Arachidonic acid esterification into membrane phospholipids is controlled by a calcium-independent phospholipase A2

BALSINDE, J.; BIANCO I.D.; ACKERMAN, E.J.; CONDE-FRIEBOES, K.; DENNIS, E.A.

NATL ACAD SCIENCES

Lugar: Washington DC, USA; Año: 1995 vol. 92 p. 8527 - 8527

BSTRACT Cellular levels of free arachidonic acid (AA)are controlled by a deacylation/reacylation cycle whereby the fatty acid is liberated by phospholipases and reincorporated by acyltransferases. We have found that the esterification of AA into membrane phospholipids is a Ca2+-independent process and that it is blocked up to 60-70%o by a bromoenollactone (BEL) that is a selective inhibitor of a newly discovered Ca2+-independent phospholipase A2 (PLA2) in macrophages. The observed inhibition correlates with a decreased steady state level of lysophospholipids as well as with the inhibition of the Ca2+-independent PLA2 activity in these cells. This inhibition is specific for the Ca2 -independent PLA2 in that neither group IV PLA2, group II PLA2, arachidonoyl-CoA synthetase, lysophospholipid:arachidonoyl-CoA acyltransferase, nor CoA-independent transacylase is affected by treatment with BEL. Moreover, two BEL analogs that are not inhibitors of the Ca2+-independent PIA2-namely a bromome