Regulation of Membrane Lipid Homeostasis in Bacteria upon Temperature Change

Abstract

The major nonpolar lipids occurring in yeast are triacylglycerols and steryl esters. These storage lipids accumulate when cells are provided with an excess of nutrients. As substantial amounts of nonpolar lipids cannot be incorporated into biomembranes, they are sequestered from the cytosolic environment in so-called lipid droplets (lipid particles). Upon requirement storage lipids are mobilized from this compartment by triacylglycerol lipases and steryl ester hydrolases. The respective degradation products serve as energy sources and/or building blocks for membrane formation. In this chapter, the reader is introduced to different mechanisms oftriacylglycerol and steryl ester synthesis, storage ofthese lipids in lipid droplets, and their subsequent mobilization. Finally, major gaps in our current knowledge about nonpolar lipid metabolism and research needs for a better understanding of nonpolar lipid turnover are highlighted.