Activation of protein kinase C by the 14-3-3 proteins homologous with Exo1 protein that stimulates calcium-dependent exocytosis

FEBS Lett. 1992 Aug 17;308(2):121-4. doi: 10.1016/0014-5793(92)81257-m.


The 14-3-3 proteins are a family of acidic proteins found mainly in the brain and are suggested to have a role in monoamine synthesis based on their ability to activate tyrosine and tryptophan hydroxylases in the presence of type II Ca2+/calmodulin-dependent protein kinase. Recently, however, it has been demonstrated that a member of the 14-3-3 family, termed Exo1, stimulates Ca(2+)-dependent exocytosis in permeabilized adrenal chromaffin cells, suggesting that this protein family may influence the protein kinase C-mediated control of Ca(2+)-dependent exocytosis. Here we show that the 14-3-3 proteins activate protein kinase C at about 2-fold more than the known level of the activated protein kinase, i.e. the activity of protein kinase C in the presence of Ca2+ and phospholipids. This raises the possibility that the cellular activity of protein kinase C is regulated by diverse members of the 14-3-3 family and that the reported ability of Exo1 to reactivate Ca(2+)-dependent exocytosis is based on its stimulatory effect on protein kinase C activity. The 14-3-3 family, therefore, appears to be a multifunctional regulator of cell signalling processes mediated by two types of Ca(2+)-dependent protein kinase, protein kinase C and type II calmodulin-dependent protein kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins
  • Amino Acid Sequence
  • Animals
  • Calcium / metabolism*
  • Cations, Divalent
  • Cattle
  • Chromatography, High Pressure Liquid
  • Enzyme Activation
  • Exocytosis*
  • Molecular Sequence Data
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / isolation & purification
  • Nerve Tissue Proteins / physiology*
  • Phosphopyruvate Hydratase / metabolism*
  • Protein Kinase C / metabolism*
  • Sequence Alignment
  • Sequence Homology, Nucleic Acid
  • Tyrosine 3-Monooxygenase*


  • 14-3-3 Proteins
  • Cations, Divalent
  • Nerve Tissue Proteins
  • Tyrosine 3-Monooxygenase
  • Protein Kinase C
  • Phosphopyruvate Hydratase
  • Calcium