PGS1 (phosphatidylglycerophosphate synthase 1) is a key enzyme in mitochondrial phospholipid biosynthesis, specifically functioning in the synthesis of phosphatidylglycerol and cardiolipin 1. The enzyme catalyzes CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase activity and localizes to the mitochondrial inner membrane and matrix 2. PGS1 forms oligomers and associates with other cardiolipin biosynthesis enzymes including CLS1 and PTPMT1, creating a cardiolipin-synthesizing scaffold within the mitochondrial inner membrane 2. This complex interacts with cardiolipin-binding mitochondrial proteins such as prohibitins, stomatin-like protein 2, and MICOS components, suggesting coordinated regulation of cardiolipin metabolism and mitochondrial membrane organization 2. Disease relevance includes involvement in septic cardiomyopathy, where PGS1 is identified as a mitochondria-related hub gene associated with immune infiltration patterns 3. PGS1 depletion can modulate mitochondrial dynamics by reducing cardiolipin content and inhibiting mitochondrial fission, which may improve respiratory defects in OPA1-deficient cells 4. The gene has also been identified as a potential biomarker in various conditions including Kawasaki disease and hepatocellular carcinoma through computational analyses 56.