Protein kinase C phosphorylates pp60src at a novel site

Cell. 1985 Oct;42(3):849-57. doi: 10.1016/0092-8674(85)90281-8.


The transforming protein of Rous sarcoma virus (pp60v-src) and its normal cellular homolog (pp60c-src) are demonstrated to be phosphorylated at serine 12 in vivo under certain conditions. We propose that protein kinase C is responsible for this modification based on the following evidence. First, the tumor promoters, 12-O-tetradecanoylphorbol-13-acetate and teleocidin, and synthetic diacylglycerol, known activators of protein kinase C in vivo, cause nearly complete phosphorylation of pp60src at serine 12. Second, among five purified serine/threonine-specific protein kinases tested, only protein kinase C phosphorylates pp60c-src and pp60v-src in vitro at serine 12. Third, purified protein kinase C phosphorylates a synthetic peptide corresponding to the N-terminal 20 amino acids of pp60c-src at serine 12. The physiological significance of this novel phosphorylation is discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Avian Sarcoma Viruses / enzymology
  • Brain / enzymology
  • Cells, Cultured
  • Kinetics
  • Mice
  • Muscles / enzymology
  • Oncogene Protein pp60(v-src)
  • Phosphorylation
  • Protein Kinase C / isolation & purification
  • Protein Kinase C / metabolism*
  • Protein Kinases / isolation & purification
  • Protein Kinases / metabolism*
  • Rabbits
  • Rats
  • Retroviridae Proteins / metabolism*
  • Serine
  • Substrate Specificity
  • Tetradecanoylphorbol Acetate / pharmacology


  • Retroviridae Proteins
  • Serine
  • Protein Kinases
  • Oncogene Protein pp60(v-src)
  • Protein Kinase C
  • Tetradecanoylphorbol Acetate