Phosphorylation of cytosolic group IV phospholipase A(2) is necessary but not sufficient for Arachidonic acid release in P388D(1) macrophages.
Activation of the cytosolic Group IV phospholipase A(2) (cPLA(2)) by agonists has been correlated with the direct phosphorylation of the enzyme by members of the mitogen-activated protein kinase (MAPK) cascade. Phosphorylation of the cPLA(2) increases the specific activity of the enzyme, thereby stimulating the arachidonic acid release. We show here, however, that conditions that lead to full phosphorylation of the cPLA(2) do not lead to enhanced AA release. As the above observations were made under both Ca(2+)-dependent and Ca(2+)-independent conditions, they emphasize that the current paradigm for activation of the cPLA(2) in cells involving both phosphorylation and Ca(2+) is incomplete and that other factors should be taken into account.
Balboa
M A
MA
Department of Chemistry, University of California at San Diego, La Jolla, California, 92093-0601, USA.
Balsinde
J
J
Dennis
E A
EA
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D054513:Group IV Phospholipases A2; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation; D008264:Macrophages / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010741:Phospholipases A / Q000378:metabolism*; D010766:Phosphorylation; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D005419:Flavonoids; D008070:Lipopolysaccharides; D016718:Arachidonic Acid; D020928:Mitogen-Activated Protein Kinases; D010741:Phospholipases A; D054513:Group IV Phospholipases A2; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium