Intersubunit physical couplings fostered by the left flipper domain facilitate channel opening of P2X4 receptors
Intersubunit physical couplings fostered by the left flipper domain facilitate channel opening of P2X4 receptors
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左鳍状肢结构域促进的亚基间物理耦合促进 P2X4 受体的通道开放。
DOI：
10.1074/jbc.m116.771121
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发表时间：
2017-05-05
影响因子：
4.8
通讯作者：
Yu, Ye
中科院分区：
文献类型：
--
作者：
Wang, Jin;Sun, Liang-Fei;Yu, Ye
P2X受体是ATP门控的三聚体通道，在多种病理生理功能中具有重要作用。因此，详细了解这些受体的门控过程的机制是非常重要的，并可能开辟新的治疗途径。P2X受体的左鳍（LF）结构域是一个灵活的环状结构，其与背鳍（DF）结构域的协调运动对于P2X受体的通道门控至关重要。然而，LF域在通道门控中的关键作用的机制仍然不清楚。在这里，我们建议，ATP诱导的LF域的变构变化，使其能够促进DF和两个下体域，这是关键的通道门控P2X4受体之间的亚基间的物理耦合。代谢组学分析表明，这些新建立的亚基间耦合与ATP结合的受体开放状态相关。此外，削弱或加强这些物理相互作用与工程intersubunit金属桥显着降低或增加受体的开放概率，分别。进一步的二硫键交联和共价修饰证实了DF和两个下体结构域之间的亚基间物理偶联由LF结构域在开放状态下促进，作为P2X4受体通道门控严格需要的整合结构元件。我们的观察提供了新的机制的见解P2X受体激活，并将刺激发展的P2X受体的新的变构调节剂。
P2X receptors are ATP-gated trimeric channels with important roles in diverse pathophysiological functions. A detailed understanding of the mechanism underlying the gating process of these receptors is thus fundamentally important and may open new therapeutic avenues. The left flipper (LF) domain of the P2X receptors is a flexible loop structure, and its coordinated motions together with the dorsal fin (DF) domain are crucial for the channel gating of the P2X receptors. However, the mechanism underlying the crucial role of the LF domain in the channel gating remains obscure. Here, we propose that the ATP-induced allosteric changes of the LF domain enable it to foster intersubunit physical couplings among the DF and two lower body domains, which are pivotal for the channel gating of P2X4 receptors. Metadynamics analysis indicated that these newly established intersubunit couplings correlate well with the ATP-bound open state of the receptors. Moreover, weakening or strengthening these physical interactions with engineered intersubunit metal bridges remarkably decreased or increased the open probability of the receptors, respectively. Further disulfide cross-linking and covalent modification confirmed that the intersubunit physical couplings among the DF and two lower body domains fostered by the LF domain at the open state act as an integrated structural element that is stringently required for the channel gating of P2X4 receptors. Our observations provide new mechanistic insights into P2X receptor activation and will stimulate development of new allosteric modulators of P2X receptors.