Growth at high pH and sodium and potassium tolerance in media above the cytoplasmic pH depend on ENA ATPases in Ustilago maydis.

ABSTRACT: Potassium and Na(+) effluxes across the plasma membrane are crucial processes for the ionic homeostasis of cells. In fungal cells, these effluxes are mediated by cation/H(+) antiporters and ENA ATPases. We have cloned and studied the functions of the two ENA ATPases of Ustilago maydis, U. maydis Ena1 (UmEna1) and UmEna2. UmEna1 is a typical K(+) or Na(+) efflux ATPase whose function is indispensable for growth at pH 9.0 and for even modest Na(+) or K(+) tolerances above pH 8.0. UmEna1 locates to the plasma membrane and has the characteristics of the low-Na(+)/K(+)-discrimination ENA ATPases. However, it still protects U. maydis cells in high-Na(+) media because Na(+) showed a low cytoplasmic toxicity. The UmEna2 ATPase is phylogenetically distant from UmEna1 and is located mainly at the en

SUBMITTER: Benito B 

PROVIDER: S-EPMC2698300 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature