Different Fast-Gate Regulation by External Cl− and H+ of the Muscle-Type Clc Chloride Channels
Different Fast-Gate Regulation by External Cl− and H+ of the Muscle-Type Clc Chloride Channels
复制标题
肌肉型 Clc 氯离子通道的外部 Cl− 和 H+ 的不同快速门调节
DOI：
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Tsung
中科院分区：
文献类型：
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作者：
Mei;Tsung
肌型ClC通道（ClC-0和ClC-1）的快速门随着膜电位(V)的变化而打开。这种门控过程与外部Cl -与通道孔的结合密切相关，Cl -在结合位点的占用增加了通道的打开概率（P o）。外部H+也增强了这些通道中的快速门打开，促使人们假设结合位点的质子化可能增加Cl−结合亲和力，这可能是H+调制的潜在机制。然而，Cl−和H+以不同的方式调制快速栅P - v曲线。改变外部Cl−浓度（[Cl−]o）使P - v曲线沿电压轴平行移动，而降低外部pH主要增加曲线的最小P - o。此外，H+在饱和和非饱和[Cl−]o的调制是相似的。因此，H+对快速门控的影响似乎不是Cl−结合亲和力增加的结果。我们之前发现，在极负电压下，超极化有利的开启过程对于确定ClC-0的快速栅p0很重要。这种不依赖于[Cl−]o的机制很少引起人们的注意，但它似乎是由外部H+调节的开放过程。
The fast gate of the muscle-type ClC channels (ClC-0 and ClC-1) opens in response to the change of membrane potential (V). This gating process is intimately associated with the binding of external Cl− to the channel pore in a way that the occupancy of Cl− on the binding site increases the channel's open probability (P o). External H+ also enhances the fast-gate opening in these channels, prompting a hypothesis that protonation of the binding site may increase the Cl− binding affinity, and this is possibly the underlying mechanism for the H+ modulation. However, Cl− and H+, modulate the fast-gate P o-V curve in different ways. Varying the external Cl− concentrations ([Cl−]o) shifts the P o-V curve in parallel along the voltage axis, whereas reducing external pH mainly increases the minimal P o of the curve. Furthermore, H+ modulations at saturating and nonsaturating [Cl−]o are similar. Thus, the H+ effect on the fast gating appears not to be a consequence of an increase in the Cl− binding affinity. We previously found that a hyperpolarization-favored opening process is important to determine the fast-gate P o of ClC-0 at very negative voltages. This [Cl−]o-independent mechanism attracted little attention, but it appears to be the opening process that is modulated by external H+.
DOI：
10.1073/pnas.81.9.2772
发表时间：
1984-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
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作者：
MILLER, C;WHITE, MM
通讯作者：
WHITE, MM