Gobert, A., Isayenkov, S., Voelker, C. et al. (2 more authors) (2007) The two pore channel TPK1 gene encodes the vacuolar K+ conductance and plays a role in K+ homeostasis. Proceedings of the National Academy of Sciences of the United States of America, 104 (25). pp. 10726-10731. ISSN 0027-8424
Abstract
The Arabidopsis thaliana genome contains five genes that encode two pore K+ (TPK) channels. The most abundantly expressed isoform of this family, TPK1, is expressed at the tonoplast where it mediates K+-selective currents between cytoplasmic and vacuolar compartments. TPK1 open probability depends on both cytoplasmic Ca2+ and cytoplasmic pH but not on the tonoplast membrane voltage. The channel shows intrinsic rectification and can be blocked by Ba2+, tetraethylammonium, and quinine. TPK1 current was found in all shoot cell types and shows all of the hallmarks of the previously described vacuolar K (VK) tonoplast channel characterized in guard cells. Characterization of TPK1 loss-of-function mutants and TPK1-overexpressing plants shows that TPK1 has a role in intracellular K+ homeostasis affecting seedling growth at high and low ambient K+ levels. In stomata, TPK1 function is consistent with vacuolar K+ release, and removal of this channel leads to slower stomatal closure kinetics. During germination, TPK1 contributes to the radicle development through vacuolar K+ deposition to provide expansion growth or in the redistribution of essential minerals.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Biology (York) |
Depositing User: | York RAE Import |
Date Deposited: | 17 Feb 2009 11:07 |
Last Modified: | 17 Feb 2009 11:07 |
Published Version: | http://dx.doi.org/10.1073/pnas.0702595104 |
Status: | Published |
Publisher: | National Academy of Sciences; 1999 |
Identification Number: | 10.1073/pnas.0702595104 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:7397 |