Vhc1, a novel transporter belonging to the family of electroneutral cation-Cl(-) cotransporters, participates in the regulation of cation content and morphology of Saccharomyces cerevisiae vacuoles

Biochim Biophys Acta. 2013 Feb;1828(2):623-31. doi: 10.1016/j.bbamem.2012.09.019. Epub 2012 Sep 27.

Abstract

Cation-Cl(-) cotransporters (CCCs) are integral membrane proteins which catalyze the coordinated symport of Cl(-) with Na(+) and/or K(+) ions in plant and mammalian cells. Here we describe the first Saccharomyces cerevisiae CCC protein, encoded by the YBR235w open reading frame. Subcellular localization studies showed that this yeast CCC is targeted to the vacuolar membrane. Deletion of the YBR235w gene in a salt-sensitive strain (lacking the plasma-membrane cation exporters) resulted in an increased sensitivity to high KCl, altered vacuolar morphology control and decreased survival upon hyperosmotic shock. In addition, deletion of the YBR235w gene in a mutant strain deficient in K(+) uptake produced a significant growth advantage over the parental strain under K(+)-limiting conditions, and a hypersensitivity to the exogenous K(+)/H(+) exchanger nigericin. These results strongly suggest that we have identified a novel yeast vacuolar ion transporter mediating a K(+)-Cl(-) cotransport and playing a role in vacuolar osmoregulation. Considering its identified function, we propose to refer to the yeast YBR235w gene as VHC1 (vacuolar protein homologous to CCC family 1).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cations / chemistry*
  • Chlorides / chemistry
  • DNA / chemistry
  • Electrochemistry / methods
  • Genotype
  • Hydrogen-Ion Concentration
  • Ion Transport
  • Membrane Potentials
  • Microscopy, Confocal / methods
  • Microscopy, Fluorescence / methods
  • Nigericin / pharmacology
  • Oligonucleotides / chemistry
  • Open Reading Frames
  • Osmotic Pressure
  • Phylogeny
  • Recombination, Genetic
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / physiology
  • Sorbitol / chemistry
  • Symporters / chemistry*
  • Symporters / physiology
  • Vacuoles / chemistry*

Substances

  • Cations
  • Chlorides
  • Oligonucleotides
  • Saccharomyces cerevisiae Proteins
  • Symporters
  • VHC1 protein, S cerevisiae
  • Sorbitol
  • DNA
  • Nigericin