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Coupling of Voltage Sensing to Channel Opening Reflects Intrasubunit Interactions in Kv Channels

Authors :
Dirk J. Snyders
Alain J. Labro
Adam Raes
Source :
The journal of general physiology, The Journal of General Physiology
Publication Year :
2004
Publisher :
Rockefeller University Press, 2004.

Abstract

Voltage-gated K+ channels play a central role in the modulation of excitability. In these channels, the voltage-dependent movement of the voltage sensor (primarily S4) is coupled to the (S6) gate that opens the permeation pathway. Because of the tetrameric structure, such coupling could occur within each subunit or between adjacent subunits. To discriminate between these possibilities, we analyzed various combinations of a S4 mutation (R401N) and a S6 mutation (P511G) in hKv1.5, incorporated into tandem constructs to constrain subunit stoichiometry. R401N shifted the voltage dependence of activation to negative potentials while P511G did the opposite. When both mutations were introduced in the same α-subunit of the tandem, the positive shift of P511G was compensated by the negative shift of R401N. With each mutation in a separate subunit of a tandem, this compensation did not occur. This suggests that for Kv channels, the coupling between voltage sensing and gating reflects primarily an intrasubunit interaction.

Details

ISSN :
15407748 and 00221295
Volume :
125
Database :
OpenAIRE
Journal :
Journal of General Physiology
Accession number :
edsair.doi.dedup.....2d99e9139e7c2e216704e09d35ea6ac1
Full Text :
https://doi.org/10.1085/jgp.200409194