PHO8 gene coding alkaline phosphatase of Saccharomyces cerevisiae is involved in polyphosphate metabolism

Abstract

It has been argued for a long time whether alkaline phosphatase (ALP) is involved in polyphosphate (polyP) metabolism in arbuscular mycorrhizal fungi. In the present study, we have analyzed the effects of disrupting the PHO8 gene, which encodes phosphate (Pi)-deficiency-inducible ALP, on the polyP contents of Saccharomyces cerevisiae. The polyP content of the Δpho8 mutant was higher than the wild type strain in the logarithmic phase under Pi-sufficient conditions. On the contrary, the chain length of polyP extracted from the Δpho8 mutant did not differ from the wild type strain. When cells in Pi-deficient conditions were supplemented with Pi, the increase of the polyP amounts in the Δpho8 mutant was similar to that in the wild type strain. These results suggest that ALP, which is encoded by PHO8, affects the polyP content, but not the chain length, and participates in polyP homeostasis in Pi-sufficient conditions.