Membrane Lipids of Yeast: Biochemical and Genetic Studies

Abstract

INTRODUCTION
Saccharomyces cerevisiae is a fairly typical eukaryotic organism with respect to the membranous organelles it contains, as well as the lipids that comprise its membranes. Like other eukaryotes, it synthesizes and incorporates sterol into its membranes. In addition, its membranes contain a typically eukaryotic mixture of phospholipids, including sphingolipids, cardiolipin, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol (see Fig. 5). The pathways for the synthesis of yeast membrane lipids are increasingly well characterized. In addition, a number of mutations affecting these pathways have been characterized, and reliable methodologies for isolation of some subcellular membrane fractions are being developed. As a result, S. cerevisiae is an attractive organism in which to conduct studies on the roles of specific lipids in membrane biogenesis and membrane-mediated processes.

In bacteria (for reviews, see Silbert et al. 1974; Silbert 1975; Raetz 1978), lipid mutants have been used to study the role of lipid synthesis on membrane biogenesis and to manipulate membrane lipid composition. Such experiments permit assessment of the role(s) of various lipids in membrane function and allow the physical properties of the membrane lipid bilayer to be experimentally manipulated in vivo. Since S. cerevisiae is a eukaryotic organism, yeast lipid mutants can be used for probing the role of lipids in the biogenesis and functioning of a variety of membranous organelles. In this paper studies of this kind are reviewed together with genetic and biochemical studies on the pathways involved in lipid synthesis in yeast.

DISTRIBUTION OF LIPIDS AND LIPID BIOSYNTHETIC ACTIVITIES INTO VARIOUS MEMBRANE...