CTP:phosphocholine cytidylyltransferase (CCT)

CTP:phosphocholine cytidylyltransferase is the **rate-limiting enzyme** in the CDP-choline pathway, also known as the Kennedy pathway, which is responsible for synthesizing phosphatidylcholine—the most abundant phospholipid in eukaryotic cell membranes. This enzyme catalyzes the conversion of phosphocholine and CTP to CDP-choline, a critical step before choline can be incorporated into diacylglycerol to form phosphatidylcholine. The activity of this enzyme regulates membrane biogenesis and cellular lipid homeostasis. It exists primarily as two isoforms—CCTα and CCTβ—encoded by separate genes; these differ in subcellular localization due to nuclear localization signals. The function of this enzyme can be inhibited by its product or analogs such as miltefosine, which has implications for antiparasitic drug action. Disruption or dysregulation of this pathway has been linked to diseases involving altered membrane composition or signaling, including cancer and neurodegeneration. The CDP-choline pathway begins with choline kinase converting choline into phosphocholine. The rate-limiting step is catalyzed by CTP:phosphocholine cytidylyltransferase... ...the Pfpmt-mediated alternative pathway for PtdCho biosynthesis... Pfpmt activity was inhibited by its product P-Chol... miltefosine also inhibited Pfpmt activity...

Other names

CCTPCYT1A (for alpha isoform)Kennedy pathway rate-limiting enzymeCholine-phosphate cytidylyltransferase

Inhibition of enzymatic activity leading to reduced phosphatidylcholine synthesis