Phospholipase that hydrolyzes phosphatidic acid, including 1,2-dioleoyl-sn-phosphatidic acid. The different isoforms may change the substrate specificity (PubMed:22922100). Required for the organization of the endoplasmic reticulum exit sites (ERES), also known as transitional endoplasmic reticulum (tER) (PubMed:17428803). 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 (PubMed:22922100). Interacts with SEC23A and SEC24C (PubMed:17428803). Highly expressed in testis. Also expressed in brain, spleen and lung. Only expressed in cerebellum in fetal brain. The disease is caused by variants affecting the gene represented in this entry. Belongs to the PA-PLA1 family. Extended N-terminus. Truncated N-terminus.