Coupling between voltage sensors and activation gate in voltage-gated K+ channels

被引:261
作者
Lu, Z [1 ]
Klem, AM [1 ]
Ramu, Y [1 ]
机构
[1] Univ Penn, Dept Physiol, Philadelphia, PA 19104 USA
关键词
shaker; DRK1; KcsA; S4-S5; linker; S6;
D O I
10.1085/jgp.20028696
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
Current through voltage-gated K+ channels underlies the action potential encoding the electrical signal in excitable cells. The four subunits of a voltage-gated K+ channel each have six transmembrane segments (S1-S6), whereas some other K+ channels, such as eukaryotic inward rectifier K+ channels and the prokaryotic KcsA channel, have only two transmembrane segments (M1 and M2). A voltage-gated K+ channel is formed by an ion-pore module (S5-S6, equivalent to M1-M2) and the surrounding voltage-sensing modules. The S4 segments are the primary voltage sensors while the intracellular activation gate is located near the COOH-terminal end of S6, although the coupling mechanism between them remains unknown. In the present study we found that two short, complementary sequences in voltage-gated K+ channels are essential for coupling the voltage sensors to the intracellular activation gate. One sequence is the so called S4-S5 linker distal to the voltage-sensing S4, while the other is around the COOH-terminal end of S6, a region containing the actual gate-forming residues.
引用
收藏
页码:663 / 676
页数:14
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