Molecular mechanism of voltage-dependent potentiation of KCNH potassium channels
Molecular mechanism of voltage-dependent potentiation of KCNH potassium channels
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DOI：
10.7554/elife.26355
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发表时间：
2017-04-27
期刊：
影响因子：
7.7
通讯作者：
Zagotta, William N.
中科院分区：
文献类型：
--
作者：
Dai, Gucan;Zagotta, William N.
EAG 样 (ELK) 电压门控钾通道在大脑中大量表达。这些通道表现出一种称为电压依赖性增强（VDP）的行为，这似乎是抑制神经元过度兴奋的专门化。 VDP 表现为电流幅度的增强、电压敏感性的超极化转变以及响应去极化预脉冲的失活减慢。在这里，我们表明斑马鱼 ELK 通道的 VDP 涉及细胞内 N 端 eag 结构域和 C 端 CNBHD 之间的结构相互作用。结合过渡金属离子 FRET、膜片钳荧光测定法和荧光非规范氨基酸的掺入，我们发现 eag 结构域-CNBHD 相互作用与 VDP 的动力学、电压依赖性和 ATP 依赖性之间存在重排。我们认为 ELK 通道的激活涉及 eag 结构域和 CNBHD 之间直接相互作用的缓慢开放状态依赖性重排，从而稳定通道的开放。
EAG-like (ELK) voltage-gated potassium channels are abundantly expressed in the brain. These channels exhibit a behavior called voltage-dependent potentiation (VDP), which appears to be a specialization to dampen the hyperexitability of neurons. VDP manifests as a potentiation of current amplitude, hyperpolarizing shift in voltage sensitivity, and slowing of deactivation in response to a depolarizing prepulse. Here we show that VDP of D. rerio ELK channels involves the structural interaction between the intracellular N-terminal eag domain and C-terminal CNBHD. Combining transition metal ion FRET, patch-clamp fluorometry, and incorporation of a fluorescent noncanonical amino acid, we show that there is a rearrangement in the eag domain-CNBHD interaction with the kinetics, voltage-dependence, and ATP-dependence of VDP. We propose that the activation of ELK channels involves a slow open-state dependent rearrangement of the direct interaction between the eag domain and CNBHD, which stabilizes the opening of the channel.