title: Functional conservation between yeast and plant endosomal Na(+)/H(+) antiporters.
abstract: Vacuolar compartmentation of Na(+) is an essential mechanism for salinity tolerance since it lowers cytosolic Na(+) levels while contributing to osmotic adjustment for cell turgor and expansion. The AtNHX1 protein of Arabidopsis thaliana substituted functionally for ScNHX1, the endosomal Na(+)/H(+) antiporter of yeast. Ion tolerance conferred by AtNHX1 and ScNHX1 correlated with ion uptake into an intracellular pool that was energetically dependent on the vacuolar (H(+))ATPase. AtNHX1 localized to vacuolar membrane fractions of yeast. Hence, both transporters share an evolutionarily conserved function in Na(+) compartmentation. AtNHX1 mRNA levels were upregulated by ABA and NaCl treatment in leaf but not in root tissue.
authors.affiliation: Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, P.O. Box 1052, Seville, Spain.
authors.forename: F J
authors.initials: FJ
authors.lastname: Quintero
authors.forename: M R
authors.initials: MR
authors.lastname: Blatt
authors.forename: J M
authors.initials: JM
authors.lastname: Pardo
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D002412:Cations / Q000378:metabolism / Q000494:pharmacology; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics / Q000502:physiology*; D011992:Endosomes / Q000737:chemistry* / Q000378:metabolism; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005816:Genetic Complementation Test; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008094:Lithium / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009994:Osmolar Concentration; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000737:chemistry / Q000378:metabolism
chemical_list: D002412:Cations; D017923:Sodium-Hydrogen Exchangers; D000040:Abscisic Acid; D008094:Lithium; D012964:Sodium