Protein kinase C-dependent phosphorylation of profilin is specifically stimulated by phosphatidylinositol bisphosphate (PIP2)

Biochem Biophys Res Commun. 1988 Jan 29;150(2):526-31. doi: 10.1016/0006-291x(88)90425-1.


Calf spleen profilin is shown to be an in vitro substrate of purified human placental protein kinase C (PKC), with an apparent Km of 4 microM. Phosphatidylinositol bisphosphate (PIP2) was an effective activator of the profilin phosphorylation by PKC and caused a maximum 13-fold increase of Vmax with a half maximal effect at 40 micrograms/ml. The action of PIP2 was not mimicked by phosphatidylserine, phosphatidic acid or phosphatidylinositol, whereas phosphatidylinositol monophosphate was slightly stimulatory. By contrast, protein kinase C-dependent phosphorylation of histone type III-S, myelin basic protein or lipocortin-I was not affected by PIP. It is suggested that PIP2 modifies the nature of the profilin-PKC interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / analysis
  • Animals
  • Cattle
  • Contractile Proteins / metabolism*
  • Female
  • Humans
  • Kinetics
  • Microfilament Proteins / isolation & purification
  • Microfilament Proteins / metabolism*
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositols / pharmacology*
  • Phosphorylation
  • Placenta / enzymology
  • Profilins
  • Protein Kinase C / metabolism*
  • Spleen / metabolism


  • Amino Acids
  • Contractile Proteins
  • Microfilament Proteins
  • PFN1 protein, human
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositols
  • Profilins
  • Protein Kinase C