Lack of Maf1 enhances pyruvate kinase activity and fermentative metabolism while influencing lipid homeostasis in Saccharomyces cerevisiae.

The Maf1 protein is a general negative repressor of RNA polymerase III, which is conserved in eukaryotes from yeast to humans. Herein, we show the yeast maf1Δ mutant increases pyruvate kinase activity, the key enzyme in glycolysis and an important player in switching between fermentative and oxidative metabolism. We observed enhanced ethanol production and elevated lipid content in the maf1Δ strain grown on glucose. However, after shifting to a non-fermentable carbon source, the opposite effect was observed, and the mutant cells accumulated smaller lipid droplets. Thus, it has been concluded that the Maf1 protein is essential for regulation of glucose metabolism and lipid homeostasis.