadic patient. Furthermore, we performed linkage study with two DNA markers (F13B on chromosome 1q, D11S916: AMF185yal on chromosome 11p-q) which are recently reported to be linked with FHCM. Three and four families showed statistically negative linkage with F13B and D11S916 (AMF185yal), respectively. These results suggest that several responsible genes for HCM may exist in Japanese and principal responsible gene for Japanese HCM is different from it for Caucasian HCM.

    [Hokkaido igaku zasshi] The Hokkaido journal of medical science 1994;69;4;1024-34

  • A new missense mutation, Arg719Gln, in the beta-cardiac heavy chain myosin gene of patients with familial hypertrophic cardiomyopathy.

    Consevage MW, Salada GC, Baylen BG, Ladda RL and Rogan PK

    Department of Pediatrics, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17036.

    Human molecular genetics 1994;3;6;1025-6

  • Prognostic implications of novel beta cardiac myosin heavy chain gene mutations that cause familial hypertrophic cardiomyopathy.

    Anan R, Greve G, Thierfelder L, Watkins H, McKenna WJ, Solomon S, Vecchio C, Shono H, Nakao S, Tanaka H et al.

    Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115.

    Three novel beta cardiac myosin heavy chain (MHC) gene missense mutations, Phe513Cys, Gly716Arg, and Arg719Trp, which cause familial hypertrophic cardiomyopathy (FHC) are described. One mutation in exon 15 (Phe513Cys) does not alter the charge of the encoded amino acid, and affected family members have a near normal life expectancy. The Gly716Arg mutation (exon 19; charge change of +1) causes FHC in three family members, one of whom underwent transplantation for heart failure. The Arg719Trp mutation (exon 19; charge change of -1) was found in four unrelated FHC families with a high incidence of premature death and an average life expectancy in affected individuals of 38 yr. A comparable high frequency of disease-related deaths in four families with the Arg719Trp mutation suggests that this specific gene defect directly accounts for the observed malignant phenotype. Further, the significantly different life expectancies associated with the Arg719Trp vs. Phe513Cys mutation (P < 0.001) support the hypothesis that mutations which alter the charge of the encoded amino acid affect survival more significantly than those that produce a conservative amino acid change.

    Funded by: NHLBI NIH HHS: HL-42467, HL-46320, P50-HL-42267

    The Journal of clinical investigation 1994;93;1;280-5

  • Familial hypertrophic cardiomyopathy. Microsatellite haplotyping and identification of a hot spot for mutations in the beta-myosin heavy chain gene.

    Dausse E, Komajda M, Fetler L, Dubourg O, Dufour C, Carrier L, Wisnewsky C, Bercovici J, Hengstenberg C, al-Mahdawi S et al.

    Institut National de la Sante et de la Recherche Médicale, U127, Hôpital Lariboisière, Paris, France.

    Familial hypertrophic cardiomyopathy (FHC) is a clinically and genetically heterogeneous disease. The first identified disease gene, located on chromosome 14q11-q12, encodes the beta-myosin heavy chain. We have performed linkage analysis of two French FHC pedigrees, 720 and 730, with two microsatellite markers located in the beta-myosin heavy chain gene (MYO I and MYO II) and with four highly informative markers, recently mapped to chromosome 14q11-q12. Significant linkage was found with MYO I and MYO II in pedigree 720, but results were not conclusive for pedigree 730. Haplotype analysis of the six markers allowed identification of affected individuals and of some unaffected subjects carrying the disease gene. Two novel missense mutations were identified in exon 13 by direct sequencing, 403Arg-->Leu and 403Arg-->Trp in families 720 and 730, respectively. The 403Arg-->Leu mutation was associated with incomplete penetrance, a high incidence of sudden deaths and severe cardiac events, whereas the consequences of the 403Arg-->Trp mutation appeared less severe. Haplotyping of polymorphic markers in close linkage to the beta-myosin heavy chain gene can, thus, provide rapid analysis of non informative pedigrees and rapid detection of carrier status. Our results also indicate that codon 403 of the beta-myosin heavy chain gene is a hot spot for mutations causing FHC.

    The Journal of clinical investigation 1993;92;6;2807-13

  • A missense mutation of cardiac beta-myosin heavy chain gene linked to familial hypertrophic cardiomyopathy in affected Japanese families.

    Harada H, Kimura A, Nishi H, Sasazuki T and Toshima H

    Third Department of Internal Medicine, Kurume University, School of Medicine, Japan.

    A novel missense mutation of the cardiac beta-myosin heavy chain gene was detected in five unrelated Japanese patients and their affected family members with hypertrophic cardiomyopathy (HCM) by using the polymerase chain reaction (PCR)-DNA conformation polymorphism (DCP) analysis. Sequencing analysis revealed an A to G transition at codon 778 leading to replacement of the Asp residue, which is adjacent to the interaction sites of myosin heavy chain (MHC) with actin and is a conserved amino acid residue in various MHC across species, to the Gly residue. Linkage study of the mutation and two dinucleotides repeat markers of the cardiac beta-MHC gene in three affected families showed that the mutation was on the same haplotype of the cardiac beta-MHC gene and linked to HCM. These observations strongly suggest that the 778Asp to Gly mutation is the cause of HCM in these affected individuals.

    Biochemical and biophysical research communications 1993;194;2;791-8

  • Detection of a new mutation in the beta-myosin heavy chain gene in an individual with hypertrophic cardiomyopathy.

    Marian AJ, Yu QT, Mares A, Hill R, Roberts R and Perryman MB

    Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.

    Familial hypertrophic cardiomyopathy (FHCM) is an autosomal dominant disease affecting primarily the myocardium. The gene responsible for FHCM has been localized to chromosome 14 in some families and several mutations have been described in the beta-myosin heavy chain (beta MHC), a candidate gene for the disease. We recently identified a family with HCM in whom we did not detect any of the known mutations in the beta MHC gene (the alpha/beta MHC hybrid gene and the missense mutation in exons 13 and 9). However, we did observe a novel 9.5-kb BamHI restriction fragment length polymorphism detected by a beta MHC probe on Southern blots of DNA from the proband of this family. Similarly, a novel 3.8-kb TaqI polymorphism and a novel 4.3-kb HindIII polymorphism were detected on Southern blots of DNA from the same proband. Polymerase chain reaction (PCR) was used to amplify the segment of the beta MHC that was detected by pSC14 probe. PCR amplification of the distal 3'-end of the beta MHC gene yielded an additional product in the DNA template from the proband which was subsequently cloned and sequenced. The sequence analysis showed a 2.4-kb nucleotide deletion involving one allele of the beta MHC gene. The deletion includes part of the intron 39, exon 40 including the 3'-untranslated region and the polyadenylation signal, and part of the beta-alpha MHC intergenic region. This deletion was inherited in Mendelian fashion in an additional three members of this small family of which only the proband has developed clinically diagnosed HCM at a very late onset (age 59 yr), the other three family members are younger and have not developed the disease at the ages of 10, 32, and 33 yr.

    Funded by: NHLBI NIH HHS: P50-HL42267-01

    The Journal of clinical investigation 1992;90;6;2156-65

Literature (74)

Pubmed - human_disease

  • Sequence analysis of nuclear genes encoding functionally important complex I subunits in children with encephalomyopathy.

    Hinttala R, Uusimaa J, Remes AM, Rantala H, Hassinen IE and Majamaa K

    Department of Neurology, University of Oulu, Finland.

    Complex I has a vital role in the energy production of the cell, and the clinical spectrum of complex I deficiency varies from severe lactic acidosis in infants to muscle weakness in adults. It has been estimated that the cause of complex I deficiency, especially in children, is often a mutation in the nuclear-encoded genes and, more rarely, in the genes encoded by mitochondrial DNA. We sequenced nine complex I subunit coding genes, NDUFAB1, NDUFS1, NDUFS2, NDUFS3, NDUFS4, NDUFS7, NDUFS8, NDUFV1 and NDUFV2, in 13 children with defined complex I deficiency. Two novel substitutions were found: a synonymous replacement 201A>T in NDUFV2 and a non-synonymous base exchange 52C>T in NDUFS8. The 52C>T substitution produced the replacement Arg18Cys in the leading peptide of the TYKY subunit. This novel missense mutation was found as a heterozygote in one patient and her mother, but not among 202 healthy controls nor among 107 children with undefined encephalomyopathy. Bioinformatic analyses suggested that Arg18Cys could lead to marked changes in the physicochemical properties of the mitochondrial-targeting peptide of TYKY, but we could not see changes in the assembly or activity of complex I or in the transcription of NDUFS8 in the fibroblasts of our patient. We suggest that Arg18Cys in the leading peptide of the TYKY subunit is not solely pathogenic, and that other genetic factors contribute to the disease-causing potential of this mutation.

    Journal of molecular medicine (Berlin, Germany) 2005;83;10;786-94

  • Beta-myosin heavy chain gene mutations and hypertrophic cardiomyopathy in Austrian children.

    Greber-Platzer S, Marx M, Fleischmann C, Suppan C, Dobner M and Wimmer M

    Department of Pediatrics, Division of Pediatric Cardiology, University of Vienna, Währinger Gürtel 18-20, Vienna, A-1090, Austria. Susanne.Greber-Platzer@akh-wien.ac.at

    Hypertrophic cardiomyopathy occurs in two variants, either as an autosomal dominant familial disorder or as a sporadic disease without familial involvement. Different genes coding sarcomeric proteins of the heart have been identified as causing hypertrophic cardiomyopathy. Missense mutations in the cardiac beta-myosin heavy chain gene are found in 30% of all cases of familial hypertrophic cardiomyopathy. We screened the beta-myosin heavy chain gene of children of nine Austrian families with hypertrophic cardiomyopathy (referred to as group A) and of seven children with sporadic hypertrophic cardiomyopathy (referred to as group B). We were able to find two previously described (V606M, R453C) and two unknown missense mutations (V406M, R663H) in group A. Additionally, in two children of group B we could identify one already known missense mutation, R249Q as well as one previously unknown missense mutation, M877K. The genetically affected children of group A developed no or only mild clinical symptoms, whereas the children of group B with genetically confirmed sporadic hypertrophic cardiomyopathy showed manifest left ventricular hypertrophy and clinical symptoms including chest pain and dyspnoea. Clinical symptoms among the adults of group A, suffering from familial hypertrophic cardiomyopathy, varied significantly. We therefore believe V406M to be a more malignant missense mutation, probably linked with sudden death in the affected family, than R663H, which seems to be more benign causing late-onset hypertrophic cardiomyopathy and mild clinical symptoms in the affected family members.

    Journal of molecular and cellular cardiology 2001;33;1;141-8

  • Autosomal dominant myopathy: missense mutation (Glu-706 --> Lys) in the myosin heavy chain IIa gene.

    Martinsson T, Oldfors A, Darin N, Berg K, Tajsharghi H, Kyllerman M and Wahlstrom J

    Departments of Clinical Genetics, Pathology, and Pediatrics, Göteborg University, Sahlgrenska University Hospital, S-41685 Göteborg, Sweden. Tommy.martinsson@clingen.gu.se

    We here report on a human myopathy associated with a mutation in a fast myosin heavy chain (MyHC) gene, and also the genetic defect in a hereditary inclusion body myopathy. The disorder has previously been described in a family with an "autosomal dominant myopathy, with joint contractures, ophthalmoplegia, and rimmed vacuoles." Linkage analysis and radiation hybrid mapping showed that the gene locus (Human Genome Map locus name: IBM3) is situated in a 2-Mb region of chromosome 17p13, where also a cluster of MyHC genes is located. These include the genes encoding embryonic, IIa, IIx/d, IIb, perinatal, and extraocular MyHCs. Morphological analysis of muscle biopsies from patients from the family indicated to us that the type 2A fibers frequently were abnormal, whereas other fiber types appeared normal. This observation prompted us to investigate the MyHC-IIa gene, since MyHC-IIa is the major isoform in type 2A fibers. The complete genomic sequence for this gene was deduced by using an "in silico" strategy. The gene, found to consist of 38 exons, was subjected to a complete mutation scan in patients and controls. We identified a missense mutation, Glu-706 --> Lys, which is located in a highly conserved region of the motor domain, the so-called SH1 helix region. By conformational changes this region communicates activity at the nucleotide-binding site to the neck region, resulting in the lever arm swing. The mutation in this region is likely to result in a dysfunctional myosin, compatible with the disorder in the family.

    Proceedings of the National Academy of Sciences of the United States of America 2000;97;26;14614-9

  • Mutations in sarcomere protein genes as a cause of dilated cardiomyopathy.

    Kamisago M, Sharma SD, DePalma SR, Solomon S, Sharma P, McDonough B, Smoot L, Mullen MP, Woolf PK, Wigle ED, Seidman JG and Seidman CE

    Cardiovascular Division, Brigham and Women's Hospital, and Harvard Medical School and Howard Hughes Medical Institute, Boston, MA, USA.

    Background: The molecular basis of idiopathic dilated cardiomyopathy, a primary myocardial disorder that results in reduced contractile function, is largely unknown. Some cases of familial dilated cardiomyopathy are caused by mutations in cardiac cytoskeletal proteins; this finding implicates defects in contractile-force transmission as one mechanism underlying this disorder. To elucidate this important cause of heart failure, we investigated other genetic causes of dilated cardiomyopathy.

    Methods: Clinical evaluations were performed in 21 kindreds with familial dilated cardiomyopathy. A genome-wide linkage study prompted a search of the genes encoding beta-myosin heavy chain, troponin T, troponin I, and alpha-tropomyosin for disease-causing mutations.

    Results: A genetic locus for mutations associated with dilated cardiomyopathy was identified at chromosome 14q11.2-13 (maximal lod score, 5.11; theta=0), where the gene for cardiac beta-myosin heavy chain is encoded. Analyses of this and other genes for sarcomere proteins identified disease-causing dominant mutations in four kindreds. Cardiac beta-myosin heavy-chain missense mutations (Ser532Pro and Phe764Leu) and a deletion in cardiac troponin T (deltaLys210) caused early-onset ventricular dilatation (average age at diagnosis, 24 years) and diminished contractile function and frequently resulted in heart failure. Affected persons had neither antecedent cardiac hypertrophy (average maximal left-ventricular-wall thickness, 8.5 mm) nor histopathological findings characteristic of hypertrophy.

    Conclusion: Mutations in sarcomere protein genes account for approximately 10 percent of cases of familial dilated cardiomyopathy and are particularly prevalent in families with early-onset ventricular dilatation and dysfunction. Because distinct mutations in sarcomere proteins cause either dilated or hypertrophic cardiomyopathy, the effects of mutant sarcomere proteins on muscle mechanics must trigger two different series of events that remodel the heart.

    The New England journal of medicine 2000;343;23;1688-96

  • The origins of hypertrophic cardiomyopathy-causing mutations in two South African subpopulations: a unique profile of both independent and founder events.

    Moolman-Smook JC, De Lange WJ, Bruwer EC, Brink PA and Corfield VA

    US/MRC Centre for Molecular and Cellular Biology, Department of Medical Biochemistry, University of Stellenbosch Medical School, Tygerberg, South Africa.

    Hypertrophic cardiomyopathy (HCM) is an autosomal dominantly inherited disease of the cardiac sarcomere, caused by numerous mutations in genes encoding protein components of this structure. Mutation carriers are at risk of sudden cardiac death, mostly as adolescents or young adults. The reproductive disadvantage incurred may explain both the global occurrence of diverse independent HCM-associated mutations and the rare reports of founder effects within populations. We have investigated whether this holds true for two South African subpopulations, one of mixed ancestry and one of northern-European descent. Previously, we had detected three novel mutations-Ala797Thr in the beta-myosin heavy-chain gene (betaMHC), Arg92Trp in the cardiac troponin T gene (cTnT), and Arg645His in the myosin-binding protein C gene (MyBPC)-and two documented betaMHC mutations (Arg403Trp and Arg249Gln). Here we report three additional novel mutations-Gln499Lys in betaMHC and Val896Met and Deltac756 in MyBPC-and the documented betaMHC Arg719Gln mutation. Seven of the nine HCM-causing mutations arose independently; no conclusions can be drawn for the remaining two. However, the betaMHC Arg403Trp and Ala797Thr and cTnT Arg92Trp mutations were detected in another one, eight, and four probands, respectively, and haplotype analysis in families carrying these recurring mutations inferred their origin from three common ancestors. The milder phenotype of the betaMHC mutations may account for the presence of these founder effects, whereas population dynamics alone may have overridden the reproductive disadvantage incurred by the more lethal, cTnT Arg92Trp mutation.

    American journal of human genetics 1999;65;5;1308-20

  • Genetic heterogeneity for familial hypertrophic cardiomyopathy in Chinese: analysis of six Chinese kindreds.

    Ko YL, Teng MS, Tang TK, Chen JJ, Lee YS, Wu CW, Lien WP and Liew CC

    First Cardiovascular Division, Chang Gung Memorial Hospital, Taipei, China.

    Objective: Familial hypertrophic cardiomyopathy (FHCM) is a primary myocardial disease characterized by unexplained ventricular hypertrophy. The application of the techniques of reverse genetics has identified at least five chromosomal loci as the major causes for FHCM in diverse ethnic populations, suggesting substantial genetic heterogeneity for FHCM. Recently, the defective gene loci of two Chinese families with FHCM have been mapped to chromosome 11 and 14q1, respectively. For further understanding of the molecular basis of FHCM in Chinese, we analyzed the linkage between four other Chinese kindreds and DNA markers from chromosome 14q1.

    Methods: Six unrelated Chinese families with FHCM, including two previously reported, were studied. Totally 90 family members were included for analysis. DNA from 80 individuals was extracted and polymerase chain reactions were performed using the primers designed according to the sequences derived from the alpha and beta myosin heavy chain gene. Totally four polymorphisms were studied, including three polymorphic microsatellite sequences and one single strand conformation polymorphism. Genetic linkage analysis were performed using the Linkage program.

    Results: In the six studied families, 39 of the 90 family members were found to be affected diagnosed either by echocardiography or by clinical evaluation. The pattern of inheritance in all six studied families was most consistent with an autosomal dominant trait with a high degree of penetrance. Genetic linkage analysis using polymorphisms on the alpha and beta MHC genes showed a combined maximal lod score of 6.2 for trinucleotide repeat polymorphism AMHC-I 15 at theta = 0.00 for three studied families without recombination. Exclusion of linkage to the chromosome 14q1 location was noted in two of three other families with the maximal lod score of -2 or less.

    Conclusions: These results provide further evidence that FHCM in Chinese is genetically heterogeneous. Chromosome 14q1 locus, probably the beta myosin heavy chain gene, is important as the molecular basis for FHCM in Chinese.

    Chinese medical journal 1998;111;5;416-21

  • Genotype-phenotype analysis in four families with mutations in beta-myosin heavy chain gene responsible for familial hypertrophic cardiomyopathy.

    Tesson F, Richard P, Charron P, Mathieu B, Cruaud C, Carrier L, Dubourg O, Lautié N, Desnos M, Millaire A, Isnard R, Hagege AA, Bouhour JB, Bennaceur M, Hainque B, Guicheney P, Schwartz K and Komajda M

    INSERM UR 153, Groupe Hospitalier Pitié-Salpétrière, Paris, France. tesson@infobiogen.fr

    Familial hypertrophic cardiomyopathy is a genetically heterogeneous disease in which one of the most frequently implicated gene is the gene encoding the beta-myosin heavy chain. To date, more than 40 distinct mutations have been found within this gene. In order to progress on the determination of genotype-phenotype relationship, we have screened the beta-myosin heavy chain gene for mutations in 18 probands from unrelated families. We identified the mutation implicated in the disease in four families. Two of them, the Glu930 codon deletion and the Ile263Thr mutation, are reported here for the first time. The two other mutations are the Arg723Cys mutation, that was previously described in a proband as a de novo mutation, and the Arg719Trp mutation. A poor prognosis was associated with the Glu930codon deletion (mean maximal wall thickness (MWT) = 19.5 mm +/- 5) and the Arg719Trp mutation (mean MWT = 15.3 mm +/- 7), whereas a good prognosis was associated with the Arg723Cys mutation (mean MWT = 20.1 mm +/- 7). The combination of clinical and genetic characteristics of each family member suggests that prognosis is related neither to the degree of left ventricular wall thickness nor to a change in the net electrical charge of the protein. Additional family studies are needed to confirm these findings and to contribute to stratify the prognosis according to the mutation involved.

    Human mutation 1998;12;6;385-92

  • A previously undescribed de novo insertion-deletion mutation in the beta myosin heavy chain gene in a kindred with familial hypertrophic cardiomyopathy.

    Cuda G, Perrotti N, Perticone F and Mattioli PL

    Dipartimento di Medicina Sperimentale e Clinica, Università di Reggio Calabria, Catanzaro, Italy.

    A previously undescribed de novo insertion-deletion mutation in the beta cardiac myosin heavy chain gene was found in a kindred with familial hypertrophic cardiomyopathy. In the mutated allele there is an inserted-deleted guanine at nucleotides 8823 and 8850 of the beta myosin heavy chain gene, resulting in a dramatic change of the amino acid sequence (AA 395-404). such a mutation, detected in the proband and in his son but not in the proband's parents, is likely to produce major impairment of myosin function.

    Heart (British Cardiac Society) 1996;76;5;451-2

  • Malignant familial hypertrophic cardiomyopathy in a family with a 453Arg-->Cys mutation in the beta-myosin heavy chain gene: coexistence of sudden death and end-stage heart failure.

    Ko YL, Chen JJ, Tang TK, Cheng JJ, Lin SY, Liou YC, Kuan P, Wu CW, Lien WP and Liew CC

    Department of Internal Medicine, National Taiwan University Hospital, Taipei, Republic of China.

    Recent genotype-phenotype correlation studies in familial hypertrophic cardiomyopathy (FHC) have revealed that some mutations in the beta- myosin heavy chain (BMHC) gene may be associated with a high incidence of sudden death and a poor prognosis. Coexistence of sudden death and end-stage heart failure in several families with FHC has recently being reported; however, the genetic basis of such families has not been clearly demonstrated. A three-generation Chinese familial hypertrophic cardiomyopathy (FHC) family (family HLI) with two cases of end-stage heart failure and three cases of sudden death was analyzed. The average age of death in the affected members in this family was 34 years old. Genetic linkage analysis using polymorphisms in the (alpha- and beta-myosin heavy chain genes revealed that FHC in this family is significantly linked to the BMHC gene without recombinations. Single-strand conformation polymorphism analysis of exons 8, 9 and 13 to 23 in the BMHC gene showed a polymorphic band on exon 14 that is in complete linkage with the disease status in this family. DNA sequencing analysis in the affected members revealed an 453Arg-->Cys mutation in the BMHC gene. To our knowledge this is the first reported mutation of FHC in Chinese. Our data suggest that the 453Arg-->Cys mutation is associated with a malignant clinical course in FHC due not only to sudden death but also to end-stage heart failure.

    Human genetics 1996;97;5;585-90

  • Core binding factor beta-smooth muscle myosin heavy chain chimeric protein involved in acute myeloid leukemia forms unusual nuclear rod-like structures in transformed NIH 3T3 cells.

    Wijmenga C, Gregory PE, Hajra A, Schröck E, Ried T, Eils R, Liu PP and Collins FS

    Laboratory of Gene Transfer, National Center for Human Genome Research, Bethesda, MD 20892-4470, USA.

    Patients with the M4Eo subtype of acute myeloid leukemia almost invariably are found to have an inversion of chromosome 16 in their leukemic cells, which results in a gene fusion between the transcription factor called core binding factor beta (CBFbeta) on 16q and a smooth muscle myosin heavy chain (SMMHC) gene on 16p. Subcellular localizations of the wild-type CBFbeta and the CBFbeta-SMMHC fusion protein were determined by immunofluorescence of NIH 3T3 cells that overexpress wild-type or fusion protein. Normal CBFbeta showed an unexpected perinuclear pattern consistent with primary localization in the Golgi complex. The CBFbeta-SMMHC fusion protein had a very different pattern. Nuclear staining included rod-like crystalline structures as long as 11 microm. The heterodimeric partner of CBFbeta, CBFalpha, formed part of this complex. Cytoplasmic staining included stress fibers that colocalized with actin, probably as a consequence of the myosin heavy chain component of the fusion protein. Deletion of different regions of the CBFbeta portion of the fusion protein showed that binding to CBFalpha was not required for nuclear translocation. However, deletion of parts of the SMMHC domain of the fusion protein involved in myosin-mediated filament formation resulted in proteins that did not form rod-like structures. These observations confirm previous indirect evidence that the CBFbeta-SMMHC fusion protein is capable of forming macromolecular nuclear aggregates and suggests possible models for the mechanism of leukemic transformation.

    Proceedings of the National Academy of Sciences of the United States of America 1996;93;4;1630-5

  • A novel deletion mutation in the beta-myosin heavy chain gene found in Japanese patients with hypertrophic cardiomyopathy.

    Nakajima-Taniguchi C, Matsui H, Eguchi N, Nagata S, Kishimoto T and Yamauchi-Takihara K

    Department of Medicine III, Osaka University Medical School, Japan.

    Mutations in the cardiac beta-myosin heavy chain (MHC) gene of 50 Japanese patients with hypertrophic cardiomyopathy (HCM) were investigated by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. A novel deletion mutation was detected in exon 3 of the cardiac beta-MHC gene in a Japanese family with HCM. Sequencing analysis revealed a three nucleotide deletion at codon 10 leading to a deletion of a glycine residue, which has been conserved in the myosin gene from birds to humans. Because this deletion mutation was not detected in other healthy family members, it was suggested that this 10Gly deletion is the cause of HCM in this family. The same deletion mutation has been found in three other unrelated patients with HCM. This is the first report of a one codon deletion in the beta-MHC gene in patients with HCM.

    Journal of molecular and cellular cardiology 1995;27;12;2607-12

  • A myosin missense mutation, not a null allele, causes familial hypertrophic cardiomyopathy.

    Nishi H, Kimura A, Harada H, Koga Y, Adachi K, Matsuyama K, Koyanagi T, Yasunaga S, Imaizumi T, Toshima H et al.

    Third Department of Internal Medicine, Kurume University School of Medicine, Japan.

    Background: Hypertrophic cardiomyopathy (HCM) is characterized by myocardial hypertrophy of unknown etiology. Missense mutations of the cardiac beta-myosin-heavy-chain (beta-MHC) gene that may be responsible for cardiac hypertrophy have been detected in patients with HCM. On the other hand, gross structural abnormalities in the cardiac beta-MHC gene, ie, an alpha/beta hybrid gene and partial deletion of the gene, have also been reported. The direct correlation between gross abnormalities and development of HCM is not well understood.

    We analyzed the structure of the cardiac beta-MHC gene from patients with HCM by using polymerase chain reaction-DNA conformation polymorphism analysis and found two sequence variations in exons 3 and 22 in one patient. These sequence variations at codon 54 (exon 3; nonsense mutation) and codon 870 (exon 22; Arg-to-His mutation) were identified by direct sequencing and dot-blot hybridization with allele-specific oligonucleotide probes. Relatives of this patient were examined for the mutations. It was revealed that the missense mutation was inherited from the affected father and the nonsense mutation from the unaffected grandmother through the unaffected mother. In addition, the missense mutation was also found in seven other patients from two other unrelated multiplex HCM families.

    Conclusions: The Arg870His mutation was suggested to cause HCM. In contrast, the gene with the nonsense mutation would encode for a cardiac beta-MHC protein of only 53 amino acid residues, which may be too short to be incorporated into the thick filament assembly of cardiac myosin chains and showed no dominant phenotype of heart disease. This is the first report of a nonsense mutation in the human cardiac beta-MHC gene.

    Circulation 1995;91;12;2911-5

  • [Genetic heterogeneity of hypertrophic cardiomyopathy in Japanese].

    Machida M

    Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Sapporo, Japan.

    Familial hypertrophic cardiomyopathy (FHCM) is thought to be caused by missense mutations in cardiac beta-myosin heavy chain (beta-MHC) gene in 30-40% of affected Caucasian individuals. On the other hand, it has been reported that Japanese FHCM is closely linked to DNA marker PALB on chromosome 18q by linkage analysis. Therefore, in order to elucidate the etiological significance of missense mutations in beta-MHC gene in Japanese HCM patients, we have investigated the sequence variation in exon 3 to 25 of beta-MHC gene from 16 multiplex FHCM kindreds and 28 sporadic patients by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method. In this study we demonstrated one missense mutation (codon741: GlyGGG-->ArgAGG) in only one kindred among 16 multiplex Japanese kindreds with FHCM. Two synonymous mutations (codon715: TryTAC-->TryTAT, codon 989: IleATT-->IleATC) are demonstrated in another kindred. The same mutation in codon 989 is also detected in one sporadic patient. Furthermore, we performed linkage study with two DNA markers (F13B on chromosome 1q, D11S916: AMF185yal on chromosome 11p-q) which are recently reported to be linked with FHCM. Three and four families showed statistically negative linkage with F13B and D11S916 (AMF185yal), respectively. These results suggest that several responsible genes for HCM may exist in Japanese and principal responsible gene for Japanese HCM is different from it for Caucasian HCM.

    [Hokkaido igaku zasshi] The Hokkaido journal of medical science 1994;69;4;1024-34

  • A new missense mutation, Arg719Gln, in the beta-cardiac heavy chain myosin gene of patients with familial hypertrophic cardiomyopathy.

    Consevage MW, Salada GC, Baylen BG, Ladda RL and Rogan PK

    Department of Pediatrics, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17036.

    Human molecular genetics 1994;3;6;1025-6

  • Prognostic implications of novel beta cardiac myosin heavy chain gene mutations that cause familial hypertrophic cardiomyopathy.

    Anan R, Greve G, Thierfelder L, Watkins H, McKenna WJ, Solomon S, Vecchio C, Shono H, Nakao S, Tanaka H et al.

    Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115.

    Three novel beta cardiac myosin heavy chain (MHC) gene missense mutations, Phe513Cys, Gly716Arg, and Arg719Trp, which cause familial hypertrophic cardiomyopathy (FHC) are described. One mutation in exon 15 (Phe513Cys) does not alter the charge of the encoded amino acid, and affected family members have a near normal life expectancy. The Gly716Arg mutation (exon 19; charge change of +1) causes FHC in three family members, one of whom underwent transplantation for heart failure. The Arg719Trp mutation (exon 19; charge change of -1) was found in four unrelated FHC families with a high incidence of premature death and an average life expectancy in affected individuals of 38 yr. A comparable high frequency of disease-related deaths in four families with the Arg719Trp mutation suggests that this specific gene defect directly accounts for the observed malignant phenotype. Further, the significantly different life expectancies associated with the Arg719Trp vs. Phe513Cys mutation (P < 0.001) support the hypothesis that mutations which alter the charge of the encoded amino acid affect survival more significantly than those that produce a conservative amino acid change.

    Funded by: NHLBI NIH HHS: HL-42467, HL-46320, P50-HL-42267

    The Journal of clinical investigation 1994;93;1;280-5

  • Familial hypertrophic cardiomyopathy. Microsatellite haplotyping and identification of a hot spot for mutations in the beta-myosin heavy chain gene.

    Dausse E, Komajda M, Fetler L, Dubourg O, Dufour C, Carrier L, Wisnewsky C, Bercovici J, Hengstenberg C, al-Mahdawi S et al.

    Institut National de la Sante et de la Recherche Médicale, U127, Hôpital Lariboisière, Paris, France.

    Familial hypertrophic cardiomyopathy (FHC) is a clinically and genetically heterogeneous disease. The first identified disease gene, located on chromosome 14q11-q12, encodes the beta-myosin heavy chain. We have performed linkage analysis of two French FHC pedigrees, 720 and 730, with two microsatellite markers located in the beta-myosin heavy chain gene (MYO I and MYO II) and with four highly informative markers, recently mapped to chromosome 14q11-q12. Significant linkage was found with MYO I and MYO II in pedigree 720, but results were not conclusive for pedigree 730. Haplotype analysis of the six markers allowed identification of affected individuals and of some unaffected subjects carrying the disease gene. Two novel missense mutations were identified in exon 13 by direct sequencing, 403Arg-->Leu and 403Arg-->Trp in families 720 and 730, respectively. The 403Arg-->Leu mutation was associated with incomplete penetrance, a high incidence of sudden deaths and severe cardiac events, whereas the consequences of the 403Arg-->Trp mutation appeared less severe. Haplotyping of polymorphic markers in close linkage to the beta-myosin heavy chain gene can, thus, provide rapid analysis of non informative pedigrees and rapid detection of carrier status. Our results also indicate that codon 403 of the beta-myosin heavy chain gene is a hot spot for mutations causing FHC.

    The Journal of clinical investigation 1993;92;6;2807-13

  • A missense mutation of cardiac beta-myosin heavy chain gene linked to familial hypertrophic cardiomyopathy in affected Japanese families.

    Harada H, Kimura A, Nishi H, Sasazuki T and Toshima H

    Third Department of Internal Medicine, Kurume University, School of Medicine, Japan.

    A novel missense mutation of the cardiac beta-myosin heavy chain gene was detected in five unrelated Japanese patients and their affected family members with hypertrophic cardiomyopathy (HCM) by using the polymerase chain reaction (PCR)-DNA conformation polymorphism (DCP) analysis. Sequencing analysis revealed an A to G transition at codon 778 leading to replacement of the Asp residue, which is adjacent to the interaction sites of myosin heavy chain (MHC) with actin and is a conserved amino acid residue in various MHC across species, to the Gly residue. Linkage study of the mutation and two dinucleotides repeat markers of the cardiac beta-MHC gene in three affected families showed that the mutation was on the same haplotype of the cardiac beta-MHC gene and linked to HCM. These observations strongly suggest that the 778Asp to Gly mutation is the cause of HCM in these affected individuals.

    Biochemical and biophysical research communications 1993;194;2;791-8

  • Detection of a new mutation in the beta-myosin heavy chain gene in an individual with hypertrophic cardiomyopathy.

    Marian AJ, Yu QT, Mares A, Hill R, Roberts R and Perryman MB

    Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.

    Familial hypertrophic cardiomyopathy (FHCM) is an autosomal dominant disease affecting primarily the myocardium. The gene responsible for FHCM has been localized to chromosome 14 in some families and several mutations have been described in the beta-myosin heavy chain (beta MHC), a candidate gene for the disease. We recently identified a family with HCM in whom we did not detect any of the known mutations in the beta MHC gene (the alpha/beta MHC hybrid gene and the missense mutation in exons 13 and 9). However, we did observe a novel 9.5-kb BamHI restriction fragment length polymorphism detected by a beta MHC probe on Southern blots of DNA from the proband of this family. Similarly, a novel 3.8-kb TaqI polymorphism and a novel 4.3-kb HindIII polymorphism were detected on Southern blots of DNA from the same proband. Polymerase chain reaction (PCR) was used to amplify the segment of the beta MHC that was detected by pSC14 probe. PCR amplification of the distal 3'-end of the beta MHC gene yielded an additional product in the DNA template from the proband which was subsequently cloned and sequenced. The sequence analysis showed a 2.4-kb nucleotide deletion involving one allele of the beta MHC gene. The deletion includes part of the intron 39, exon 40 including the 3'-untranslated region and the polyadenylation signal, and part of the beta-alpha MHC intergenic region. This deletion was inherited in Mendelian fashion in an additional three members of this small family of which only the proband has developed clinically diagnosed HCM at a very late onset (age 59 yr), the other three family members are younger and have not developed the disease at the ages of 10, 32, and 33 yr.

    Funded by: NHLBI NIH HHS: P50-HL42267-01

    The Journal of clinical investigation 1992;90;6;2156-65

Pubmed - other

  • Genetic susceptibility to distinct bladder cancer subphenotypes.

    Guey LT, García-Closas M, Murta-Nascimento C, Lloreta J, Palencia L, Kogevinas M, Rothman N, Vellalta G, Calle ML, Marenne G, Tardón A, Carrato A, García-Closas R, Serra C, Silverman DT, Chanock S, Real FX, Malats N and EPICURO/Spanish Bladder Cancer Study investigators

    Spanish National Cancer Research Centre, Madrid, Spain.

    Background: Clinical, pathologic, and molecular evidence indicate that bladder cancer is heterogeneous with pathologic/molecular features that define distinct subphenotypes with different prognoses. It is conceivable that specific patterns of genetic susceptibility are associated with particular subphenotypes.

    Objective: To examine evidence for the contribution of germline genetic variation to bladder cancer heterogeneity.

    The Spanish Bladder Cancer/EPICURO Study is a case-control study based in 18 hospitals located in five areas in Spain. Cases were patients with a newly diagnosed, histologically confirmed, urothelial cell carcinoma of the bladder from 1998 to 2001. Case diagnoses were reviewed and uniformly classified by pathologists following the World Health Organisation/International Society of Urological Pathology 1999 criteria. Controls were hospital-matched patients (n=1149).

    Measurements: A total of 1526 candidate variants in 423 candidate genes were analysed. Three distinct subphenotypes were defined according to stage and grade: low-grade nonmuscle invasive (n=586), high-grade nonmuscle invasive (n=219), and muscle invasive (n=246). The association between each variant and subphenotype was assessed by polytomous risk models adjusting for potential confounders. Heterogeneity in genetic susceptibility among subphenotypes was also tested.

    Two established bladder cancer susceptibility genotypes, NAT2 slow-acetylation and GSTM1-null, exhibited similar associations among the subphenotypes, as did VEGF-rs25648, which was previously identified in our study. Other variants conferred risks for specific tumour subphenotypes such as PMS2-rs6463524 and CD4-rs3213427 (respective heterogeneity p values of 0.006 and 0.004), which were associated with muscle-invasive tumours (per-allele odds ratios [95% confidence interval] of 0.56 [0.41-0.77] and 0.71 [0.57-0.88], respectively) but not with non-muscle-invasive tumours. Heterogeneity p values were not robust in multiple testing according to their false-discovery rate.

    Conclusions: These exploratory analyses suggest that genetic susceptibility loci might be related to the molecular/pathologic diversity of bladder cancer. Validation through large-scale replication studies and the study of additional genes and single nucleotide polymorphisms are required.

    Funded by: Intramural NIH HHS: ZIA CP010136-16

    European urology 2010;57;2;283-92

  • Upregulation of myosin Va by Snail is involved in cancer cell migration and metastasis.

    Lan L, Han H, Zuo H, Chen Z, Du Y, Zhao W, Gu J and Zhang Z

    Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Cell Biology, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing 100142, People's Republic of China.

    Cell migration, which involves acto-myosin dynamics, cell adhesion, membrane trafficking and signal transduction, is a prerequisite for cancer cell metastasis. Here, we report that an actin-dependent molecular motor, unconventional myosin Va, is involved in this process and implicated in cancer metastasis. The mRNA expression of myosin Va is increased in a number of highly metastatic cancer cell lines and metastatic colorectal cancer tissues. Suppressing the expression of myosin Va by lentivirus-based RNA interference in highly metastatic cancer cells impeded their migration and metastasis capabilities both in vitro and in vivo. In addition, the levels of myosin Va in cancer cell lines are positively correlated with the expression of Snail, a transcriptional repressor that triggers epithelial-mesenchymal transition. Repression or overexpression of Snail in cancer cells caused reduced or elevated levels of myosin Va, respectively. Furthermore, Snail can bind to an E-box of the myosin Va promoter and induce its activity, which indicates that Snail might act as a transcriptional activator. These data demonstrate an essential role of myosin Va in cancer cell migration and metastasis, and suggest a novel target for Snail in its regulation of cancer progression.

    International journal of cancer 2010;126;1;53-64

  • PTEN identified as important risk factor of chronic obstructive pulmonary disease.

    Hosgood HD, Menashe I, He X, Chanock S and Lan Q

    Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.

    Common genetic variation may play an important role in altering chronic obstructive pulmonary disease (COPD) risk. In Xuanwei, China, the COPD rate is more than twice the Chinese national average, and COPD is strongly associated with in-home coal use. To identify genetic variation that may be associated with COPD in a population with substantial in-home coal smoke exposures, we evaluated 1261 single nucleotide polymorphisms (SNPs) in 380 candidate genes potentially relevant for cancer and other human diseases in a population-based case-control study in Xuanwei (53 cases; 107 controls). PTEN was the most significantly associated gene with COPD in a minP analysis using 20,000 permutations (P=0.00005). SNP-based analyses found that homozygote variant carriers of PTEN rs701848 (OR(TT)=0.12, 95% CI=0.03-0.47) had a significant decreased risk of COPD. PTEN, or phosphatase and tensin homolog, is an important regulator of cell cycle progression and cellular survival via the AKT signaling pathway. Our exploratory analysis suggests that genetic variation in PTEN may be an important risk factor of COPD in Xuanwei. However, due to the small sample size, additional studies are needed to evaluate these associations within Xuanwei and other populations with coal smoke exposures.

    Funded by: Intramural NIH HHS: Z99 CA999999

    Respiratory medicine 2009;103;12;1866-70

  • Myosin-Va restrains the trafficking of Na+/K+-ATPase-containing vesicles in alveolar epithelial cells.

    Lecuona E, Minin A, Trejo HE, Chen J, Comellas AP, Sun H, Grillo D, Nekrasova OE, Welch LC, Szleifer I, Gelfand VI and Sznajder JI

    Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University, Chicago, IL 60611, USA. e-lecuona@northwestern.edu

    Stimulation of Na(+)/K(+)-ATPase activity in alveolar epithelial cells by cAMP involves its recruitment from intracellular compartments to the plasma membrane. Here, we studied the role of the actin molecular motor myosin-V in this process. We provide evidence that, in alveolar epithelial cells, cAMP promotes Na(+)/K(+)-ATPase recruitment to the plasma membrane by increasing the average speed of Na(+)/K(+)-ATPase-containing vesicles moving to the cell periphery. We found that three isoforms of myosin-V are expressed in alveolar epithelial cells; however, only myosin-Va and Vc colocalized with the Na(+)/K(+)-ATPase in intracellular membrane fractions. Overexpression of dominant-negative myosin-Va or knockdown with specific shRNA increased the average speed and distance traveled by the Na(+)/K(+)-ATPase-containing vesicles, as well as the Na(+)/K(+)-ATPase activity and protein abundance at the plasma membrane to similar levels as those observed with cAMP stimulation. These data show that myosin-Va has a role in restraining Na(+)/K(+)-ATPase-containing vesicles within intracellular pools and that this restrain is released after stimulation by cAMP allowing the recruitment of the Na(+)/K(+)-ATPase to the plasma membrane and thus increased activity.

    Funded by: NHLBI NIH HHS: HL076139, HL48129, HL71643; NIGMS NIH HHS: GM52111, R01 GM052111

    Journal of cell science 2009;122;Pt 21;3915-22

  • FGFR2 is associated with hair thickness in Asian populations.

    Fujimoto A, Nishida N, Kimura R, Miyagawa T, Yuliwulandari R, Batubara L, Mustofa MS, Samakkarn U, Settheetham-Ishida W, Ishida T, Morishita Y, Tsunoda T, Tokunaga K and Ohashi J

    Computational Science Research Program, RIKEN, Tokyo, Japan.

    Hair morphology is one of the most differentiated traits among human populations. A previous study has shown that a nonsynonymous single nucleotide polymorphism (SNP) in the EDAR gene, EDAR 1540T/C, is strongly associated with hair thickness in Asian populations. However, the contributions of other genes remain to be elucidated. In this study, 12 SNPs on 10 hair formation-related genes with high differentiation between Asian and other populations were examined to further identify genes associated with hair morphology. A multiple regression analysis adjusted for age, sex, population and the effect of EDAR 1540T/C revealed an SNP in intron 9 of FGFR2, rs4752566, to be significantly associated with hair thickness (cross-sectional area; P-value=0.0052, small diameter; P-value=0.029 and large diameter; P-value=0.0015). In the genomic region containing the FGFR2 gene, rs4752566 was not in strong linkage disequilibrium (LD) with the surrounding SNPs, indicating that the significant association of rs4752566 with the hair thickness is not due to LD with polymorphisms of the other genes. The rs4752566-T allele of FGFR2, associated with thicker hair, was also shown to be associated with higher mRNA level of FGFR2 (P-value=0.0270). These results suggest that the FGFR2 polymorphism affects the variation in hair thickness in Asia through alteration in the expression level of FGFR2.

    Journal of human genetics 2009;54;8;461-5

  • Pigmentation-related genes and their implication in malignant melanoma susceptibility.

    Fernandez LP, Milne RL, Pita G, Floristan U, Sendagorta E, Feito M, Avilés JA, Martin-Gonzalez M, Lázaro P, Benítez J and Ribas G

    Human Genetics Group, Human Cancer Genetics Program, Spanish National Cancer Research Centre, Madrid E-28029, Spain.

    Human pigmentation appears to be one of the main modulators of individual risk of developing malignant melanoma (MM). A large number of genes are known to be involved in rare pigmentary disorders and explain most of the variation in pigmentation phenotypes seen in human populations. This Spanish case-control study included 205 patients with melanoma and 245 control subjects. Thirty-one single nucleotide polymorphisms (SNPs) in genes that had been mainly associated with congenital pigmentation syndromes (ADTB3A, ATRN, CHS1, EDNRB, HPS, KIT, MGRN1, MITF, MLANA, MYO5A, MYO7A, OA1, OCA2, PAX3 and SOX10) were selected. We found that the variant allele of OCA2 R419Q (rs1800407) was associated with increased risk of MM (OR 1.55, 95% CI 1.04-2.31, P = 0.03). This effect on melanoma risk appeared to be stronger among individuals with solar lentigines, or at least 50 nevi. We also describe, for the first time, an association with the variant S1666C (rs2276288) in the MYO7A gene (OR 1.35; 95% CI 1.04-1.76; P = 0.03). Again, this association appeared to be stronger in several phenotypic groups such as individuals with fair skin and those with childhood sunburns. We also found that several variants in the pigmentation genes considered were associated with intermediate phenotypic characteristics. Our findings highlight the potential importance of pigmentation genes in sporadic MM susceptibility.

    Experimental dermatology 2009;18;7;634-42

  • Alternative splicing in class V myosins determines association with Rab10.

    Roland JT, Lapierre LA and Goldenring JR

    Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37232-2733, USA.

    Rab proteins influence vesicle trafficking pathways through the assembly of regulatory protein complexes. Previous investigations have documented that Rab11a and Rab8a can interact with the tail region of myosin Vb and regulate distinct trafficking pathways. We have now determined that a related Rab protein, Rab10, can interact with myosin Va, myosin Vb, and myosin Vc. Rab10 localized to a system of tubules and vesicles that have partially overlapping localization with Rab8a. Both Rab8a and Rab10 were mislocalized by the expression of dominant-negative myosin V tails. Interaction with Rab10 was dependent on the presence of the alternatively spliced exon D in myosin Va and myosin Vb and the homologous region in myosin Vc. Yeast two-hybrid assays and fluorescence resonance energy transfer studies confirmed that Rab10 binding to myosin V tails in vivo required the alternatively spliced exon D. In contrast to our previous work, we found that Rab11a can interact with both myosin Va and myosin Vb tails independent of their splice isoform. These results indicate that Rab GTPases regulate diverse endocytic trafficking pathways through recruitment of multiple myosin V isoforms.

    Funded by: NCI NIH HHS: CA68485, P30 CA068485; NEI NIH HHS: EY08126, P30 EY008126; NICHD NIH HHS: HD15052, P30 HD015052; NIDDK NIH HHS: DK20593, DK58404, DK59637, F32 DK072789, P30 DK020593, P30 DK058404, P60 DK020593, R01 DK070856, R01 DK48370, U24 DK059637

    The Journal of biological chemistry 2009;284;2;1213-23

  • Interaction of KLRG1 with E-cadherin: new functional and structural insights.

    Rosshart S, Hofmann M, Schweier O, Pfaff AK, Yoshimoto K, Takeuchi T, Molnar E, Schamel WW and Pircher H

    Department of Immunology, Institute of Medical Microbiology and Hygiene, University of Freiburg, Germany.

    The killer cell lectin-like receptor G1 (KLRG1) is an inhibitory receptor expressed by memory T cells and NK cells in man and mice. It is frequently used as a cell differentiation marker and members of the cadherin family are ligands for KLRG1. The present study provides new insights into the interaction of mouse KLRG1 with E-cadherin. Firstly, we demonstrate that co-engagement of KLRG1 and CD3/TCR in a spatially linked manner was required for inhibition arguing against the notion that KLRG1-ligation per se transmits inhibitory signals. Secondly, experiments with T cells carrying Y(7)F-mutant KLRG1 molecules with a replacement of the tyrosine residue to phenylalanine in the single ITIM indicated that the inhibitory activity of KLRG1 is counteracted to some degree by increased interaction of KLRG1(+) T cells with E-cadherin expressing target cells. Thirdly, we demonstrate that deletion of the first or the second external domain of E-cadherin abolished reactivity in KLRG1-reporter cell assays. Finally, we made the intriguing observation that KLRG1 formed multimeric protein complexes in T cells in addition to the previously described mono- and dimeric molecules.

    European journal of immunology 2008;38;12;3354-64

  • Knockdown of myosin Va isoforms by RNAi as a tool to block melanosome transport in primary human melanocytes.

    Van Gele M, Geusens B, Schmitt AM, Aguilar L and Lambert J

    Department of Dermatology, Ghent University Hospital, Ghent, Belgium. mireille.vangele@ugent.be

    The movement of melanosomes, dense melanin-containing organelles, within human melanocytes is actin-dependent and mediated through the formation of a Rab27a-Slac2-a-myosin Va (MyoVa) protein complex. We previously showed that only the melanocyte-specific exon F isoforms of MyoVa are involved in melanosome transport to the dendrite extremities. Here, we investigate siRNA to downregulate the exon F-containing isoforms of MyoVa in primary human melanocytes. Efficient and specific knockdown of the MyoVa exon F isofoms were shown at both mRNA and protein levels. Further, a stable shRNA against the MyoVa exon F isoforms was prepared by using a lentiviral system to improve and confirm the silencing effect in hard-to-transfect melanocyte cells. Immunofluorescence microscopy shows that knockdown of the exon F isoforms results in blockade of intramelanocytic melanosome transport due to the inability to form the Rab27a-Slac2-a-MyoVa tripartite complex. Interestingly, the observed phenotypic effect (that is, perinuclear accumulation of melanosomes) is the same as that seen in melanocytes from patients with human Griscelli syndrome causing abnormal pigmentation. We conclude that our siRNA-based strategy provides a previously unreported tool to block the intracellular melanosome movement in primary human melanocytes and may become an innovative drug to treat hyperpigmentation.

    The Journal of investigative dermatology 2008;128;10;2474-84

  • Pathway-based evaluation of 380 candidate genes and lung cancer susceptibility suggests the importance of the cell cycle pathway.

    Hosgood HD, Menashe I, Shen M, Yeager M, Yuenger J, Rajaraman P, He X, Chatterjee N, Caporaso NE, Zhu Y, Chanock SJ, Zheng T and Lan Q

    Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. hosgoodd@mail.nih.gov

    Common genetic variation may play an important role in altering lung cancer risk. We conducted a pathway-based candidate gene evaluation to identify genetic variations that may be associated with lung cancer in a population-based case-control study in Xuan Wei, China (122 cases and 111 controls). A total of 1260 single-nucleotide polymorphisms (SNPs) in 380 candidate genes for lung cancer were successfully genotyped and assigned to one of 10 pathways based on gene ontology. Logistic regression was used to assess the marginal effect of each SNP on lung cancer susceptibility. The minP test was used to identify statistically significant associations at the gene level. Important pathways were identified using a test of proportions and the rank truncated product methods. The cell cycle pathway was found as the most important pathway (P = 0.044) with four genes significantly associated with lung cancer (PLA2G6 minP = 0.001, CCNA2 minP = 0.006, GSK3 beta minP = 0.007 and EGF minP = 0.013), after adjusting for multiple comparisons. Interestingly, most cell cycle genes that were associated with lung cancer in this analysis were concentrated in the AKT signaling pathway, which is essential for regulation of cell cycle progression and cellular survival, and may be important in lung cancer etiology in Xuan Wei. These results should be viewed as exploratory until they are replicated in a larger study.

    Funded by: Intramural NIH HHS; NCI NIH HHS: TU2 CA105666

    Carcinogenesis 2008;29;10;1938-43

  • Intramanchette transport during primate spermiogenesis: expression of dynein, myosin Va, motor recruiter myosin Va, VIIa-Rab27a/b interacting protein, and Rab27b in the manchette during human and monkey spermiogenesis.

    Hayasaka S, Terada Y, Suzuki K, Murakawa H, Tachibana I, Sankai T, Murakami T, Yaegashi N and Okamura K

    Department of Obstetrics and Gynecology, Tohoku University School of Medicine, Sendai, Miyagi, Japan.

    Aim: To show whether molecular motor dynein on a microtubule track, molecular motor myosin Va, motor recruiter myosin Va, VIIa-Rab27a/b interacting protein (MyRIP), and vesicle receptor Rab27b on an F-actin track were present during human and monkey spermiogenesis involving intramanchette transport (IMT).

    Methods: Spermiogenic cells were obtained from three men with obstructive azoospermia and normal adult cynomolgus monkey (Macaca fascicularis). Immunocytochemical detection and reverse transcription-polymerase chain reaction (RT-PCR) analysis of the proteins were carried out. Samples were analyzed by light microscope.

    Results: Using RT-PCR, we found that dynein, myosin Va, MyRIP and Rab27b were expressed in monkey testis. These proteins were localized to the manchette, as shown by immunofluorescence, particularly during human and monkey spermiogenesis.

    Conclusion: We speculate that during primate spermiogenesis, those proteins that compose microtubule-based and actin-based vesicle transport systems are actually present in the manchette and might possibly be involved in intramanchette transport.

    Asian journal of andrology 2008;10;4;561-8

  • Myosin Va phosphorylated on Ser1650 is found in nuclear speckles and redistributes to nucleoli upon inhibition of transcription.

    Pranchevicius MC, Baqui MM, Ishikawa-Ankerhold HC, Lourenço EV, Leão RM, Banzi SR, dos Santos CT, Roque-Barreira MC, Barreira MC, Espreafico EM and Larson RE

    Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.

    Nuclear actin and nuclear myosins have been implicated in the regulation of gene expression in vertebrate cells. Myosin V is a class of actin-based motor proteins involved in cytoplasmic vesicle transport and anchorage, spindle-pole alignment and mRNA translocation. In this study, myosin-Va, phosphorylated on a conserved serine in the tail domain (phospho-ser(1650) MVa), was localized to subnuclear compartments. A monoclonal antibody, 9E6, raised against a peptide corresponding to phosphoserine(1650) and flanking regions of the murine myosin Va sequence, was immunoreactive to myosin Va heavy chain in cellular and nuclear extracts of HeLa cells, PC12 cells and B16-F10 melanocytes. Immunofluorescence microscopy with this antibody revealed discrete irregular spots within the nucleoplasm that colocalized with SC35, a splicing factor that earmarks nuclear speckles. Phospho-ser(1650) MVa was not detected in other nuclear compartments, such as condensed chromatin, Cajal bodies, gems and perinucleolar caps. Although nucleoli also were not labeled by 9E6 under normal conditions, inhibition of transcription in HeLa cells by actinomycin D caused the redistribution of phospho-ser(1650) MVa to nucleoli, as well as separating a fraction of phospho-ser(1650) MVa from SC35 into near-neighboring particles. These observations indicate a novel role for myosin Va in nuclear compartmentalization and offer a new lead towards the understanding of actomyosin-based gene regulation.

    Cell motility and the cytoskeleton 2008;65;6;441-56

  • Toward a confocal subcellular atlas of the human proteome.

    Barbe L, Lundberg E, Oksvold P, Stenius A, Lewin E, Björling E, Asplund A, Pontén F, Brismar H, Uhlén M and Andersson-Svahn H

    Department of Biotechnology, AlbaNova University Center, Royal Institute of Technology, SE-106 91 Stockholm, Sweden.

    Information on protein localization on the subcellular level is important to map and characterize the proteome and to better understand cellular functions of proteins. Here we report on a pilot study of 466 proteins in three human cell lines aimed to allow large scale confocal microscopy analysis using protein-specific antibodies. Approximately 3000 high resolution images were generated, and more than 80% of the analyzed proteins could be classified in one or multiple subcellular compartment(s). The localizations of the proteins showed, in many cases, good agreement with the Gene Ontology localization prediction model. This is the first large scale antibody-based study to localize proteins into subcellular compartments using antibodies and confocal microscopy. The results suggest that this approach might be a valuable tool in conjunction with predictive models for protein localization.

    Molecular & cellular proteomics : MCP 2008;7;3;499-508

  • Myosin-V makes two brownian 90 degrees rotations per 36-nm step.

    Komori Y, Iwane AH and Yanagida T

    Laboratories for Nanobiology, Graduate School of Frontier Biosciences, Osaka University, 1-3, Yamadaoka, Suita, Osaka, 565-0871, Japan.

    Myosin-V processively walks on actin filaments in a hand-over-hand fashion. The identical structures of the heads predict a symmetric hand-over-hand mechanism where regular, unidirectional rotation occurs during a 36-nm step. We investigated this by observing how fixed myosin-V rotates actin filaments. Actin filaments randomly rotated 90 degrees both clockwise and counter-clockwise during each step. Furthermore, ATP-dependent rotations were regularly followed by ATP-independent ones. Kinetic analysis indicated that the two 90 degrees rotations relate to the coordinated unbinding and rebinding of the heads with actin. We propose a 'brownian rotation hand-over-hand' model, in which myosin-V randomly rotates by thermally twisting its elastic neck domains during the 36-nm step. The brownian rotation may be advantageous for cargo transport through a crowded actin meshwork and for carrying cargoes reliably via multiple myosin-V molecules in the cell.

    Nature structural & molecular biology 2007;14;10;968-73

  • Myosin va mediates docking of secretory granules at the plasma membrane.

    Desnos C, Huet S, Fanget I, Chapuis C, Böttiger C, Racine V, Sibarita JB, Henry JP and Darchen F

    Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique, Unité Propre de Recherche 1929, Université Paris 7 Denis Diderot, 75005 Paris, France.

    Myosin Va (MyoVa) is a prime candidate for controlling actin-based organelle motion in neurons and neuroendocrine cells. Its function in secretory granule (SG) trafficking was investigated in enterochromaffin cells by wide-field and total internal reflection fluorescence microscopy. The distribution of endogenous MyoVa partially overlapped with SGs and microtubules. Impairing MyoVa function by means of a truncated construct (MyoVa tail) or RNA interference prevented the formation of SG-rich regions at the cell periphery and reduced SG density in the subplasmalemmal region. Individual SG trajectories were tracked to analyze SG mobility. A wide distribution of their diffusion coefficient, D(xy), was observed. Almost immobile SGs (D(xy) < 5 x 10(-4) microm2 x s(-1)) were considered as docked at the plasma membrane based on two properties: (1) SGs that undergo exocytosis have a D(xy) below this threshold value for at least 2 s before fusion; (2) a negative autocorrelation of the vertical motion was found in subtrajectories with a D(xy) below the threshold. Using this criterion of docking, we found that the main effect of MyoVa inhibition was to reduce the number of docked granules, leading to reduced secretory responses. Surprisingly, this reduction was not attributable to a decreased transport of SGs toward release sites. In contrast, MyoVa silencing reduced the occurrence of long-lasting, but not short-lasting, docking periods. We thus propose that, despite its known motor activity, MyoVa directly mediates stable attachment of SGs at the plasma membrane.

    The Journal of neuroscience : the official journal of the Society for Neuroscience 2007;27;39;10636-45

  • 'Should I stay or should I go?': myosin V function in organelle trafficking.

    Desnos C, Huet S and Darchen F

    Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique, UPR 1929, Université Paris 7 Denis Diderot, Paris, France. claire.desnos@ibpc.fr

    Actin- and microtubule-based motors can propel different cargos along filaments. Within cells, they control the distribution of membrane-bound compartments by performing complementary tasks. Organelles make long journeys along microtubules, with class V myosins ensuring their capture and their dispersal in actin-rich regions. Myosin Va is recruited on to diverse organelles, such as melanosomes and secretory vesicles, by a mechanism involving Rab GTPases. The role of myosin Va in the recruitment of secretory vesicles at the plasma membrane reveals that the cortical actin network cannot merely be seen as a physical barrier hindering vesicle access to release sites. In neurons, myosin Va controls the targeting of IP(3) (inositol 1,4,5-trisphosphate)-sensitive Ca(2+) stores to dendritic spines and the transport of mRNAs. These defects probably account for the severe neurological symptoms observed in Griscelli syndrome due to mutations in the MYO5A gene.

    Biology of the cell 2007;99;8;411-23

  • A kinetic model of coordinated myosin V.

    Wu Y, Gao YQ and Karplus M

    Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.

    We present a kinetic model for the walking of myosin V on actin under conditions of zero external force. The model includes three pathways and the termination of the processivity. Experimentally measured kinetic parameters are used in the model to obtain quantitative results. Using the model and associated parameters, we compute the proportion of the pathway containing an intermediate state, as well as the walking velocities and run lengths at various concentrations of ATP and ADP. The resulting trends agree with experimental data. The model explains the surprising experimental finding that myosin walks at a faster speed but for a shorter distance as the ATP concentration increases in the absence of ADP. It also suggests that under physiological condition ([ADP] approximately 12-50 microM), myosin walks with a higher speed and for longer distances when ATP is more abundant.

    Biochemistry 2007;46;21;6318-30

  • Alternatively spliced exon B of myosin Va is essential for binding the tail-associated light chain shared by dynein.

    Hódi Z, Németh AL, Radnai L, Hetényi C, Schlett K, Bodor A, Perczel A and Nyitray L

    Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary.

    A 10 kDa dynein light chain (DLC), previously identified as a tail light chain of myosin Va, may function as a cargo-binding and/or regulatory subunit of both myosin and dynein. Here, we identify and characterize the binding site of DLC on myosin Va. Fragments of the human myosin Va tail and the DLC2 isoform were expressed, and their complex formation was analyzed by pull-down assays, gel filtration, and spectroscopic methods. DLC2 was found to bind as a homodimer to a approximately 15 residue segment (Ile1280-Ile1294) localized between the medial and distal coiled-coil domains of the tail. The binding region contains the three residues coded by the alternatively spliced exon B (Asp1284-Lys1286). Removal of exon B eliminates DLC2 binding. Co-localization experiments in a transfected mammalian cell line confirm our finding that exon B is essential for DLC2 binding. Using circular dichroism, we demonstrate that binding of DLC2 to a approximately 85 residue disordered domain (Pro1235-Arg1320) induces some helical structure and stabilizes both flanking coiled-coil domains (melting temperature increases by approximately 7 degrees C). This result shows that DLC2 promotes the assembly of the coiled-coil domains of myosin Va. Nuclear magnetic resonance spectroscopy and docking simulations show that a 15 residue peptide (Ile1280-Ile1294) binds to the surface grooves on DLC2 similarly to other known binding partners of DLCs. When our data are taken together, they suggest that exon B and its associated DLC2 have a significant effect on the structure of parts of the coiled-coil tail domains and such a way could influence the regulation and cargo-binding function of myosin Va.

    Biochemistry 2006;45;41;12582-95

  • Association of mitochondrial complex I subunit gene NDUFV2 at 18p11 with schizophrenia in the Japanese population.

    Washizuka S, Kametani M, Sasaki T, Tochigi M, Umekage T, Kohda K and Kato T

    Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Saitama, Japan.

    Schizophrenia and bipolar disorder share common genetic background. Several loci such as 18p11, 13q32, and 22q11-13 were commonly linked with these diseases. Since mitochondrial dysfunction has been suggested in both of these disorders, NDUFV2 at 18p11, encoding a subunit of the complex I, NADH ubiquinone oxidoreductase, is a candidate gene for these diseases. We previously reported that single nucleotide polymorphisms (SNPs) in the upstream region of NDUFV2 were associated with bipolar disorder in Japanese. The association of haplotype consisting of two SNPs, -3542G > A and -602G > A, with bipolar disorder was also seen both in Japanese and the National Institute of Mental Health Pedigrees trios. In this study, 2 polymorphisms, -3542G > A and -602G > A, were investigated in 229 schizophrenic patients as compared with controls. Individual genotypes were not associated with schizophrenia. However, the haplotype consisting of these two SNPs were significantly associated with schizophrenia. These results suggested that inter-individual variation of the genomic sequence of the promoter region of NDUFV2 might be a genetic risk factor common to bipolar disorder and schizophrenia.

    American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics 2006;141B;3;301-4

  • Global phosphoproteome analysis on human HepG2 hepatocytes using reversed-phase diagonal LC.

    Gevaert K, Staes A, Van Damme J, De Groot S, Hugelier K, Demol H, Martens L, Goethals M and Vandekerckhove J

    Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology, Ghent University, Ghent, Belgium.

    We present a phosphoproteomics approach using diagonal RP chromatography as the basic isolation principle. Phosphopeptides present in a tryptic digest of total cellular lysates were first enriched by Fe3+-immobilized metal ion affinity chromatography. Further sorting of the phosphopeptides took place in three steps. First, the resulting peptide mixture was fractionated over reversed-phase chromatography. Second, peptides present in each fraction were treated with phosphatases. Third, the dephosphorylated peptides were then more hydrophobic and shifted towards a later elution interval from the contaminating non-phosphopeptides eluting at the same position as during the primary run. Since the phosphopeptides are isolated as their dephosphorylated form, additional proof for their original phosphorylation state was obtained by split-differential 16O-18O labeling. The method was validated with alpha-casein phosphopeptides and consecutively applied on HepG2 cells. We identified 190 phosphorylated peptides from 152 different proteins. This dataset includes 38 novel protein phosphorylation sites.

    Proteomics 2005;5;14;3589-99

  • Myosin Va transports dense core secretory vesicles in pancreatic MIN6 beta-cells.

    Varadi A</Ini 12d tials> <AffiliationInfo> <Affiliation>Henry Wellcome Laboratories for Integrated Cell Signalling, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom.</Affiliation> </AffiliationInfo> </Auth 1e0b or> <Author ValidYN="Y"> <LastName>Tsuboi</LastName> <ForeName>Takashi</ForeName> <Initials>T and Rutter GA

    Henry Wellcome Laboratories for Integrated Cell Signalling, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom.

    The role of unconventional myosins in neuroendocrine cells is not fully understood, with involvement suggested in the movement of both secretory vesicles and mitochondria. Here, we demonstrate colocalization of myosin Va (MyoVa) with insulin in pancreatic beta-cells and show that MyoVa copurifies with insulin in density gradients and with the vesicle marker phogrin-enhanced green fluorescent protein upon fluorescence-activated sorting of vesicles. By contrast, MyoVa immunoreactivity was poorly colocalized with mitochondrial or other markers. Demonstrating an important role for MyoVa in the recruitment of secretory vesicles to the cell surface, a reduction of MyoVa protein levels achieved by RNA interference caused a significant decrease in glucose- or depolarization-stimulated insulin secretion. Similarly, expression of the dominant-negative-acting globular tail domain of MyoVa decreased by approximately 50% the number of vesicles docked at the plasma membrane and by 87% the number of depolarization-stimulated exocytotic events detected by total internal reflection fluorescence microscopy. We conclude that MyoVa-driven movements of vesicles along the cortical actin network are essential for the terminal stages of regulated exocytosis in beta-cells.

    Funded by: Wellcome Trust

    Molecular biology of the cell 2005;16;6;2670-80

  • CART: an Hrs/actinin-4/BERP/myosin V protein complex required for efficient receptor recycling.

    Yan Q, Sun W, Kujala P, Lotfi Y, Vida TA and Bean AJ

    Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030, USA.

    Altering the number of surface receptors can rapidly modulate cellular responses to extracellular signals. Some receptors, like the transferrin receptor (TfR), are constitutively internalized and recycled to the plasma membrane. Other receptors, like the epidermal growth factor receptor (EGFR), are internalized after ligand binding and then ultimately degraded in the lysosome. Routing internalized receptors to different destinations suggests that distinct molecular mechanisms may direct their movement. Here, we report that the endosome-associated protein hrs is a subunit of a protein complex containing actinin-4, BERP, and myosin V that is necessary for efficient TfR recycling but not for EGFR degradation. The hrs/actinin-4/BERP/myosin V (CART [cytoskeleton-associated recycling or transport]) complex assembles in a linear manner and interrupting binding of any member to its neighbor produces an inhibition of transferrin recycling rate. Disrupting the CART complex results in shunting receptors to a slower recycling pathway that involves the recycling endosome. The novel CART complex may provide a molecular mechanism for the actin-dependence of rapid recycling of constitutively recycled plasma membrane receptors.

    Funded by: NIGMS NIH HHS: GM-052092, R01 GM052092; NIMH NIH HHS: MH-58920, R01 MH058920

    Molecular biology of the cell 2005;16;5;2470-82

  • Cyclic AMP promotes a peripheral distribution of melanosomes and stimulates melanophilin/Slac2-a and actin association.

    Passeron T, Bahadoran P, Bertolotto C, Chiaverini C, Buscà R, Valony G, Bille K, Ortonne JP and Ballotti R

    INSERM U597, Biologie et Pathologie des Celllules Mélanocytaires, Faculté de Médecine, Nice, France.

    Melanosomes are melanin-containing organelles that belong to a recently individualized group of lysosome-related organelles. Recently, numerous reports have dissected the molecular mechanisms that control melanosome transport, but nothing was known about the possible regulation of melanosome distribution by exogenous physiological stimulus. In the present report, we demonstrate that a physiological melanocyte-differentiating agent such as alpha-melanocyte-stimulating hormone, through the stimulation of the cAMP pathway, induces a rapid centrifugal transport of melanosomes, leading to their accumulation at the dendrite tips of melanocytes. Interestingly, the small GTP binding proteins of the p21Rho family and one of their effectors, p160 Rho-associated kinase, but not PKA, play a key role in redistribution of melanosomes at the extremities of the dendrites. Further, we have investigated, at the molecular level, the effect of cAMP on the different proteins involved in the control of melanosome transport. We demonstrate that cAMP stimulates the expression of Rab27a and rapidly increases the interaction of the melanophilin/Slac2-a with actin. Thus, we propose that the stimulation of the interaction between melanophilin/Slac2-a and actin would allow the rapid accumulation of melanosomes in the actin-rich region of the dendrite extremities.

    FASEB journal : official publication of the Federation of American Societies for Experimental Biology 2004;18;9;989-91

  • Rab GTPases and myosin motors in organelle motility.

    Seabra MC and Coudrier E

    Cell and Molecular Biology, Division of Biomedical Sciences, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK. m.seabra@imperial.ac.uk

    The actin cytoskeleton is essential to ensure the proper location of, and communication between, intracellular organelles. Some actin-based myosin motors have been implicated in this process, particularly members of the class V myosins. We discuss here the emerging role of the Ras-like GTPases of the Rab family as regulators of myosin function in organelle transport. Evidence from yeast secretory vesicles and mitochondria, and mammalian melanosomes and endosomes suggests that Rab GTPases are crucial components of the myosin organelle receptor machinery. Better understood is the case of the melanosome where Rab27a recruits a specific effector called melanophilin, which in turn binds myosin Va. The presence of a linker protein between a Rab and a myosin may represent a general mechanism. We argue that Rabs are ideally suited to perform this role as they are exquisite organelle markers. Furthermore, the molecular switch property of Rabs may enable them to regulate the timing of the myosin association with the target organelle.

    Traffic (Copenhagen, Denmark) 2004;5;6;393-9

  • Missense mutations in the globular tail of myosin-Va in dilute mice partially impair binding of Slac2-a/melanophilin.

    Fukuda M and Kuroda TS

    Fukuda Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. mnfukuda@brain.riken.go.jp

    The well-known coat-color mutant mouse dilute exhibits a defect in melanosome transport, and although various mutations in the myosin-Va gene, which encodes an actin-based motor protein, have been identified in dilute mice, why missense mutations in the globular tail of myosin-Va, a putative cargo-binding site, cause the dilute phenotype (i.e. lighter coat color) has never been elucidated. In this study we discovered that missense mutations (I1510N, M1513K and D1519G) in the globular tail (GT) of myosin-Va partially impair the binding of Slac2-a/melanophilin, a linker protein between myosin-Va and Rab27A on the melanosome. The myosin-Va-GT-binding site in Slac2-a was mapped to the region (amino acids 147-240) adjacent to the N-terminal Rab27A-binding site, but it is distinct from the myosin-Va-exon-F-binding site (amino acids 320-406). The myosin-Va-GT.Slac2-a interaction was much weaker than the myosin-Va-exon-F.Slac2-a interaction. The missense mutations in the GT found in dilute mice abrogated only the myosin-Va-GT.Slac2-a interaction and had no effect on the myosin-Va-exon-F.Slac2-a interaction. We further showed that expression of green fluorescence protein-tagged Slac2-a lacking the myosin-Va-GT-binding site (DeltaGT), but not the wild-type Slac2-a, severely inhibits melanosome transport in melan-a cells, especially at the melanosome transfer step from microtubles to actin filaments (i.e. perinuclear aggregation of melanosomes). On the basis of our findings, we propose that myosin-Va interacts with Slac2-a.Rab27A complex on the melanosome via two distinct domains, both of which are essential for melanosome transport in melanocytes.

    Journal of cell science 2004;117;Pt 4;583-91

  • Complete sequencing and characterization of 21,243 full-length human cDNAs.

    Ota T, Suzuki Y, Nishikawa T, Otsuki T, Sugiyama T, Irie R, Wakamatsu A, Hayashi K, Sato H, Nagai K, Kimura K, Makita H, Sekine M, Obayashi M, Nishi T, Shibahara T, Tanaka T, Ishii S, Yamamoto J, Saito K, Kawai Y, Isono Y, Nakamura Y, Nagahari K, Murakami K, Yasuda T, Iwayanagi T, Wagatsuma M, Shiratori A, Sudo H, Hosoiri T, Kaku Y, Kodaira H, Kondo H, Sugawara M, Takahashi M, Kanda K, Yokoi T, Furuya T, Kikkawa E, Omura Y, Abe K, Kamihara K, Katsuta N, Sato K, Tanikawa M, Yamazaki M, Ninomiya K, Ishibashi T, Yamashita H, Murakawa K, Fujimori K, Tanai H, Kimata M, Watanabe M, Hiraoka S, Chiba Y, Ishida S, Ono Y, Takiguchi S, Watanabe S, Yosida M, Hotuta T, Kusano J, Kanehori K, Takahashi-Fujii A, Hara H, Tanase TO, Nomura Y, Togiya S, Komai F, Hara R, Takeuchi K, Arita M, Imose N, Musashino K, Yuuki H, Oshima A, Sasaki N, Aotsuka S, Yoshikawa Y, Matsunawa H, Ichihara T, Shiohata N, Sano S, Moriya S, Momiyama H, Satoh N, Takami S, Terashima Y, Suzuki O, Nakagawa S, Senoh A, Mizoguchi H, Goto Y, Shimizu F, Wakebe H, Hishigaki H, Watanabe T, Sugiyama A, Takemoto M, Kawakami B, Yamazaki M, Watanabe K, Kumagai A, Itakura S, Fukuzumi Y, Fujimori Y, Komiyama M, Tashiro H, Tanigami A, Fujiwara T, Ono T, Yamada K, Fujii Y, Ozaki K, Hirao M, Ohmori Y, Kawabata A, Hikiji T, Kobatake N, Inagaki H, Ikema Y, Okamoto S, Okitani R, Kawakami T, Noguchi S, Itoh T, Shigeta K, Senba T, Matsumura K, Nakajima Y, Mizuno T, Morinaga M, Sasaki M, Togashi T, Oyama M, Hata H, Watanabe M, Komatsu T, Mizushima-Sugano J, Satoh T, Shirai Y, Takahashi Y, Nakagawa K, Okumura K, Nagase T, Nomura N, Kikuchi H, Masuho Y, Yamashita R, Nakai K, Yada T, Nakamura Y, Ohara O, Isogai T and Sugano S

    Helix Research Institute, 1532-3 Yana, Kisarazu, Chiba 292-0812, Japan.

    As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.

    Nature genetics 2004;36;1;40-5

  • Griscelli syndrome restricted to hypopigmentation results from a melanophilin defect (GS3) or a MYO5A F-exon deletion (GS1).

    Ménasché G, Ho CH, Sanal O, Feldmann J, Tezcan I, Ersoy F, Houdusse A, Fischer A and de Saint Basile G

    Unité de Recherhe sur le Développement Normal et Pathologique du Systéme Immunitaire, Hôpital Necker-Enfants Malades, Paris, France.

    Griscelli syndrome (GS) is a rare autosomal recessive disorder that associates hypopigmentation, characterized by a silver-gray sheen of the hair and the presence of large clusters of pigment in the hair shaft, and the occurrence of either a primary neurological impairment or a severe immune disorder. Two different genetic forms, GS1 and GS2, respectively, account for the mutually exclusive neurological and immunological phenotypes. Mutations in the gene encoding the molecular motor protein Myosin Va (MyoVa) cause GS1 and the dilute mutant in mice, whereas mutations in the gene encoding the small GTPase Rab27a are responsible for GS2 and the ashen mouse model. We herein present genetic and functional evidence that a third form of GS (GS3), whose expression is restricted to the characteristic hypopigmentation of GS, results from mutation in the gene that encodes melanophilin (Mlph), the ortholog of the gene mutated in leaden mice. We also show that an identical phenotype can result from the deletion of the MYO5A F-exon, an exon with a tissue-restricted expression pattern. This spectrum of GS conditions pinpoints the distinct molecular pathways used by melanocytes, neurons, and immune cells in secretory granule exocytosis, which in part remain to be unraveled.

    The Journal of clinical investigation 2003;112;3;450-6

  • Characterization of the molecular defects in Rab27a, caused by RAB27A missense mutations found in patients with Griscelli syndrome.

    Bahadoran P, Busca R, Chiaverini C, Westbroek W, Lambert J, Bille K, Valony G, Fukuda M, Naeyaert JM, Ortonne JP and Ballotti R

    INSERM U385, Biologie et Physiopathologie de la Peau, Faculté de Médecine, Avenue de Valombrose, 06107, Nice cedex 2, France.

    Rab27a plays a pivotal role in the transport of melanosomes to dendrite tips of melanocytes and mutations in RAB27A, which impair melanosome transport cause the pigmentary dilution and the immune deficiency found in several patients with Griscelli syndrome (GS). Interestingly, three GS patients present single homozygous missense mutations in RAB27A, leading to W73G, L130P, and A152P transitions that affect highly conserved residues among Rab proteins. However, the functional consequences of these mutations have not been studied. In the present report, we evaluated the effect of overexpression of these mutants on melanosome, melanophilin, and myosin-Va localization in B16 melanoma cells. Then we studied several key parameters for Rab27a function, including GTP binding and interaction with melanophilin/myosin-Va complex, which links melanosomes to the actin network. Our results showed that Rab27a-L130P cannot bind GTP, does not interact with melanophilin, and consequently cannot allow melanosome transport on the actin filaments. Interestingly, Rab27a-W73G binds GTP but does not interact with melanophilin. Thus, Rab27a-W73G cannot support the actin-dependent melanosome transport. Finally, Rab27a-A152P binds both GTP and melanophilin. However, Rab27a-A152P does not allow melanosome transport and acts as a dominant negative mutant, because its overexpression, in B16 melanoma cells, mimics a GS phenotype. Hence, the interaction of Rab27a with melanophilin/myosin-Va is not sufficient to ensure a correct melanosome transport. Our results pointed to an unexpected complexity of Rab27a function and open the way to the search for new Rab27a effectors or regulators that control the transport of Rab27a-dependent vesicles.

    The Journal of biological chemistry 2003;278;13;11386-92

  • Interactions of human Myosin Va isoforms, endogenously expressed in human melanocytes, are tightly regulated by the tail domain.

    Westbroek W, Lambert J, Bahadoran P, Busca R, Herteleer MC, Smit N, Mommaas M, Ballotti R and Naeyaert JM

    Department of Dermatology, Ghent University Hospital, B-Gent, Belgium.

    Primary human epidermal melanocytes express six endogenous isoforms of the human actin-associated myosin Va motor protein, involved in organelle transport. As isoforms containing exon F are most abundant in melanocytes, we hypothesized that these isoforms probably have a melanocyte-specific function. To uncover the biologic role of the six isoforms we introduced enhanced green fluorescent protein (eGFP)-myosin Va tail constructs in human melanocytes. We found that the medial tail, undergoing alternative splicing, has to be expressed in combination with the globular tail in order to obtain clear colocalization with organelles. Our data show that isoforms lacking exon F but containing exon D are associated with vesicles near the Golgi area. Myosin Va isoforms containing exon F are able to colocalize with and influence melanosome distribution by indirect interaction with rab27a and direct interaction with melanophilin. These results indicate that the myosin Va medial tail domain provides the globular tail domain with organelle-interacting specificity.

    The Journal of investigative dermatology 2003;120;3;465-75

  • Myosin Va binding to neurofilaments is essential for correct myosin Va distribution and transport and neurofilament density.

    Rao MV, Engle LJ, Mohan PS, Yuan A, Qiu D, Cataldo A, Hassinger L, Jacobsen S, Lee VM, Andreadis A, Julien JP, Bridgman PC and Nixon RA

    Center for Dementia Research, Nathan Kline Institute, NYU School of Medicine, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.

    The identification of molecular motors that modulate the neuronal cytoskeleton has been elusive. Here, we show that a molecular motor protein, myosin Va, is present in high proportions in the cytoskeleton of mouse CNS and peripheral nerves. Immunoelectron microscopy, coimmunoprecipitation, and blot overlay analyses demonstrate that myosin Va in axons associates with neurofilaments, and that the NF-L subunit is its major ligand. A physiological association is indicated by observations that the level of myosin Va is reduced in axons of NF-L-null mice lacking neurofilaments and increased in mice overexpressing NF-L, but unchanged in NF-H-null mice. In vivo pulse-labeled myosin Va advances along axons at slow transport rates overlapping with those of neurofilament proteins and actin, both of which coimmunoprecipitate with myosin Va. Eliminating neurofilaments from mice selectively accelerates myosin Va translocation and redistributes myosin Va to the actin-rich subaxolemma and membranous organelles. Finally, peripheral axons of dilute-lethal mice, lacking functional myosin Va, display selectively increased neurofilament number and levels of neurofilament proteins without altering axon caliber. These results identify myosin Va as a neurofilament-associated protein, and show that this association is essential to establish the normal distribution, axonal transport, and content of myosin Va, and the proper numbers of neurofilaments in axons.

    Funded by: NIA NIH HHS: 2T32 AG 00222, AG 05604, R01 AG005604, R37 AG005604, T32 AG000222; NIDDK NIH HHS: P30 DK 19525, P30 DK019525

    The Journal of cell biology 2002;159;2;279-90

  • Identification of mRNA/protein (mRNP) complexes containing Puralpha, mStaufen, fragile X protein, and myosin Va and their association with rough endoplasmic reticulum equipped with a kinesin motor.

    Ohashi S, Koike K, Omori A, Ichinose S, Ohara S, Kobayashi S, Sato TA and Anzai K

    Division of Biochemistry, College of Pharmacy, Nihon University, Chiba 274-8555, Japan.

    Puralpha, which is involved in diverse aspects of cellular functions, is strongly expressed in neuronal cytoplasm. Previously, we have reported that this protein controls BC1 RNA expression and its subsequent distribution within dendrites and that Puralpha is associated with polyribosomes. Here, we report that, following treatment with EDTA, Puralpha was released from polyribosomes in mRNA/protein complexes (mRNPs), which also contained mStaufen, Fragile X Mental Retardation Protein (FMRP), myosin Va, and other proteins with unknown functions. As the coimmunoprecipitation of these proteins by an anti-Puralpha antibody was abolished by RNase treatment, Puralpha may assist mRNP assembly in an RNA-dependent manner and be involved in targeting mRNPs to polyribosomes in cooperation with other RNA-binding proteins. The immunoprecipitation of mStaufen- and FMRP-containing mRNPs provided additional evidence that the anti-Puralpha detected structurally or functionally related mRNA subsets, which are distributed in the somatodendritic compartment. Furthermore, mRNPs appear to reside on rough endoplasmic reticulum equipped with a kinesin motor. Based on our present findings, we propose that this rough endoplasmic reticulum structure may form the molecular machinery that mediates and regulates multistep transport of polyribosomes along microtubules and actin filaments, as well as localized translation in the somatodendritic compartment.

    The Journal of biological chemistry 2002;277;40;37804-10

  • Evidence that Griscelli syndrome with neurological involvement is caused by mutations in RAB27A, not MYO5A.

    Anikster Y, Huizing M, Anderson PD, Fitzpatrick DL, Klar A, Gross-Kieselstein E, Berkun Y, Shazberg G, Gahl WA and Hurvitz H

    Heritable Disorders Branch, National Institute of Child Health and Human Development, National Institutes of Health, Building 10, 10 Center Drive, Bethesda, MD 20892-1830, USA.

    Griscelli syndrome (GS), a rare autosomal recessive disorder, is characterized by partial albinism, along with immunologic abnormalities or severe neurological impairment or both. Mutations in one of two different genes on chromosome 15q can cause the different subtypes of GS. Most patients with GS display the hemophagocytic syndrome and have mutations in RAB27A, which codes for a small GTPase. Two patients with neurological involvement have mutations in MYO5A, which codes for an actin-based molecular motor. The RAB27A and MYO5A gene products interact with each other and function in vesicle trafficking. We report the molecular basis of GS in a Muslim Arab kindred whose members have extremely variable neurological involvement, along with the hemophagocytic syndrome and immunologic abnormalities. The patients have normal MYO5A genes but exhibit a homozygous 67.5-kb deletion that eliminates RAB27A mRNA and immunocytofluorescence-detectable protein. We also describe the molecular organization of RAB27A and a multiplex polymerase chain reaction assay for the founder deletion in this kindred. Finally, we propose that all patients with GS have RAB27A mutations and immunologic abnormalities that sometimes result in secondary neurological involvement. The two patients described elsewhere who have MYO5A mutations and neurological complications but no immunologic defects may not have GS but instead may have Elejalde syndrome, a condition characterized by mild hypopigmentation and severe, primary neurological abnormalities.

    American journal of human genetics 2002;71;2;407-14

  • A family of Rab27-binding proteins. Melanophilin links Rab27a and myosin Va function in melanosome transport.

    Strom M, Hume AN, Tarafder AK, Barkagianni E and Seabra MC

    Department of Cell and Molecular Biology, Division of Biomedical Sciences, Faculty of Medicine, Imperial College, London SW7 2AZ, United Kingdom.

    The Rab27a GTPase regulates diverse processes involving lysosome-related organelles, including melanosome motility in melanocytes, and lytic granule release in cytotoxic T lymphocytes. Toward an understanding of Rab27a function, we searched for proteins that interact with Rab27a(GTP) using the yeast two-hybrid system and identified JFC1/Slp1, a protein of unknown function. JFC1/Slp1 and related proteins, including melanophilin, contain a conserved amino-terminal domain similar to the Rab3a-binding domain of Rabphilin-3. We used several methods to demonstrate that this conserved amino-terminal domain is a Rab27-binding domain. We show that this domain interacts directly, and in a GTP-dependent manner with Rab27a. Furthermore, overexpression of this domain in melanocytes results in perinuclear clustering of melanosomes, suggesting that this region is sufficient for interaction with, and perturbation of function of, Rab27a in a physiological context. Thus, we identified a novel family of Rab27-binding proteins. We also show that melanophilin associates with Rab27a and myosin Va on melanosomes in melanocytes, and present evidence that a domain within the carboxyl-terminal region of melanophilin interacts with the carboxyl-terminal tail of the melanocyte-specific splice isoform of myosin Va. Thus, melanophilin can associate simultaneously with activated Rab27a and myosin Va via distinct regions, and serve as a linker between these proteins.

    The Journal of biological chemistry 2002;277;28;25423-30

  • Griscelli disease: genotype-phenotype correlation in an array of clinical heterogeneity.

    Sanal O, Ersoy F, Tezcan I, Metin A, Yel L, Ménasché G, Gürgey A, Berkel I and de Saint Basile G

    Hacettepe University, Ihsan Doğramaci Children's Hospital, Immunology Division, Ankara, Turkey.

    Griscelli disease is a rare autosomal recessive disorder characterized by diffuse pigmentary dilution and occurrence of acute phases of uncontrolled lymphocyte and macrophage activation, so-called "hemophagocytic syndrome" (HS) that leads to death. Recently, two closely linked genes located on human 15q21 region have been found to be responsible for the disease. We present clinical and laboratory findings of 13 unrelated patients with Griscelli disease as well as mutation analyses in an effort to define a genotype-phenotype correlation. Eight patients who showed RAB27A mutations presented with HS. In contrast, two patients who primarily presented with a neurological impairment in the absence of infection susceptibility or HS were found to have homozygous MYO5A mutations. No mutation in RAB27A could be detected in the other three patients. One of the latter developed HS at a rather late age, while the other two are free of HS at 12 and 15 years of age. Griscelli disease presents with a heterogeneous clinical picture that seems to reflect the involved gene defect. This genotype-phenotype correlation suggests that the natural course of the disease and outcome is dictated by the site and type of the genetic mutation.

    Journal of clinical immunology 2002;22;4;237-43

  • Rab27a is an essential component of melanosome receptor for myosin Va.

    Wu X, Wang F, Rao K, Sellers JR and Hammer JA

    Laboratories of Cell Biology and Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.

    Melanocytes that lack the GTPase Rab27a (ashen) are disabled in myosin Va-dependent melanosome capture because the association of the myosin with the melanosome surface depends on the presence of this resident melanosomal membrane protein. One interpretation of these observations is that Rab27a functions wholly or in part as the melanosome receptor for myosin Va (Myo5a). Herein, we show that the ability of the myosin Va tail domain to localize to the melanosome and generate a myosin Va null (dilute) phenotype in wild-type melanocytes is absolutely dependent on the presence of exon F, one of two alternatively spliced exons present in the tail of the melanocyte-spliced isoform of myosin Va but not the brain-spliced isoform. Exon D, the other melanocyte-specific tail exon, is not required. Similarly, the ability of full-length myosin Va to colocalize with melanosomes and to rescue their distribution in dilute melanocytes requires exon F but not exon D. These results predict that an interaction between myosin Va and Rab27a should be exon F dependent. Consistent with this, Rab27a present in detergent lysates of melanocytes binds to beads coated with purified, full-length melanocyte myosin Va and melanocyte myosin Va lacking exon D, but not to beads coated with melanocyte myosin Va lacking exon F or brain myosin Va. Moreover, the preparation of melanocyte lysates in the presence of GDP rather than guanosine-5'-O-(3-thio)triphosphate reduces the amount of Rab27a bound to melanocyte myosin Va-coated beads by approximately fourfold. Finally, pure Rab27a does not bind to myosin Va-coated beads, suggesting that these two proteins interact indirectly. Together, these results argue that Rab27a is an essential component of a protein complex that serves as the melanosome receptor for myosin Va, suggest that this complex contains at least one additional protein capable of bridging the indirect interaction between Rab27a and myosin Va, and imply that the recruitment of myosin Va to the melanosome surface in vivo should be regulated by factors controlling the nucleotide state of Rab27a.

    Molecular biology of the cell 2002;13;5;1735-49

  • Melanophilin directly links Rab27a and myosin Va through its distinct coiled-coil regions.

    Nagashima K, Torii S, Yi Z, Igarashi M, Okamoto K, Takeuchi T and Izumi T

    Laboratory of Gene Engineering, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, Japan.

    Rab GTPases regulate the membrane transport pathways by recruiting their specific effector proteins. Melanophilin, a putative Rab effector, has recently been identified as a gene that is mutated in leaden mice, in which peripheral localization of melanosomes is impaired in melanocytes. Genetic studies suggest that three coat-color mutation genes, dilute (MyoVa(d)), ashen (Rab27a(ash)), and leaden (Mlph(ln)), act in the same or overlapping pathways. Here we have cloned and characterized a human melanophilin homolog, which belongs to the rabphilin3/granuphilin-like Rab effector family. Cosedimentation assays using recombinant proteins reveal that melanophilin directly binds to Rab27a and myosin Va through its N-terminal and its first C-terminal coiled-coil region, respectively. Moreover, we show that Rab27a, melanophilin, and myosin Va form a ternary complex in the human melanocyte cell line HMV-II. These findings suggest that melanophilin has a role in bridging Rab27a on melanosomes and myosin Va on actin filaments during melanosome transport. We also propose that the Rab-binding region conserved in a novel rabphilin3/granuphilin-like Rab effector family constitutes an alpha-helix-based coiled-coil structure.

    FEBS letters 2002;517;1-3;233-8

  • Slac2-a/melanophilin, the missing link between Rab27 and myosin Va: implications of a tripartite protein complex for melanosome transport.

    Fukuda M, Kuroda TS and Mikoshiba K

    Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. mnfukuda@brain.riken.go.jp

    Myosin Va is a member of the unconventional class V myosin family, and a mutation in the myosin Va gene causes pigment granule transport defects in human Griscelli syndrome and dilute mice. How myosin Va recognizes its cargo (i.e. melanosomes), however, has remained undetermined over the past decade. In this study, we discovered Slac2-a/melanophilin to be the "missing link" between myosin Va and GTP-Rab27A present in the melanosome. Deletion analysis and site-directed mutagenesis showed that the N-terminal Slp (synaptotagmin-like protein) homology domain of Slac2-a specifically binds Rab27A/B isoforms and that the C-terminal half directly binds the globular tail of myosin Va. The tripartite protein complex (Rab27A.Slac2-a.myosin Va) in melanoma cells was further confirmed by immunoprecipitation. The discovery that myosin Va indirectly recognizes its cargo through Slac2-a, a novel Rab27A/B effector, should shed light on molecular recognition of its specific cargo by class V myosin.

    The Journal of biological chemistry 2002;277;14;12432-6

  • Human myosin-Vc is a novel class V myosin expressed in epithelial cells.

    Rodriguez OC and Cheney RE

    Department of Cell and Molecular Physiology, Medical Science Research Building, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.

    Class V myosins are one of the most ancient and widely distributed groups of the myosin superfamily and are hypothesized to function as motors for actin-dependent organelle transport. We report the discovery and initial characterization of a novel member of this family, human myosin-Vc (Myo5c). The Myo5c protein sequence shares approximately 50% overall identity with the two other class V myosins in vertebrates, myosin-Va (Myo5a) and myosin-Vb (Myo5b). Systematic analysis of the mRNA and protein distribution of these myosins indicates that Myo5a is most abundant in brain, whereas Myo5b and Myo5c are expressed chiefly in non-neuronal tissues. Myo5c is particularly abundant in epithelial and glandular tissues including pancreas, prostate, mammary, stomach, colon and lung. Immunolocalization in colon and exocrine pancreas indicates that Myo5c is expressed chiefly in epithelial cells. A dominant negative approach using a GFP-Myo5c tail construct in HeLa cells reveals that the Myo5c tail selectively colocalizes with and perturbs a membrane compartment containing the transferrin receptor and rab8. Transferrin also accumulates in this compartment, suggesting that Myo5c is involved in transferrin trafficking. As a class V myosin of epithelial cells, Myo5c is likely to power actin-based membrane trafficking in many physiologically crucial tissues of the human body.

    Funded by: NIDCD NIH HHS: DC03299, R29 DC003299; NIDDK NIH HHS: DK34987

    Journal of cell science 2002;115;Pt 5;991-1004

  • Bmf: a proapoptotic BH3-only protein regulated by interaction with the myosin V actin motor complex, activated by anoikis.

    Puthalakath H, Villunger A, O'Reilly LA, Beaumont JG, Coultas L, Cheney RE, Huang DC and Strasser A

    The Walter and Eliza Hall Institute of Medical Research, Melbourne, P.O. Royal Melbourne Hospital, 3050 VIC, Australia.

    Bcl-2 family members bearing only the BH3 domain are essential inducers of apoptosis. We identified a BH3-only protein, Bmf, and show that its BH3 domain is required both for binding to prosurvival Bcl-2 proteins and for triggering apoptosis. In healthy cells, Bmf is sequestered to myosin V motors by association with dynein light chain 2. Certain damage signals, such as loss of cell attachment (anoikis), unleash Bmf, allowing it to translocate and bind prosurvival Bcl-2 proteins. Thus, at least two mammalian BH3-only proteins, Bmf and Bim, function to sense intracellular damage by their localization to distinct cytoskeletal structures.

    Funded by: NCI NIH HHS: CA 80188; NIDCD NIH HHS: R29 DC003299

    Science (New York, N.Y.) 2001;293;5536;1829-32

  • Molecular cloning and characterization of neural activity-related RING finger protein (NARF): a new member of the RBCC family is a candidate for the partner of myosin V.

    Ohkawa N, Kokura K, Matsu-Ura T, Obinata T, Konishi Y and Tamura TA

    Department of Biology, Faculty of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan. nokawa@bio.s.chiba-u.ac.jp

    Activity-dependent synaptic plasticity has been thought to be a cellular basis of memory and learning. The late phase of long-term potentiation (L-LTP), distinct from the early phase, lasts for up to 6 h and requires de novo synthesis of mRNA and protein. Many LTP-related genes are enhanced in the hippocampus during pentyrenetetrazol (PTZ)- and kainate (KA)-mediated neural activation. In this study, mice were administered intraperitoneal injections of PTZ 10 times, once every 48 h, and showed an increase in seizure indexes. Genes related to plasticity were efficiently induced in the mouse hippocampus. We used a PCR-based cDNA subtraction method to isolate genes that are expressed in the hippocampus of repeatedly PTZ-treated mice. One of these genes, neural activity-related RING finger protein (NARF), encodes a new protein containing a RING finger, B-box zinc finger, coiled-coil (RBCC domain) and beta-propeller (NHL) domain, and is predominantly expressed in the brain, especially in the hippocampus. In addition, KA up-regulated the expression of NARF mRNA in the hippocampus. This increase correlated with the activity of the NMDA receptor. By analysis using GFP-fused NARF, the protein was found to localize in the cytoplasm. Enhanced green fluorescent protein-fused NARF was also localized in the neurites and growth cones in neuronal differentiated P19 cells. The C-terminal beta-propeller domain of NARF interacts with myosin V, which is one of the most abundant myosin isoforms in neurons. The NARF protein increases in hippocampal and cerebellar neurons after PTZ-induced seizure. These observations indicated that NARF expression is enhanced by seizure-related neural activities, and NARF may contribute to the alteration of neural cellular mechanisms along with myosin V.

    Journal of neurochemistry 2001;78;1;75-87

  • The 8-kDa dynein light chain binds to its targets via a conserved (K/R)XTQT motif.

    Lo KW, Naisbitt S, Fan JS, Sheng M and Zhang M

    Department of Biochemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China.

    Cytoplasmic dynein is a large, multisubunit molecular motor that translocates cargoes toward the minus ends of microtubules. Proper functioning of the dynein motor requires precise assembly of its various subunits. Using purified recombinant proteins, we show that the highly conserved 8-kDa light chain (DLC8) binds to the intermediate chain of the dynein complex. The DLC8-binding region was mapped to a highly conserved 10-residue fragment (amino acid sequence SYSKETQTPL) C-terminal to the second alternative splicing site of dynein intermediate chain. Yeast two-hybrid screening using DLC8 as bait identified numerous additional DLC8-binding proteins. Biochemical and mutational analysis of selected DLC8-binding proteins revealed that DLC8 binds to a consensus sequence containing a (K/R)XTQT motif. The (K/R)XTQT motif interacts with the common target-accepting grooves of DLC8 dimer. The role of each conserved amino acid residue in this pentapeptide motif in supporting complex formation with DLC8 was systematically studied using site-directed mutagenesis.

    The Journal of biological chemistry 2001;276;17;14059-66

  • Mutations in the NMMHC-A gene cause autosomal dominant macrothrombocytopenia with leukocyte inclusions (May-Hegglin anomaly/Sebastian syndrome).

    Kunishima S, Kojima T, Matsushita T, Tanaka T, Tsurusawa M, Furukawa Y, Nakamura Y, Okamura T, Amemiya N, Nakayama T, Kamiya T and Saito H

    First Department of Internal Medicine, Nagoya University School of Medicine, Showa-ku, Nagoya, Japan.

    Macrothrombocytopenia with leukocyte inclusions is a rare autosomal dominant platelet disorder characterized by a triad of giant platelets, thrombocytopenia, and characteristic Döhle body-like leukocyte inclusions. A previous study mapped a locus for the disease on chromosome 22q12.3-q13.2 by genome-wide linkage analysis. In addition, the complete DNA sequence of human chromosome 22 allowed a positional candidate approach, and results here indicate that the gene encoding nonmuscle myosin heavy chain-A, NMMHC-A, is mutated in this disorder. Mutations were found in 6 of 7 Japanese families studied: 3 missense mutations, a nonsense mutation, and a one-base deletion resulting in a premature termination. Immunofluorescence studies revealed that NMMHC-A distribution in neutrophils appeared to mimic the inclusion bodies. These results provide evidence for the involvement of abnormal NMMHC-A in the formation of leukocyte inclusions and also in platelet morphogenesis.

    Blood 2001;97;4;1147-9

  • Interaction of the postsynaptic density-95/guanylate kinase domain-associated protein complex with a light chain of myosin-V and dynein.

    Naisbitt S, Valtschanoff J, Allison DW, Sala C, Kim E, Craig AM, Weinberg RJ and Sheng M

    Howard Hughes Medical Institute, Department of Neurobiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.

    NMDA receptors interact directly with postsynaptic density-95 (PSD-95), a scaffold protein that organizes a cytoskeletal- signaling complex at the postsynaptic membrane. The molecular mechanism by which the PSD-95-based protein complex is trafficked to the postsynaptic site is unknown but presumably involves specific motor proteins. Here we demonstrate a direct interaction between the PSD-95-associated protein guanylate kinase domain-associated protein (GKAP) and dynein light chain (DLC), a light chain subunit shared by myosin-V (an actin-based motor) and cytoplasmic dynein (a microtubule-based motor). A yeast two-hybrid screen with GKAP isolated DLC2, a novel protein 93% identical to the previously cloned 8 kDa dynein light chain (DLC1). A complex containing PSD-95, GKAP, DLC, and myosin-V can be immunoprecipitated from rat brain extracts. DLC colocalizes with PSD-95 and F-actin in dendritic spines of cultured neurons and is enriched in biochemical purifications of PSD. Immunogold electron microscopy reveals a concentration of DLC in the postsynaptic compartment of asymmetric synapses of brain in which it is associated with the PSD and the spine apparatus. We discuss the possibility that the GKAP/DLC interaction may be involved in trafficking of the PSD-95 complex by motor proteins.

    Funded by: NINDS NIH HHS: NS29879, NS33184, NS35050

    The Journal of neuroscience : the official journal of the Society for Neuroscience 2000;20;12;4524-34

  • arg-cys substitution at codon 1246 of the human myosin Va gene is not associated with Griscelli syndrome.

    Lambert J, Naeyaert JM, De Paepe A, Van Coster R, Ferster A, Song M and Messiaen L

    Department of Dermatology, University Hospital, Gent, Belgium. jo.lambert@rug.ac.be

    Myosin Va is an actin-associated motor protein involved in organelle transport such as melanosomes and neuron synaptic vesicles and has always been proposed as the candidate gene for the autosomal recessive Griscelli-Pruniéras syndrome, one of the silvery hair syndromes, which is a lethal disease combining immunodeficiency and neurologic and pigmentary abnormalities. Thus far, two mutations in the myosin Va gene have been described to be associated with this syndrome. One of these mutations was a homozygous mis-sense mutation causing an arginine to cysteine alteration at codon 1246. Because we also found this particular substitution after mutation analysis of a Griscelli patient, we checked its relevance in a control group of 124 unrelated healthy individuals and found it to be present, even in homozygous state, in normal unaffected individuals. It is clear that this arg1246cys substitution is a polymorphism occurring in the human population and not occurring in association with Griscelli syndrome. Distinguishing a polymorphism from a bona fide mutation is of utmost importance and has major ethical implications with regard to prenatal genetic counseling in affected families.

    The Journal of investigative dermatology 2000;114;4;731-3

  • Two genes are responsible for Griscelli syndrome at the same 15q21 locus.

    Pastural E, Ersoy F, Yalman N, Wulffraat N, Grillo E, Ozkinay F, Tezcan I, Gediköglu G, Philippe N, Fischer A and de Saint Basile G

    Unité de Recherches sur le développement normal et pathologique du système immunitaire, INSERM U429, Hôpital Necker Enfants Malades, 149 rue de Sèvres, Paris Cedex 15, 75743, France.

    Griscelli syndrome is a rare autosomal recessive disease characterized by pigment dilution, variable cellular immunodeficiency, and an acute phase of uncontrolled T lymphocyte and macrophage activation. We previously mapped the disease locus to 15q21 and showed that a MyoVa gene (HGMW-approved symbol MYO5A) defect leads to Griscelli syndrome. We report a second MyoVa mutation in a new patient, confirming this first finding. However, in four other Griscelli syndrome patients analyzed, the MYOVA protein is expressed, and no mutation can be detected in the MyoVa gene coding sequence, even in the alternatively spliced region for which exon-intron boundaries were characterized. Linkage analysis performed in 15 Griscelli families thus far studied confirms the first localization. However, fine haplotype analysis in three families strongly suggests the existence of a second gene at the same locus for Griscelli syndrome less than 7.3 cM distant from the MyoVa gene.

    Genomics 2000;63;3;299-306

  • Myosin-V is a processive actin-based motor.

    Mehta AD, Rock RS, Rief M, Spudich JA, Mooseker MS and Cheney RE

    Department of Biochemistry, Stanford University Medical Center, California 94305, USA.

    Class-V myosins, one of 15 known classes of actin-based molecular motors, have been implicated in several forms of organelle transport, perhaps working with microtubule-based motors such as kinesin. Such movements may require a motor with mechanochemical properties distinct from those of myosin-II, which operates in large ensembles to drive high-speed motility as in muscle contraction. Based on its function and biochemistry, it has been suggested that myosin-V may be a processive motor like kinesin. Processivity means that the motor undergoes multiple catalytic cycles and coupled mechanical advances for each diffusional encounter with its track. This allows single motors to support movement of an organelle along its track. Here we provide direct evidence that myosin-V is indeed a processive actin-based motor that can move in large steps approximating the 36-nm pseudo-repeat of the actin filament.

    Funded by: NIDCD NIH HHS: R29 DC003299

    Nature 1999;400;6744;590-3

  • Inhibition of dendrite formation in mouse melanocytes transiently transfected with antisense DNA to myosin Va.

    Edgar AJ and Bennett JP

    Division of Biomedical Sciences, Imperial College School of Medicine, London, UK.

    In mice a molecular motor of the myosin V class (designated myosin Va) is known to be the product of the dilute locus, where a mutation prevents melanosome transport in melanocytes. There is conflicting evidence about whether it has a role in dendrite outgrowth. We investigated its role by transiently transfecting antisense oligonucleotides to inhibit its expression in a melanocyte cell line. We demonstrated mRNA and protein expression of myosin Va in 3 mouse melanocyte lines and 1 human melanoma cell line, using RT-PCR and immunoblotting. Two splice variants were found in human cells whilst only the longer transcript, containing an additional exon, was present in mouse melanocyte lines. The shorter variant was detected in other mouse tissues. Myosin Va protein levels were similar in 3 melanocyte lines with differing amounts of pigmentation, indicating that expression of myosin Va is not tightly coupled to expression of melanin. Immunocytochemistry showed 2 types of myosin Va localisation. A punctate pattern of staining concentrated in the perinuclear region was indicative of organelle association, and the observation of occasional linear punctate staining aligned with F-actin bundles supported the idea that myosin Va has a role in transporting melanosomes along actin filaments. Staining was also intense at tips of dendrites and at sites of dendrite-cell contact, consistent with a possible role in dendrite growth. Transient transfection of antisense phosphorothioate oligodeoxynucleotides targeted against myosin Va mRNA reduced expression of myosin Va protein in cultured mouse melan-a melanocytes by over 70 % 20 h after transfection whereas a control (shuffled sequence) oligonucleotide did not. Upon trypsinisation and replating these cells the capacity of the transfected cells to extend new dendrites was reduced in the cells containing the specific antisense oligonucleotides but unaffected by the control oligonucleotide. Image analysis confirmed that the effect of transfection on morphology was statistically significant (P < 0.01). In contrast when cells were not trypsinised and replated following transfection so that previously existing dendrites could persist, the normal dendritic morphology continued to be observed. We conclude that in addition to its involvement in melanosome transport, myosin Va has a role in the extension of new dendrites by melanocytes but not in maintenance of pre-existing dendrites.

    Journal of anatomy 1999;195 ( Pt 2);173-84

  • Cloning and characterization of a novel RING finger protein that interacts with class V myosins.

    El-Husseini AE and Vincent SR

    Graduate Program in Neuroscience, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.

    We have identified a novel protein (BERP) that is a specific partner for the tail domain of myosin V. Class V myosins are a family of molecular motors thought to interact via their unique C-terminal tails with specific proteins for the targeted transport of organelles. BERP is highly expressed in brain and contains an N-terminal RING finger, followed by a B-box zinc finger, a coiled-coil (RBCC domain), and a unique C-terminal beta-propeller domain. A yeast two-hybrid screening indicated that the C-terminal beta-propeller domain mediates binding to the tail of the class V myosin myr6 (myosin Vb). This interaction was confirmed by immunoprecipitation, which also demonstrated that BERP could associate with myosin Va, the product of the dilute gene. Like myosin Va, BERP is expressed in a punctate pattern in the cytoplasm as well as in the neurites and growth cones of PC12 cells. We also found that the RBCC domain of BERP is involved in protein dimerization. Stable expression of a mutant form of BERP lacking the myosin-binding domain but containing the dimerization domain resulted in defective PC12 cell spreading and prevented neurite outgrowth in response to nerve growth factor. Our studies present a novel interaction for the beta-propeller domain and provide evidence for a role for BERP in myosin V-mediated cargo transport.

    The Journal of biological chemistry 1999;274;28;19771-7

  • The localization of myosin VI at the golgi complex and leading edge of fibroblasts and its phosphorylation and recruitment into membrane ruffles of A431 cells after growth factor stimulation.

    Buss F, Kendrick-Jones J, Lionne C, Knight AE, Côté GP and Paul Luzio J

    Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 2QR, United Kingdom. fb1@mole.bio.cam.ac.uk

    Myosin VI is an unconventional myosin that may play a role in vesicular membrane traffic through actin rich regions of the cytoplasm in eukaryotic cells. In this study we have cloned and sequenced a cDNA encoding a chicken intestinal brush border myosin VI. Polyclonal antisera were raised to bacterially expressed fragments of this myosin VI. The affinity purified antibodies were highly specific for myosin VI by immunoblotting and immunoprecipitation and were used to study the localization of the protein by immunofluorescence and immunoelectron microscopy. It was found that in NRK and A431 cells, myosin VI was associated with both the Golgi complex and the leading, ruffling edge of the cell as well as being present in a cytosolic pool. In A431 cells in which cell surface ruffling was stimulated by EGF, myosin VI was phosphorylated and recruited into the newly formed ruffles along with ezrin and myosin V. In vitro experiments suggested that a p21-activated kinase (PAK) might be the kinase responsible for phosphorylation in the motor domain. These results strongly support a role for myosin VI in membrane traffic on secretory and endocytic pathways.

    The Journal of cell biology 1998;143;6;1535-45

  • Human myosin V gene produces different transcripts in a cell type-specific manner.

    Lambert J, Naeyaert JM, Callens T, De Paepe A and Messiaen L

    Department of Dermatology, University Hospital, Gent, Belgium. jo.lambert@rug.ac.be

    In mice, tissue-specific alternative splicing of the myosin V gene in the C-terminal tail domain is well documented with exclusion of exon F from brain transcripts, but present in skin, particularly in melanocytes. As alternative splicing of the myosin V C-terminal tail domain in human tissues is undocumented, we studied the presence of myosin V splice forms in different types of human cultured normal skin cells, i.e., dermal fibroblasts, melanocytes, and keratinocytes as well as in human blood leukocytes, using an RT-PCR-based method. In all cell types studied, several different length transcripts were present containing different exon combinations, including exon F. This is the first report showing the presence of exon F as well as alternative splicing in the human myosin V tail domain. As the full-length transcript is most abundant in melanocytes and leukocytes and both cell types are involved in Griscelli syndrome, a tissue-specific role of this particular transcript needs further investigation.

    Biochemical and biophysical research communications 1998;252;2;329-33

  • The cardiac beta-myosin heavy chain gene is not the predominant gene for hypertrophic cardiomyopathy in the Finnish population.

    Jääskeläinen P, Soranta M, Miettinen R, Saarinen L, Pihlajamäki J, Silvennoinen K, Tikanoja T, Laakso M and Kuusisto J

    Department of Medicine, University of Kuopio, Finland.

    Objectives: The aim of the study was to screen 36 unrelated patients with hypertrophic cardiomyopathy (HCM; 16 familial and 20 sporadic cases) from a genetically homogeneous area in eastern Finland for variants in the cardiac beta-myosin heavy chain (beta-MHC) and alpha-tropomyosin (alpha-TM) genes.

    Background: Mutations in the beta-MHC and alpha-TM genes have been reported to be responsible for 30% to 40% and less than 5% of familial HCM cases, respectively. However, most genetic studies have included patients from tertiary care centers and are subject to referral bias.

    Methods: Exons 3-26 and 40 of the beta-MHC gene and the nine exons of the alpha-TM gene were screened with the PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) method. Linkage analyses between familial HCM locus and two intragenic polymorphic markers (MYO I and MYO II) of the beta-MHC gene were performed in 16 familial HCM kindreds.

    Results: A previously reported Arg719Trp (arginine converted to tryptophan in codon 719) mutation of the beta-MHC gene was found in one proband and two relatives. In addition, a novel Asn696Ser (asparagine converted to serine in codon 696) substitution was found in one HCM patient. No linkage between familial HCM and the beta-MHC gene was observed in 16 familial kindreds. A previously reported Aspl75Asn (aspartic acid converted to asparagine in codon 175) mutation of the alpha-TM gene was found in four probands and 16 relatives. Mutations in the beta-MHC and alpha-TM genes accounted for 6% and 25% familial HCM cases and 3% and 11% of all cases, respectively.

    Conclusions: Our results indicate that the beta-MHC gene is not the predominant gene for HCM in the Finnish population, whereas HCM caused by the Aspl75Asn mutation of the a-TM gene is more common than previously reported.

    Journal of the American College of Cardiology 1998;32;6;1709-16

  • Griscelli disease maps to chromosome 15q21 and is associated with mutations in the myosin-Va gene.

    Pastural E, Barrat FJ, Dufourcq-Lagelouse R, Certain S, Sanal O, Jabado N, Seger R, Griscelli C, Fischer A and de Saint Basile G

    Unité de Recherches sur le Dévelopement Normal et Pathologique de Systéme Immunitaire INSERM U429 Paris, France.

    Griscelli disease (OMIM 214450) is a rare autosomal recessive disorder characterized by pigmentary dilution, variable cellular immunodeficiency and onset of acute phases of uncontrolled lymphocyte and macrophage activation, leading to death in the absence of bone-marrow transplantation. The pigmentary dilution is characterized by a diffuse skin pigmentation, silvery hair, large clumps of pigments in the hair shafts (Fig. 1) and an accumulation of melanosomes in melanocytes, with abnormal transfer of the melanin granules to the keratinocytes. Immunological abnormalities are characterized by absent delayed-type cutaneous hypersensitivity and an impaired natural-killer cell function. A similar disorder has been described in the dilute lethal mouse--which, however, differs by the occurrence of a severe neurological disorder. The dilute locus encodes myosin-Va, a member of the unconventional myosin family. Myosins bind actin and produce mechanical force through ATP hydrolysis. Some members of this family are thought to participate in organelle-transport machinery. Because of the phenotype resulting in the dilute mouse and because of their potential role in intracellular transport, unconventional myosin-encoding genes were regarded as candidate genes for Griscelli disease. Here we report that the Griscelli disease locus co-localizes on chromosome 15q21 with the myosin-Va gene, MYO5a, and that mutations of this gene occur in two patients with the disease. Griscelli disease is therefore a human equivalent of dilute expression in the mouse.

    Nature genetics 1997;16;3;289-92

  • Cloning and regional assignment of the human myosin heavy chain 12 (MYH12) gene to chromosome band 15q21.

    Moore KJ, Testa JR, Francke U, Milatovich A, Copeland NG and Jenkins NA

    Mammalian Genetics Laboratory, NCI-Frederick Cancer Research and Development Center, MD 21702.

    Sequences encoding 1,235 bp of the human myosin heavy chain 12 (MYH12) gene have been cloned from a human brain cDNA library by PCR amplification. The human sequence is 95.8% identical to the mouse sequence at the amino acid level, indicating that the MYH12 gene has been evolutionarily well conserved. Somatic cell hybrid analysis and in situ hybridization place the MYH12 gene on human chromosome 15, at band q21, and extend distally the known region of chromosome 15 linkage homology on mouse chromosome 9.

    Funded by: NCI NIH HHS: CA-45745, N01-CO-74101; NHGRI NIH HHS: R01-HG00298; ...

    Cytogenetics and cell genetics 1995;69;1-2;53-8

  • Identification and overlapping expression of multiple unconventional myosin genes in vertebrate cell types.

    Bement WM, Hasson T, Wirth JA, Cheney RE and Mooseker MS

    Department of Biology, Yale University, New Haven, CT 06520-8103.

    Myosin diversity in the human epithelial cell line Caco-2BBe, the porcine epithelial cell line LLC-PK1 (CL-4), human peripheral blood leukocytes, and human liver was analyzed. PCR amplification yielded 8-11 putative myosins (depending on the cDNA source) representing six distinct myosin classes. Analysis of clones obtained by hybridization screening demonstrated that the original PCR products correspond to bona fide myosins, based on the presence of sequences highly conserved in other myosins. RNase protection analysis confirmed mRNA expression of 11 myosins in Caco-2BBe cells. Immunoblot analysis showed that at least 6 myosin immunogens are expressed in Caco-2BBe cells. The results reveal the existence of at least 11 unconventional human myosin genes, most of which are expressed in an overlapping fashion in different cell types. The abundance of myosins suggests that the myosin I vs. myosin II paradigm is inadequate to explain actin-based cellular motility.

    Funded by: NIDDK NIH HHS: DK 25387, DK 34989, DK 38979

    Proceedings of the National Academy of Sciences of the United States of America 1994;91;14;6549-53

  • Cloning, analysis, and chromosomal localization of myoxin (MYH12), the human homologue to the mouse dilute gene.

    Engle LJ and Kennett RH

    Department of Human Genetics, University of Pennsylvania School of Medicine, Philadelphia 19104.

    The mouse dilute gene encodes a novel type of non-muscle myosin that structurally combines elements from both nonmuscle myosin type I and nonmuscle myosin type II. Phenotypically, mutations in the mouse dilute gene result not only in the lightening of coat color, but also in the onset of severe neurological defects shortly after birth. This may indicate that the mouse dilute gene is important in maintaining the normal neuronal function in the mouse. We report the isolation and sequencing of "myoxin" (MYH12), the human homologue of the mouse dilute gene, and its assignment to human chromosome 15.

    Funded by: NCI NIH HHS: CA-16520; NIDDK NIH HHS: P30-DK19525

    Genomics 1994;19;3;407-16

Gene lists (8)

Gene List Source Species Name Description Gene count
L00000009 G2C Homo sapiens Human PSD Human orthologues of mouse PSD adapted from Collins et al (2006) 1080
L00000015 G2C Homo sapiens Human NRC Human orthologues of mouse NRC adapted from Collins et al (2006) 186
L00000016 G2C Homo sapiens Human PSP Human orthologues of mouse PSP adapted from Collins et al (2006) 1121
L00000034 G2C Homo sapiens Pocklington H3 Human orthologues of cluster 3 (mouse) from Pocklington et al (2006) 30
L00000059 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-CONSENSUS Human cortex PSD consensus 748
L00000061 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-CONSENSUS Mouse cortex PSD consensus (ortho) 984
L00000069 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-FULL Human cortex biopsy PSD full list 1461
L00000071 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-FULL Mouse cortex PSD full list (ortho) 1556
© G2C 2014. The Genes to Cognition Programme received funding from The Wellcome Trust and the EU FP7 Framework Programmes:
EUROSPIN (FP7-HEALTH-241498), SynSys (FP7-HEALTH-242167) and GENCODYS (FP7-HEALTH-241995).

Cookies Policy | Terms and Conditions. This site is hosted by Edinburgh University and the Genes to Cognition Programme.