Activation of protein kinase C by purified bovine brain 14-3-3: comparison with tyrosine hydroxylase activation

J Neurochem. 1994 Nov;63(5):1908-16. doi: 10.1046/j.1471-4159.1994.63051908.x.


In the course of the purification of 14-3-3 protein (14-3-3) we found that 14-3-3 isolated from bovine forebrain activates protein kinase C (PKC), rather than the previously reported protein kinase C inhibitory activity (KCIP). We have characterized the 14-3-3 activation of PKC. The physical properties of purified PKC activator are the same as those previously reported for 14-3-3 and KCIP; i.e., (1) it is composed of subunits of molecular weight 32,000, 30,000, and 29,000; (2) it is homogeneous with respect to molecular weight, as judged by native gradient-gel electrophoresis, with a molecular weight of 53,000; and (3) it is composed of at least six isoforms when analyzed by reverse-phase HPLC. The concentration dependence of PKC activation by 14-3-3 is in the same range as that shown previously for KCIP inhibition of PKC, and as that required for 14-3-3 activation of tyrosine hydroxylase; a maximal stimulation of two- to three-fold occurs at 40-100 micrograms/ml. 14-3-3's activation of PKC is sensitive to alpha-chymotrypsin digestion but is not heat labile. Activation is specific to PKC; at least two other protein kinases, cyclic AMP- and calcium/calmodulin-dependent protein kinases, are not activated. The activation of PKC by 14-3-3 is independent of phosphatidylserine and calcium and, as such, is an alternative mechanism for the activation of PKC that obviates its translocation to membranes.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 14-3-3 Proteins
  • Animals
  • Brain / enzymology*
  • Brain Chemistry
  • Cattle
  • Chromatography, High Pressure Liquid
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation / drug effects
  • Molecular Weight
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • Proteins / analysis
  • Proteins / isolation & purification
  • Proteins / pharmacology*
  • Tyrosine 3-Monooxygenase / metabolism*


  • 14-3-3 Proteins
  • Proteins
  • Tyrosine 3-Monooxygenase
  • Protein Kinase C