Identification of phosphorylation sites in keratinocyte transglutaminase

Robert H. Rice, Majid Mehrpouyan, Qin Qin, Marjorie A. Phillips, Young M. Lee

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Phosphorylation of keratinocyte transglutaminase occurs in its N-terminal extension and is stimulated several-fold by the protein kinase C agonist phorbol myristate acetate. In the present work, this stimulation was prevented by simultaneous treatment of the cells with the protein kinase C-selective inhibitor GF109203X, In contrast, phosphorylation occurring in the absence of phorbol ester was essentially unaffected by GF109203X, although it was decreased dramatically by the non-selective kinase inhibitor staurosporine. Four serine residues that are subject to phosphorylation have been identified by sequencing of radioactive tryptic peptides. Serines at positions 24 and 92, each containing 2-8% of the total radioactivity with or without phorbol ester stimulation, were minor sites of phosphorylation. Serine-82 was by far the dominant site of phosphorylation in the absence of phorbol ester treatment, and was also the major site in its presence. Serine-85 was phosphorylated to a high degree in the presence but not in the absence of phorbol ester stimulation. Thus the data indicate the influence of at least two different kinase activities in transglutaminase phosphorylation.

Original languageEnglish (US)
Pages (from-to)547-550
Number of pages4
JournalBiochemical Journal
Volume320
Issue number2
StatePublished - Dec 1 1996

ASJC Scopus subject areas

  • Biochemistry

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    Rice, R. H., Mehrpouyan, M., Qin, Q., Phillips, M. A., & Lee, Y. M. (1996). Identification of phosphorylation sites in keratinocyte transglutaminase. Biochemical Journal, 320(2), 547-550.