Vacuolar cation/H+ antiporters of Saccharomyces cerevisiae.

We previously demonstrated that Saccharomyces cerevisiae vnx1 mutant strains displayed an almost total loss of Na+ and K+/H+ antiporter activity in a vacuolar-enriched fraction. However, using different in vitro transport conditions we were able to reveal additional K+/H+ antiporter activity. By disrupting genes encoding transporters potentially involved in the vnx1 ...
mutant strain, we determined that Vcx1p is responsible for this activity. This result was further confirmed by complementation of the vnx1vcx1 nhx1 triple mutant with Vcx1p and its inactivated mutant Vcx1p-H303A. Like the Ca2+/H+ antiporter activity catalyzed by Vcx1p, the K+/H+ antiporter activity was strongly inhibited by Cd2+, and to a lesser extend by Zn2+. Unlike previously observed for Nhx1 or Vnx1, Vcx1 overexpression only marginally improved the growth of yeast strain AXT3 in the presence of high concentrations of K+, and had no effect on hygromycin sensitivity. Subcellular localization showed that Vcx1 and Vnx1 are targeted to the vacuolar membrane, while Nhx1p is targeted to prevacuoles. The relative importance of Nhx1p, Vnx1p, and Vcx1p in the vacuolar accumulation of monovalent cations will be discussed.
Mesh Terms:
Affinity Labels, Chromatography, Affinity, Chromatography, Liquid, Electrophoresis, Polyacrylamide Gel, Multiprotein Complexes, Peptide Mapping, Protein Interaction Mapping, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Tandem Mass Spectrometry
Unknown
Date: Aug. 13, 2010
Download Curated Data For This Publication
103017
Switch View:
  • Interactions 6