Brave little yeast, please guide us to Thebes: sphingolipid function in S-cerevisiae

Sphingolipids typically cover the exoplasmic leaflet of the plasma membrane of eukaryotic cells. They differ from the more abundant glycerophospholipi ds in that they contain ceramide instead of diacylglycerol as a hydrophobic anchor. Why did nature choose to invent this complex class of lipids, and why do eukaryotic cells follow elaborate remodelling pathways in order to g enerate dozens to hundreds of different molecular species of sphingolipid, depending on cell type? Yeast may, once again, serve as a model to dissect sphingolipid function at various levels. Almost the complete pathway for sp hingolipid synthesis in yeast has been uncovered during the past two decade s. More recently, key enzymes in sphingolipid degradation and signalling ha ve been identified. Together with a wealth of genetic data obtained from th e characterization of various suppressor mutants, this information now allo ws for an unprecedented analysis of sphingolipid function in this organism. This overview summarizes recent data on sphingolipid function in cell sign alling, their role in the heat-stress response and Ca2+ homeostasis, and ad dresses their function in transport of glycosylphosphatidylinositol-anchore d proteins. BioEssays 21:1004-1010, 1999. (C) 1999 John Wiley & Sons, Inc.