AGPAT5 (1-acylglycerol-3-phosphate O-acyltransferase 5) is a lipid metabolic enzyme that catalyzes the second acylation step in glycerophospholipid synthesis 1. The enzyme converts lysophosphatidic acid (LPA) to phosphatidic acid (PA) by incorporating acyl groups at the sn-2 position of the glycerol backbone, preferentially using C18:1-CoA as the acyl donor for LPA substrates containing saturated or unsaturated fatty acids (C15:0-C20:4) 1. AGPAT5 also demonstrates activity toward lysophosphatidylethanolamine with oleoyl-CoA and lysophosphatidylinositol with arachidonoyl-CoA, showing substrate and fatty acid specificity distinct from related isoforms 1. Subcellularly, AGPAT5 localizes to mitochondria, nuclear envelope, and endoplasmic reticulum 1, supporting mitochondrial glycerophospholipid synthesis capacity. Genetically, AGPAT5 associates with insulin resistance and related metabolic traits in mice 2, with liver-specific deletion protecting against sucrose-induced hyperinsulinemia and glucose intolerance through modulation of phosphatidylglycerol and cardiolipin levels 3. Additionally, AGPAT5 is identified as a component of prognostic gene signatures in hepatocellular carcinoma, where elevated expression associates with worse survival outcomes and altered immune microenvironment characteristics 45.