| Cloning and electrophysiological analysis of KST1, an inward rectifying K+ channel expressed in potato guard cells. | |
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MedLine Citation:
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PMID: 7781596 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Potassium uptake by guard cells represents part of the osmotic motor which drives stomatal opening. Patch-clamp measurements have identified inward rectifying K+ channels capable of mediating K+ uptake in guard cells and various other plant cell types. Here we report the molecular cloning and characterization of a voltage-dependent K+ channel (KST1) from potato (Solanum tuberosum L.) guard cells. In situ hybridization shows expression of kst1 in guard cells. Two-electrode voltage-clamp and patch-clamp studies of the gene product after cRNA injection into Xenopus oocytes identified KST1 as a slowly activating, voltage-dependent, inward rectifying K+ channel. The single channel current voltage curve was linear in the range -160 to +20 mV, with a deduced single channel conductance of 7 pS in symmetrical 100 mM K+. This channel type, modulated by pH changes within the physiological range, required ATP for activation. In line with the properties of a K(+)-selective channel, KST1 was permeable to K+, Rb+ and NH4+ and excluded Na+ and Li+. Cs+ at submillimolar concentrations blocked the channel in a voltage-dependent manner. Related studies on potato guard cell protoplasts confirmed the biophysical characteristics of the kst1 gene product (KST1) in the heterologous expression system. Therefore, KST1 represents a major K+ uptake channel in potato guard cells. |
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Authors:
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B Müller-Röber; J Ellenberg; N Provart; L Willmitzer; H Busch; D Becker; P Dietrich; S Hoth; R Hedrich |
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Publication Detail:
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Type: Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The EMBO journal Volume: 14 ISSN: 0261-4189 ISO Abbreviation: EMBO J. Publication Date: 1995 Jun |
Date Detail:
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Created Date: 1995-07-19 Completed Date: 1995-07-19 Revised Date: 2010-09-13 |
Medline Journal Info:
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Nlm Unique ID: 8208664 Medline TA: EMBO J Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 2409-16 Citation Subset: IM |
Affiliation:
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Institut für Genbiologische Forschung Berlin GmbH, Germany. |
| Data Bank Information | |
Bank Name/Acc. No.:
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GENBANK/X79779 |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acid Sequence Animals Base Sequence Cations Cloning, Molecular DNA, Complementary / genetics DNA, Plant / genetics Electrophysiology Female Gene Expression Genes, Plant* Hydrogen-Ion Concentration Molecular Sequence Data Oocytes / metabolism Plants / genetics*, metabolism* Potassium Channels / genetics*, metabolism* Sequence Homology, Amino Acid Solanum tuberosum / genetics, metabolism Xenopus |
| Chemical | |
Reg. No./Substance:
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0/Cations; 0/DNA, Complementary; 0/DNA, Plant; 0/Potassium Channels |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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