Phorbol 12-myristate 13-acetate-dependent protein kinase C delta-Tyr311 phosphorylation in cardiomyocyte caveolae

J Biol Chem. 2008 Jun 27;283(26):17777-88. doi: 10.1074/jbc.M800333200. Epub 2008 Apr 3.

Abstract

Protein kinase Cdelta (PKCdelta) activation is generally attributed to lipid cofactor-dependent allosteric activation mechanisms at membranes. However, recent studies indicate that PKCdelta also is dynamically regulated through tyrosine phosphorylation in H(2)O(2)- and phorbol 12-myristate 13-acetate (PMA)-treated cardiomyocytes. H(2)O(2) activates Src and related Src-family kinases (SFKs), which function as dual PKCdelta-Tyr(311) and -Tyr(332) kinases in vitro and contribute to H(2)O(2)-dependent PKCdelta-Tyr(311)/Tyr(332) phosphorylation in cardiomyocytes and in mouse embryo fibroblasts. H(2)O(2)-dependent PKCdelta-Tyr(311)/Tyr(332) phosphorylation is defective in SYF cells (deficient in SFKs) and restored by Src re-expression. PMA also promotes PKCdelta-Tyr(311) phosphorylation, but this is not associated with SFK activation or PKCdelta-Tyr(332) phosphorylation. Rather, PMA increases PKCdelta-Tyr(311) phosphorylation by delivering PKCdelta to SFK-enriched caveolae. Cyclodextrin treatment disrupts caveolae and blocks PMA-dependent PKCdelta-Tyr(311) phosphorylation, without blocking H(2)O(2)-dependent PKCdelta-Tyr(311) phosphorylation. The enzyme that acts as a PKCdelta-Tyr(311) kinase without increasing PKCdelta phosphorylation at Tyr(332) in PMA-treated cardiomyocytes is uncertain. Although in vitro kinase assays implicate c-Abl as a selective PKCdelta-Tyr(311) kinase, PMA-dependent PKCdelta-Tyr(311) phosphorylation persists in cardiomyocytes treated with the c-Abl inhibitor ST1571 and c-Abl is not detected in caveolae; these results effectively exclude a c-Abl-dependent process. Finally, we show that 1,2-dioleoyl-sn-glycerol mimics the effect of PMA to drive PKCdelta to caveolae and increase PKCdelta-Tyr(311) phosphorylation, whereas G protein-coupled receptor agonists such as norepinephrine and endothelin-1 do not. These results suggest that norepinephrine and endothelin-1 increase 1,2-dioleoyl-sn-glycerol accumulation and activate PKCdelta exclusively in non-caveolae membranes. Collectively, these results identify stimulus-specific PKCdelta localization and tyrosine phosphorylation mechanisms that could be targeted for therapeutic advantage.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cyclodextrins / pharmacology
  • Endothelins / metabolism
  • Enzyme Activation
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Myocardium / metabolism
  • Myocytes, Cardiac / metabolism*
  • Norepinephrine / metabolism
  • Phosphorylation
  • Protein Kinase C-delta / chemistry*
  • Proto-Oncogene Proteins c-abl / antagonists & inhibitors
  • Rats
  • Rats, Wistar
  • Tetradecanoylphorbol Acetate / chemistry*
  • Tyrosine / chemistry*

Substances

  • Cyclodextrins
  • Endothelins
  • Enzyme Inhibitors
  • Tyrosine
  • Hydrogen Peroxide
  • Proto-Oncogene Proteins c-abl
  • Protein Kinase C-delta
  • Tetradecanoylphorbol Acetate
  • Norepinephrine