The function of PNPLA2 (patatin like domain 2, triacylglycerol lipase, ENSG00000177666) is as follows. Catalyzes the initial step in triglyceride hydrolysis in adipocyte and non-adipocyte lipid droplets (PubMed:15364929, PubMed:15550674, PubMed:16150821, PubMed:16239926, PubMed:17603008, PubMed:34903883). Exhibits a strong preference for the hydrolysis of long-chain fatty acid esters at the sn-2 position of the glycerol backbone and acts coordinately with LIPE/HLS and DGAT2 within the lipolytic cascade (By similarity). Also possesses acylglycerol transacylase and phospholipase A2 activities (PubMed:15364929, PubMed:17032652, PubMed:17603008). Transfers fatty acid from triglyceride to retinol, hydrolyzes retinylesters, and generates 1,3- diacylglycerol from triglycerides (PubMed:17603008). Regulates adiposome size and may be involved in the degradation of adiposomes (PubMed:16239926). Catalyzes the formation of an ester bond between hydroxy fatty acids and fatty acids derived from triglycerides or diglycerides to generate fatty acid esters of hydroxy fatty acids (FAHFAs) in adipocytes (PubMed:35676490). Acts antagonistically with LDAH in regulation of cellular lipid stores (PubMed:28578400). Inhibits LDAH-stimulated lipid droplet fusion (PubMed:28578400). May play an important role in energy homeostasis (By similarity). May play a role in the response of the organism to starvation, enhancing hydrolysis of triglycerides and providing free fatty acids to other tissues to be oxidized in situations of energy depletion (By similarity). {ECO:0000250|UniProtKB:Q8BJ56, ECO:0000269|PubMed:15364929, ECO:0000269|PubMed:15550674, ECO:0000269|PubMed:16150821, ECO:0000269|PubMed:16239926, ECO:0000269|PubMed:17032652, ECO:0000269|PubMed:17603008, ECO:0000269|PubMed:28578400, ECO:0000269|PubMed:34903883, ECO:0000269|PubMed:35676490}.