Stabilizing the closed S6 gate in the shaker Kv channel through modification of a hydrophobic seal

Tetsuya Kitaguchi, Manana Sukhareva, Kenton J. Swartz*

*この研究の対応する著者

研究成果: Article査読

58 被引用数 (Scopus)

抄録

The primary activation gate in K+ channels is thought to reside near the intracellular entrance to the ion conduction pore. In a previous study of the S6 activation gate in Shaker (Hackos et al., 2002), we found that mutation of V478 to W results in a channel that cannot conduct ions even though the voltage sensors are competent to translocate gating charge in response to membrane depolarization. In the present study we explore the mechanism underlying the nonconducting phenotype in V478W and compare it to that of W434F, a mutation located in an extracellular region of the pore that is nonconducting because the channel is predominantly found in an inactivated state. We began by examining whether the intracellular gate moves using probes that interact with the intracellular pore and by studying the inactivation properties of heterodimeric channels that are competent to conduct ions. The results of these experiments support distinct mechanisms underlying nonconduction in W434F and V478W, suggesting that the gate in V478W either remains closed, or that the mutation has created a large barrier to ion permeation in the open state. Single channel recordings for heterodimeric and double mutant constructs in which ion conduction is rescued suggest that the V478W mutation does not dramatically alter unitary conductance. Taken together, our results suggest that the V478W mutation causes a profound shift of the closed to open equilibrium toward the closed state. This mechanism is discussed in the context of the structure of this critical region in K+ channels.

本文言語English
ページ(範囲)319-332
ページ数14
ジャーナルJournal of General Physiology
124
4
DOI
出版ステータスPublished - 2004 10
外部発表はい

ASJC Scopus subject areas

  • 生理学

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