title: The protein-tyrosine kinase fer associates with signaling complexes containing insulin receptor substrate-1 and phosphatidylinositol 3-kinase.
abstract: In a screen for 3T3-F442A adipocyte proteins that bind SH2 domains, we isolated a cDNA encoding Fer, a nonreceptor protein-tyrosine kinase of the Fes/Fps family that contains a functional SH2 domain. A truncated splicing variant, iFer, was also cloned. iFer is devoid of both the tyrosine kinase domain and a functional SH2 domain but displays a unique 42-residue C terminus and retains the ability to form oligomers with Fer. Expression of both Fer and iFer proteins are strikingly increased upon differentiation of 3T3-L1 fibroblasts to adipocytes. Platelet-derived growth factor treatment of the cultured adipocytes caused rapid tyrosine phosphorylation of Fer and its recruitment to complexes containing platelet-derived growth factor receptor and the p85 regulatory subunit of phosphatidylinositol (PI) 3-kinase. Insulin treatment of 3T3-L1 adipocytes stimulated association of Fer with complexes containing tyrosine phosphorylated IRS-1 and PI 3-kinase but did not stimulate tyrosine phosphorylation of Fer. PI 3-kinase activity in anti-Fer immunoprecipitates was also acutely activated by insulin treatment of cultured adipocytes. These data demonstrate the presence of Fer tyrosine kinase in insulin signaling complexes, suggesting a role of Fer in insulin action.
authors.affiliation: Program in Molecular Medicine and Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
authors.forename: M
authors.initials: M
authors.lastname: Iwanishi
authors.forename: M P
authors.initials: MP
authors.lastname: Czech
authors.forename: A D
authors.initials: AD
authors.lastname: Cherniack
mesh_terms: D016475:3T3 Cells; D017667:Adipocytes / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002454:Cell Differentiation; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D015723:Gene Library; D015151:Immunoblotting; D007328:Insulin / Q000494:pharmacology; D055504:Insulin Receptor Substrate Proteins; D051379:Mice; D008969:Molecular Sequence Data; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains
chemical_list: D018076:DNA, Complementary; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D020033:Protein Isoforms; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; C052602:proto-oncogene protein c-fes-fps; D014443:Tyrosine; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases