The Influence of Knockouts of <i>PPN1</i> Polyphosphatase and <i>VTC4</i> Polyphosphate Synthetase Genes on Growth on Ethanol and Mitochondrial Polyphosphates in <i>Saccharomyces cerevisiae</i>

Abstract

One of the functions of inorganic polyphosphates (polyP), as compounds with phosphoester bonds, is participation in energy metabolism. Yeast mitochondria contain their own pool of polyphosphates; however, the ways in which these polymers are involved in the functioning of mitochondria in these microorganisms are not well understood. The aim of this work was to identify the effect of knockout mutations of the VTC4 polyphosphate synthetase gene and PPN1 one of the polyphosphatases gene on the content of polyphosphates and polyphosphatase activity in mitochondria of S. cerevisiae and the characteristics of the growth of mutant strains on ethanol. It was shown that knockout of the VTC4 gene led to a significant decrease in the content of polyP in mitochondria. Knockout of the PPN1 gene led to the disappearance of polyphosphatase activity, but only to a slight increase in the content of polyphosphates in mitochondria during growth on glucose. When grown on ethanol, the polyP content in the mitochondria of this strain coincided with that of the parental strain, and in both strains, it was approximately two times less than when grown on glucose. Both mutants are able to grow on a medium with ethanol as a carbon source; however, they are characterized by an elongation of the lag phase upon the transition from glucose consumption to ethanol consumption. It has been suggested that mitochondrial polyphosphates may represent the energy reserve of these organelles, which is necessary for the formation of full-fledged mitochondria during the transition from glycolysis to oxidative phosphorylation.