Identification of a phosphorylation site of the rat insulin receptor catalyzed by protein kinase C in an intact cell.
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.
Koshio
O
O
Institute for Diabetes Care and Research, Asahi Life Foundation, Tokyo, Japan.
Akanuma
Y
Y
Kasuga
M
M
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
D010750:Phosphoproteins; D010769:Phosphothreonine; D013912:Threonine; D011972:Receptor, Insulin; D011493:Protein Kinase C; D014357:Trypsin