Saccharomyces cerevisiae PDE genes influence medium acidification and cell viability

Abstract

The yeast Saccharomyces cerevisiae contains two genes, PDE1 and PDE2, which encode a low-affinity and a high-affinity cAMP phosphodiesterase, respectively, and are regulators of the amount of the secondary messenger cAMP. Deletion of PDE2 and PDE1 changes the ability of yeast cells to survive stress conditions such as heat shock and nitrogen starvation. In this study, we analysed the influence of low-affinity and high-affinity cAMP phosphodiesterases on medium acidification (caused by a peculiarity in yeast metabolism) during cell growth and on yeast cell viability during a gradual medium acidification and in acid stress conditions. A statistically significant increase in ΔPde1 cell viability during a gradual acidification of the medium and also in acid stress conditions allows us to suggest that the PDE1 gene is a negative regulator of cell viability in acidic conditions. Our study also shows that inactivation of the PDE2 gene decreases cell viability after acid shock induction. It can be suggested that Pde2p is a positive regulator of cell viability in acid stress conditions. The two yeast phosphodiesterases play different roles in the regulation of cell viability in acidic conditions. Keywords: Saccharomyces cerevisiae, PDE1, PDE2 phosphodiesterases, medium acidification, acid stress, cell viability