Phospholipase that hydrolyzes phosphatidic acid, including 1,2-dioleoyl-sn-phosphatidic acid. The different isoforms may change the substrate specificity (By similarity). Required for the organization of the endoplasmic reticulum exit sites (ERES), also known as transitional endoplasmic reticulum (tER) (By similarity). 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = (9Z)-octadecenoate + 2-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H(+) Forms homooligomers and, to a much smaller extent, heterooligomers with DDHD2. Interacts with SEC23A and SEC24C. Belongs to the PA-PLA1 family.