AtCHX13 Is a Plasma Membrane K+ Transporter
| Autor: | Naomi Gonzales, Heven Sze, Kendal D. Hirschi, Senthilkumar Padmanaban, Ninghui Cheng, Elison B. Blancaflor, Christy M. Motes, Jian Zhao, John M. Ward, Miranda Moore |
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| Rok vydání: | 2008 |
| Předmět: |
Physiology
Molecular Sequence Data Saccharomyces cerevisiae Mutant Arabidopsis Plant Science Biology Plant Roots Gene Expression Regulation Plant Genetics Arabidopsis thaliana Na+/K+-ATPase Cation Transport Proteins Arabidopsis Proteins Reverse Transcriptase Polymerase Chain Reaction Cell Membrane Biological Transport biology.organism_classification Plant cell Yeast Cell biology Phenotype Biochemistry RNA Plant Potassium Homeostasis Plasmids Research Article |
| Zdroj: | Plant Physiology. 148:796-807 |
| ISSN: | 1532-2548 |
| DOI: | 10.1104/pp.108.124248 |
| Popis: | Potassium (K+) homeostasis is essential for diverse cellular processes, although how various cation transporters collaborate to maintain a suitable K+ required for growth and development is poorly understood. The Arabidopsis (Arabidopsis thaliana) genome contains numerous cation:proton antiporters (CHX), which may mediate K+ transport; however, the vast majority of these transporters remain uncharacterized. Here, we show that AtCHX13 (At2g30240) has a role in K+ acquisition. AtCHX13 suppressed the sensitivity of yeast (Saccharomyces cerevisiae) mutant cells defective in K+ uptake. Uptake experiments using 86Rb+ as a tracer for K+ demonstrated that AtCHX13 mediated high-affinity K+ uptake in yeast and in plant cells with a K m of 136 and 196 μ m, respectively. Functional green fluorescent protein-tagged versions localized to the plasma membrane of both yeast and plant. Seedlings of null chx13 mutants were sensitive to K+ deficiency conditions, whereas overexpression of AtCHX13 reduced the sensitivity to K+ deficiency. Collectively, these results suggest that AtCHX13 mediates relatively high-affinity K+ uptake, although the mode of transport is unclear at present. AtCHX13 expression is induced in roots during K+-deficient conditions. These results indicate that one role of AtCHX13 is to promote K+ uptake into plants when K+ is limiting in the environment. |
| Databáze: | OpenAIRE |
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