title: Altered Na+ and Li+ homeostasis in Saccharomyces cerevisiae cells expressing the bacterial cation antiporter NhaA.
abstract: The bacterial Na+ (Li+)/H+ antiporter NhaA has been expressed in the yeast Saccharomyces cerevisiae. NhaA was present in both the plasma membrane and internal membranes, and it conferred lithium but not sodium tolerance. In cells containing the yeast Ena1-4 (Na+, Li+) extrusion ATPase, the extra lithium tolerance conferred by NhaA was dependent on a functional vacuolar H+ ATPase and correlated with an increase of lithium in an intracellular pool which exhibited slow efflux of cations. In yeast mutants without (Na+, Li+) ATPase, lithium tolerance conferred by NhaA was not dependent on a functional vacuolar H+ ATPase and correlated with a decrease of intracellular lithium. NhaA was able to confer sodium tolerance and to decrease intracellular sodium accumulation in a double mutant devoid of both plasma membrane (Na+, Li+) ATPase and vacuolar H+ ATPase. These results indicate that the bacterial antiporter NhaA expressed in yeast is functional at both the plasma membrane and the vacuolar membrane. The phenotypes conferred by its expression depend on the functionally of plasma membrane (Na+, Li+) ATPase and vacuolar H+ ATPase.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Ros
authors.forename: C
authors.initials: C
authors.lastname: Montesinos
authors.forename: A
authors.initials: A
authors.lastname: Rimon
authors.forename: E
authors.initials: E
authors.lastname: Padan
authors.forename: R
authors.initials: R
authors.lastname: Serrano
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002462:Cell Membrane / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D029968:Escherichia coli Proteins; D006706:Homeostasis; D007425:Intracellular Membranes / Q000378:metabolism; D017136:Ion Transport; D008094:Lithium / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D029968:Escherichia coli Proteins; C102839:NhaA protein, E coli; D011994:Recombinant Proteins; D017923:Sodium-Hydrogen Exchangers; D008094:Lithium; D012964:Sodium; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases