Lipin phosphatidic acid phosphatases: Structure, function, regulation, and disease association.

Lipids play essential roles as structural barriers in cell membranes, long-term energy storage, and as signaling molecules. One class of enzymes involved in lipid synthesis are lipins. Lipins are magnesium-dependent phosphatidic acid phosphatases that produce diacylglycerol, playing key roles in TAG synthesis, de novo phospholipid synthesis and metabolism. Here, we review recent advances on the structure, function, and regulation of lipins with a particular focus on the structural impacts of missense mutations associated with rhabdomyolysis, Majeed syndrome and neuropathies. Structural insights reveal that while some disease-associated mutations directly disrupt catalysis, many missense mutations are not near the active site, but still play a key role in PAP activity. With the resolved crystal structure of a lipin homolog Tt Pah2, AlphaFold, and AlphaMissense it has become increasingly possible to predict the pathogenicity and structural contributions of individual residues and mutations. Going forward, this structural information can be used to predict and understand new mutations as they arise.