Suppression of Inward-Rectifying K + Channels KAT1 and AKT2 by Dominant Negative Point Mutations in the KAT1 α-Subunit
| Autor: | Nobuyuki Uozumi, Stephan Clemens, Victor M. Baizabal-Aguirre, Julian I. Schroeder |
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| Rok vydání: | 1999 |
| Předmět: |
Genetics
Patch-Clamp Techniques Potassium Channels biology Arabidopsis Proteins Physiology Point mutation Mutant Arabidopsis Biophysics Wild type Cell Biology Membrane hyperpolarization biology.organism_classification Potassium channel Animals Point Mutation Arabidopsis thaliana Patch clamp Potassium Channels Inwardly Rectifying Ion Channel Gating Plant Proteins G alpha subunit |
| Zdroj: | Journal of Membrane Biology. 167:119-125 |
| ISSN: | 1432-1424 0022-2631 |
| DOI: | 10.1007/s002329900476 |
| Popis: | The Arabidopsis thaliana cDNA, KAT1 encodes a hyperpolarization-activated K+ (K+in) channel. In the present study, we identify and characterize dominant negative point mutations that suppress K+in channel function. Effects of two mutations located in the H5 region of KAT1, at positions 256 (T256R) and 262 (G262K), were studied. The co-expression of either T256R or G262K mutants with KAT1 produced an inhibition of K+ currents upon membrane hyperpolarization. The magnitude of this inhibition was dependent upon the molar ratio of cRNA for wild-type to mutant channel subunits injected. Inhibition of KAT1 currents by the co-expression of T256R or G262K did not greatly affect the ion selectivity of residual currents for Rb+, Na+, Li+, or Cs+. When T256R or G262K were co-expressed with a different K+ channel, AKT2, an inhibition of the channel currents was also observed. Voltage-dependent Cs+ block experiments with co-expressed wild type, KAT1 and AKT2, channels further indicated that KAT1 and AKT2 formed heteromultimers. These data show that AKT2 and KAT1 are able to co-assemble and suggest that suppression of channel function can be pursued in vivo by the expression of the dominant negative K+in channel mutants described here. |
| Databáze: | OpenAIRE |
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