Synthesis, metabolism, and trans-bilayer movement of long-chain base

Abstract

Long-chain bases (LCBs), mainly sphingosine in mammals and phytosphingosine in plants and fungi, act not only as structural constituents of sphingolipids but also as signaling molecules. LCBs can be converted to other bioactive lipid molecules, ceramide and long-chain base 1-phosphates (sphingosine 1-phosphate in mammals). In theory, the balance of these lipids determines cell fate (the sphingolipid rheostat model). Therefore, the regulation of the synthesis and metabolism of LCBs is quite important. To function as a signaling molecule or to become a substrate for certain metabolizing enzymes, the LCB must be localized in a specific leaflet of the lipid bilayer. Thus, regulation of LCB trans-bilayer movement is also important. This review focuses on recent gains in our understanding of the synthesis, metabolism, and trans-bilayer movement of LCBs. © Springer-Verlag Tokyo 2006. All rights reserved.