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.
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.
Lin
W H
WH
Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Huang
C J
CJ
Liu
M W
MW
Chang
H M
HM
Chen
Y J
YJ
Tai
T Y
TY
Chuang
L M
LM
D000595:Amino Acid Sequence; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000473:pathology; D002871:Chromosome Banding; D002874:Chromosome Mapping; D002879:Chromosomes, Human, Pair 10 / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005091:Exons; D005260:Female; D005796:Genes / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007438:Introns; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology; D008840:Microfilament Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics; D016315:Proto-Oncogene Proteins c-abl / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D018076:DNA, Complementary; D008840:Microfilament Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; C432967:SORBS1 protein, human; D011972:Receptor, Insulin; D016315:Proto-Oncogene Proteins c-abl