CTP : phosphocholine cytidylyltransferase: Insights into regulatory mechanisms and novel functions

A key regulatory enzyme in phosphatidylcholine biosynthesis, CTP:cholinepho sphate cytidylyltransferase (CCT), catalyzes the formation of CDP-choline. This review discusses the essential features of CCT and addresses intriguin g new insights into the catalytic and regulatory properties of this complex enzyme. Characterization of a lipid-binding segment in rat CCT is describe d and the role of lipids in CCT activation is discussed. An analysis of the phosphorylation domain is presented and possible physiological rationales for reversible phosphorylation of CCT are discussed. The nuclear localizati on of CCT is examined in the context of multiple CCT isoforms, as is recent evidence establishing a potential link between CCT activity and vesicular transport. (C) 1999 Academic Press.