Mechanism of BK Channel Gating

BK通道门控机制

• 批准号: 10018643
• 负责人: JONATHAN R SILVA
• 金额: $ 71.58万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10018643
• 关键词: Address; Affect; Amino Acids; Aplysia; Binding; Binding Sites; Biological Models; Biophysics; Cell physiology; Characteristics; Chemicals; Coupling; Cryoelectron Microscopy; Docking; Drug Targeting; Epilepsy; Event; Face; Foundations; Goals; Hypertension; Impaired cognition; Ion Channel; Ion Channel Gating; Ischemia; Lead; Ligands; Measures; Mechanics; Mediating; Membrane; Methods; Molecular; Molecular Conformation; Muscle Cells; Muscle Contraction; Mutation; Nature; Neurons; Output; Paroxysmal Dyskinesias; Pathologic; Peptides; Pharmaceutical Preparations; Physiological; Play; Potassium Channel; Process; Proteins; Role; Schizophrenia; Side; Stimulus; Structure; Synaptic Transmission; Testing; Trauma; base; circadian pacemaker; design; drug development; in silico; insight; large-conductance calcium-activated potassium channels; molecular dynamics; mutation screening; novel; response; screening; sensor; small molecule; structured data; therapeutic target; voltage

Our long-term goal is to understand the molecular mechanisms of BK channel activation. BK-type K+ channels are activated by voltage and intracellular Ca2+. These channels are important in modulating muscle contraction, neural transmission and circadian pacemaker output, and have been shown to associate with hypertension, schizophrenia, epilepsy and paroxysmal dyskinesia. These channels are being pursued as therapeutic targets for neuronal ischemia, trauma and cognitive decline. The voltage sensor and Ca2+ binding sites in BK channels have been identified. However, the structural basis for the coupling between sensors and the activation gate, which are located in different structural domains, still remains elusive. A central question in this crucial step of BK channel gating is how these different structural domains interact with one another to mediate the coupling between the sensors and the activation gate. This proposal is motivated by the long- awaited and recently solved atomic structures of a whole BK channel. These structures offer new insights on fundamental mechanisms of sensor-pore coupling that may differ from the previous understanding. The structure and functional studies lead to a general hypothesis for answering this question: interactions among the voltage sensor domain (VSD), the cytosolic domain (CTD), and the pore-gate domain (PGD) all contribute to the sensor-pore coupling. We propose three specific aims to examine three key aspects of this hypothesis: 1) the VSD-PGD interactions in VSD-pore coupling, 2) the VSD-CTD interactions in both VSD-pore and Ca2+- pore couplings, and 3) the role of a peptide linker between PGD and CTD in both the VSD-pore and Ca2+-pore couplings. We will use novel structure based screening methods to identify compounds that modulate channel function. These compounds and mutations in the channel protein will serve as probes to indicate the structural motifs that are key to the sensor-pore coupling in BK channels. Threading the biophysics of mutations and modulators onto the channel structures will allow us to understand the molecular mechanisms of how physiological stimuli open BK channels. The results of these studies will identify novel binding sites, chemical cores and new mechanisms of altering channel function by drugs, which will directly help drug development targeting BK channels. Our studies on BK channels may provide insights for the understanding of other ion channels that share similar structural and functional characteristics.

我们的长期目标是了解BK通道激活的分子机制。BK型K+ 电压和细胞内钙离子激活通道。这些通道在调节肌肉方面很重要。 收缩、神经传递和昼夜起搏器输出，并已被证明与 高血压、精神分裂症、癫痫和阵发性运动障碍。这些渠道正在被视为 治疗神经元缺血、创伤和认知功能衰退的靶点。电压传感器与钙离子结合 已经确定了BK频道中的站点。然而，传感器和传感器之间耦合的结构基础 位于不同结构域的激活门仍然难以捉摸。中的一个中心问题 BK通道门控的这个关键步骤是这些不同的结构域如何相互作用以 协调传感器和激活门之间的耦合。这项提议的动机是长期的- 等待和最近解决的整个BK通道的原子结构。这些结构提供了关于 传感器-孔道耦合的基本机制可能与以前的理解不同。这个 结构和功能研究导致了回答这个问题的一个普遍假设： 电压传感器结构域(VSD)、胞浆结构域(CTD)和孔门结构域(PGD)都有贡献 到传感器-孔道耦合。我们提出了三个具体目标来检验这一假设的三个关键方面： 1)VSD-孔耦合中的VSD-PGD相互作用；2)VSD-孔和钙-孔中的VSD-CTD相互作用 孔偶联，以及3)PgD和CTD之间的多肽连接物在VSD孔和钙孔中的作用 联轴器。我们将使用新的基于结构的筛选方法来识别调节通道的化合物 功能。这些化合物和通道蛋白中的突变将作为探针来指示结构 BK通道中传感器-孔道耦合的关键基序。研究突变和突变的生物物理学 通道结构上的调制器将使我们能够理解分子机制如何 生理刺激打开BK通道。这些研究的结果将确定新的结合部位，化学物质 药物改变通道功能的核心和新机制，将直接有助于药物开发 瞄准BK频道。我们对BK通道的研究可能会为理解其他离子提供一些启示 具有相似结构和功能特征的通道。