Two separate interfaces between the voltage sensor and pore are required for the function of voltage-dependent K(+) channels.
Two separate interfaces between the voltage sensor and pore are required for the function of voltage-dependent K(+) channels.
复制标题
电压传感器和孔之间需要两个独立的接口来实现电压依赖性 K(+) 通道的功能。
DOI：
10.1371/journal.pbio.1000047
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发表时间：
2009-03-03
期刊：
影响因子：
9.8
通讯作者：
MacKinnon, Roderick
中科院分区：
文献类型：
--
作者：
Lee, Seok-Yong;Banerjee, Anirban;MacKinnon, Roderick
电压依赖性 K+ (Kv) 通道门响应膜电压而打开。为了进一步了解细胞膜电压如何调节 Kv 通道的开放，我们研究了将电压传感器域连接到孔的蛋白质界面。在晶体结构中，存在三个物理界面。根据 360 Kv 通道序列的统计耦合分析，其中只有两种由在电压传感器和孔之间的界面共同进化的氨基酸组成。第一个共同进化的界面由 S4-S5 连接器（四个电压传感器各一个）形成，它形成一个围绕细胞内表面 S6 排列的孔开口的袖带。晶体结构和已发表的突变研究支持以下假设：S4-S5 连接器将电压传感器运动直接转换为栅极打开和关闭。第二个共同进化的界面在电压传感器的 S1 和细胞外表面附近的孔螺旋之间形成一个小接触表面。我们通过诱变证明该界面对于两个不同 Kv 通道的功能和/或结构是必需的。该第二界面位置良好，可充当电压传感器和孔之间的第二锚定点，从而允许将构象变化有效传输到孔的栅极。电压依赖性离子通道以非常陡峭的电压依赖性打开。这种陡峭的电压依赖性对于神经脉冲的传播至关重要，源于离子通道的电压传感器域与其孔之间的相互作用。电压传感器域将电压驱动的构象变化传输到孔。为了了解这种“机电耦合”机制的工作原理，我们利用生物信息学、电生理记录、定点诱变和化学交联研究了将电压传感器连接到孔的蛋白质-蛋白质界面。我们确定了两个功能上重要的接口：一个将移动的“电压传感器桨”连接到细胞内膜表面附近的孔的门，而另一个将电压传感器的固定区域连接到细胞外膜表面附近的孔。这两个界面仅占电压传感器表面积的一小部分，但似乎协同工作以实现电压传感器内的电压驱动构象变化，从而有效地调节孔的栅极。电压传感器域通过两个表面接触钾通道中的孔：一个表面将电压传感器附着到孔上，而另一个表面对栅极施加力，这一过程对于神经细胞中动作电位的产生至关重要。
Voltage-dependent K+ (Kv) channels gate open in response to the membrane voltage. To further our understanding of how cell membrane voltage regulates the opening of a Kv channel, we have studied the protein interfaces that attach the voltage-sensor domains to the pore. In the crystal structure, three physical interfaces exist. Only two of these consist of amino acids that are co-evolved across the interface between voltage sensor and pore according to statistical coupling analysis of 360 Kv channel sequences. A first co-evolved interface is formed by the S4-S5 linkers (one from each of four voltage sensors), which form a cuff surrounding the S6-lined pore opening at the intracellular surface. The crystal structure and published mutational studies support the hypothesis that the S4-S5 linkers convert voltage-sensor motions directly into gate opening and closing. A second co-evolved interface forms a small contact surface between S1 of the voltage sensor and the pore helix near the extracellular surface. We demonstrate through mutagenesis that this interface is necessary for the function and/or structure of two different Kv channels. This second interface is well positioned to act as a second anchor point between the voltage sensor and the pore, thus allowing efficient transmission of conformational changes to the pore's gate. Voltage-dependent ion channels open with a voltage dependence that is remarkably steep. This steep voltage dependence, which is essential to the propagation of nerve impulses, originates in the interaction between voltage-sensor domains of the ion channel and its pore. The voltage-sensor domains transmit voltage-driven conformational changes to the pore. To understand how this “electromechanical coupling” mechanism works, we have studied the protein–protein interfaces that connect the voltage sensors to the pore using bioinformatics, electrophysiological recordings, site-directed mutagenesis, and chemical cross-linking. We identify two functionally important interfaces: one links the mobile “voltage-sensor paddle” to the pore's gate near the intracellular membrane surface, while the other links an immobile region of the voltage sensor to the pore near the extracellular membrane surface. The two interfaces encompass only a small fraction of the voltage-sensor surface area, but appear to operate in unison to enable voltage-driven conformational changes within the voltage sensor so as to efficiently regulate the pore's gate. Voltage-sensor domains contact the pore in potassium channels through two surfaces: one attaches the voltage sensor to the pore, while the other imparts force on the gate, in a process that is central to the generation of action potentials in nerve cells.
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影响因子：
16.2
作者：
Aggarwal, SK;MacKinnon, R
通讯作者：
MacKinnon, R
DOI：
10.1073/pnas.0711533105
发表时间：
2008-02-05
影响因子：
11.1
作者：
Clayton, Gina M.;Altieri, Steve;Morais-Cabral, Joao H.
通讯作者：
Morais-Cabral, Joao H.
影响因子：
16.2
作者：
Larsson, HP;Baker, OS;Isacoff, EY
通讯作者：
Isacoff, EY
影响因子：
64.8
作者：
Long, Stephen B.;Tao, Xiao;MacKinnon, Roderick
通讯作者：
MacKinnon, Roderick
影响因子：
4.8
作者：
Mathur, R;Zhou, J;Koren, G
通讯作者：
Koren, G