Ceramide 1-phosphate is required for the translocation of group IVA cytosolic phospholipase A2 and prostaglandin synthesis

J Biol Chem. 2009 Sep 25;284(39):26897-907. doi: 10.1074/jbc.M109.001677. Epub 2009 Jul 23.

Abstract

Little is known about the regulation of eicosanoid synthesis proximal to the activation of cytosolic phospholipase A(2)alpha (cPLA(2)alpha), the initial rate-limiting step. The current view is that cPLA(2)alpha associates with intracellular/phosphatidylcholine-rich membranes strictly via hydrophobic interactions in response to an increase of intracellular calcium. In opposition to this accepted mechanism of two decades, ceramide 1-phosphate (C1P) has been shown to increase the membrane association of cPLA(2)alpha in vitro via a novel site in the cationic beta-groove of the C2 domain (Stahelin, R. V., Subramanian, P., Vora, M., Cho, W., and Chalfant, C. E. (2007) J. Biol. Chem. 282, 20467-204741). In this study we demonstrate that C1P is a proximal and required bioactive lipid for the translocation of cPLA(2)alpha to intracellular membranes in response to inflammatory agonists (e.g. calcium ionophore and ATP). Last, the absolute requirement of the C1P/cPLA(2)alpha interaction was demonstrated for the production of eicosanoids using murine embryonic fibroblasts (cPLA(2)alpha(-/-)) coupled to "rescue" studies. Therefore, this study provides a paradigm shift in how cPLA(2)alpha is activated during inflammation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Calcium / metabolism
  • Cell Line
  • Cell Line, Tumor
  • Cells, Cultured
  • Ceramides / metabolism*
  • Female
  • Fibroblasts / cytology
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Group IV Phospholipases A2 / genetics
  • Group IV Phospholipases A2 / metabolism*
  • Humans
  • Immunoblotting
  • Interleukin-1beta / pharmacology
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Male
  • Microscopy, Confocal
  • Mutation
  • Pregnancy
  • Prostaglandins / biosynthesis*
  • Protein Transport / drug effects
  • RNA Interference
  • Transfection

Substances

  • Ceramides
  • Interleukin-1beta
  • Luminescent Proteins
  • Prostaglandins
  • ceramide 1-phosphate
  • Adenosine Triphosphate
  • Group IV Phospholipases A2
  • PLA2G4A protein, human
  • Calcium