LPIN3 (lipin 3) is a magnesium-dependent phosphatidate phosphatase that catalyzes the conversion of phosphatidic acid to diacylglycerol, regulating fatty acid and lipid metabolism 1. Beyond its canonical enzymatic function, LPIN3 has emerged as a key regulator in multiple disease contexts. In colorectal cancer, LPIN3 promotes tumor growth by activating β-catenin signaling and suppressing CD8+ T cell-mediated anti-tumor immunity through reduced antigen presentation 2. In acetaminophen-induced liver injury, LPIN3 acts protectively by directly inhibiting JAK1 phosphorylation, thereby suppressing hepatocyte ferroptosis and pyroptosis via the JAK1-STAT3 axis 1. LPIN3 also plays a role in viral infections; knockdown of LPIN3 reduces SARS-CoV-2 replication by disrupting glycerophospholipid metabolism 3. Genetically, LPIN3 variants are associated with metabolic diseases and dementia susceptibility, with rs150562240 identified as a shared causal variant across dementia, Alzheimer's disease, and atherosclerosis 4. Unlike LPIN1 mutations which cause severe rhabdomyolysis, LPIN3 mutations are rarely associated with primary muscular manifestations 5. The protein contains a cell-penetrating peptide sequence enabling potential therapeutic applications 6.