Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/37498
Share/Impact:
Título : Mutants of the Arabidopsis thaliana Cation/H+ Antiporter AtNHX1 Conferring Increased Salt Tolerance in Yeast . The Endosome/prevacuolar compartment is a target for salt toxicity
Autor : Hernández, Agustín, Jiang, Xingyu, Cubero, Beatriz, Nieto, Pedro M., Bressan, Ray A., Hasegawa, Paul M., Pardo, José M.
Palabras clave : Cation Transport Proteins
Structure
Sodium_Hydrogen Antiporter
Biogenesis
Arabidopsis proteins
Magnetic Resonance Spectroscopy
Fecha de publicación : 22-May-2009
Editor: American Society for Biochemistry and Molecular Biology
Citación : The Journal of Biological Chemistry 284 (21): 14276-14285 (2009)
Resumen: Mutants of the plant cation/H+ antiporter AtNHX1 that confer greater halotolerance were generated by random mutagenesis and selected in yeast by phenotypic complementation. The amino acid substitutions that were selected were conservative and occurred in the second half of the membrane-associated N terminus. AtNHX1 complemented the lack of endogenous ScNHX1 in endosomal protein trafficking assays. Growth enhancement on hygromycin B and vanadate media agreed with a generally improved endosomal/prevacuolar function of the mutated proteins. In vivo measurements by 31P NMR revealed that wild-type and mutant AtNHX1 transporters did not affect cytosolic or vacuolar pH. Surprisingly, when yeast cells were challenged with lithium, a tracer for sodium, the main effect of the mutations in AtNHX1 was a reduction in the amount of compartmentalized lithium. When purified and reconstituted into proteoliposomes or assayed in intact vacuoles isolated from yeast cells, a representative mutant transporter (V318I) showed a greater cation discrimination favoring potassium transport over that of sodium or lithium. Together, our data suggest that the endosome/prevacuolar compartment is a target for salt toxicity. Poisoning by toxic cations in the endosome/prevacuolar compartment is detrimental for cell functions, but it can be alleviated by improving the discrimination of transported alkali cations by the resident cation/H+ antiporter.
Descripción : 10 páginas, 8 figuras, 1 tabla.
Versión del editor: http://dx.doi.org/10.1074/jbc.M806203200
URI : http://hdl.handle.net/10261/37498
ISSN: 0021-9258
DOI: 10.1074/jbc.M806203200
Appears in Collections:(IRNAS) Artículos
(IIQ) Artículos

Files in This Item:
There are no files associated with this item.
Show full item record
 
CSIC SFX LinksSFX Query


Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.