Involvement of Nha1 antiporter in regulation of intracellular pH in Saccharomyces cerevisiae

The Nhal antiporter is involved in regulation of intracellular pH in Saccharomyces cerevisiae. We report that deletion of the NHAl gene resulted in an increase of cytoplasmic pH in cells suspended in water or acidic buffers. Addition of KCl or NaCl to exponentially growing cells lowered the internal pH but the difference between cells with or without NHAl was maintained. Addition of KCI to starved cells resulted in much higher alkalinization of cytoplasmic pH in a strain lacking Nhalp compared to the wild-type or Nhal p-overexpressing strains. The H+/K+(Na+) exchange mechanism of Nhalp was confirmed in reconstituted plasma membrane vesicles. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.