Defining the conductance of the closed state in a voltage-gated K+ channel.

Gilberto J Soler-Llavina's picture
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TitleDefining the conductance of the closed state in a voltage-gated K+ channel.
Publication TypeJournal Article
Year of Publication2003
AuthorsSoler-Llavina, GJ, Holmgren, M, Swartz, KJ
JournalNeuron
Volume38
Issue1
Pagination61-7
Date Published2003 Apr 10
ISSN0896-6273
Abstract

The opening and closing of the ion conduction pathway in ion channels underlies the generation and propagation of electrical signals in biological systems. Although electrophysiological approaches to measuring the flow of ions in the open state have contributed profoundly to our understanding of ion permeation and gating, it remains unclear how much the ion-throughput rate decreases upon closure of the ion conduction pore. To address this fundamental question, we expressed the Shaker Kv channel at high levels and then measured macroscopic K+ currents at negative membrane voltages and counted the number of channels by quantifying the translocation of gating charge. Our results show that the conductance of the closed state is between 0 and 0.16 fS, or at least 100,000 times lower than for the open state of the channel, indicating that the flow of ions is very tightly regulated in this class of K+ channels.

Alternate JournalNeuron
PubMed ID12691664
Grant ListZIA NS002945-13 / NS / NINDS NIH HHS / United States