Identification of caspase 3 motifs and critical aspartate residues in human Phospholipase D1b and Phopsholipase D2a

Abstract

Stimulation of mammalian cells frequently initiates phospholipase D-catalysed hydrolysis of phosphatidylcholine in the plasma membrane to yield phosphatidic acid (PA) a novel lipid messenger. PA plays a regulatory role in important cellular processes such as secretion, cellular shape change and movement. A number of studies have highlighted that PLD-based signalling also plays a pro-mitogenic and pro-survival role in cells and therefore anti-apoptotic. We show that human PLD1b and PLD2a contain functional caspase-3 cleavage sites and identify the critical aspartate residues within PLD1b that affect its activation by phorbol esters and attenuate phosphatidylcholine hydrolysis during apoptosis