title: Identification of the major SHPTP2-binding protein that is tyrosine-phosphorylated in response to insulin.
abstract: Immunoprecipitation of the cytosolic Src homology 2 domain-containing protein-tyrosine phosphatase, SHPTP2, from insulin-stimulated 3T3L1 adipocytes or Chinese hamster ovary cells expressing the human insulin receptor resulted in the coimmunoprecipitation of a diffuse tyrosine-phosphorylated band in the 115-kDa protein region on SDS-polyacrylamide gels. Although platelet-derived growth factor induced the tyrosine phosphorylation of the platelet-derived growth factor receptor and SHPTP2, there was no significant increase in the coimmunoprecipitation of tyrosine-phosphorylated pp115 with SHPTP2. SHPTP2 was also associated with tyrosine-phosphorylated insulin receptor substrate-1, but this only accounted for < 2% of the total immunoreactive SHPTP2 protein. Similarly, only a small fraction of the total amount of tyrosine-phosphorylated insulin receptor substrate-1 (< 4%) was associated with SHPTP2. Expression and immunoprecipitation of a Myc epitope-tagged wild-type SHPTP2 (Myc-WT-SHPTP2) and a catalytically inactive point mutant of SHPTP2 (Myc-C/S-SHPTP2) also demonstrated an insulin-dependent association of SHPTP2 with tyrosine-phosphorylated pp115. Furthermore, expression of the catalytically inactive SHPTP2 mutant resulted in a marked enhancement in the amount of coimmunoprecipitated tyrosine-phosphorylated pp115 compared with the expression of wild-type SHPTP2. These data indicate that the insulin-stimulated tyrosine-phosphorylated 115-kDa protein is the predominant in vivo SHPTP2-binding protein and that pp115 may function as a physiological substrate for the SHPTP2 protein-tyrosine phosphatase.
authors.affiliation: Department of Physiology and Biophysics, University of Iowa, Iowa City 52242, USA.
authors.forename: K
authors.initials: K
authors.lastname: Yamauchi
authors.forename: V
authors.initials: V
authors.lastname: Ribon
authors.forename: A R
authors.initials: AR
authors.lastname: Saltiel
authors.forename: J E
authors.initials: JE
authors.lastname: Pessin
mesh_terms: D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002384:Catalysis; D006224:Cricetinae; D051380:GRB2 Adaptor Protein; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D015513:Oncogene Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D050737:Proto-Oncogene Proteins c-crk; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495949:Grb2 protein, mouse; D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; C078332:Nck protein; D015513:Oncogene Proteins; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D050737:Proto-Oncogene Proteins c-crk; D014443:Tyrosine; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse