Secreted acid phosphatases maintain replicative lifespan via inositol polyphosphate metabolism in budding yeast

Abstract

Secreted acid phosphatases (APases) dephosphorylate extracellular organic phosphate compounds to supply inorganic phosphate (Pi) to maintain cellular functions. Here, we show that APases are necessary to maintain a normal replicative lifespan in Saccharomyces cerevisiae. Deletion of all four APase genes shortened the lifespan in yeast strains on synthetic media (irrespective of the concentrations of Pi in the media), but it did not affect the intracellular ortho- and polyphosphate levels. Deletion of inositol-pentakisphosphate 2-kinase (IPK1), which encodes inositol-pentakisphosphate 2-kinase, restored the lifespan in APase-null mutants, and IPK1 overexpression shortened the lifespan in wild-type strains. Overexpression of inositol hexakisphosphate (IP6) and heptakisphosphate kinases, KCS1 and VIP1, recovered the lifespan in APase-null mutants. Thus, yeast APases modulate the replicative lifespan, probably through dephosphorylation of intracellular IP6.