G2Cdb::Gene report

Gene id
Gene symbol
Homo sapiens
myosin, heavy chain 10, non-muscle
G00000761 (Mus musculus)

Databases (7)

ENSG00000133026 (Ensembl human gene)
4628 (Entrez Gene)
177 (G2Cdb plasticity & disease)
MYH10 (GeneCards)
160776 (OMIM)
Marker Symbol
HGNC:7568 (HGNC)
Protein Sequence
P35580 (UniProt)

Synonyms (1)


Literature (39)

Pubmed - other

  • Myosin II tailpiece determines its paracrystal structure, filament assembly properties, and cellular localization.

    Ronen D and Ravid S

    Department of Biochemistry and Molecular Biology, the Institute for Medical Research, Israel-Canada, the Hebrew University, Hadassah Medical School, Jerusalem 91220, Israel.

    Non muscle myosin II (NMII) is a major motor protein present in all cell types. The three known vertebrate NMII isoforms share high sequence homology but play different cellular roles. The main difference in sequence resides in the C-terminal non-helical tailpiece (tailpiece). In this study we demonstrate that the tailpiece is crucial for proper filament size, overcoming the intrinsic properties of the coiled-coil rod. Furthermore, we show that the tailpiece by itself determines the NMII filament structure in an isoform-specific manner, thus providing a possible mechanism by which each NMII isoform carries out its unique cellular functions. We further show that the tailpiece determines the cellular localization of NMII-A and NMII-B and is important for NMII-C role in focal adhesion complexes. We mapped NMII-C sites phosphorylated by protein kinase C and casein kinase II and showed that these phosphorylations affect its solubility properties and cellular localization. Thus phosphorylation fine-tunes the tailpiece effects on the coiled-coil rod, enabling dynamic regulation of NMII-C assembly. We thus show that the small tailpiece of NMII is a distinct domain playing a role in isoform-specific filament assembly and cellular functions.

    The Journal of biological chemistry 2009;284;37;24948-57

  • Defining the human deubiquitinating enzyme interaction landscape.

    Sowa ME, Bennett EJ, Gygi SP and Harper JW

    Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.

    Deubiquitinating enzymes (Dubs) function to remove covalently attached ubiquitin from proteins, thereby controlling substrate activity and/or abundance. For most Dubs, their functions, targets, and regulation are poorly understood. To systematically investigate Dub function, we initiated a global proteomic analysis of Dubs and their associated protein complexes. This was accomplished through the development of a software platform called CompPASS, which uses unbiased metrics to assign confidence measurements to interactions from parallel nonreciprocal proteomic data sets. We identified 774 candidate interacting proteins associated with 75 Dubs. Using Gene Ontology, interactome topology classification, subcellular localization, and functional studies, we link Dubs to diverse processes, including protein turnover, transcription, RNA processing, DNA damage, and endoplasmic reticulum-associated degradation. This work provides the first glimpse into the Dub interaction landscape, places previously unstudied Dubs within putative biological pathways, and identifies previously unknown interactions and protein complexes involved in this increasingly important arm of the ubiquitin-proteasome pathway.

    Funded by: NIA NIH HHS: AG085011, R01 AG011085, R01 AG011085-16; NIDDK NIH HHS: K01 DK098285; NIGMS NIH HHS: GM054137, GM67945, R01 GM054137, R01 GM054137-14, R01 GM067945

    Cell 2009;138;2;389-403

  • Cardiac myosin binding protein-C phosphorylation in a {beta}-myosin heavy chain background.

    Sadayappan S, Gulick J, Klevitsky R, Lorenz JN, Sargent M, Molkentin JD and Robbins J

    Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Ohio, USA.

    Background: Cardiac myosin binding protein-C (cMyBP-C) phosphorylation modulates cardiac contractility. When expressed in cMyBP-C-null (cMyBP-C((t/t))) hearts, a cMyBP-C phosphomimetic (cMyBP-C(AllP+)) rescued cardiac dysfunction and protected the hearts from ischemia/reperfusion injury. However, cMyBP-C function may be dependent on the myosin isoform type. Because these replacements were performed in the mouse heart, which contains predominantly alpha-myosin heavy chain (alpha-MyHC), the applicability of the data to humans, whose cardiomyocytes contain predominantly beta-MyHC, is unclear. We determined the effect(s) of cMyBP-C phosphorylation in a beta-MyHC transgenic mouse heart in which >80% of the alpha-MyHC was replaced by beta-MyHC, which is the predominant myosin isoform in human cardiac muscle.

    To determine the effects of cMyBP-C phosphorylation in a beta-MyHC background, transgenic mice expressing normal cMyBP-C (cMyBP-C(WT)), nonphosphorylatable cMyBP-C (cMyBP-C(AllP)(-)), or cMyBP-C(AllP+) were bred into the beta-MyHC background (beta). These mice were then crossed into the cMyBP-C((t/t)) background to ensure the absence of endogenous cMyBP-C. cMyBP-C((t/t)/beta) and cMyBP-C(AllP)(-)(:(t/t)/beta) mice died prematurely because of heart failure, confirming that cMyBP-C phosphorylation is essential in the beta-MyHC background. cMyBP-C(AllP+:(t/t)/beta) and cMyBP-C(WT:(t/t)/beta) hearts showed no morbidity and mortality, and cMyBP-C(AllP+:(t/t)/beta) hearts were significantly cardioprotected from ischemia/reperfusion injury.

    Conclusions: cMyBP-C phosphorylation is necessary for basal myocardial function in the beta-MyHC background and can preserve function after ischemia/reperfusion injury. Our studies justify exploration of cMyBP-C phosphorylation as a therapeutic target in the human heart.

    Funded by: NHLBI NIH HHS: P01 HL059408, P01 HL069779, P01 HL069779-040001, P01 HL069779-06A1, P01 HL069779-06A10001, P01 HL069779-06A17080, P01HL059408, P01HL69799, P50 HL074728, P50 HL074728-050004, P50 HL077101, P50 HL077101-010005, P50 HL077101-020005, P50 HL077101-030005, P50 HL077101-040005, P50HL074728, P50HL077101, R01 HL087862, R01HL087862; NICHD NIH HHS: P30 HD028827-109005

    Circulation 2009;119;9;1253-62

  • The C-terminal tail region of nonmuscle myosin II directs isoform-specific distribution in migrating cells.

    Sandquist JC and Means AR

    Department of Pharmacology and Cancer Biology, Duke University Medical Center; Durham, NC 27710, USA.

    Nonmuscle myosin II isoforms A and B (hereafter, IIA and IIB) perform unique roles in cell migration, even though both isoforms share the same basic molecular functions. That IIA and IIB assume distinct subcellular distribution in migrating cells suggests that discrete spatiotemporal regulation of each isoform's activity may provide a basis for its unique migratory functions. Here, we make the surprising finding that swapping a small C-terminal portion of the tail between IIA and IIB inverts the distinct distribution of these isoforms in migrating cells. Moreover, swapping this region between isoforms also inverts their specific turnover properties, as assessed by fluorescence recovery after photobleaching and Triton solubility. These data, acquired through the use of chimeras of IIA and IIB, suggest that the C-terminal region of the myosin heavy chain supersedes the distinct motor properties of the two isoforms as the predominant factor directing isoform-specific distribution. Furthermore, our results reveal a correlation between isoform solubility and distribution, leading to the proposal that the C-terminal region regulates isoform distribution by tightly controlling the amount of each isoform that is soluble and therefore available for redistribution into new protrusions.

    Funded by: Howard Hughes Medical Institute; NCI NIH HHS: CA-082845, R01 CA082845

    Molecular biology of the cell 2008;19;12;5156-67

  • Cellular nonmuscle myosins NMHC-IIA and NMHC-IIB and vertebrate heart looping.

    Lu W, Seeholzer SH, Han M, Arnold AS, Serrano M, Garita B, Philp NJ, Farthing C, Steele P, Chen J and Linask KK

    Department of Pediatrics, USF/ACH-Children's Research Institute, St. Petersburg, Florida 33701, USA.

    Flectin, a protein previously described to be expressed in a left-dominant manner in the embryonic chick heart during looping, is a member of the nonmuscle myosin II (NMHC-II) protein class. During looping, both NMHC-IIA and NMHC-IIB are expressed in the mouse heart on embryonic day 9.5. The patterns of localization of NMHC-IIB, rather than NMHC-IIA in the mouse looping heart and in neural crest cells, are equivalent to what we reported previously for flectin. Expression of full-length human NMHC-IIA and -IIB in 10 T1/2 cells demonstrated that flectin antibody recognizes both isoforms. Electron microscopy revealed that flectin antibody localizes in short cardiomyocyte cell processes extending from the basal layer of the cardiomyocytes into the cardiac jelly. Flectin antibody also recognizes stress fibrils in the cardiac jelly in the mouse and chick heart; while NMHC-IIB antibody does not. Abnormally looping hearts of the Nodal(Delta 600) homozygous mouse embryos show decreased NMHC-IIB expression on both the mRNA and protein levels. These results document the characterization of flectin and extend the importance of NMHC-II and the cytoskeletal actomyosin complex to the mammalian heart and cardiac looping.

    Developmental dynamics : an official publication of the American Association of Anatomists 2008;237;12;3577-90

  • Myosin II regulates the shape of three-dimensional intestinal epithelial cysts.

    Ivanov AI, Hopkins AM, Brown GT, Gerner-Smidt K, Babbin BA, Parkos CA and Nusrat A

    Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, USA. Andrei_Ivanov@urmc.rochester.edu

    The development of luminal organs begins with the formation of spherical cysts composed of a single layer of epithelial cells. Using a model three-dimensional cell culture, this study examines the role of a cytoskeletal motor, myosin II, in cyst formation. Caco-2 and SK-CO15 intestinal epithelial cells were embedded into Matrigel, and myosin II was inhibited by blebbistatin or siRNA-mediated knockdown. Whereas control cells formed spherical cysts with a smooth surface, inhibition of myosin II induced the outgrowth of F-actin-rich surface protrusions. The development of these protrusions was abrogated after inhibition of F-actin polymerization or of phospholipase C (PLC) activity, as well as after overexpression of a dominant-negative ADF/cofilin. Surface protrusions were enriched in microtubules and their formation was prevented by microtubule depolymerization. Myosin II inhibition caused a loss of peripheral F-actin bundles and a submembranous extension of cortical microtubules. Our findings suggest that inhibition of myosin II eliminates the cortical F-actin barrier, allowing microtubules to reach and activate PLC at the plasma membrane. PLC-dependent stimulation of ADF/cofilin creates actin-filament barbed ends and promotes the outgrowth of F-actin-rich protrusions. We conclude that myosin II regulates the spherical shape of epithelial cysts by controlling actin polymerization at the cyst surface.

    Funded by: NIDDK NIH HHS: DK 064399, DK 55679, DK 59888, DK 61379, DK 72564

    Journal of cell science 2008;121;11;1803-14

  • Dystrophin deficiency in canine X-linked muscular dystrophy in Japan (CXMDJ) alters myosin heavy chain expression profiles in the diaphragm more markedly than in the tibialis cranialis muscle.

    Yuasa K, Nakamura A, Hijikata T and Takeda S

    Department of Anatomy and Cell Biology, Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, Nishi-tokyo, Tokyo 202-8585, Japan. k_yuasa@musashino-u.ac.jp

    Background: Skeletal muscles are composed of heterogeneous collections of muscle fiber types, the arrangement of which contributes to a variety of functional capabilities in many muscle types. Furthermore, skeletal muscles can adapt individual myofibers under various circumstances, such as disease and exercise, by changing fiber types. This study was performed to examine the influence of dystrophin deficiency on fiber type composition of skeletal muscles in canine X-linked muscular dystrophy in Japan (CXMDJ), a large animal model for Duchenne muscular dystrophy.

    Methods: We used tibialis cranialis (TC) muscles and diaphragms of normal dogs and those with CXMDJ at various ages from 1 month to 3 years old. For classification of fiber types, muscle sections were immunostained with antibodies against fast, slow, or developmental myosin heavy chain (MHC), and the number and size of these fibers were analyzed. In addition, MHC isoforms were detected by gel electrophoresis.

    Results: In comparison with TC muscles of CXMDJ, the number of fibers expressing slow MHC increased markedly and the number of fibers expressing fast MHC decreased with growth in the affected diaphragm. In populations of muscle fibers expressing fast and/or slow MHC(s) but not developmental MHC of CXMDJ muscles, slow MHC fibers were predominant in number and showed selective enlargement. Especially, in CXMDJ diaphragms, the proportions of slow MHC fibers were significantly larger in populations of myofibers with non-expression of developmental MHC. Analyses of MHC isoforms also indicated a marked increase of type I and decrease of type IIA isoforms in the affected diaphragm at ages over 6 months. In addition, expression of developmental (embryonic and/or neonatal) MHC decreased in the CXMDJ diaphragm in adults, in contrast to continuous high-level expression in affected TC muscle.

    Conclusion: The CXMDJ diaphragm showed marked changes in fiber type composition unlike TC muscles, suggesting that the affected diaphragm may be effectively adapted toward dystrophic stress by switching to predominantly slow fibers. Furthermore, the MHC expression profile in the CXMDJ diaphragm was markedly different from that in mdx mice, indicating that the dystrophic dog is a more appropriate model than a murine one, to investigate the mechanisms of respiratory failure in DMD.

    BMC musculoskeletal disorders 2008;9;1

  • Downregulation of myosin II-B by siRNA alters the subcellular localization of the amyloid precursor protein and increases amyloid-beta deposition in N2a cells.

    Massone S, Argellati F, Passalacqua M, Armirotti A, Melone L, d'Abramo C, Marinari UM, Domenicotti C, Pronzato MA and Ricciarelli R

    Department of Experimental Medicine, University of Genoa, Via L.B. Alberti 2, 16132 Genoa, Italy.

    The Alzheimer's disease (AD) brain pathology is characterized by extracellular deposits of amyloid-beta (Abeta) peptides and intraneuronal fibrillar structures. These pathological features may be functionally linked, but the mechanism by which Abeta accumulation relates to neuronal degeneration is still poorly understood. Abeta peptides are fragments cleaved from the amyloid precursor protein (APP), a transmembrane protein ubiquitously expressed in the nervous system. Although the proteolytic processing of APP has been implicated in AD, the physiological function of APP and the subcellular site of APP cleavages remain unknown. The overall structure of the protein and its fast anterograde transport along the axon support the idea that APP functions as a vesicular receptor for cytoskeletal motor proteins. In the current study, we test the hypothesis that myosin II, important contributor to the cytoskeleton of neuronal cells, may influence the trafficking and/or the processing of APP. Our results demonstrate that downregulation of myosin II-B, the major myosin isoform in neurons, is able to increase Abeta deposition, concomitantly altering the subcellular localization of APP. These new insights might be important for the understanding of the function of APP and provide a novel conceptual framework in which to analyze its pathological role.

    Biochemical and biophysical research communications 2007;362;3;633-8

  • Two regions of the tail are necessary for the isoform-specific functions of nonmuscle myosin IIB.

    Sato MK, Takahashi M and Yazawa M

    Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810 Japan.

    To function in the cell, nonmuscle myosin II molecules assemble into filaments through their C-terminal tails. Because myosin II isoforms most likely assemble into homo-filaments in vivo, it seems that some self-recognition mechanisms of individual myosin II isoforms should exist. Exogenous expression of myosin IIB rod fragment is thus expected to prevent the function of myosin IIB specifically. We expected to reveal some self-recognition sites of myosin IIB from the phenotype by expressing appropriate myosin IIB rod fragments. We expressed the C-terminal 305-residue rod fragment of the myosin IIB heavy chain (BRF305) in MRC-5 SV1 TG1 cells. As a result, unstable morphology was observed like MHC-IIB(-/-) fibroblasts. This phenotype was not observed in cells expressing BRF305 mutants: 1) with a defect in assembling, 2) lacking N-terminal 57 residues (N-57), or 3) lacking C-terminal 63 residues (C-63). A myosin IIA rod fragment ARF296 corresponding to BRF305 was not effective. However, the chimeric ARF296, in which the N-57 and C-63 of BRF305 were substituted for the corresponding regions of ARF296, acquired the ability to induce unstable morphology. We propose that the N-57 and C-63 of BRF305 are involved in self-recognition when myosin IIB molecules assemble into homo-filament.

    Molecular biology of the cell 2007;18;3;1009-17

  • Estrogen modulation of MgATPase activity of nonmuscle myosin-II-B filaments.

    Gorodeski GI

    Department of Reproductive Biology, Case Western Reserve University, Cleveland, Ohio 44106, USA. gig@cwru.edu

    The study tested the hypothesis that estrogen controls epithelial paracellular resistance through modulation of myosin. The objective was to understand how estrogen modulates nonmuscle myosin-II-B (NMM-II-B), the main component of the cortical actomyosin in human epithelial cervical cells. Experiments used human cervical epithelial cells CaSki as a model, and end points were NMM-II-B phosphorylation, filamentation, and MgATPase activity. The results were as follows: 1) treatment with estrogen increased phosphorylation and MgATPase activity and decreased NMM-II-B filamentation; 2) estrogen effects could be blocked by antisense nucleotides for the estrogen receptor-alpha and by ICI-182,780, tamoxifen, and the casein kinase-II (CK2) inhibitor, 5,6-dichloro-1-beta-(D)-ribofuranosylbenzimidazole and attenuated by AG1478 and PD98059 (inhibitors of epithelial growth factor receptor and ERK/MAPK) but not staurosporine [blocker of protein kinase C (PKC)]; 3) treatments with the PKC activator sn-1,2-dioctanoyl diglyceride induced biphasic effect on NMM-II-B MgATPase activity: an increase at 1 nm to 1 microM and a decrease in activity at more than 1 microM; 4) sn-1,2-dioctanoyl diglyceride also decreased NMM-II-B filamentation in a monophasic and saturable dose dependence (EC(50) 1-10 microM); 5) when coincubated directly with purified NMM-II-B filaments, both CK2 and PKC decreased filamentation and increased MgATPase activity; 6) assays done on disassembled NMM-II-B filaments showed MgATPase activity in filaments obtained from estrogen-treated cells but not estrogen-depleted cells; and 7) incubations in vitro with CK2, but not PKC, facilitated MgATPase activity, even in disassembled NMM-II-B filaments. The results suggest that estrogen, in an effect mediated by estrogen receptor-alpha and CK2 and involving the epithelial growth factor receptor and ERK/MAPK cascades, increases NMM-II-B MgATPase activity independent of NMM-II-B filamentation status.

    Funded by: NIA NIH HHS: AG15955, R01 AG015955, R01 AG015955-09; NICHD NIH HHS: HD29924

    Endocrinology 2007;148;1;279-92

  • Large-scale mapping of human protein-protein interactions by mass spectrometry.

    Ewing RM, Chu P, Elisma F, Li H, Taylor P, Climie S, McBroom-Cerajewski L, Robinson MD, O'Connor L, Li M, Taylor R, Dharsee M, Ho Y, Heilbut A, Moore L, Zhang S, Ornatsky O, Bukhman YV, Ethier M, Sheng Y, Vasilescu J, Abu-Farha M, Lambert JP, Duewel HS, Stewart II, Kuehl B, Hogue K, Colwill K, Gladwish K, Muskat B, Kinach R, Adams SL, Moran MF, Morin GB, Topaloglou T and Figeys D

    Protana, Toronto, Ontario, Canada.

    Mapping protein-protein interactions is an invaluable tool for understanding protein function. Here, we report the first large-scale study of protein-protein interactions in human cells using a mass spectrometry-based approach. The study maps protein interactions for 338 bait proteins that were selected based on known or suspected disease and functional associations. Large-scale immunoprecipitation of Flag-tagged versions of these proteins followed by LC-ESI-MS/MS analysis resulted in the identification of 24,540 potential protein interactions. False positives and redundant hits were filtered out using empirical criteria and a calculated interaction confidence score, producing a data set of 6463 interactions between 2235 distinct proteins. This data set was further cross-validated using previously published and predicted human protein interactions. In-depth mining of the data set shows that it represents a valuable source of novel protein-protein interactions with relevance to human diseases. In addition, via our preliminary analysis, we report many novel protein interactions and pathway associations.

    Molecular systems biology 2007;3;89

  • Rho kinase differentially regulates phosphorylation of nonmuscle myosin II isoforms A and B during cell rounding and migration.

    Sandquist JC, Swenson KI, Demali KA, Burridge K and Means AR

    Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.

    The actin-myosin cytoskeleton is generally accepted to produce the contractile forces necessary for cellular processes such as cell rounding and migration. All vertebrates examined to date are known to express at least two isoforms of non-muscle myosin II, referred to as myosin IIA and myosin IIB. Studies of myosin IIA and IIB in cultured cells and null mice suggest that these isoforms perform distinct functions. However, how each myosin II isoform contributes individually to all the cellular functions attributed to "myosin II" has yet to be fully characterized. Using isoform-specific small-interfering RNAs, we found that depletion of either isoform resulted in opposing migration phenotypes, with myosin IIA- and IIB-depleted cells exhibiting higher and lower wound healing migration rates, respectively. In addition, myosin IIA-depleted cells demonstrated impaired thrombin-induced cell rounding and undertook a more motile morphology, exhibiting decreased amounts of stress fibers and focal adhesions, with concomitant increases in cellular protrusions. Cells depleted of myosin IIB, however, were efficient in thrombin-induced cell rounding, displayed a more retractile phenotype, and maintained focal adhesions but only in the periphery. Last, we present evidence that Rho kinase preferentially regulates phosphorylation of the regulatory light chain associated with myosin IIA. Our data suggest that the myosin IIA and IIB isoforms are regulated by different signaling pathways to perform distinct cellular activities and that myosin IIA is preferentially required for Rho-mediated contractile functions.

    Funded by: NCI NIH HHS: CA 082845; NIGMS NIH HHS: GM 29860

    The Journal of biological chemistry 2006;281;47;35873-83

  • Global, in vivo, and site-specific phosphorylation dynamics in signaling networks.

    Olsen JV, Blagoev B, Gnad F, Macek B, Kumar C, Mortensen P and Mann M

    Center for Experimental BioInformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark.

    Cell signaling mechanisms often transmit information via posttranslational protein modifications, most importantly reversible protein phosphorylation. Here we develop and apply a general mass spectrometric technology for identification and quantitation of phosphorylation sites as a function of stimulus, time, and subcellular location. We have detected 6,600 phosphorylation sites on 2,244 proteins and have determined their temporal dynamics after stimulating HeLa cells with epidermal growth factor (EGF) and recorded them in the Phosida database. Fourteen percent of phosphorylation sites are modulated at least 2-fold by EGF, and these were classified by their temporal profiles. Surprisingly, a majority of proteins contain multiple phosphorylation sites showing different kinetics, suggesting that they serve as platforms for integrating signals. In addition to protein kinase cascades, the targets of reversible phosphorylation include ubiquitin ligases, guanine nucleotide exchange factors, and at least 46 different transcriptional regulators. The dynamic phosphoproteome provides a missing link in a global, integrative view of cellular regulation.

    Cell 2006;127;3;635-48

  • PAK1 and aPKCzeta regulate myosin II-B phosphorylation: a novel signaling pathway regulating filament assembly.

    Even-Faitelson L and Ravid S

    Department of Biochemistry, Institute of Medical Sciences, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.

    Many signaling pathways regulate the function of the cellular cytoskeleton. Yet we know very little about the proteins involved in the cross-talk between the signaling and the cytoskeletal systems. Here we show that myosin II-B, an important cytoskeletal protein, resides in a complex with p21-activated kinase 1 (PAK1) and atypical protein kinase C (PKC) zeta (aPKCzeta) and that the interaction between these proteins is EGF-dependent. We further show that PAK1 is involved in aPKCzeta phosphorylation and that aPKCzeta phosphorylates myosin II-B directly on a specific serine residue in an EGF-dependent manner. This latter phosphorylation is specific to isoform B of myosin II, and it leads to slower filament assembly of myosin II-B. Furthermore, a decrease in aPKCzeta expression in the cells alters myosin II-B cellular organization. Our finding of a new signaling pathway involving PAK1, aPKCzeta, and myosin II-B, which is implicated in myosin II-B filament assembly and cellular organization, provides an important link between the signaling system and cytoskeletal dynamics.

    Molecular biology of the cell 2006;17;7;2869-81

  • Non-muscle myosin heavy chain IIA and IIB interact and co-localize in living cells: relevance for MYH9-related disease.

    Marini M, Bruschi M, Pecci A, Romagnoli R, Musante L, Candiano G, Ghiggeri GM, Balduini C, Seri M and Ravazzolo R

    Laboratory of Molecular Genetics, G. Gaslini Institute, 16147 Genova, Italy.

    Myosins of class II constitute part of a superfamily of several classes of proteins expressed in almost all eukaryotic cell types. Differences in the heavy chains produce three isoforms of class II non-muscle myosins (A, B and C), which are widely distributed in most tissues and thought to be components of the cell motor systems, although specific functional roles are largely unknown. In particular, it is still a matter of debate whether they interact and have overlapping or distinct functions. This argument is relevant not only to cell physiology, but also to human pathology since mutations of the MYH9 gene encoding non-muscle myosin heavy chain II A (NMMHC-A) cause MYH9-related disease (MYH9-RD), an autosomal dominant disorder characterized by platelet macrocytosis, thrombocytopenia and leukocyte inclusions, variably associated with sensorineural hearing loss, cataracts and/or glomerulonephritis. In this study, we report the results of yeast two-hybrid screening showing that the C-terminals of NMMHC-A and -B interact. This interaction was confirmed by immunoprecipitation in transfected COS-7 cells and in skin fibroblasts naturally expressing both isoforms. Moreover, our immunomorphological study revealed that isoforms A and B co-localize in fibroblasts, erythroblasts and kidney cells. These results suggest that isoforms A and B are strictly related molecules and support the hypothesis that their interrelationship could be involved both in the variability of clinical phenotype and selectivity of tissue damage of MYH9-RD.

    International journal of molecular medicine 2006;17;5;729-36

  • Protein kinase Cgamma regulates myosin IIB phosphorylation, cellular localization, and filament assembly.

    Rosenberg M and Ravid S

    Department of Biochemistry, Institute of Medical Sciences, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.

    Nonmuscle myosin II is an important component of the cytoskeleton, playing a major role in cell motility and chemotaxis. We have previously demonstrated that, on stimulation with epidermal growth factor (EGF), nonmuscle myosin heavy chain II-B (NMHC-IIB) undergoes a transient phosphorylation correlating with its cellular localization. We also showed that members of the PKC family are involved in this phosphorylation. Here we demonstrate that of the two conventional PKC isoforms expressed by prostate cancer cells, PKCbetaII and PKCgamma, PKCgamma directly phosphorylates NMHC-IIB. Overexpression of wild-type and kinase dead dominant negative PKCgamma result in both altered NMHC-IIB phosphorylation and subcellular localization. We have also mapped the phosphorylation sites of PKCgamma on NMHC-IIB. Conversion of the PKCgamma phosphorylation sites to alanine residues, reduces the EGF-dependent NMHC-IIB phosphorylation. Aspartate substitution of these sites reduces NMHC-IIB localization into cytoskeleton. These results indicate that PKCgamma regulates NMHC-IIB phosphorylation and cellular localization in response to EGF stimulation.

    Molecular biology of the cell 2006;17;3;1364-74

  • Disease-associated mutations and alternative splicing alter the enzymatic and motile activity of nonmuscle myosins II-B and II-C.

    Kim KY, Kovács M, Kawamoto S, Sellers JR and Adelstein RS

    Laboratory of Molecular Cardiology and Laboratory of Molecular Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA.

    Human families with single amino acid mutations in nonmuscle myosin heavy chain (NMHC) II-A (MYH9) and II-C (MYH14) have been described as have mice generated with a point mutation in NMHC II-B (MYH10). These mutations (R702C and N93K in human NMHC II-A, R709C in murine NMHC II-B, and R726S in human NMHC II-C) result in phenotypes affecting kidneys, platelets, and leukocytes (II-A), heart and brain (II-B), and the inner ear (II-C). To better understand the mechanisms underlying these defects, we characterized the in vitro activity of mutated and wild-type baculovirus-expressed heavy meromyosin (HMM) II-B and II-C. We also expressed two alternatively spliced isoforms of NMHC II-C which differ by inclusion/exclusion of eight amino acids in loop 1, with and without mutations. Comparison of the actin-activated MgATPase activity and in vitro motility shows that mutation of residues Asn-97 and Arg-709 in HMM II-B and the homologous residue Arg-722 (Arg-730 in the alternatively spliced isoform) in HMM II-C decreases both parameters but affects in vitro motility more severely. Analysis of the transient kinetics of the HMM II-B R709C mutant shows an extremely tight affinity of HMM for ADP and a very slow release of ADP from acto-HMM. Although mutations generally decreased HMM activity, the R730S mutation in HMM II-C, unlike the R730C mutation, had no effect on actin-activated MgATPase activity but decreased the rate of in vitro motility by 75% compared with wild type. Insertion of eight amino acids into the HMM II-C heavy chain increases both actin-activated MgATPase activity and in vitro motility.

    The Journal of biological chemistry 2005;280;24;22769-75

  • Vertebrate nonmuscle myosin II isoforms rescue small interfering RNA-induced defects in COS-7 cell cytokinesis.

    Bao J, Jana SS and Adelstein RS

    Laboratory of Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA.

    RNA interference (RNAi) treatment of monkey COS-7 cells, a cell line that lacks nonmuscle myosin heavy chain II-A (NMHC II-A) but contains NMHC II-B and II-C, was used to investigate the participation of NMHC isoforms in cytokinesis. We specifically suppressed the expression of NMHC II-B or II-C using 21 nucleotide small interfering RNA (siRNA) duplexes. Down-regulation of NMHC II-B protein expression to 10.2 +/- 0.7% inhibited COS-7 cell proliferation by 50% in the RNAi-treated cells compared with control cells. Moreover, whereas 8.7 +/- 1.0% of control cells were multinucleated, 62.4 +/- 8.8% of the NMHC II-B RNAi-treated cells were multinucleated 72 h after transfection. The RNAi-treated cells had increased surface areas and, unlike control cells, lacked actin stress fibers. Treatment of the COS-7 cells with NMHC II-C siRNA decreased NMHC II-C expression to 5.2 +/- 0.1% compared with the endogenous content of II-C; however, down-regulation of NMHC II-C did not cause increased multinucleation. Immunoblot analysis using a pan-myosin antibody showed that the content of NMHC II-C was less than one-twentieth the amount of NMHC II-B, thereby explaining the lack of response to II-C siRNA. Introducing green fluorescent protein (GFP)-tagged NMHC II isoforms into II-B siRNA-treated cells resulted in reduction of multinucleation from 62.4 +/- 8.8% to 17.8 +/- 2.2% using GFP-NMHC II-B, to 29.8 +/- 7.4% using GFP-NMHC II-A, and to 34.1 +/- 8.6% using NMHC II-C-GFP. These studies have shown that expression of endogenous NMHC II-C in COS-7 cells is insufficient for normal cytokinesis and that exogenous NMHC II-A and NMHC II-C can, at least partially, rescue the defect in cytokinesis due to the loss of NMHC II-B.

    The Journal of biological chemistry 2005;280;20;19594-9

  • Critical regions for assembly of vertebrate nonmuscle myosin II.

    Nakasawa T, Takahashi M, Matsuzawa F, Aikawa S, Togashi Y, Saitoh T, Yamagishi A and Yazawa M

    Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.

    Myosin II molecules assemble and form filaments through their C-terminal rod region, and the dynamic filament assembly-disassembly process of nonmuscle myosin II molecules is important for cellular activities. To estimate the critical region for filament formation of vertebrate nonmuscle myosin II, we assessed the solubility of a series of truncated recombinant rod fragments of nonmuscle myosin IIB at various concentrations of NaCl. A C-terminal 248-residue rod fragment (Asp 1729-Glu 1976) was shown by its solubility behavior to retain native assembly features, and two regions within it were found to be necessary for assembly: 35 amino acid residues from Asp 1729 to Thr 1763 and 39 amino acid residues from Ala 1875 to Ala 1913, the latter containing a sequence similar to the assembly competence domain (ACD) of skeletal muscle myosin. Fragments lacking either of the two regions were soluble at any NaCl concentration. We referred to these two regions as nonmuscle myosin ACD1 (nACD1) and nACD2, respectively. In addition, we constructed an alpha-helical coiled-coil model of the rod fragment, and found that a remarkable negative charge cluster (termed N1) and a positive charge cluster (termed P2) were present within nACD1 and nACD2, respectively, besides another positive charge cluster (termed P1) in the amino-terminal vicinity of nACD2. From these results, we propose two major electrostatic interactions that are essential for filament formation of nonmuscle myosin II: the antiparallel interaction between P2 and N1 which is essential for the nucleation step and the parallel interaction between P1 and N1 which is important for the elongation step.

    Biochemistry 2005;44;1;174-83

  • Anillin binds nonmuscle myosin II and regulates the contractile ring.

    Straight AF, Field CM and Mitchison TJ

    Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA. astraight@stanford.edu

    We demonstrate that the contractile ring protein anillin interacts directly with nonmuscle myosin II and that this interaction is regulated by myosin light chain phosphorylation. We show that despite their interaction, anillin and myosin II are independently targeted to the contractile ring. Depletion of anillin in Drosophila or human cultured cells results in cytokinesis failure. Human cells depleted for anillin fail to properly regulate contraction by myosin II late in cytokinesis and fail in abscission. We propose a role for anillin in spatially regulating the contractile activity of myosin II during cytokinesis.

    Funded by: NIGMS NIH HHS: GM-023928, R01 GM023928

    Molecular biology of the cell 2005;16;1;193-201

  • Myosin regulation in the migration of tumor cells and leukocytes within a three-dimensional collagen matrix.

    Bastian P, Lang K, Niggemann B, Zaenker KS and Entschladen F

    Institute of Immunology, Witten/Herdecke University, Stockumer Strasse 10, 58448 Witten, Germany.

    The migration of cells is a complex regulatory process which results in the generation of motor forces through the reorganization of the cytoskeleton. Here we present a comparative study of the expression and involvement of myosin in the regulation of the physiological migration of leukocytes and the pathological migration of tumor cells. We show that the involvement of myosin in the migration is distinct in these two cell types. In leukocytes, the activity of non-muscle myosin II is essential for both the spontaneous (matrix-induced) migration and the migration induced by ligands to G protein-coupled receptors, i.e. chemokines and neurotransmitters. In contrast, spontaneous tumor cell migration is largely independent of non-muscle myosin II activity, whereas the norepinephrine-induced migration is completely inhibited by either direct inhibition of non-muscle myosin II or of the kinases phosphorylating the myosin light chain, namely ROCK or the calcium/calmodulin-dependent myosin light-chain kinase.

    Cellular and molecular life sciences : CMLS 2005;62;1;65-76

  • Transforming growth factor-beta1 regulates cell growth and causes downregulation of SMemb/non-muscle myosin heavy chain B mRNA in human prostate stromal cells.

    Obara K, Bilim V, Suzuki K, Kobayashi K, Hara N, Kasahara T, Nishiyama T and Takahashi K

    Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. obarak@med.niigata-u.ac.jp

    Objectives: SMemb/non-muscle myosin heavy chain B (SMemb/NMMHC-B) is most abundantly expressed in proliferating smooth muscle cells and correlates with phenotypic changes from a contractive to a proliferative type. The stromal cells of the prostate play a crucial role in the regulation of prostatic growth and function. The aim of this study was to investigate the effects of the multifunctional cytokine transforming growth factor-beta1 (TGF-beta1) on SMemb/NMMHC-B mRNA expression and stromal cell growth. The expression of the SM2 isoform of smooth muscle myosin heavy chain (SMMHC) mRNA was also examined.

    Primary cultures of prostate stromal cells were established by means of an explant method from eight normal prostates. The effects of TGF-beta1 on stromal cell growth were determined by means of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide conversion assay. SMemb/NMMHC-B and SM2 mRNA expression were analyzed quantitatively by means of real-time polymerase chain reaction.

    Results: In the absence of TGF-beta1, cells expressed alpha-smooth muscle actin and vimentin. After TGF-beta1 treatment, the expression of alpha-smooth muscle actin increased and cells also expressed desmin. TGF-beta1 at concentrations of 1.0, 5.0 and 10 ng/ml suppressed cell growth by 72%, 62% and 56%, respectively, downregulated SMemb/NMMHC-B mRNA expression by 71%, 52% and 38%, respectively and upregulated SM2 mRNA expression 2.1-, 3.0- and 5.3-fold, respectively.

    Conclusions: These results demonstrate that TGF-beta1 modulates the smooth muscle cell phenotype from a proliferative to a contractile type and that the inhibitory effects of TGF-beta1 on stromal cell growth correlate with downregulation of the SMemb/NMMHC-B gene.

    Scandinavian journal of urology and nephrology 2005;39;5;366-71

  • MARK4 is a novel microtubule-associated proteins/microtubule affinity-regulating kinase that binds to the cellular microtubule network and to centrosomes.

    Trinczek B, Brajenovic M, Ebneth A and Drewes G

    Department of Medicinal Chemistry, University of Kansas, Malott Hall, Lawrence, Kansas 66045, USA.

    The MARK protein kinases were originally identified by their ability to phosphorylate a serine motif in the microtubule-binding domain of tau that is critical for microtubule binding. Here, we report the cloning and expression of a novel human paralog, MARK4, which shares 75% overall homology with MARK1-3 and is predominantly expressed in brain. Homology is most pronounced in the catalytic domain (90%), and MARK4 readily phosphorylates tau and the related microtubule-associated protein 2 (MAP2) and MAP4. In contrast to the three paralogs that all exhibit uniform cytoplasmic localization, MARK4 colocalizes with the centrosome and with microtubules in cultured cells. Overexpression of MARK4 causes thinning out of the microtubule network, concomitant with a reorganization of microtubules into bundles. In line with these findings, we show that a tandem affinity-purified MARK4 protein complex contains alpha-, beta-, and gamma-tubulin. In differentiated neuroblastoma cells, MARK4 is localized prominently at the tips of neurite-like processes. We suggest that although the four MARK/PAR-1 kinases might play multiple cellular roles in concert with different targets, MARK4 is likely to be directly involved in microtubule organization in neuronal cells and may contribute to the pathological phosphorylation of tau in Alzheimer's disease.

    The Journal of biological chemistry 2004;279;7;5915-23

  • Kinetic mechanism of non-muscle myosin IIB: functional adaptations for tension generation and maintenance.

    Wang F, Kovacs M, Hu A, Limouze J, Harvey EV and Sellers JR

    Laboratory of Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1762, USA.

    Besides driving contraction of various types of muscle tissue, conventional (class II) myosins serve essential cellular functions and are ubiquitously expressed in eukaryotic cells. Three different isoforms in the human myosin complement have been identified as non-muscle class II myosins. Here we report the kinetic characterization of a human non-muscle myosin IIB subfragment-1 construct produced in the baculovirus expression system. Transient kinetic data show that most steps of the actomyosin ATPase cycle are slowed down compared with other class II myosins. The ADP affinity of subfragment-1 is unusually high even in the presence of actin filaments, and the rate of ADP release is close to the steady-state ATPase rate. Thus, non-muscle myosin IIB subfragment-1 spends a significantly higher proportion of its kinetic cycle strongly attached to actin than do the muscle myosins. This feature is even more pronounced at slightly elevated ADP levels, and it may be important in carrying out the cellular functions of this isoform working in small filamentous assemblies.

    The Journal of biological chemistry 2003;278;30;27439-48

  • Nonmuscle myosin promotes cytoplasmic localization of PBX.

    Huang H, Paliouras M, Rambaldi I, Lasko P and Featherstone M

    McGill Cancer Centre, Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada H3G 1Y6.

    In the absence of MEIS family proteins, two mechanisms are known to restrict the PBX family of homeodomain (HD) transcription factors to the cytoplasm. First, PBX is actively exported from the nucleus via a CRM1-dependent pathway. Second, nuclear localization signals (NLSs) within the PBX HD are masked by intramolecular contacts. In a screen to identify additional proteins directing PBX subcellular localization, we identified a fragment of murine nonmuscle myosin II heavy chain B (NMHCB). The interaction of NMHCB with PBX was verified by coimmunoprecipitation, and immunofluorescence staining revealed colocalization of NMHCB with cytoplasmic PBX in the mouse embryo distal limb bud. The interaction domain in PBX mapped to a conserved PBC-B region harboring a potential coiled-coil structure. In support of the cytoplasmic retention function, the NMHCB fragment competes with MEIS1A to redirect PBX, and the fly PBX homologue EXD, to the cytoplasm of mammalian and insect cells. Interestingly, MEIS1A also localizes to the cytoplasm in the presence of the NMHCB fragment. These activities are largely independent of nuclear export. We show further that the subcellular localization of EXD is deregulated in Drosophila zipper mutants that are depleted of nonmuscle myosin heavy chain. This study reveals a novel and evolutionarily conserved mechanism controlling the subcellular distribution of PBX and EXD proteins.

    Molecular and cellular biology 2003;23;10;3636-45

  • Conditional expression of a truncated fragment of nonmuscle myosin II-A alters cell shape but not cytokinesis in HeLa cells.

    Wei Q and Adelstein RS

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

    A truncated fragment of the nonmuscle myosin II-A heavy chain (NMHC II-A) lacking amino acids 1-591, delta N592, was used to examine the cellular functions of this protein. Green fluorescent protein (GFP) was fused to the amino terminus of full-length human NMHC II-A, NMHC II-B, and delta N592 and the fusion proteins were stably expressed in HeLa cells by using a conditional expression system requiring absence of doxycycline. The HeLa cell line studied normally expressed only NMHC II-A and not NMHC II-B protein. Confocal microscopy indicated that the GFP fusion proteins of full-length NMHC II-A, II-B, and delta N592 were localized to stress fibers. However, in vitro assays showed that baculovirus-expressed delta N592 did not bind to actin, suggesting that delta N592 was localized to actin stress fibers through incorporation into endogenous myosin filaments. There was no evidence for the formation of heterodimers between the full-length endogenous nonmuscle myosin and truncated nonmuscle MHCs. Expression of delta N592, but not full-length NMHC II-A or NMHC II-B, induced cell rounding with rearrangement of actin filaments and disappearance of focal adhesions. These cells returned to their normal morphology when expression of delta N592 was repressed by addition of doxycycline. We also show that GFP-tagged full-length NMHC II-A or II-B, but not delta N592, were localized to the cytokinetic ring during mitosis, indicating that, in vertebrates, the amino-terminus part of mammalian nonmuscle myosin II may be necessary for localization to the cytokinetic ring.

    Molecular biology of the cell 2000;11;10;3617-27

  • Caspase-resistant BAP31 inhibits fas-mediated apoptotic membrane fragmentation and release of cytochrome c from mitochondria.

    Nguyen M, Breckenridge DG, Ducret A and Shore GC

    Department of Biochemistry, McGill University, Montreal, Quebec, Canada.

    BAP31 is a 28-kDa integral membrane protein of the endoplasmic reticulum whose cytosolic domain contains two identical caspase recognition sites (AAVD.G) that are preferentially cleaved by initiator caspases, including caspase 8. Cleavage of BAP31 during apoptosis generates a p20 fragment that remains integrated in the membrane and, when expressed ectopically, is a potent inducer of cell death. To examine the consequences of maintaining the structural integrity of BAP31 during apoptosis, the caspase recognition aspartate residues were mutated to alanine residues, and Fas-mediated activation of caspase 8 and cell death were examined in human KB epithelial cells stably expressing the caspase-resistant mutant crBAP31. crBAP31 only modestly slowed the time course for activation of caspases, as assayed by the processing of procaspases 8 and 3 and the measurement of total DEVDase activity. As a result, cleavage of the caspase targets poly(ADP-ribosyl) polymerase and endogenous BAP31, as well as the redistribution of phosphatidylserine and fragmentation of DNA, was observed. In contrast, cytoplasmic membrane blebbing and fragmentation and apoptotic redistribution of actin were strongly inhibited, cell morphology was retained near normal, and the irreversible loss of cell growth potential following removal of the Fas stimulus was delayed. Of note, crBAP31-expressing cells also resisted Fas-mediated release of cytochrome c from mitochondria, and the mitochondrial electrochemical potential was only partly reduced. These results argue that BAP31 cleavage is important for manifesting cytoplasmic apoptotic events associated with membrane fragmentation and reveal an unexpected cross talk between mitochondria and the endoplasmic reticulum during Fas-mediated apoptosis in vivo.

    Molecular and cellular biology 2000;20;18;6731-40

  • Myosin heavy chain gene expression in normal and hyperplastic human prostate tissue.

    Lin VK, Wang D, Lee IL, Vasquez D, Fagelson JE and McConnell JD

    Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9110, USA. victor.lin@email.swmed.edu

    Background: Benign prostatic hyperplasia (BPH) is common among aging men. Over 80% of males 50-60 years and older have various degrees of bladder outlet obstruction secondary to BPH. Despite the tremendous medical impact of BPH, its molecular pathophysiology remains unclear. Current BPH research focuses on steroid hormonal effects, stromal-epithelial cell interaction, and oncogenes and growth factors. But little is known about the potential prostatic smooth muscle (SM) alterations that may occur during stromal hyperplasia.

    Methods: To study SM phenotypic modulation in hyperplastic prostatic growth, we isolated and characterized the 3' end of human SM myosin heavy chain (SMMHC) cDNA as a molecular probe. Expression of SMMHC and nonmuscle myosin heavy chain (NMMHC) in human prostates was analyzed using Western blot, Northern blot, and in situ hybridization to determine if BPH tissue expresses significantly less SMMHC and more NMMHC than a normal prostate. In addition, a competitive, reverse transcription (RT) polymerase chain reaction (PCR) method was adapted to quantify SMMHC and NMMHC mRNA expression at the sensitivity level of 10(-21) mole per mg of wet tissue.

    Results: Western blot, Northern blot, and in situ hybridization results reveal that both SMMHC and NMMHC are expressed in the human prostate, while SMMHC is the predominant form found in normal prostate stroma. Results from competitive RT-PCR analysis indicate that NMMHC mRNA expression is approximately 10(-20) mole/mg of tissue. The SMMHC mRNA expressed is approximately 10(-18) mole/mg. No significant difference was found when NMMHC mRNA expression was compared between normal and BPH periurethral tissues. However, SMMHC expression was reduced almost fivefold in BPH compared to normal prostate, despite an increase in prostatic stromal mass.

    Conclusions: Our results suggest the pathogenesis of BPH is associated with a unique type of SM proliferation. Such proliferation is characterized by downregulation of SMMHC mRNA expression but without upregulation of NMMHC mRNA expression, the pattern seen in proliferating SM cells in culture and in other pathologic forms of SM hyperplasia (e.g., atherosclerosis). These findings support a model of BPH typified by active smooth muscle proliferation early in the disease process, and supports clinical observations that suggest ongoing prostate growth of the prostate is minimal in older men. Therapeutic strategies to prevent disease progression should therefore focus on early phases of prostatic growth.

    Funded by: NIDDK NIH HHS: DK47657

    The Prostate 2000;44;3;193-203

  • Effect of Mts1 on the structure and activity of nonmuscle myosin II.

    Ford HL, Silver DL, Kachar B, Sellers JR and Zain SB

    Department of Biochemistry and Cancer Center, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642, USA.

    The mts1 gene codes for a 9 kDa protein belonging to the S100 subfamily of Ca2+-binding proteins and is known to play a role in metastasis. Its role in metastasis may be through cellular locomotion, as transfection of mts1 into mouse mammary adenocarcinoma cells increases cellular motility in modified Boyden chemotaxis chambers. The Mts1 protein interacts with nonmuscle myosin II in the presence of Ca2+ with an affinity of approximately 7.9 x 10(4) M-1 and an approximate stoichiometry of 3 mol of Mts1/mol of myosin heavy chain. No interaction was found with myosin I or myosin V. The binding site of Mts1 on myosin is in the rod region, particularly to the light meromyosin portion of the rod. To understand the mechanism by which Mts1 alters cellular motility, we examined its effect on myosin structure and activity. Cosedimentation analysis and electron microscopy suggest that Mts1 destabilizes myosin filaments. In the presence of Ca2+, Mts1 inhibits the actin-activated MgATPase activity of myosin in vitro. The data demonstrate an effect of Mts1 on both myosin structure and function, and suggest a route through which Mts1 affects motility as well as metastasis.

    Funded by: NCI NIH HHS: P30CA11198, R01CA62376

    Biochemistry 1997;36;51;16321-7

  • Neuron-specific alternative splicing of nonmuscle myosin II heavy chain-B pre-mRNA requires a cis-acting intron sequence.

    Kawamoto S

    Laboratory of Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1762, USA.

    In addition to the ubiquitously expressed form of nonmuscle myosin II heavy chain-B (MHC-B), the existence of a neuron-specific MHC-B isoform, which contains a 30-nucleotide inserted sequence near the ATP binding region, has been reported (Takahashi, M., Kawamoto, S., and Adelstein, R. S.(1992) J. Biol. Chem. 267, 17864-17871). In this study, the genomic location of the neuron-specific inserted 30-nucleotide sequence found in the cDNA is determined to be a single cassette type exon, N30, in the human nonmuscle MHC-B gene. Inclusion or exclusion of exon N30 is cell type-specific, with inclusion being restricted to neuronal cells and being regulated during cell differentiation. Expression of a minigene construct that contains the alternative exon N30 along with the flanking introns and exons was studied in human neuronal retinoblastoma Y79 cells. Inclusion of the N30 exon in the mRNA from the transfected minigene occurs in differentiated Y79 cells that have been treated with butyrate but not in the undifferentiated Y79 cells and non-neuronal cell lines. Systematic deletion and mutation analysis of the minigene construct established that neuron-specific N30 exon recognition requires a cis-acting RNA sequence located approximately 1.5 kilobases downstream of the N30 exon.

    The Journal of biological chemistry 1996;271;30;17613-6

  • Characterization of the nonmuscle myosin heavy chain IIB promoter: regulation by E2F.

    Weir L and Chen D

    Department of Medicine (Cardiology), St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA 02135, USA.

    To identify DNA sequences important for the transcriptional regulation of the nonmuscle myosin heavy chain IIB (NMMHC-IIB) gene we isolated and sequenced genomic clones that contain the promoter of the gene for both human and mouse. In addition to considerable homology in the first (untranslated) exon (91%) we found 80% sequence identity in the 700 base pairs immediately upstream of the major start of transcription (+1) as well as significant homologies as far as 1500 base pairs upstream. The promoter region was characterized using luciferase reporter constructs transiently transfected into NIH3T3 cells. Consensus binding sites for several known transcription factors are present that are completely conserved between the mouse and human genes, including CRE/ATF, Sp1, CAAT, and the cell-cycle transcription factor E2F. Gel shift assays indicated that E2F can bind to its putative binding site in vitro. To test whether this site is functional we cotransfected NMMHC-IIB promoter constructs driving luciferase with a vector expressing E2F-1. The E2F-1 vector stimulated luciferase activity from an intact promoter whereas mutation of the site eliminates binding and diminishes transactivation. These data provide strong evidence that E2F or an E2F-related transcription factor is involved in the regulation of nonmuscle myosin expression.

    Funded by: NIAMS NIH HHS: AR40580

    Gene expression 1996;6;1;45-57

  • Cloning of the cDNA encoding human nonmuscle myosin heavy chain-B and analysis of human tissues with isoform-specific antibodies.

    Phillips CL, Yamakawa K and Adelstein RS

    Laboratory of Molecular Cardiology National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.

    Previously, we reported the sequence of cDNA clones encoding amino acids 63 through 723 of the human nonmuscle myosin heavy chain-B isoform. In this paper, we present the derived sequence of the remaining 1303 amino acids along with 5' and 3' untranslated sequences. We made use of the differences between the derived nonmuscle myosin heavy chain-A and -B amino acid sequences to raise isoform-specific antibodies. Immunoblot analysis reveals a differential expression of both myosin heavy chain isoforms in a variety of human adult and foetal tissues and cells. When extracts of human adult aorta were subjected to gel electrophoresis, two distinct Coomassie Blue-stained bands and a fused band were seen migrating at approximately 200 kDa. These bands can be detected with four different specific antibodies recognizing the two different smooth muscle myosin heavy chain isoforms (204 kDa and 200 kDa) and the two different nonmuscle myosin heavy chain isoforms (A and B). Using immunohistochemistry, we confirmed the presence of the four different isoforms in adult and foetal aortas.

    Journal of muscle research and cell motility 1995;16;4;379-89

  • A human homologue of the Drosophila tumour suppressor gene l(2)gl maps to 17p11.2-12 and codes for a cytoskeletal protein that associates with nonmuscle myosin II heavy chain.

    Strand D, Unger S, Corvi R, Hartenstein K, Schenkel H, Kalmes A, Merdes G, Neumann B, Krieg-Schneider F, Coy JF et al.

    Department of Developmental Genetics, Deutsches Krebsforschungszentrum, Heidelberg, Germany.

    Inactivation of the tumour suppressor gene lethal(2) giant larvae (D-lgl) of Drosophila leads to malignant transformation of the presumptive adult optic centers in the larval brain and tumours of the imaginal discs. These malignancies result from the disorganization of a cytoskeletal network in which the D-LGL protein participates. Here we describe the isolation of a cDNA encoding the human homologue to the D-lgl gene designated as hugl. The hugl cDNA detects a locus spanning at least 25 kilobases (kb) in human chromosome band 17p11.2-12, which is centromeric to the p53 gene and recognizes a 4.5 kb RNA transcript. The hugl gene is expressed in brain, kidney and muscle but is barely seen in heart and placenta. Sequence analysis of the hugl cDNA demonstrates a long open reading frame, which has the potential to encode a protein of 1057 amino acids with a predicted molecular weight of 115 kDaltons (kD). To further substantiate and identify the HUGL protein, we have prepared polyclonal rabbit antibodies against synthetic peptides corresponding to the amino and carboxyl termini of the conceptual translation product of the hugl gene. The affinity-purified anti-HUGL antibodies recognize a single protein with an apparent molecular weight of approximately 115 kD. Similar to the Drosophila protein, HUGL is part of a cytoskeletal network and, is associated with nonmuscle myosin II heavy chain and a kinase that specifically phosphorylates HUGL at serine residues.

    Oncogene 1995;11;2;291-301

  • Neuronal cell expression of inserted isoforms of vertebrate nonmuscle myosin heavy chain II-B.

    Itoh K and Adelstein RS

    Laboratory of Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1762, USA.

    Previous work has demonstrated that unique isoforms of nonmuscle myosin heavy chain II-B (MHC-B) are expressed in chicken and human neuronal cells (Takahashi, M., Kawamoto, S., and Adelstein, R. S. (1992) J. Biol. Chem. 267, 17864-17871). These isoforms, which appear to be generated by alternative splicing of pre-mRNA, differ from the MHC-B isoform present in a large number of nonmuscle cells in that they contain inserted cassettes of amino acids near the ATP binding region and/or near the actin binding region. The insert near the ATP binding region begins after amino acid 211 and consists of either 10 or 16 amino acids. The insert near the actin binding region begins after amino acid 621 and consists of 21 amino acids. Using a variety of techniques, we have studied the distribution and expression of the inserted MHC-B isoforms. In the developing chicken brain, mRNA encoding the 10-amino acid insert gradually increases after embryonic day 4, peaks in the 10-14-day embryo, and then declines. In contrast, the mRNA encoding the 21-amino acid insert appears just before birth and is abundantly expressed in the adult chicken cerebellum. There is a marked species difference between the distribution of the inserted isoforms in adult tissues. The mRNA encoding MHC-B containing the 10-amino acid insert near the ATP binding region is expressed at low levels in the adult chicken brain, but makes up most of the MHC-B mRNA expressed in the human cerebrum and approximately 90% of MHC-B in the human retina. It is also expressed in neuronal cell lines. The mRNA encoding MHC-B containing the 21-amino acid insert is abundantly expressed in the chicken cerebellum and human cerebrum, but is absent from the retina and cell lines. Employing human retinoblastoma (Y-79) and neuroblastoma (SK-N-SH) cell lines, an increase in expression of mRNA encoding the 10-amino acid inserted isoform was seen following treatment by a number of agonists or by serum deprivation. In each case, expression of the inserted MHC-B isoform correlated with cell differentiation (neuronal phenotype) and inhibition of cell division. Using a rat pheochromocytoma cell line (PC12), we found that prior to treatment with nerve growth factor (NGF), there was no evidence for either inserted isoform, although noninserted MHC-B was present. NGF treatment resulted in the appearance of mRNA encoding MHC-B containing the 10-amino acid insert, concomitant with neurite outgrowth.(ABSTRACT TRUNCATED AT 250 WORDS)

    The Journal of biological chemistry 1995;270;24;14533-40

  • Differential localization of myosin-II isozymes in human cultured cells and blood cells.

    Maupin P, Phillips CL, Adelstein RS and Pollard TD

    Department of Cell Biology and Anatomy, Johns Hopkins Medical School, Baltimore, MD 21205-2196.

    We used purified polyclonal antibodies to human cytoplasmic myosin-IIA and myosin-IIB directly labeled with fluorescent dyes to localize these myosin-II isozymes in HeLa cells, melanoma cells and blood cells. Both antibodies react strongly with myosin-II isozymes in HeLa cells, melanoma cells and blood eosinophils, but only anti-myosin-IIA antibodies stain platelets, lymphocytes, neutrophils and monocytes in smears of human blood. Both antibodies stain small spots along the stress fibers of interphase HeLa cells and melanoma cells, but double staining revealed that the detailed distributions of myosin-IIA and myosin-IIB differ. A low concentration of diffuse myosin-IIB is present in the cortex, both in lamellar regions around the periphery of the cell and over the free surface. Myosin-IIB is also concentrated in spots along perinuclear stress fibers. Myosin-IIA is absent from the cortex but is concentrated in spots along stress fibers located near the basal surface of cultured cells. This population of peripheral stress fibers is highly enriched in myosin-IIA relative to myosin-IIB, but both are found together in centrally located stress fibers. In prophase and metaphase both isozymes are concentrated in the cortex in small spots less than 04.micron in size, similar to those in stress fibers. As the chromosomes begin the separate at anaphase, most of the myosin-II spots become concentrated in the outer 0.7 micron of the equatorial cortex in 100% of cells. This concentration of myosin-II isozymes in the cleavage furrow is maintained until the daughter cells separate. The superimposition of these small spots concentrated in the cleavage furrow produces the intense, uniform staining observed in conventional micrographs of whole cells.

    Funded by: NIGMS NIH HHS: GM-26132

    Journal of cell science 1994;107 ( Pt 11);3077-90

  • Human smooth muscle myosin heavy chain isoforms as molecular markers for vascular development and atherosclerosis.

    Aikawa M, Sivam PN, Kuro-o M, Kimura K, Nakahara K, Takewaki S, Ueda M, Yamaguchi H, Yazaki Y, Periasamy M et al.

    Third Department of Internal Medicine, University of Tokyo, Japan.

    Smooth muscle myosin heavy chains (MHCs) exist in multiple isoforms. Rabbit smooth muscles contain at least three types of MHC isoforms: SM1 (204 kD), SM2 (200 kD), and SMemb (200 kD). SM1 and SM2 are specific to smooth muscles, but SMemb is a nonmuscle-type MHC abundantly expressed in the embryonic aorta. We recently reported that these three MHC isoforms are differentially expressed in rabbit during normal vascular development and in experimental arteriosclerosis and atherosclerosis. The purpose of this study was to clarify whether expression of human smooth muscle MHC isoforms is regulated in developing arteries and in atherosclerotic lesions. To accomplish this, we have isolated and characterized three cDNA clones from human smooth muscle: SMHC94 (SM1), SMHC93 (SM2), and HSME6 (SMemb). The expression of SM2 mRNA in the fetal aorta was significantly lower as compared with SM1 mRNA, but the ratio of SM2 to SM1 mRNA was increased after birth. SMemb mRNA in the aorta was decreased after birth but appeared to be increased in the aged. To further examine the MHC expression at the histological level, we have developed three antibodies against human SM1, SM2, and SMemb using the isoform-specific sequences of the carboxyl terminal end. Immunohistologically, SM1 was constitutively positive from the fetal stage to adulthood in the apparently normal media of the aorta and coronary arteries, whereas SM2 was negative in fetal arteries of the early gestational stage. In human, unlike rabbit, aorta or coronary arteries, SMemb was detected even in the adult. However, smaller-sized arteries, like the vasa vasorum of the aorta or intramyocardial coronary arterioles, were negative for SMemb. Diffuse intimal thickening in the major coronary arteries was found to be composed of smooth muscles, reacting equally to three antibodies for MHC isoforms, but reactivities with anti-SM2 antibody were reduced with aging. With progression of atherosclerosis, intimal smooth muscles diminished the expression of not only SM2 but also SM1, whereas alpha-smooth muscle actin was well preserved. We conclude from these results that smooth muscle MHC isoforms are important molecular markers for studying human vascular smooth muscle cell differentiation as well as the cellular mechanisms of atherosclerosis.

    Funded by: NHLBI NIH HHS: R01 HL-38355-06

    Circulation research 1993;73;6;1000-12

  • Cleavage of human and mouse cytoskeletal and sarcomeric proteins by human immunodeficiency virus type 1 protease. Actin, desmin, myosin, and tropomyosin.

    Shoeman RL, Sachse C, Höner B, Mothes E, Kaufmann M and Traub P

    Max-Planck-Institut für Zellbiologie, Ladenburg, Federal Republic of Germany.

    HeLa cell actin was cleaved by human immunodeficiency virus type 1 protease when in its soluble, globular form (G-actin). No cleavage of the polymerized, filamentous form of actin (F-actin) was observed when examined by denaturing gel electrophoresis; however, electron microscopy revealed a low level of cleavage of F-actin. Immunoblotting of mouse skeletal and human pectoral muscle myofibrils treated in vitro with human immunodeficiency virus type 1 protease showed that myosin heavy chain, desmin, tropomyosin, and a fraction of the actin were all cleaved. Electron microscopy of these myofibrils demonstrated changes consistent with cleavage of these proteins: Z-lines were rapidly lost, the length of the A bands was shortened, and the thick filaments (myosin filaments) were often laterally frayed such that the structures disintegrated. Nonmuscle myosin heavy chains were also cleaved by this enzyme in vitro. These data demonstrate that this protease can cause alterations in muscle cell ultrastructure in vitro that may be of clinical relevance in infected individuals.

    The American journal of pathology 1993;142;1;221-30

  • Human nonmuscle myosin heavy chains are encoded by two genes located on different chromosomes.

    Simons M, Wang M, McBride OW, Kawamoto S, Yamakawa K, Gdula D, Adelstein RS and Weir L

    Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892.

    We report the cloning of cDNAs encoding two different human nonmuscle myosin heavy chains designated NMMHC-A and NMMHC-B. The mRNAs encoding NMMHC-A and NMMHC-B are both 7.5 kb in size but are shown to be the products of different genes, which are localized to chromosome 22q11.2 and chromosome 17q13, respectively. In aggreement with previously reported results using avian tissues, we show that the mRNAs encoding the two myosin heavy chain isoforms are differentially expressed in rat nonmuscle and muscle tissues as well as in a number of human cell lines. The cDNA sequence encoding the 5' portion of the NMMHC-A isoform completes the previously published 3' cDNA sequence encoding a human myosin heavy chain, thus providing the cDNA sequence encoding the entire NMMHC-A amino acid sequence. Comparison of this sequence to cDNA clones encoding the amino-terminal one third of the NMMHC-B sequence (amino acids 58-718) shows them to be 89% identical at the amino acid level and 74% identical at the nucleotide level.

    Circulation research 1991;69;2;530-9

Gene lists (9)

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
L00000011 G2C Homo sapiens Human clathrin Human orthologues of mouse clathrin coated vesicle genes adapted from Collins et al (2006) 150
L00000012 G2C Homo sapiens Human Synaptosome Human orthologues of mouse synaptosome adapted from Collins et al (2006) 152
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
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).

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