CEPT1 (choline/ethanolamine phosphotransferase 1) is a dual-specificity enzyme that catalyzes the final step in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthesis via the Kennedy pathway, transferring phosphate groups from CDP-choline or CDP-ethanolamine to diacylglycerol 12. The enzyme exhibits higher cholinephosphotransferase activity than ethanolaminephosphotransferase activity and localizes primarily to the endoplasmic reticulum 3. Structurally, CEPT1 forms dimers with 10 transmembrane segments per protomer, featuring a conserved catalytic domain with a hydrophobic chamber that coordinates acyl tails during catalysis 2. Beyond phospholipid synthesis, CEPT1 plays protective roles by suppressing ferroptosis through interactions with phospholipases and breakdown of pro-ferroptotic polyunsaturated fatty acid-containing phospholipids 4. In skeletal muscle, CEPT1 regulates insulin sensitivity and contractile function by modulating sarcoplasmic reticulum phospholipid composition and calcium handling 5. Additionally, endothelial CEPT1 promotes angiogenesis through PPARα and VEGF-A signaling pathways, particularly important in diabetic vascular recovery 6. Clinically, CEPT1 expression correlates inversely with insulin sensitivity in obese humans and is elevated in peripheral artery disease 56.