AtKuP1: a dual-affinity K+ transporter from Arabidopsis.
AUTOR(ES)
Fu, H H
RESUMO
Plant roots contain both high- and low-affinity transport systems for uptake of K+ from the soil. In this study, we characterize a K+ transporter that functions in both high- and low-affinity uptake. Using yeast complementation analysis, we isolated a cDNA for a functional K+ transporter from Arabidopsis (referred to as AtKUP1 for Arabidopsis thaliana K+ uptake). When expressed in a yeast mutant, AtKUP1 dramatically increased K+ uptake capacity at both a low and high [K+] range. Kinetic analyses showed that AtKUP1-mediated K+ uptake displays a "biphasic" pattern similar to that observed in plant roots. The transition from the high-affinity phase (K(m) of 44 microM) to the low-affinity phase (K(m) of 11 mM) occurred at 100 to 200 microM external K+. Both low- and high-affinity K+ uptake via AtKUP1 were inhibited by 5 mM or higher concentrations of NaCl. In addition, AtKUP1-mediated K+ uptake was inhibited by K+ channel blockers, including tetraethylammonium, Cs+, and Ba2+. Consistent with a possible function in K+ uptake from the soil, the AtKUP1 gene is primarily expressed in roots. We conclude that the AtKUP1 gene product may function as a K+ transporter in Arabidopsis roots over a broad range of [K+] in the soil.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=143931Documentos Relacionados
- CHL1 is a dual-affinity nitrate transporter of Arabidopsis involved in multiple phases of nitrate uptake.
- AtKUP1: an Arabidopsis gene encoding high-affinity potassium transport activity.
- The Arabidopsis Dual-Affinity Nitrate Transporter Gene AtNRT1.1 (CHL1) Is Activated and Functions in Nascent Organ Development during Vegetative and Reproductive Growth
- Switching between the two action modes of the dual-affinity nitrate transporter CHL1 by phosphorylation
- Pht2;1 encodes a low-affinity phosphate transporter from Arabidopsis.