G2Cdb::Gene report

Gene id
G00001383
Gene symbol
SORBS1 (HGNC)
Species
Homo sapiens
Description
sorbin and SH3 domain containing 1
Orthologue
G00000134 (Mus musculus)

Databases (7)

Gene
ENSG00000095637 (Ensembl human gene)
10580 (Entrez Gene)
486 (G2Cdb plasticity & disease)
SORBS1 (GeneCards)
Literature
605264 (OMIM)
Marker Symbol
HGNC:14565 (HGNC)
Protein Sequence
Q9BX66 (UniProt)

Synonyms (5)

  • CAP
  • FLJ12406
  • KIAA1296
  • ponsin
  • sh3p12

Literature (41)

Pubmed - other

  • Cbl-associated protein is tyrosine phosphorylated by c-Abl and c-Src kinases.

    Fernow I, Tomasovic A, Siehoff-Icking A and Tikkanen R

    Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany. inga.fernow@web.de

    Background: The c-Cbl-associated protein (CAP), also known as ponsin, localizes to focal adhesions and stress fibers and is involved in signaling events. Phosphorylation has been described for the other two members of the sorbin homology family, vinexin and ArgBP2, but no data exist about the putative phosphorylation of CAP. According to previous findings, CAP binds to tyrosine kinase c-Abl. However, it is not known if CAP is a substrate of c-Abl or other tyrosine kinases or if phosphorylation regulates its localization.

    Results: We here show that CAP is Tyr phosphorylated by and interacts with both c-Abl and c-Src. One major phosphorylation site, Tyr360, and two minor contributors Tyr326 and Tyr632 were identified as Abl phosphorylation sites, whereas Src preferentially phosphorylates Tyr326 and Tyr360. Phosphorylation of CAP was not necessary for its localization to focal adhesions and stress fibers, but Tyr326Phe substitution alters the function of CAP during cell spreading.

    Conclusion: This is the first demonstration of phosphorylation of CAP by any kinase. Our findings suggest that coordinated action of Src and Abl might regulate the function of CAP and reveal a functional role especially for the Src-mediated Tyr phosphorylation of CAP in cell spreading.

    BMC cell biology 2009;10;80

  • Association of polymorphisms of SORBS1, GCK and WISP1 with hypertension in community-dwelling Japanese individuals.

    Yamada Y, Ando F and Shimokata H

    Department of Human Functional Genomics, Life Science Research Center, Mie University, Tsu, Mie, Japan. yamada@gene.mie-u.ac.jp

    Although various loci and genes have been implicated in predisposition to hypertension by genetic linkage analyses and candidate gene association studies, the genes that confer susceptibility to this condition remain to be identified definitively. We have now examined the relationships of 22 candidate gene polymorphisms with the prevalence of hypertension and with blood pressure (BP) in a 6-year population-based longitudinal cohort study and observed significant relationships of three polymorphisms of SORBS1, GCK and WISP1 with hypertension. The 2233 subjects (1106 women, 1127 men) were aged 40-79 years and were randomly recruited to a population-based prospective cohort study of aging and age-related diseases in Japan. BP was measured with subjects having rested in the sitting position for at least 15 min. Genotypes for the 682A --> G (Thr228Ala) polymorphism of SORBS1, the -30G --> A polymorphism of GCK and the 2364A --> G polymorphism of WISP1 were determined by melting curve analysis. Longitudinal analysis with a generalized estimating equation revealed that the polymorphisms of SORBS1 and GCK and that of WISP1 were significantly associated with the prevalence of hypertension in women and men, respectively. Longitudinal analysis with a mixed-effect model revealed that the polymorphism of SORBS1 was significantly related to diastolic BP in women and that those of GCK and WISP1 were significantly related to both systolic and diastolic BP in women and men, respectively. These results suggest that SORBS1 and GCK are susceptibility loci for hypertension in Japanese women and that WISP1 is such a locus in men.

    Hypertension research : official journal of the Japanese Society of Hypertension 2009;32;5;325-31

  • Prefrontal cortex shotgun proteome analysis reveals altered calcium homeostasis and immune system imbalance in schizophrenia.

    Martins-de-Souza D, Gattaz WF, Schmitt A, Rewerts C, Maccarrone G, Dias-Neto E and Turck CW

    Laboratório de Neurociências, Instituto de Psiquiatria, Universidade de São Paulo, Rua. Dr. Ovidio Pires de Campos, no 785, Consolação, São Paulo, SP 05403-010, Brazil.

    Schizophrenia is a complex disease, likely to be caused by a combination of serial alterations in a number of genes and environmental factors. The dorsolateral prefrontal cortex (Brodmann's Area 46) is involved in schizophrenia and executes high-level functions such as working memory, differentiation of conflicting thoughts, determination of right and wrong concepts and attitudes, correct social behavior and personality expression. Global proteomic analysis of post-mortem dorsolateral prefrontal cortex samples from schizophrenia patients and non-schizophrenic individuals was performed using stable isotope labeling and shotgun proteomics. The analysis resulted in the identification of 1,261 proteins, 84 of which showed statistically significant differential expression, reinforcing previous data supporting the involvement of the immune system, calcium homeostasis, cytoskeleton assembly, and energy metabolism in schizophrenia. In addition a number of new potential markers were found that may contribute to the understanding of the pathogenesis of this complex disease.

    European archives of psychiatry and clinical neuroscience 2009;259;3;151-63

  • Multiple genetic variants along candidate pathways influence plasma high-density lipoprotein cholesterol concentrations.

    Lu Y, Dollé ME, Imholz S, van 't Slot R, Verschuren WM, Wijmenga C, Feskens EJ and Boer JM

    Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands. kevin.lu@wur.nl

    The known genetic variants determining plasma HDL cholesterol (HDL-C) levels explain only part of its variation. Three hundred eighty-four single nucleotide polymorphisms (SNPs) across 251 genes based on pathways potentially relevant to HDL-C metabolism were selected and genotyped in 3,575 subjects from the Doetinchem cohort, which was examined thrice over 11 years. Three hundred fifty-three SNPs in 239 genes passed the quality-control criteria. Seven SNPs [rs1800777 and rs5882 in cholesteryl ester transfer protein (CETP); rs3208305, rs328, and rs268 in LPL; rs1800588 in LIPC; rs2229741 in NRIP1] were associated with plasma HDL-C levels with false discovery rate (FDR) adjusted q values (FDR_q) < 0.05. Five other SNPs (rs17585739 in SC4MOL, rs11066322 in PTPN11, rs4961 in ADD1, rs6060717 near SCAND1, and rs3213451 in MBTPS2 in women) were associated with plasma HDL-C levels with FDR_q between 0.05 and 0.2. Two less well replicated associations (rs3135506 in APOA5 and rs1800961 in HNF4A) known from the literature were also observed, but their significance disappeared after adjustment for multiple testing (P = 0.008, FDR_q = 0.221 for rs3135506; P = 0.018, FDR_q = 0.338 for rs1800961, respectively). In addition to replication of previous results for candidate genes (CETP, LPL, LIPC, HNF4A, and APOA5), we found interesting new candidate SNPs (rs2229741 in NRIP1, rs3213451 in MBTPS2, rs17585739 in SC4MOL, rs11066322 in PTPN11, rs4961 in ADD1, and rs6060717 near SCAND1) for plasma HDL-C levels that should be evaluated further.

    Journal of lipid research 2008;49;12;2582-9

  • Polymorphism in the sorbin and SH3-domain-containing-1 (SORBS1) gene and the risk of brain infarction in the Japanese population: the Fukuoka Stroke Registry and the Hisayama study.

    Hagiwara N, Kitazono T, Kamouchi M, Kuroda J, Ago T, Hata J, Ninomiya T, Ooboshi H, Kumai Y, Yoshimura S, Tamaki K, Fujii K, Nagao T, Okada Y, Toyoda K, Nakane H, Sugimori H, Yamashita Y, Wakugawa Y, Kubo M, Tanizaki Y, Kiyohara Y, Ibayashi S, Iida M, Fukuoka Stroke Registry and Hisayama study

    Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.

    Sorbin and SH3-domain-containing-1 (SORBS1) is an important adaptor protein in insulin-signalling pathway, and its genetic polymorphism may regulate the activity of insulin resistance. We investigated the association between the SORBS1 T228A polymorphism and ischaemic stroke.

    Methods: Genotyping was achieved by a rapid-cycle PCR and melting curve analysis using fluorescent probes in 1049 incident cases of ischaemic stroke and 1049 age- and sex-matched control subjects recruited from the Hisayama study.

    Results: The allele distributions of the SORBS1 T228A polymorphism were similar amongst cases and controls. The multivariate-adjusted odds ratio (OR) of the AA genotype for ischaemic stroke was 2.897 (95% CI, 0.907-8.018) compared with the TT genotype. In terms of stroke subtype, there was a trend toward a difference in the AA genotypes for lacunar infarction, compared with the TT genotype (OR = 8.740, P = 0.0510), and combined TT and TA genotypes (OR = 8.768, P = 0.0505). The other polymorphisms genotyped were not associated with any subtypes of ischaemic stroke. T228A polymorphism of SORBS1 was not associated with the prevalence of diabetes.

    Conclusions: The AA genotype of SORBS1 T228A polymorphism may play a role in lacunar infarction in the Japanese population.

    European journal of neurology 2008;15;5;481-6

  • Paxillin and ponsin interact in nascent costameres of muscle cells.

    Gehmlich K, Pinotsis N, Hayess K, van der Ven PF, Milting H, El Banayosy A, Körfer R, Wilmanns M, Ehler E and Fürst DO

    Institute of Biochemistry and Biology, University of Potsdam, Germany. k.gehmlich@ucl.ac.uk <k.gehmlich@ucl.ac.uk&gt;

    Muscle differentiation requires the transition from motile myoblasts to sessile myotubes and the assembly of a highly regular contractile apparatus. This striking cytoskeletal remodelling is coordinated with a transformation of focal adhesion-like cell-matrix contacts into costameres. To assess mechanisms underlying this differentiation process, we searched for muscle specific-binding partners of paxillin. We identified an interaction of paxillin with the vinexin adaptor protein family member ponsin in nascent costameres during muscle differentiation, which is mediated by an interaction of the second src homology domain 3 (SH3) domain of ponsin with the proline-rich region of paxillin. To understand the molecular basis of this interaction, we determined the structure of this SH3 domain at 0.83 A resolution, as well as its complex with the paxillin binding peptide at 1.63 A resolution. Upon binding, the paxillin peptide adopts a polyproline-II helix conformation in the complex. Contrary to the charged SH3 binding interface, the peptide contains only non-polar residues and for the first time such an interaction was observed structurally in SH3 domains. Fluorescence titration confirmed the ponsin/paxillin interaction, characterising it further by a weak binding affinity. Transfection experiments revealed further characteristics of ponsin functions in muscle cells: All three SH3 domains in the C terminus of ponsin appeared to synergise in targeting the protein to force-transducing structures. The overexpression of ponsin resulted in altered muscle cell-matrix contact morphology, suggesting its involvement in the establishment of mature costameres. Further evidence for the role of ponsin in the maintenance of mature mechanotransduction sites in cardiomyocytes comes from the observation that ponsin expression was down-regulated in end-stage failing hearts, and that this effect was reverted upon mechanical unloading. These results provide new insights in how low affinity protein-protein interactions may contribute to a fine tuning of cytoskeletal remodelling processes during muscle differentiation and in adult cardiomyocytes.

    Funded by: Medical Research Council: G0400153

    Journal of molecular biology 2007;369;3;665-82

  • 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

  • CAP interacts with cytoskeletal proteins and regulates adhesion-mediated ERK activation and motility.

    Zhang M, Liu J, Cheng A, Deyoung SM, Chen X, Dold LH and Saltiel AR

    Department of Internal Medicine, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.

    CAP/Ponsin belongs to the SoHo family of adaptor molecules that includes ArgBP2 and Vinexin. These proteins possess an N-terminal sorbin homology (SoHo) domain and three C-terminal SH3 domains that bind to diverse signaling molecules involved in a variety of cellular processes. Here, we show that CAP binds to the cytoskeletal proteins paxillin and vinculin. CAP localizes to cell-extracellular matrix (ECM) adhesion sites, and this process requires binding to vinculin. Overexpression of CAP induces the aggregation of paxillin, vinculin and actin at cell-ECM adhesion sites. Moreover, CAP inhibits adhesion-dependent processes such as cell spreading and focal adhesion turnover, whereas a CAP mutant that is unable to localize to cell-ECM adhesion sites is incapable of exerting these effects. Finally, depletion of CAP by siRNA-mediated knockdown leads to enhanced cell spreading, migration and the activation of the PAK/MEK/ERK pathway in REF52 cells. Taken together, these results indicate that CAP is a cytoskeletal adaptor protein involved in modulating adhesion-mediated signaling events that lead to cell migration.

    Funded by: NIDDK NIH HHS: DK60591, DK61618, F32 DK064551, R01 DK060591, R01 DK061618

    The EMBO journal 2006;25;22;5284-93

  • Identification of preferred protein interactions by phage-display of the human Src homology-3 proteome.

    Kärkkäinen S, Hiipakka M, Wang JH, Kleino I, Vähä-Jaakkola M, Renkema GH, Liss M, Wagner R and Saksela K

    Institute of Medical Technology, University of Tampere and Tampere University Hospital, Biokatu 8, Tampere 33014, Finland.

    We have determined the human genome to contain 296 different Src homology-3 (SH3) domains and cloned them into a phage-display vector. This provided a powerful and unbiased system for simultaneous assaying of the complete human SH3 proteome for the strongest binding to target proteins of interest, without the limitations posed by short linear peptide ligands or confounding variables of more indirect methods for protein interaction screening. Studies involving three ligand proteins, human immunodeficiency virus-1 Nef, p21-activated kinase (PAK)2 and ADAM15, showed previously reported as well as novel SH3 partners with nanomolar affinities specific for them. This argues that SH3 domains may have a more dominant role in directing cellular protein interactions than has been assumed. Besides showing potentially important new SH3-directed interactions, these studies also led to the discovery of novel signalling proteins, such as the PAK2-binding adaptor protein POSH2 and the ADAM15-binding sorting nexin family member SNX30.

    EMBO reports 2006;7;2;186-91

  • The LIFEdb database in 2006.

    Mehrle A, Rosenfelder H, Schupp I, del Val C, Arlt D, Hahne F, Bechtel S, Simpson J, Hofmann O, Hide W, Glatting KH, Huber W, Pepperkok R, Poustka A and Wiemann S

    Division Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany. a.mehrle@dkfz.de

    LIFEdb (http://www.LIFEdb.de) integrates data from large-scale functional genomics assays and manual cDNA annotation with bioinformatics gene expression and protein analysis. New features of LIFEdb include (i) an updated user interface with enhanced query capabilities, (ii) a configurable output table and the option to download search results in XML, (iii) the integration of data from cell-based screening assays addressing the influence of protein-overexpression on cell proliferation and (iv) the display of the relative expression ('Electronic Northern') of the genes under investigation using curated gene expression ontology information. LIFEdb enables researchers to systematically select and characterize genes and proteins of interest, and presents data and information via its user-friendly web-based interface.

    Nucleic acids research 2006;34;Database issue;D415-8

  • A scan of chromosome 10 identifies a novel locus showing strong association with late-onset Alzheimer disease.

    Grupe A, Li Y, Rowland C, Nowotny P, Hinrichs AL, Smemo S, Kauwe JS, Maxwell TJ, Cherny S, Doil L, Tacey K, van Luchene R, Myers A, Wavrant-De Vrièze F, Kaleem M, Hollingworth P, Jehu L, Foy C, Archer N, Hamilton G, Holmans P, Morris CM, Catanese J, Sninsky J, White TJ, Powell J, Hardy J, O'Donovan M, Lovestone S, Jones L, Morris JC, Thal L, Owen M, Williams J and Goate A

    Celera Diagnostics, Alameda, CA, USA.

    Strong evidence of linkage to late-onset Alzheimer disease (LOAD) has been observed on chromosome 10, which implicates a wide region and at least one disease-susceptibility locus. Although significant associations with several biological candidate genes on chromosome 10 have been reported, these findings have not been consistently replicated, and they remain controversial. We performed a chromosome 10-specific association study with 1,412 gene-based single-nucleotide polymorphisms (SNPs), to identify susceptibility genes for developing LOAD. The scan included SNPs in 677 of 1,270 known or predicted genes; each gene contained one or more markers, about half (48%) of which represented putative functional mutations. In general, the initial testing was performed in a white case-control sample from the St. Louis area, with 419 LOAD cases and 377 age-matched controls. Markers that showed significant association in the exploratory analysis were followed up in several other white case-control sample sets to confirm the initial association. Of the 1,397 markers tested in the exploratory sample, 69 reached significance (P < .05). Five of these markers replicated at P < .05 in the validation sample sets. One marker, rs498055, located in a gene homologous to RPS3A (LOC439999), was significantly associated with Alzheimer disease in four of six case-control series, with an allelic P value of .0001 for a meta-analysis of all six samples. One of the case-control samples with significant association to rs498055 was derived from the linkage sample (P = .0165). These results indicate that variants in the RPS3A homologue are associated with LOAD and implicate this gene, adjacent genes, or other functional variants (e.g., noncoding RNAs) in the pathogenesis of this disorder.

    Funded by: Intramural NIH HHS; Medical Research Council: G0300429, G0701075, G9810900; NHGRI NIH HHS: T32 HG000045; NIA NIH HHS: AG 05146, AG05128, P01 AG003991, P01 AG03991, P50 AG005128, P50 AG005131, P50 AG005146, P50 AG005681, P50 AG008671, P50 AG016570, P50 AG05131, P50 AG05681, P50 AG16570, P50-AG08671, R01 AG016208, R01 AG16208, U24 AG021886; NIGMS NIH HHS: GM065509, P50 GM065509; NIMH NIH HHS: MH60451, P50 MH060451, U01 MH046281, U01 MH046290, U01 MH046373; NINDS NIH HHS: NS39764, P50 NS039764

    American journal of human genetics 2006;78;1;78-88

  • The intracellular domain of teneurin-1 interacts with MBD1 and CAP/ponsin resulting in subcellular codistribution and translocation to the nuclear matrix.

    Nunes SM, Ferralli J, Choi K, Brown-Luedi M, Minet AD and Chiquet-Ehrismann R

    Friedrich Miescher Institute, Novartis Research Foundation, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.

    Teneurin-1 is a type II transmembrane protein expressed in neurons of the developing and adult central nervous system. To investigate the intracellular signaling of teneurin-1, we searched for proteins interacting with its intracellular domain. One of the proteins identified is the c-Cbl-associated protein CAP/ponsin, an adaptor protein containing SH3 domains. This interaction results on one hand in the recruitment of the soluble intracellular domain of teneurin-1 to the cell membrane enriched in CAP/ponsin. On the other hand, it leads to the translocation of CAP/ponsin to the nucleus, the major site of accumulation of the intracellular domain of teneurin-1. The second interacting protein identified is the methyl-CpG binding protein MBD1. In the nucleus, the intracellular domain of teneurin-1 colocalizes with this transcriptional repressor in foci associated with the nuclear matrix. We propose that these interactions are part of a specific signaling pathway. Evidence for cleavage and nuclear translocation of the intracellular domain has been obtained by the detection of endogenous teneurin-1 immunoreactivity in nuclear speckles in chick embryo fibroblasts. Furthermore, in the nuclear matrix fraction of these cells as well as in cells expressing a hormone-inducible full-length teneurin-1 protein, a teneurin-1 fragment of identical size could be detected as in cells transfected with the intracellular domain alone.

    Experimental cell research 2005;305;1;122-32

  • A novel isoform of Cbl-associated protein that binds protein kinase A.

    Matson SA, Pare GC and Kapiloff MS

    Department of Pediatrics, Oregon Health and Science University, NRC5, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239, United States.

    A novel isoform of Cbl-associated protein (CAP) was identified in a yeast two-hybrid screen for A-kinase anchoring proteins expressed in the heart. CAP is a scaffold protein implicated in insulin signaling and cytoskeleton regulation. The protein kinase A binding site is encoded by a previously unidentified, alternatively spliced exon.

    Funded by: NHLBI NIH HHS: K08 HL04229, R01 HL075398, R01 HL075398-02

    Biochimica et biophysica acta 2005;1727;2;145-9

  • The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).

    Gerhard DS, Wagner L, Feingold EA, Shenmen CM, Grouse LH, Schuler G, Klein SL, Old S, Rasooly R, Good P, Guyer M, Peck AM, Derge JG, Lipman D, Collins FS, Jang W, Sherry S, Feolo M, Misquitta L, Lee E, Rotmistrovsky K, Greenhut SF, Schaefer CF, Buetow K, Bonner TI, Haussler D, Kent J, Kiekhaus M, Furey T, Brent M, Prange C, Schreiber K, Shapiro N, Bhat NK, Hopkins RF, Hsie F, Driscoll T, Soares MB, Casavant TL, Scheetz TE, Brown-stein MJ, Usdin TB, Toshiyuki S, Carninci P, Piao Y, Dudekula DB, Ko MS, Kawakami K, Suzuki Y, Sugano S, Gruber CE, Smith MR, Simmons B, Moore T, Waterman R, Johnson SL, Ruan Y, Wei CL, Mathavan S, Gunaratne PH, Wu J, Garcia AM, Hulyk SW, Fuh E, Yuan Y, Sneed A, Kowis C, Hodgson A, Muzny DM, McPherson J, Gibbs RA, Fahey J, Helton E, Ketteman M, Madan A, Rodrigues S, Sanchez A, Whiting M, Madari A, Young AC, Wetherby KD, Granite SJ, Kwong PN, Brinkley CP, Pearson RL, Bouffard GG, Blakesly RW, Green ED, Dickson MC, Rodriguez AC, Grimwood J, Schmutz J, Myers RM, Butterfield YS, Griffith M, Griffith OL, Krzywinski MI, Liao N, Morin R, Morrin R, Palmquist D, Petrescu AS, Skalska U, Smailus DE, Stott JM, Schnerch A, Schein JE, Jones SJ, Holt RA, Baross A, Marra MA, Clifton S, Makowski KA, Bosak S, Malek J and MGC Project Team

    The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline.

    Funded by: PHS HHS: N01-C0-12400

    Genome research 2004;14;10B;2121-7

  • From ORFeome to biology: a functional genomics pipeline.

    Wiemann S, Arlt D, Huber W, Wellenreuther R, Schleeger S, Mehrle A, Bechtel S, Sauermann M, Korf U, Pepperkok R, Sültmann H and Poustka A

    Molecular Genome Analysis, German Cancer Research Center, 69120 Heidelberg, Germany. s.wiemann@dkfz.de

    As several model genomes have been sequenced, the elucidation of protein function is the next challenge toward the understanding of biological processes in health and disease. We have generated a human ORFeome resource and established a functional genomics and proteomics analysis pipeline to address the major topics in the post-genome-sequencing era: the identification of human genes and splice forms, and the determination of protein localization, activity, and interaction. Combined with the understanding of when and where gene products are expressed in normal and diseased conditions, we create information that is essential for understanding the interplay of genes and proteins in the complex biological network. We have implemented bioinformatics tools and databases that are suitable to store, analyze, and integrate the different types of data from high-throughput experiments and to include further annotation that is based on external information. All information is presented in a Web database (http://www.dkfz.de/LIFEdb). It is exploited for the identification of disease-relevant genes and proteins for diagnosis and therapy.

    Genome research 2004;14;10B;2136-44

  • Recruitment of Pyk2 and Cbl to lipid rafts mediates signals important for actin reorganization in growing neurites.

    Haglund K, Ivankovic-Dikic I, Shimokawa N, Kruh GD and Dikic I

    Institute for Biochemistry II, Building 75, Goethe University Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.

    Protein tyrosine kinase Pyk2 and multifunctional adaptor protein Cbl are implicated in the regulation of the cytoskeleton in several cell types. We report that Pyk2 and Cbl form a signaling complex that is translocated to lipid rafts and is enriched in growth cones of differentiating PC12 cells following growth factor stimulation. We found that Pyk2 and Cbl interacted with the adaptor protein ArgBP2, which also bound to flotillin-1, a component of lipid raft microdomains. These interactions contributed to recruitment of the Pyk2/Cbl complex to lipid raft compartments. In addition, Pyk2, Cbl and ArgBP2 were found co-localized with actin in axons and growth cones of differentiated PC12 cells. Moreover, co-expression of Pyk2, ArgBP2 and Cbl facilitated growth factor-induced formation of lamellipodia at the tip of neurites. Formation of these growth cone lamellipodia was dependent on intact lipid rafts and the Cbl-associated effectors Crk and phosphatidylinositol 3 (PI 3)-kinase. Our results indicate that recruitment of Pyk2/Cbl complexes to lipid rafts participates in growth factor-induced regulation of the actin cytoskeleton in growing neurites.

    Journal of cell science 2004;117;Pt 12;2557-68

  • 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

  • Smooth muscle contraction and relaxation.

    Webb RC

    Department of Physiology, Medical College of Georgia, Augusta, Georgia 30912, USA. cwebb@mcg.edu

    This brief review serves as a refresher on smooth muscle physiology for those educators who teach in medical and graduate courses of physiology. Additionally, those professionals who are in need of an update on smooth muscle physiology may find this review to be useful. Smooth muscle lacks the striations characteristic of cardiac and skeletal muscle. Layers of smooth muscle cells line the walls of various organs and tubes in the body, and the contractile function of smooth muscle is not under voluntary control. Contractile activity in smooth muscle is initiated by a Ca(2+)-calmodulin interaction to stimulate phosphorylation of the light chain of myosin. Ca(2+) sensitization of the contractile proteins is signaled by the RhoA/Rho kinase pathway to inhibit the dephosphorylation of the light chain by myosin phosphatase, thereby maintaining force generation. Removal of Ca(2+) from the cytosol and stimulation of myosin phosphatase initiate the process of smooth muscle relaxation.

    Funded by: NHLBI NIH HHS: HL-18575, HL-71138

    Advances in physiology education 2003;27;1-4;201-6

  • Frequency of the T228A polymorphism in the SORBS1 gene in children with premature pubarche and in adolescent girls with hyperandrogenism.

    Witchel SF, Trivedi RN and Kammerer C

    Division of Endocrinology, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. selma.witchel@chp.edu

    Objective: Because the metabolic actions of insulin are more impaired than the mitogenic pathways in polycystic ovary syndrome (PCOS), genes coding for proteins involved in insulin-mediated glucose transport can be considered as candidate genes. The sorbin and SH3-domain-containing-1 (SORBS1) gene codes for c-Cbl-associated protein (CAP) involved in insulin-mediated glucose uptake. An association study showed that a missense variant of the SORBS1 gene is protective against obesity and diabetes. We tested the hypothesis that the frequency of the protective allele would be decreased in children with premature pubarche and adolescent girls with hyperandrogenism.

    Design: Association study.

    Setting: Academic research environment.

    Children referred for the evaluation of premature pubarche (n = 79), adolescent girls with hyperandrogenism (n = 56), and healthy nondiabetic controls (n = 50).

    None.

    Frequency of the T228A allele in our patients and the relationship of body mass index to presence or absence of the T228A variant in our patient population.

    Using allele-specific restriction fragment length polymorphism, allele frequencies were found to be similar among the premature pubarche, hyperandrogenism, and control groups (6.0%, 4.6%, and 8.0%, respectively). No statistically significant relationships were found between the SORBS1 genotypes and body mass index or hormone status.

    This SORBS1 polymorphism does not play a major role in premature pubarche, hyperandrogenism, and/or polycystic ovary syndrome in our patient population.

    Funded by: NCRR NIH HHS: 5M01-RR-00084; NICHD NIH HHS: R29-HD34808

    Fertility and sterility 2003;80;1;128-32

  • mRNA levels of the insulin-signaling molecule SORBS1 in the adipose depots of nondiabetic women.

    Yang WS, Lee WJ, Huang KC, Lee KC, Chao CL, Chen CL, Tai TY and Chuang LM

    Department of Internal Medicine, National Taiwan University, Taipei, Taiwan.

    Objectives: The SORBS1 gene has been shown to be an important adaptor protein in the insulin-signaling pathway in many molecular and cellular biology studies. However, its roles in humans either in health or disease are rarely explored. In this report, we measured the SORBS1 mRNA levels in human adipose tissues.

    Adipose tissues of both the abdominal subcutaneous and omental depots were obtained from 62 nondiabetic women. The relative SORBS1 mRNA levels were quantified using real-time polymerase chain reaction.

    Results: The relative SORBS1 mRNA levels from these two depots significantly correlated with each other (gamma = 0.85, p = 0.0000). The relative SORBS1 mRNA levels in the omental depots were lower than those in the subcutaneous depots (p = 0.053 by two-tailed test, p = 0.026 by one-tailed paired Student's t test). The mean SORBS1 expression level in the omental depots was approximately 70% that in the subcutaneous depots. Moreover, the relative SORBS1 mRNA levels in the omental depots were significantly related to BMI using either correlation analysis (gamma = -0.41, p = 0.0008) or multivariate linear regression analysis (beta = -0.20 +/- 0.09, p = 0.031) with adjustment for age, plasma glucose, serum insulin, triglyceride, and total cholesterol levels.

    Discussion: Our preliminary results indicate the depot-specific differential expression of SORBS1 in relation to BMI. Further investigation of the functional significance of this phenomenon in human obesity is warranted.

    Obesity research 2003;11;4;586-90

  • The c-Cbl-associated protein and c-Cbl are two new partners of the SH2-containing inositol polyphosphate 5-phosphatase SHIP2.

    Vandenbroere I, Paternotte N, Dumont JE, Erneux C and Pirson I

    Institute of Interdisciplinary Research, IRIBHM, School of Medicine, Free University of Brussels, Campus Erasme, Blg C, Route de Lennik 808, Brussels B-1070, Belgium.

    SHIP2 is a phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) 5-phosphatase which contains motifs susceptible to mediate protein-protein interaction. Using yeast two-hybrid, GST-pulldown, and coimmunoprecipitation studies, we isolated the CAP cDNA as a specific partner of SHIP2 proline-rich domain and showed by GST-pulldown experiments that the interaction took place with the SH3C of CAP. The interaction was not modulated in COS-7 cells stimulated by EGF neither in CHO cells overexpressing the insulin receptor in the presence or absence of insulin stimulation. We also showed that SHIP2 was able to coimmunoprecipitate with endogenous c-Cbl protein in the absence of CAP and with the insulin receptor in CHO-IR cell extracts. The presence of SHIP2 in a complex around the insulin receptor could account for the very specific increase in insulin sensitivity of SHIP2 knock-out mice.

    Biochemical and biophysical research communications 2003;300;2;494-500

  • Progesterone receptor interacting coregulatory proteins and cross talk with cell signaling pathways.

    Edwards DP, Wardell SE and Boonyaratanakornkit V

    Program in Molecular Biology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, B216 Denver, CO 80262, USA. dean.edwards@uchsc.edu

    Progesterone receptor (PR) is a member of the nuclear receptor family of ligand-dependent transcription activators and is expressed as two different sized proteins from a single gene; PR-A and PR-B. The two PR isoforms are identical in their DNA binding domains (DBD) and C-terminal ligand binding domains (LBD), differing only in the N-terminal domain that is truncated in PR-A. PR also contains two autonomous transcription activation domains (AD), ligand-dependent AF-2 in the C-terminus and constitutive AF-1 in the N-terminus. AF-2 is highly conserved and a family of p160 coactivators that interacts with and mediates the activity of AF-2 has been well characterized. By contrast the N-terminal domain and AF-1 are not conserved and little is known about AF-1 coactivators. The N-terminal domain is functionally important as it is required for full transcription activity of PR and is responsible for the distinct activities of the two PR isoforms, as well as cell and promoter specific functions of PR. This paper describes our efforts to identify PR N-terminal interacting coregulatory proteins. We summarize our work on the role of jun dimerization protein-2 (JDP-2) as an AF-1 coactivator of PR. JDP-2, initially defined as a repressor of jun and other bZIP transcription factors, also functions as a potent PR selective coactivator. JDP-2 lacks an intrinsic activation domain and through association with the DBD, we propose that JDP-2 potentiates AF-1 by recruiting other coactivators independent of AF-2 and p160 pathways. We also discovered that PR contains an SH3 domain interaction motif in the N-terminus that mediates interaction with Src tyrosine kinases and other signaling molecules. This interaction mediates rapid progesterone activation of Src/MAP K signaling pathways and defines a molecular mechanism for some of the rapid non-genomic actions of progesterone.

    Funded by: NIDDK NIH HHS: DK 49030

    The Journal of steroid biochemistry and molecular biology 2002;83;1-5;173-86

  • [A novel adaptor protein family regulating cytoskeletal organization and signal transduction--Vinexin, CAP/ponsin, ArgBP2].

    Kioka N

    Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502.

    Seikagaku. The Journal of Japanese Biochemical Society 2002;74;11;1356-60

  • Protein-protein interactions between large proteins: two-hybrid screening using a functionally classified library composed of long cDNAs.

    Nakayama M, Kikuno R and Ohara O

    Department of Human Gene Research, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan. nmanabu@kazusa.or.jp

    Large proteins have multiple domains that are potentially capable of binding many kinds of partners. It is conceivable, therefore, that such proteins could function as an intricate framework of assembly protein complexes. To comprehensively study protein-protein interactions between large KIAA proteins, we have constructed a library composed of 1087 KIAA cDNA clones based on prior functional classifications done in silico. We were guided by two principles that raise the success rate for detecting interactions per tested combination: we avoided testing low-probability combinations, and reduced the number of potential false negatives that arise from the fact that large proteins cannot reliably be expressed in yeast. The latter was addressed by constructing a cDNA library comprised of random fragments encoding large proteins. Cytoplasmic domains of KIAA transmembrane proteins (>1000 amino acids) were used as bait for yeast two-hybrid screening. Our analyses reveal that several KIAA proteins bearing a transmembrane region have the capability of binding to other KIAA proteins containing domains (e.g., PDZ, SH3, rhoGEF, and spectrin) known to be localized to highly specialized submembranous sites, indicating that they participate in cellular junction formation, receptor or channel clustering, and intracellular signaling events. Our representative library should be a very useful resource for detecting previously unidentified interactions because it complements conventional expression libraries, which seldom contain large cDNAs.

    Genome research 2002;12;11;1773-84

  • Polymorphisms in candidate obesity genes and their interaction with dietary intake of n-6 polyunsaturated fatty acids affect obesity risk in a sub-sample of the EPIC-Heidelberg cohort.

    Nieters A, Becker N and Linseisen J

    German Cancer Research Center, Division of Clinical Epidemiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. a.nieters@dkfz.de

    In several genes coding for molecules involved in the regulation of body weight (fat mass) and thermogenesis, polymorphisms have been reported which possibly modify human obesity risk. The aim of this study was a) to reproduce these observations with data and biological material from the Heidelberg cohort of EPIC, a large European prospective investigation into diet and cancer, and b) to investigate potential effects of interactions between dietary fatty acid intake and allelic variants on obesity risk.

    Within EPIC-Heidelberg, 154 subjects with a body mass index > 35 kg/m(2) and 154 age- and sex-matched normal-weight controls were selected and genotypes determined for 11 candidate genes. Dietary intake was assessed by a validated food frequency questionnaire. Odds ratios (OR) were computed by means of unconditional logistic regression and different adjustment models. Genotyping was performed by PCR-RFLP and allele-specific PCR.

    Results: For most of the investigated genes (PPARA, PPARG2, UCP1, UCP2, UCP3, BAR-2, APM1, leptin, SORBS1, HSL, and TNFA) an indication for a minor effect on obesity risk was found. Indication of a risk-increasing effect was strongest for the homozygous form of leptin -2548AA with an adjusted OR of 3.53 (p < 0.009). Additionally, for the polymorphic sites of BAR-2 (Arg16Gly and Gln27Glu) a significant effect on obesity risk was seen. Importantly, the results of the analysis of gene-diet interactions suggest that the allelic variants of candidate genes (leptin, TNFA, PPARG2) might strongly affect diet-related obesity risk.

    Conclusions: The results support some but not all previous reports about a risk-modulating effect of polymorphisms in genes affecting obesity risk. The most important finding is an indication of substantial interaction between allelic variants of particular genes and fatty acid intake-related obesity risk. These observations suggest that future studies on polymorphisms in obesity genes should take data on dietary habits into account.

    European journal of nutrition 2002;41;5;210-21

  • The zinc-finger transcription factor INSM1 is expressed during embryo development and interacts with the Cbl-associated protein.

    Xie J, Cai T, Zhang H, Lan MS and Notkins AL

    Experimental Medicine Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, 20892-4322, USA.

    Here we describe the isolation and characterization of the mouse homolog of the human zinc-finger transcription factor INSM1 (IA-1) and identify an interacting protein. A 2.9-kb cDNA with an open reading frame of 1563 nucleotides, corresponding to a translated protein of 521 amino acids, was isolated from a mouse beta TC-1 cDNA library. Mouse INSM1 was found to be 86% identical to human INSM1 and both proteins contain proline-rich regions and multiple zinc-finger DNA-binding motifs. Sequencing of mouse Insm1 genomic DNA revealed that it is an intronless gene. Chromosomal mapping localized Insm1 to chromosome 2. Northern blot analysis showed that mouse Insm1 expression begins at 10.5 days in the embryo, decreases after 13.5 days, and is barely detected at 18.5 days. In mouse brain, Insm1 is strongly expressed for 2 weeks after birth but shows little or no expression thereafter. Transfection of cells with GFP-tagged INSM1 revealed that INSM1 is expressed exclusively in the nucleus. We identified proteins that interacted with INSM1 by the yeast two-hybrid system and the binding of one of them, Cbl-associated protein (CAP), to INSM1 was confirmed by in vitro pull-down experiments, nuclear colocalization, and co-immunoprecipitation assays. Further studies showed that both INSM1 and CAP proteins were present in the nucleus of insulinoma cells and that endogenous INSM1 protein was co-precipitated with antibody to CAP. These findings raise the possibility that during embryo development CAP may enter the nucleus through its own nuclear localization signal or by binding to INSM1.

    Funded by: NIDDK NIH HHS: R01 DK061436

    Genomics 2002;80;1;54-61

  • APS facilitates c-Cbl tyrosine phosphorylation and GLUT4 translocation in response to insulin in 3T3-L1 adipocytes.

    Liu J, Kimura A, Baumann CA and Saltiel AR

    Department of Internal Medicine and Physiology, Life Science Institute, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA.

    APS is a Cbl-binding protein that is tyrosine phosphorylated by the insulin receptor kinase. Insulin-stimulated phosphorylation of tyrosine 618 in APS is necessary for its association with c-Cbl and the subsequent tyrosine phosphorylation of Cbl by the insulin receptor in both 3T3-L1 adipocytes and CHO-IR cells. When overexpressed in these cells, wild-type APS but not an APS/Y(618)F mutant facilitated the tyrosine phosphorylation of coexpressed Cbl and its association with Crk upon insulin stimulation. APS-facilitated phosphorylation occurred on tyrosines 371, 700, and 774 in the Cbl protein. APS also interacted directly with the c-Cbl-associated protein (CAP) and colocalized with the protein in cells. The association was dependent on the SH3 domains of CAP and was independent of insulin treatment. Overexpression of the APS/Y(618)F mutant in 3T3-L1 adipocytes blocked the insulin-stimulated tyrosine phosphorylation of endogenous Cbl and binding to Crk. Moreover, the translocation of GLUT4 from intracellular vesicles to the plasma membrane was also inhibited by overexpression of the APS/Y(618)F mutant. These data suggest that APS serves as an adapter protein linking the CAP/Cbl pathway to the insulin receptor and, further, that APS-facilitated Cbl tyrosine phosphorylation catalyzed by the insulin receptor is a crucial event in the stimulation of glucose transport by insulin.

    Molecular and cellular biology 2002;22;11;3599-609

  • The SH2/SH3 adaptor Grb4 transduces B-ephrin reverse signals.

    Cowan CA and Henkemeyer M

    Center for Developmental Biology and Kent Waldrep Foundation Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas 75390-9133, USA.

    Bidirectional signals mediated by membrane-anchored ephrins and Eph receptor tyrosine kinases have important functions in cell-cell recognition events, including those that occur during axon pathfinding and hindbrain segmentation. The reverse signal that is transduced into B-ephrin-expressing cells is thought to involve tyrosine phosphorylation of the signal's short, conserved carboxy-terminal cytoplasmic domain. The Src-homology-2 (SH2) domain proteins that associate with activated tyrosine-phosphorylated B-subclass ephrins have not been identified, nor has a defined cellular response to reverse signals been described. Here we show that the SH2/SH3 domain adaptor protein Grb4 binds to the cytoplasmic domain of B ephrins in a phosphotyrosine-dependent manner. In response to B-ephrin reverse signalling, cells increase FAK catalytic activity, redistribute paxillin, lose focal adhesions, round up, and disassemble F-actin-containing stress fibres. These cellular responses can be blocked in a dominant-negative fashion by expression of the isolated Grb4 SH2 domain. The Grb4 SH3 domains bind a unique set of other proteins that are implicated in cytoskeletal regulation, including the Cbl-associated protein (CAP/ponsin), the Abl-interacting protein-1 (Abi-1), dynamin, PAK1, hnRNPK and axin. These data provide a biochemical pathway whereby cytoskeletal regulators are recruited to Eph-ephrin bidirectional signalling complexes.

    Nature 2001;413;6852;174-9

  • Molecular scanning of the human sorbin and SH3-domain-containing-1 (SORBS1) gene: positive association of the T228A polymorphism with obesity and type 2 diabetes.

    Lin WH, Chiu KC, Chang HM, Lee KC, Tai TY and Chuang LM

    Department of Internal Medicine, National Taiwan University Hospital, 7 Chung Shan South Road, Taipei, Taiwan.

    In the mouse, the SH3P12 or the c-Cbl-associated protein (CAP) has been shown as an important signaling molecule in insulin-stimulated glucose uptake. The human homolog for the sorbin and SH3-domain-containing-1 gene, termed SORBS1, might play a role in human disorders with insulin resistance. To explore the genetic role of SORBS1 in human obesity and type 2 diabetes, we investigated the nucleotide polymorphisms in the SORBS1 gene with molecular scanning. After scanning for a total of 13,136 bp in each of 40 chromosomes, we have identified 14 single nucleotide polymorphisms (SNPs) in the human SORBS1 gene. Among them, two SNPs affected amino acid coding (R74W and T228A), four occurred within exons but did not affect amino acid coding, and the remaining eight occurred within introns, which were located outside of the consensus region of the splicing mechanism. Further studies in 202 non-obese, 113 obese and 455 subjects with type 2 diabetes revealed that the A-allele of the T228A polymorphism in exon 7 exerted a protective role for both obesity [relative risk 0.466; 95% confidence interval (95% CI) 0.265-0.821] and diabetes (relative risk 0.668; 95% CI 0.472-0.945). Neither allele of the R74W polymorphism was associated with either obesity or diabetes. In conclusion, our results suggest that the A228 allele of the T228A polymorphism of the SORBS1 gene is a protective factor for both obesity and diabetes, and also imply that the SORBS1 gene plays an important role in the pathogenesis of human disorders with insulin resistance.

    Funded by: NIDDK NIH HHS: R01DK52337

    Human molecular genetics 2001;10;17;1753-60

  • The sorbin homology domain: a motif for the targeting of proteins to lipid rafts.

    Kimura A, Baumann CA, Chiang SH and Saltiel AR

    Department of Internal Medicine and Physiology, Life Sciences Institute, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.

    On phosphorylation of Cbl, the c-Cbl-associated protein (CAP)/Cbl complex dissociates from the insulin receptor and translocates to a lipid raft membrane fraction to form a ternary complex with flotillin. Deletion analyses of the CAP gene identified a 115-aa region responsible for flotillin binding. This region is homologous to the peptide sorbin and is referred to as the sorbin homology (SoHo) domain. This domain is present in two other proteins, vinexin and ArgBP2. Vinexin also interacted with flotillin, and deletion of its SoHo domain similarly blocked flotillin binding. The overexpression of a CAP mutant in which the SoHo domain had been deleted (CAPDeltaSoHo) prevented the translocation of Cbl to lipid rafts and subsequently blocked the recruitment of CrkII and C3G. Moreover, overexpression of CAPDeltaSoHo prevented the stimulation of glucose transport and GLUT4 translocation by insulin. These results suggest a mechanism for localization of signaling proteins to the lipid raft that mediates the compartmentalization of crucial signal transduction pathways.

    Proceedings of the National Academy of Sciences of the United States of America 2001;98;16;9098-103

  • Ataxin-7 interacts with a Cbl-associated protein that it recruits into neuronal intranuclear inclusions.

    Lebre AS, Jamot L, Takahashi J, Spassky N, Leprince C, Ravisé N, Zander C, Fujigasaki H, Kussel-Andermann P, Duyckaerts C, Camonis JH and Brice A

    INSERM U289, Hôpital de la Salpêtrière, 47 boulevard de l'Hôpital, 75651 Paris, Cedex 13, France.

    Spinocerebellar ataxia 7 (SCA7) is a neurodegenerative disease caused by expansion of a CAG repeat in the coding region of the SCA7 gene. The disease primarily affects the cerebellum and the retina, but also many other central nervous system (CNS) structures as the disease progresses. Ataxin-7, encoded by the SCA7 gene, is a protein of unknown function expressed in many tissues including the CNS. In normal brain, ataxin-7 is found in the cytoplasm and/or nucleus of neurons, but in SCA7 brain ataxin-7 accumulates in intranuclear inclusions. Ataxin-7 is expressed ubiquitously, but mutation leads to neuronal death in only certain areas of the brain. This selective pattern of degeneration might be explained by interaction with a partner that is specifically expressed in vulnerable cells. We used a two-hybrid approach to screen a human retina cDNA library for ataxin-7-binding proteins, and isolated R85, a splice variant of Cbl-associated protein (CAP). R85 and CAP are generated by alternative splicing of the gene SH3P12 which we localized on chromosome 10q23-q24. The interaction between ataxin-7 and the SH3P12 gene products (SH3P12GPs) was confirmed by pull-down and co-immunoprecipitation. SH3P12GPs are expressed in Purkinje cells in the cerebellum. Ataxin-7 colocalizes with full-length R85 (R85FL) in co-transfected Cos-7 cells and with one of the SH3P12GPs in neuronal intranuclear inclusions in brain from a SCA7 patient. We propose that this interaction is part of a physiological pathway related to the function or turnover of ataxin-7. Its role in the pathophysiological process of SCA7 disease is discussed.

    Human molecular genetics 2001;10;11;1201-13

  • Cloning, mapping, and characterization of the human sorbin and SH3 domain containing 1 (SORBS1) gene: a protein associated with c-Abl during insulin signaling in the hepatoma cell line Hep3B.

    Lin WH, Huang CJ, Liu MW, Chang HM, Chen YJ, Tai TY and Chuang LM

    Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.

    SH3P12/CAP/ponsin, a gene product with a sorbin homology domain and three consecutive SH3 domains in the carboxy-terminus, has been isolated from murine adipocytes and identified as an important adaptor during insulin signaling. Here we describe the cloning, mapping, and expression of the human homologue, termed SORBS1 (sorbin and SH3 domain containing 1). Multiple transcripts of this gene with different mRNA isoforms were observed among different tissues. Here we report 13 alternatively spliced exons, which were ascertained from the full-length cDNA cloned in adipose, liver, and skeletal muscle tissues. Among the major isoforms, the shortest, 2223-bp, open reading frame (ORF) encodes a protein with a predicted molecular weight of 81.5 kDa, while the longest, 3879-bp, ORF encodes a protein of about 142.2 kDa. This gene was mapped to human chromosome 10q23.3-q24.1, which is a candidate region for insulin resistance found in Pima Indians. In human hepatoma Hep3B cells, SORBS1 was partly dissociated from the insulin receptor complex and bound to c-Abl protein upon insulin stimulation. This interaction with c-Abl was through the third SH3 domain and a possible conformational change of SORBS1 induced by insulin. Our data suggest that c-Abl oncoprotein via SORBS1 might play a role in the insulin signaling pathway.

    Genomics 2001;74;1;12-20

  • Toward a catalog of human genes and proteins: sequencing and analysis of 500 novel complete protein coding human cDNAs.

    Wiemann S, Weil B, Wellenreuther R, Gassenhuber J, Glassl S, Ansorge W, Böcher M, Blöcker H, Bauersachs S, Blum H, Lauber J, Düsterhöft A, Beyer A, Köhrer K, Strack N, Mewes HW, Ottenwälder B, Obermaier B, Tampe J, Heubner D, Wambutt R, Korn B, Klein M and Poustka A

    Molecular Genome Analysis, German Cancer Research Center, 69120 Heidelberg, Germany. s.wiemann@dkfz.de

    With the complete human genomic sequence being unraveled, the focus will shift to gene identification and to the functional analysis of gene products. The generation of a set of cDNAs, both sequences and physical clones, which contains the complete and noninterrupted protein coding regions of all human genes will provide the indispensable tools for the systematic and comprehensive analysis of protein function to eventually understand the molecular basis of man. Here we report the sequencing and analysis of 500 novel human cDNAs containing the complete protein coding frame. Assignment to functional categories was possible for 52% (259) of the encoded proteins, the remaining fraction having no similarities with known proteins. By aligning the cDNA sequences with the sequences of the finished chromosomes 21 and 22 we identified a number of genes that either had been completely missed in the analysis of the genomic sequences or had been wrongly predicted. Three of these genes appear to be present in several copies. We conclude that full-length cDNA sequencing continues to be crucial also for the accurate identification of genes. The set of 500 novel cDNAs, and another 1000 full-coding cDNAs of known transcripts we have identified, adds up to cDNA representations covering 2%--5 % of all human genes. We thus substantially contribute to the generation of a gene catalog, consisting of both full-coding cDNA sequences and clones, which should be made freely available and will become an invaluable tool for detailed functional studies.

    Genome research 2001;11;3;422-35

  • DNA cloning using in vitro site-specific recombination.

    Hartley JL, Temple GF and Brasch MA

    Life Technologies, Inc., Rockville, Maryland 20850, USA. jhartley@lifetech.com

    As a result of numerous genome sequencing projects, large numbers of candidate open reading frames are being identified, many of which have no known function. Analysis of these genes typically involves the transfer of DNA segments into a variety of vector backgrounds for protein expression and functional analysis. We describe a method called recombinational cloning that uses in vitro site-specific recombination to accomplish the directional cloning of PCR products and the subsequent automatic subcloning of the DNA segment into new vector backbones at high efficiency. Numerous DNA segments can be transferred in parallel into many different vector backgrounds, providing an approach to high-throughput, in-depth functional analysis of genes and rapid optimization of protein expression. The resulting subclones maintain orientation and reading frame register, allowing amino- and carboxy-terminal translation fusions to be generated. In this paper, we outline the concepts of this approach and provide several examples that highlight some of its potential.

    Genome research 2000;10;11;1788-95

  • CAP defines a second signalling pathway required for insulin-stimulated glucose transport.

    Baumann CA, Ribon V, Kanzaki M, Thurmond DC, Mora S, Shigematsu S, Bickel PE, Pessin JE and Saltiel AR

    Department of Physiology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109, USA.

    Insulin stimulates the transport of glucose into fat and muscle cells. Although the precise molecular mechanisms involved in this process remain uncertain, insulin initiates its actions by binding to its tyrosine kinase receptor, leading to the phosphorylation of intracellular substrates. One such substrate is the Cbl proto-oncogene product. Cbl is recruited to the insulin receptor by interaction with the adapter protein CAP, through one of three adjacent SH3 domains in the carboxy terminus of CAP. Upon phosphorylation of Cbl, the CAP-Cbl complex dissociates from the insulin receptor and moves to a caveolin-enriched, triton-insoluble membrane fraction. Here, to identify a molecular mechanism underlying this subcellular redistribution, we screened a yeast two-hybrid library using the amino-terminal region of CAP and identified the caveolar protein flotillin. Flotillin forms a ternary complex with CAP and Cbl, directing the localization of the CAP-Cbl complex to a lipid raft subdomain of the plasma membrane. Expression of the N-terminal domain of CAP in 3T3-L1 adipocytes blocks the stimulation of glucose transport by insulin, without affecting signalling events that depend on phosphatidylinositol-3-OH kinase. Thus, localization of the Cbl-CAP complex to lipid rafts generates a pathway that is crucial in the regulation of glucose uptake.

    Nature 2000;407;6801;202-7

  • Prediction of the coding sequences of unidentified human genes. XVI. The complete sequences of 150 new cDNA clones from brain which code for large proteins in vitro.

    Nagase T, Kikuno R, Ishikawa KI, Hirosawa M and Ohara O

    Kazusa DNA Research Institute, Kisarazu, Chiba, Japan. nagase@kazusa.or.jp

    We have carried out a human cDNA sequencing project to accumulate information regarding the coding sequences of unidentified human genes. As an extension of the preceding reports, we herein present the entire sequences of 150 cDNA clones of unknown human genes, named KIAA1294 to KIAA1443, from two sets of size-fractionated human adult and fetal brain cDNA libraries. The average sizes of the inserts and corresponding open reading frames of cDNA clones analyzed here reached 4.8 kb and 2.7 kb (910 amino acid residues), respectively. From sequence similarities and protein motifs, 73 predicted gene products were functionally annotated and 97% of them were classified into the following four functional categories: cell signaling/communication, nucleic acid management, cell structure/motility and protein management. Additionally, the chromosomal loci of the genes were assigned by using human-rodent hybrid panels for those genes whose mapping data were not available in the public databases. The expression profiles of the genes were also studied in 10 human tissues, 8 brain regions, spinal cord, fetal brain and fetal liver by reverse transcription-coupled polymerase chain reaction, products of which were quantified by enzyme-linked immunosorbent assay.

    DNA research : an international journal for rapid publication of reports on genes and genomes 2000;7;1;65-73

  • Similar and differential behaviour between the nectin-afadin-ponsin and cadherin-catenin systems during the formation and disruption of the polarized junctional alignment in epithelial cells.

    Asakura T, Nakanishi H, Sakisaka T, Takahashi K, Mandai K, Nishimura M, Sasaki T and Takai Y

    Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita 565-0871, Japan.

    Background: We have recently identified a novel cell-cell adhesion system, named NAP system, which is localized at cadherin-based cell-cell adherens junctions (AJs). The NAP system is composed of at least nectin, afadin and ponsin. Nectin is an immunoglobulin-like cell adhesion molecule. Afadin is an actin filament-binding protein which associates nectin with the actin cytoskeleton. Ponsin is an afadin-binding protein which furthermore binds to vinculin and provides a possible linkage of nectin-afadin to cadherin-catenin through vinculin. We compared here the behaviour of the NAP and cadherin-catenin systems during the formation and disruption of the polarized junctional alignment in epithelial cells.

    Results: At the early stage of the formation of the polarized junctional alignment in MTD-1 A cells, primordial spot-like junctions were formed at the tips of thin cellular protrusions radiating from adjacent cells. Nectin, afadin, ponsin, cadherin and catenin were simultaneously recruited to these junctions. As the cell polarization proceeded, the spot-like junctions were gradually fused to form belt-like AJs where all these proteins were concentrated. The disruption of cell-cell AJs in MDCK cells by culturing at a low Ca2+ concentration caused rapid endocytosis of cadherin, but not that of nectin or afadin. Addition of 12-O-tetradecanoylphorbol-13-acetate to the cells formed a tight junction-like structure where nectin and afadin, but not cadherin, accumulated.

    Conclusion: These results indicate that the NAP and cadherin-catenin systems show similar and differential behaviour during the formation and disruption of the polarized junctional alignment in epithelial cells.

    Genes to cells : devoted to molecular & cellular mechanisms 1999;4;10;573-81

  • Ponsin/SH3P12: an l-afadin- and vinculin-binding protein localized at cell-cell and cell-matrix adherens junctions.

    Mandai K, Nakanishi H, Satoh A, Takahashi K, Satoh K, Nishioka H, Mizoguchi A and Takai Y

    Takai Biotimer Project, ERATO, Japan Science and Technology Corporation, c/o JCR Pharmaceuticals Co., Ltd., 2-2-10 Murotani, Nishi-ku, Kobe 651-2241, Japan.

    We recently isolated a novel actin filament (F-actin)-binding protein, afadin, that has two isoforms, l- and s-afadins. l-Afadin is ubiquitously expressed and specifically localized at zonula adherens (ZA) in epithelial cells and at cell-cell adherens junction (AJ) in nonepithelial cells, whereas s-afadin is abundantly expressed in neural tissue. l-Afadin has one PDZ domain, three proline-rich regions, and one F-actin-binding domain, whereas s-afadin lacks the third proline-rich region and the F-actin-binding domain. To understand the molecular mechanism of the specific localization of l-afadin at ZA in epithelial cells and at cell-cell AJ in nonepithelial cells, we attempted here to identify an l-afadin-binding protein(s) and isolated a protein, named ponsin. Ponsin had many splicing variants and the primary structures of two of them were determined. Both the two variants had three Src homology 3 (SH3) domains and turned out to be splicing variants of SH3P12. The third proline-rich region of l-afadin bound to the region of ponsin containing the second and third SH3 domains. Ponsin was ubiquitously expressed and localized at ZA in epithelial cells, at cell-cell AJ in nonepithelial cells, and at cell-matrix AJ in both types of cells. Ponsin furthermore directly bound vinculin, an F-actin-binding protein localized at ZA in epithelial cells, at cell-cell AJ in nonepithelial cells, and at cell-matrix AJ in both types of cells. Vinculin has one proline-rich region where two proline-rich sequences are located. The proline-rich region bound to the region of ponsin containing the first and second SH3 domains. l-Afadin and vinculin bound to ponsin in a competitive manner and these three proteins hardly formed a ternary complex. These results indicate that ponsin is an l-afadin- and vinculin-binding protein localized at ZA in epithelial cells, at cell-cell AJ in nonepithelial cells, and at cell-matrix AJ in both types of cells.

    The Journal of cell biology 1999;144;5;1001-17

  • A role for CAP, a novel, multifunctional Src homology 3 domain-containing protein in formation of actin stress fibers and focal adhesions.

    Ribon V, Herrera R, Kay BK and Saltiel AR

    Department of Physiology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109, USA.

    c-Cbl-associated protein, CAP, was originally cloned from a 3T3-L1 adipocyte cDNA expression library using full-length c-Cbl as a bait. CAP contains a unique structure, with three adjacent Src homology-3 (SH3) domains in the COOH terminus and a region sharing significant sequence similarity with the peptide hormone sorbin. Expression of CAP in NIH-3T3 cells overexpressing the insulin receptor induced the formation of stress fibers and focal adhesions. This effect of CAP expression on the organization of the actin-based cytoskeleton was independent of the type of integrin receptors engaged with extracellular matrix, whereas membrane ruffling and decreased actin stress fibers induced by insulin were not affected by expression of CAP. Immunofluorescence microscopy demonstrated that CAP colocalized with actin stress fibers. Moreover, CAP interacted with the focal adhesion kinase, p125FAK, both in vitro and in vivo through one of the SH3 domains of CAP. The increased formation of stress fibers and focal adhesions in CAP-expressing cells was correlated with decreased tyrosine phosphorylation of p125FAK in growing cells or upon integrin-mediated cell adhesion. These results suggest that CAP may mediate signals for the formation of stress fibers and focal adhesions.

    The Journal of biological chemistry 1998;273;7;4073-80

  • A novel, multifuntional c-Cbl binding protein in insulin receptor signaling in 3T3-L1 adipocytes.

    Ribon V, Printen JA, Hoffman NG, Kay BK and Saltiel AR

    Department of Physiology, University of Michigan School of Medicine, Ann Arbor 48109, USA.

    The protein product of the c-Cbl proto-oncogene is prominently tyrosine phosphorylated in response to insulin in 3T3-L1 adipocytes and not in 3T3-L1 fibroblasts. After insulin-dependent tyrosine phosphorylation, c-Cbl specifically associates with endogenous c-Crk and Fyn. These results suggest a role for tyrosine-phosphorylated c-Cbl in 3T3-L1 adipocyte activation by insulin. A yeast two-hybrid cDNA library prepared from fully differentiated 3T3-L1 adipocytes was screened with full-length c-Cbl as the target protein in an attempt to identify adipose-specific signaling proteins that interact with c-Cbl and potentially are involved in its tyrosine phosphorylation in 3T3-L1 adipocytes. Here we describe the isolation and the characterization of a novel protein that we termed CAP for c-Cbl-associated protein. CAP contains a unique structure with three adjacent Src homology 3 (SH3) domains in the C terminus and a region showing significant sequence similarity with the peptide hormone sorbin. Both CAP mRNA and proteins are expressed predominately in 3T3-L1 adipocytes and not in 3T3-L1 fibroblasts. CAP associates with c-Cbl in 3T3-L1 adipocytes independently of insulin stimulation in vivo and in vitro in an SH3-domain-mediated manner. Furthermore, we detected the association of CAP with the insulin receptor. Insulin stimulation resulted in the dissociation of CAP from the insulin receptor. Taken together, these data suggest that CAP represents a novel c-Cbl binding protein in 3T3-L1 adipocytes likely to participate in insulin signaling.

    Molecular and cellular biology 1998;18;2;872-9

Gene lists (6)

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
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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