Responses to phosphate deprivation in yeast cells.

Inorganic phosphate is an essential nutrient because it is required for the biosynthesis of nucleotides, phospholipids and metabolites in energy metabolism. During phosphate starvation, phosphatases play a major role in phosphate acquisition by hydrolyzing phosphorylated macromolecules. In Saccharomyces cerevisiae, PHM8 (YER037W), a lysophosphatidic acid phosphatase, plays an important role in phosphate acquisition by hydrolyzing lysophosphatidic acid and nucleotide monophosphate that results in accumulation of triacylglycerol and nucleotides under phosphate limiting conditions. Under phosphate limiting conditions, it is transcriptionally regulated by Pho4p, a phosphate-responsive transcription factor. In this review, we focus on triacylglycerol metabolism in transcription factors deletion mutants involved in phosphate metabolism and propose a link between phosphate and triacylglycerol metabolism. Deletion of these transcription factors results in an increase in triacylglycerol level. Based on these observations, we suggest that PHM8 is responsible for the increase in triacylglycerol in phosphate metabolising gene deletion mutants.