Ligand-activated transcription factor. Key regulator of lipid metabolism. Activated by the endogenous ligand 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine (16:0/18:1-GPC). Activated by oleylethanolamide, a naturally occurring lipid that regulates satiety. Receptor for peroxisome proliferators such as hypolipidemic drugs and fatty acids. Regulates the peroxisomal beta-oxidation pathway of fatty acids. Functions as transcription activator for the ACOX1 and P450 genes. Transactivation activity requires heterodimerization with RXRA and is antagonized by NR2C2. May be required for the propagation of clock information to metabolic pathways regulated by PER2 (By similarity). Heterodimer; with RXRA. This heterodimerization is required for DNA binding and transactivation activity. Interacts with NCOA3 coactivator. Interacts with CITED2; the interaction stimulates its transcriptional activity. Also interacts with PPARBP in vitro. Interacts with AKAP13, LPIN1, PRDM16 and coactivator NCOA6. Interacts with ASXL1 and ASXL2. Interacts with PER2. Interacts with SIRT1; the interaction seems to be modulated by NAD(+) levels (By similarity). Interacts with CRY1 and CRY2 (By similarity). Belongs to the nuclear hormone receptor family. NR1 subfamily.