Regulation of the biosynthesis of acyl analogs of platelet-activating factor by purinergic agonist in endothelial cells

Abstract

We have previously shown that platelet-activating factor (PAF)-dependent transacetylase (TA) contains three catalytic activities, namely PAF: lysophospholipid TA (TA L), PAF: sphingosine TA (TA S) and PAF acetylhydrolase. It serves as a modifier of PAF actions by producing different lipid signal molecules. The TA L activity is involved in the biosynthesis of acyl analogs of PAF (acyl-PAF, 1-acyl-2-acetyl- sn-glycero-3-phosphocholine, acylacetyl-GPC) in agonist-stimulated endothelial cells. In the present investigation, we have studied the mechanism(s) by which the TA activity is regulated in ATP-treated endothelial cells. We have demonstrated that ATP, and thiol-modifying agents with ATP, specifically regulate only the TA L part of the TA activities.