Plays a role in cell growth. Hydrolyzes membrane phospholipids, such as PtdCho (phosphatidylcholine), producing the free headgroup and PtdOH (phosphatidic acid; signaling molecule on its own). Involved in the inhibition of actin-based motility and endocytosis. Its inhibition causes complete collapse of F-actin organization. Plays an important role in cell migration by localizing along the anterior cell membrane. Overexpression leads to the inability to aggregate even at higher cell density. Also known as a negative regulator of quorum sensing. a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1,2-diacyl-sn-glycero-3-phosphate + choline + H(+) Inhibited by butan-1-ol. In migrating cells, localized at the protruding regions of pseudopodia. Not expressed in vegetative cells. Expression is apparent by 8 hours and peaked by 16 hours. Becomes present during aggregation and throughout development. Null cells show a motility defect; migration speed of vegetative cells is reduced to 73% of that of the wild-type, an aggregation ability at lower cell density and an ability to initiate and finish aggregation rapidly. Have altered cAR1 expression. Belongs to the phospholipase D family.