Involvement of helices at the dimer interface in ClC-1 common gating.
Involvement of helices at the dimer interface in ClC-1 common gating.
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DOI：
10.1085/jgp.20028741
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发表时间：
2003-02
期刊：
影响因子：
--
通讯作者：
Roberts M
中科院分区：
文献类型：
--
作者：
Duffield M;Rychkov G;Bretag A;Roberts M
ClC-1是一种存在于骨骼肌中的二聚体、双孔氯离子通道。该通道的突变可能导致肌强直，这是一种肌肉功能紊乱，包括肌肉僵硬程度增加。已经证明，肌强直的主要形式通常是由于突变而导致的，这些突变影响了ClC-1通道的所谓缓慢或常见的门控过程。导致显性肌强直的突变可以聚集在ClC-1通道单体的界面上。这项研究调查了位于这个界面上的H、I、P和Q螺旋以及位于H和I螺旋后面的G螺旋在CLC-1门控中的作用。利用定点突变技术获得了11个突变的ClC-1通道(T268M、C277S、C278S、S289A、T310M、S312A、V321S、T539A、S541A、M559T和S572V)，并用电生理技术研究了这些通道的门控特性。G、H和I的七个突变中的六个，以及P和Q的四个突变中的两个，导致了ClC-1开放概率的变化。在大多数情况下，这是由于普通门控过程中的变化，只有三个突变体显示出快速门控的任何变化。许多突变通道也表现出普通门控过程的动力学变化，特别是在正电位下。在普通门控中观察到的变化是由打开速率(例如T310M)、关闭速率(例如C277S)或两者的变化引起的。这些结果表明，形成二聚体界面的螺旋的突变能够通过改变开放和/或关闭通道状态的能量来改变CLC-1常见的门控过程，从而改变这些状态之间的跃迁速率。
ClC-1 is a dimeric, double-pored chloride channel that is present in skeletal muscle. Mutations of this channel can result in the condition myotonia, a muscle disorder involving increased muscle stiffness. It has been shown that the dominant form of myotonia often results from mutations that affect the so-called slow, or common, gating process of the ClC-1 channel. Mutations causing dominant myotonia are seen to cluster at the interface of the ClC-1 channel monomers. This study has investigated the role of the H, I, P, and Q helices, which lie on this interface, as well as the G helix, which is situated immediately behind the H and I helices, on ClC-1 gating. 11 mutant ClC-1 channels (T268M, C277S, C278S, S289A, T310M, S312A, V321S, T539A, S541A, M559T, and S572V) were produced using site-directed mutagenesis, and gating properties of these channels were investigated using electrophysiological techniques. Six of the seven mutations in G, H, and I, and two of the four mutations in P and Q, caused shifts of the ClC-1 open probability. In the majority of cases this was due to alterations in the common gating process, with only three of the mutants displaying any change in fast gating. Many of the mutant channels also showed alterations in the kinetics of the common gating process, particularly at positive potentials. The changes observed in common gating were caused by changes in the opening rate (e.g. T310M), the closing rate (e.g. C277S), or both rates. These results indicate that mutations in the helices forming the dimer interface are able to alter the ClC-1 common gating process by changing the energy of the open and/or closed channel states, and hence altering transition rates between these states.
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DOI：
10.1152/ajpcell.1998.274.4.c966
发表时间：
1998-04-01
影响因子：
5.5
作者：
Fong, PY;Rehfeldt, A;Jentsch, TJ
通讯作者：
Jentsch, TJ
影响因子：
5.5
作者：
Bennetts, B;Roberts, ML;Rychkov, GY
通讯作者：
Rychkov, GY
影响因子：
16.2
作者：
Pusch, M;Steinmeyer, K;Jentsch, TJ
通讯作者：
Jentsch, TJ
影响因子：
11.4
作者：
STEINMEYER, K;LORENZ, C;JENTSCH, TJ
通讯作者：
JENTSCH, TJ
影响因子：
2.9
作者：
MIDDLETON, RE;PHEASANT, DJ;MILLER, C
通讯作者：
MILLER, C