Polyphosphate, Polyphosphatase and Stress Resistance of Knockout Mutants in the PPN1 and PPN2 Genes of Saccharomyces cerevisiae

Abstract

Yeast cells possess high levels of inorganic polyphosphate, which is involved in various processes regulating vital activities. In this work, using the commercially available Saccharomyces cerevisiae knockout mutants in the PPN1 and PPN2 genes encoding polyphosphatases, we have shown that each of the two single mutations leads to a set of similar physiological effects at the stationary stage of growth on glucose: the increased resistance to manganese and peroxide stresses, lack of polyphosphatase activity in mitochondria, and the increase in long-chained polyphosphate level. We suggest, that the increased stress resistance of ∆ppn1 and ∆ppn2 strains is associated with the increase in the level of long-chained polyphosphate. The cells of ∆ppn1 and ∆ppn2 mutants showed no significant differences in growth parameters in the media with ethanol or glucose compared to the parent strain. Earlier, we observed the inability to grow on non-fermentable carbon sources and mitochondrial defects in the ∆ppn1 mutant CRN constructed from another parent strain. The ∆ppn1 strain from the Dharmacon collection has no defects in mitochondria function. The data obtained provide evidence in favor of the participation of polyphosphates in stress adaptation of yeast cells.