HOW IS MEMBRANE PHOSPHOLIPID BIOSYNTHESIS CONTROLLED IN NEURAL TISSUES

Phospholipids are the major constituents of cell membranes, and have n umerous structural and functional roles in the nervous system, Althoug h the metabolic pathways responsible for the syntheses of the phosphat ides phosphatidylcholine (PtdCho), phosphatidylethanolamine (PtdEtn), and phsophatidylserine (PtdSer) are well understood, the mechanisms co ntrolling these pathways in neural tissue have not been fully characte rized, Recent studies have suggested that the main factors controlling PtdCho and PtdEtn synthesis by the Kennedy cycle tend to be the intra cellular levels of key substrates for the biosynthetic enzymes, or cha nges in the activities of the rate-limiting enzymes, Moreover, differe nt control mechanisms may operate, depending upon the functional state of the tissue. (C) 1998 Wiley-Liss, Inc.