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Evidence that cytosolic phospholipase A 2 is down‐regulated by protein kinase C in intact human platelets stimulated with fluoroaluminate
Author(s) -
Nucciarelli Fabio,
Gresele Paolo,
Nardicchi Vincenza,
Porcellati Serena,
Macchioni Lara,
Nenci Giuseppe G.,
Goracci Gianfrancesco
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00436-6
Subject(s) - protein kinase c , arachidonic acid , phospholipase a2 , cytosol , extracellular , phospholipase c , activator (genetics) , phospholipase a , phospholipase , intracellular , biochemistry , platelet , bapta , chemistry , enzyme , biology , immunology , gene
We reported that protein kinase C (PKC) inhibitors increase the release of arachidonic acid induced by fluoroaluminate (AlF 4 − ), an unspecific G‐protein activator, in intact human platelets. Now we demonstrate that this effect is independent of the extracellular Ca 2+ concentration and that AlF 4 − ‐induced release of AA is abolished by BAPTA, an intracellular Ca 2+ chelator, even in the presence of GF 109203X, a specific and potent PKC inhibitor. This compound also blocks the liberation of the secretory phospholipase A 2 in the extracellular medium, indicating that this enzyme is not involved in the potentiation of arachidonic acid by PKC inhibitors. On the other hand, the latter effect is completely abolished by treatment of platelets with AACOCF 3 , a specific inhibitor of cytosolic phospholipase A 2 (cPLA 2 ). These observations indicate that cPLA 2 is responsible for the AlF 4 − ‐induced release of arachidonic acid by a mechanism that is down‐regulated by PKC.