title: Characterization of a 60-kilodalton substrate of the insulin receptor kinase.
abstract: A 60-kDa tyrosine-phosphorylated protein has been observed after insulin treatment of cells in immunoprecipitations of the GTPase-activating protein of Ras (called GAP) as well as the phosphatidylinositol 3-kinase. In the present studies, these two 60-kDa proteins have been shown to differ by limited proteolytic digestions as well as by immunoprecipitation with a monoclonal antibody. This monoclonal antibody was also utilized to show that the 60-kDa GAP-associated protein was rapidly phosphorylated in intact cells after insulin stimulation and to associate with GAP only after insulin treatment of the cells. In addition, the 60-kDa protein was found to be phosphorylated in vitro by the insulin receptor. Finally, the 60-kDa protein immunoprecipitated by this antibody was found not to react with a polyclonal antibody directed against a 62-kDa tyrosine-phosphorylated GAP-associated protein previously observed in src-transformed cells. These studies indicate that insulin stimulates the tyrosine phosphorylation of at least two distinct 60-kDa proteins, one that becomes associated with GAP and appears to be a direct substrate of the insulin receptor kinase and another that associates with the phosphatidylinositol 3-kinase.
authors.affiliation: Hyogo Institute of Clinical Research, Akashi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hosomi
authors.forename: K
authors.initials: K
authors.lastname: Shii
authors.forename: W
authors.initials: W
authors.lastname: Ogawa
authors.forename: H
authors.initials: H
authors.lastname: Matsuba
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
authors.forename: K
authors.initials: K
authors.lastname: Yokono
authors.forename: M
authors.initials: M
authors.lastname: Kasuga
authors.forename: S
authors.initials: S
authors.lastname: Baba
authors.forename: R A
authors.initials: RA
authors.lastname: Roth
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D016466:CHO Cells; D006224:Cricetinae; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D020690:GTPase-Activating Proteins; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008970:Molecular Weight; D019000:Phosphotyrosine; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism; D011972:Receptor, Insulin / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000378:metabolism; D020703:ras GTPase-Activating Proteins
chemical_list: D000911:Antibodies, Monoclonal; D020690:GTPase-Activating Proteins; D007328:Insulin; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011972:Receptor, Insulin