Identification of serines-1035/1037 in the kinase domain of the insulin receptor as protein kinase C alpha mediated phosphorylation sites.
A new site of serine phosphorylation (Ser-1035/1037) has been identified in the kinase domain of the insulin receptor. Mutant receptors missing these two serines were expressed in Chinese hamster ovary cells overexpressing protein kinase C alpha. These mutant receptors lacked a phorbol ester-stimulated phosphoserine containing tryptic peptide as demonstrated by both high percentage polyacrylamide/urea gel electrophoresis and two-dimensional tlc. Moreover, a synthetic peptide with the sequence of this tryptic peptide was phosphorylated by isolated protein kinase C alpha and co-migrated with the phosphopeptide from in vivo labeled receptor. These results indicate that serine-1035 and/or 1037 in the kinase domain of the insulin receptor are phosphorylated in response to activation of protein kinase C alpha.
Liu
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F
Department of Molecular Pharmacology, Stanford University School of Medicine, CA 94305.
Roth
R A
RA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D016466:CHO Cells; D006224:Cricetinae; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D010748:Phosphopeptides / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D011972:Receptor, Insulin / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012694:Serine / Q000032:analysis*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D014357:Trypsin
D007527:Isoenzymes; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments; D010748:Phosphopeptides; D011994:Recombinant Proteins; D010768:Phosphoserine; D012694:Serine; D011972:Receptor, Insulin; D011493:Protein Kinase C; D014357:Trypsin; D013755:Tetradecanoylphorbol Acetate