Acts as a magnesium-dependent phosphatidate phosphatase enzyme which catalyzes the conversion of phosphatidic acid to diacylglycerol during triglyceride, phosphatidylcholine and phosphatidylethanolamine biosynthesis and therefore controls the metabolism of fatty acids at different levels (PubMed:17158099). Acts also as nuclear transcriptional coactivator for PPARGC1A/PPARA regulatory pathway to modulate lipid metabolism gene expression (PubMed:16950137). Is involved in adipocyte differentiation (PubMed:16049017). Recruited at the mitochondrion outer membrane and is involved in mitochondrial fission by converting phosphatidic acid to diacylglycerol. a 1,2-diacyl-sn-glycero-3-phosphate + H2O = a 1,2-diacyl-sn-glycerol + phosphate 1-octadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycerol + phosphate 1-octadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycerol + phosphate 1-octadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycerol + phosphate 1-octadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycerol + phosphate 1-octadecanoyl-2-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(9Z,12Z)-octadecadienoyl-sn-glycerol + phosphate 1-octadecanoyl-2-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(9Z,12Z)-octadecadienoyl-sn-glycerol + phosphate 1-octadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(9Z-octadecenoyl)-sn-glycerol + phosphate 1-octadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = 1-octadecanoyl-2-(9Z-octadecenoyl)-sn-glycerol + phosphate 1-hexadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycerol + phosphate 1-hexadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycerol + phosphate 1,2-dioctadecanoyl-sn-glycero-3-phosphate + H2O = 1,2-dioctadecanoyl-sn-glycerol + phosphate 1-hexadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycerol + phosphate 1-hexadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-sn-glycerol + phosphate 1-hexadecanoyl-2-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(9Z,12Z-octadecadienoyl)-sn-glycerol + phosphate 1-hexadecanoyl-2-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(9Z,12Z-octadecadienoyl)-sn-glycerol + phosphate 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycerol + phosphate 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycerol + phosphate 1,2-di-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycero-3-phosphate + H2O = 1,2-di-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycerol + phosphate 1,2-di-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycero-3-phosphate + H2O = 1,2-di-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycerol + phosphate 1,2-di-(5Z,8Z,11Z,14Z)-eicosatetraenoyl-sn-glycero-3-phosphate + H2O = 1,2-di-(5Z,8Z,11Z,14Z)-eicosatetraenoyl-sn-glycerol + phosphate 1,2-di-(5Z,8Z,11Z,14Z)-eicosatetraenoyl-sn-glycero-3-phosphate + H2O = 1,2-di-(5Z,8Z,11Z,14Z)-eicosatetraenoyl-sn-glycerol + phosphate 1,2-di-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phosphate + H2O = 1,2-di-(9Z,12Z-octadecadienoyl)-sn-glycerol + phosphate 1,2-di-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phosphate + H2O = 1,2-di-(9Z,12Z-octadecadienoyl)-sn-glycerol + phosphate 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = 1,2-di-(9Z-octadecenoyl)-sn-glycerol + phosphate 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphate + H2O = 1,2-di-(9Z-octadecenoyl)-sn-glycerol + phosphate 1,2-dihexadecanoyl-sn-glycero-3-phosphate + H2O = 1,2-dihexadecanoyl-sn-glycerol + phosphate Inhibited by N-ethylmaleimide treatment. Interacts (via LXXIL motif) with PPARA (PubMed:16950137). Interacts with PPARGC1A (PubMed:16950137). Interaction with PPARA and PPARGC1A leads to the formation of a complex that modulates gene transcription (PubMed:16950137). Interacts with MEF2C (PubMed:19753306). Recruited at the mitochondrion outer membrane following phosphatidic acid formation mediated by PLD6. In neuronals cells, isoform 1 is exclusively cytoplasmic (PubMed:21397848). In 3T3-L1 pre-adipocytes, it primarily located in the cytoplasm (PubMed:16049017). Nuclear localization requires both CNEP1R1 and CTDNEP1 (PubMed:22134922). In neuronals cells, localized in both the cytoplasm and the nucleus (PubMed:19753306). In 3T3-L1 pre-adipocytes, it is predominantly nuclear (PubMed:16049017). Translocates from the cytosol to the endoplasmic reticulum following acetylation by KAT5 (By similarity). Specifically expressed in skeletal muscle. Also expressed prominently in adipose tissue, and testis. Lower expression also detected in kidney, lung, brain and liver. Predominant isoform in the liver. Predominant isoform in the brain. By fasting, glucocorticoids and diabetes in the liver in a PPARGC1A-dependent manner. Up-regulated during differentiation of 3T3-L1 pre-adipocytes. Contains one Asp-Xaa-Asp-Xaa-Thr (DXDXT) motif, a catalytic motif essential for phosphatidate phosphatase activity. Contains one Leu-Xaa-Xaa-Ile-Leu (LXXIL), a transcriptional binding motif, which mediates interaction with PPARA. Phosphorylated at multiple sites in response to insulin. Phosphorylation is controlled by the mTOR signaling pathway. Phosphorylation is decreased by epinephrine. Phosphorylation may not directly affect the catalytic activity but may regulate the localization. Dephosphorylated by the CTDNEP1-CNEP1R1 complex. Sumoylation is important in brain and is marginal in other tissues. Sumoylation facilitates nuclear localization of isoform 2 in neuronals cells and its transcriptional coactivator activity. Acetylation at Lys-459 and Lys-629 by KAT5 in response to fatty acids promotes translocation to the endoplasmic reticulum and synthesis of diacylglycerol. Defects in Lpin1 are the cause of the fatty liver dystrophy phenotype (fld). Fld mutant mice are characterized by neonatal fatty liver and hypertriglyceridemia that resolve at weaning, and neuropathy affecting peripheral nerve in adulthood. Adipose tissue deficiency, glucose intolerance and increased susceptibility to atherosclerosis are associated with this mutation too. Two independent mutant alleles are characterized in this phenotype, fld and fld2j. Belongs to the lipin family.