title: Identification of a phosphorylation site of the rat insulin receptor catalyzed by protein kinase C in an intact cell.
abstract: In two-dimensional tryptic phosphopeptide mapping, the beta-subunit of the insulin receptor phosphorylated by 12-O-tetradecanoylphorbol-13-acetate in rat hepatoma cells (H-35) was separated into one phosphothreonine-containing peptide and several phosphoserine-containing peptides. The synthetic peptide coding residues 1327-1343 in the C-terminal region of the rat insulin receptor was phosphorylated at the threonine residue by protein kinase C in a phosphatidylserine and oleoylacetylglycerol dependent manner. Tryptic digest of this phosphopeptide migrated to the same position as the phosphothreonine containing peptide obtained from the beta-subunit in two-dimensional phosphopeptide mapping. These data suggested that Thr 1336 of the insulin receptor is the site of phosphorylation by protein kinase C in intact cells.
authors.affiliation: Institute for Diabetes Care and Research, Asahi Life Foundation, Tokyo, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Koshio
authors.forename: Y
authors.initials: Y
authors.lastname: Akanuma
authors.forename: M
authors.initials: M
authors.lastname: Kasuga
mesh_terms: D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000032:analysis; D010766:Phosphorylation; D010769:Phosphothreonine / Q000032:analysis; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011972:Receptor, Insulin / Q000032:analysis*; D013912:Threonine / Q000378:metabolism; D014357:Trypsin
chemical_list: D010750:Phosphoproteins; D010769:Phosphothreonine; D013912:Threonine; D011972:Receptor, Insulin; D011493:Protein Kinase C; D014357:Trypsin