PNPLA4 (patatin-like phospholipase domain-containing protein 4) encodes a lipid hydrolase with both triacylglycerol lipase and transacylase activity, suggesting a dual role in lipid hydrolysis and remodeling. Multiple transcript variants, including transcript variant 2, have been identified; however, they encode the same isoform, highlighting regulatory diversity rather than structural differences. PNPLA4 shows broad tissue expression, consistent with a role in maintaining lipid homeostasis.
Comparative genomic analyses indicate that PNPLA4 is a relatively small member of the PNPLA family (≈252–255 amino acids) containing the conserved patatin domain with a Ser–Asp catalytic dyad and oxyanion hole motif. The human gene is located on the X chromosome (Xp22.3) and is conserved across vertebrates, supporting its essential metabolic function.