ISSN:
1432-1424
Keywords:
Key words: KAT1 — AKT2 — K+ channel — Co-assembly — Dominant negative — Oocytes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract. 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002329900476
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