This entry includes patatin-like phospholipase domain-containing proteins 1-5 (PNPLA1-5) from humans and Atgl-1 from Caenorhabditis elegans. They are a group of lipid hydrolases. Atgl-1 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. Human PNPLA1 plays a role in glycerophospholipid metabolism. PNPLA2 catalyses the initial step in triglyceride hydrolysis in adipocyte and non-adipocyte lipid droplets. PNPLA3 has both triacylglycerol lipase and acylglycerol O-acyltransferase activities.