Protein kinase C isotypes and signaling in neutrophils. Differential substrate specificities of a translocatable calcium- and phospholipid-dependent beta-protein kinase C and a phospholipid-dependent protein kinase which is inhibited by long chain fatty acyl coenzyme A

J Biol Chem. 1991 May 15;266(14):9285-94.

Abstract

Neutrophils possess a classical Ca2+, phosphatidyl serine (PS) and diglyceride (DG)-dependent protein kinase C (beta-PKC) which was translocatable from cytosol to membrane in response to elevated Ca2+ in the physiologic range or to pretreatment with phorbol myristate acetate (PMA). The translocatable beta-PKC was purified from neutrophil membranes prepared in the presence of Ca2+, eluted with EGTA and subjected to hydroxyapatite chromatography. An 80-kDa protein possessing Ca/DG/PS-dependent histone phosphorylating activity was recognized by a monoclonal antibody to beta-PKC but not to alpha-PKC or gamma-PKC. A cytosolic kinase activity remaining after Ca(2+)-induced translocation of beta-PKC was dependent on PS and DG but did not require Ca2+. This novel Ca(2+)-independent, PS/DG-dependent kinase, termed nPKC, eluted from hydroxyapatite between alpha-PKC and beta-PKC, ran as a 76-kDa band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and was reactive to a polyclonal consensus antibody but not to monoclonal antibodies to alpha-PKC, beta-PKC, or gamma-PKC. Long chain fatty acyl-CoA, but not the corresponding free fatty acids, inhibited nPKC in the 1-10 microM range. The chemotactic peptide fMet-Leu-Phe triggered prompt but transient increases in neutrophil long chain fatty acid acyl-CoA, suggesting that nPKC is regulated by fatty acyl-CoA as well as DG during neutrophil activation. Purified beta-PKC phosphorylated a number of cytosolic proteins in a Ca(2+)-dependent manner, including a major 47-kDa cytosolic protein, which may be implicated in superoxide anion generation. In contrast, nPKC did not phosphorylate the 47-kDa protein, but phosphorylated numerous cytosolic proteins in a Ca(2+)-independent manner, including a 66-kDa protein which was not phosphorylated by beta-PKC. Differences in location, substrate specificity, and cofactor dependence between nPKC and beta-PKC suggest these kinases may play selective roles in the activation sequence of the neutrophil.

Publication types

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

MeSH terms

  • Acyl Coenzyme A / pharmacology
  • Amino Acid Sequence
  • Antibodies, Monoclonal / immunology
  • Calcium / physiology
  • Cell Compartmentation
  • Coenzyme A / metabolism
  • Diglycerides / physiology
  • Fatty Acids, Nonesterified / pharmacology
  • Humans
  • In Vitro Techniques
  • Molecular Sequence Data
  • N-Formylmethionine Leucyl-Phenylalanine / pharmacology
  • Neutrophils / enzymology*
  • Peptides / chemistry
  • Phosphatidylserines / physiology
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Kinase C / classification
  • Protein Kinase C / immunology
  • Protein Kinase C / isolation & purification
  • Protein Kinase C / physiology*
  • Signal Transduction
  • Tetradecanoylphorbol Acetate / pharmacology

Substances

  • Acyl Coenzyme A
  • Antibodies, Monoclonal
  • Diglycerides
  • Fatty Acids, Nonesterified
  • Peptides
  • Phosphatidylserines
  • Phosphoproteins
  • N-Formylmethionine Leucyl-Phenylalanine
  • Protein Kinase C
  • Tetradecanoylphorbol Acetate
  • Coenzyme A
  • Calcium