Catalyzes the dephosphorylation of diacylglycerol diphosphate (DGPP) to phosphatidate (PA) and the subsequent dephosphorylation of PA to diacylglycerol (DAG). Together with DPP1, regulates intracellular DGPP and PA levels which are phospholipid molecules believed to play a signaling role in stress response. Can also use lysophosphatidic acid (LPA) as a substrate. Substrate preference is PA > DGPP > LPA. a 1,2-diacyl-sn-glycerol 3-diphosphate + H2O = a 1,2-diacyl-sn-glycero-3-phosphate + H(+) + phosphate a 1,2-diacyl-sn-glycero-3-phosphate + H2O = a 1,2-diacyl-sn-glycerol + phosphate a 1-acyl-sn-glycero-3-phosphate + H2O = a 1-acyl-sn-glycerol + phosphate PA phosphatase activity is magnesium ion-independent and potently inhibited by N-ethylmaleimide. Also inhibited by phenylglyoxal and propranolol. The phosphatase sequence motif I (including Arg-143) and II (including His-189) are part of the cytoplasmic loop 2 and phosphatase sequence motif III (including His-235) is part of the cytoplasmic loop 3. Present with 300 molecules/cell in log phase SD medium. Belongs to the PA-phosphatase related phosphoesterase family.