Inositol Metabolism in Yeasts

Publisher Summary The chapter discusses the inositol metabolism in yeasts. Saccharomyces cerevisiae ( Sacch. cerevisiae) is an attractive organism because of its accessibility to genetic and molecular studies in which studies of the complex roles of phosphoinositides and other inositol-containing metabolites are pursued. Biochemical studies have clearly demonstrated that Phosphatidylinositol (PI), PIP, Triphosphorylated phosphatidylinositol (PIP 2 ), and the inositol phosphates derived from them exist in Sacch. cerevisiae. Most eukaryotic organisms have the capacity to synthesize inositol 1-phosphate (IlP) de novo by conversion of glucose 6-phosphate (G6P). Inositol-l-phosphate synthase (IlPS) activity has been detected in mammalian tissues, higher plants and a variety of fungi, including Neurospora and Sacch. Cerevisiae . Recent studies on yeast have suggested that inositol phospholipids may play roles in complex signaling pathways similar to those detected in animal cells. In addition, inositol has been demonstrated to function in yeast as a global regulator of phospholipid synthesis. This regulation occurs on a transcriptional level and is highly complex.