Ca2+ Dependent K+ Channels: Allosteric Gating

描述（由申请人提供）：本提案的长期目标是了解离子通道门控的机制，这是一个已知的调节各种生理和病理过程的关键分子事件。研究bk型、电压、Ca2+和Mg2+依赖的K+通道作为模型系统，本提案的重点是研究电压传感器运动、Ca2+或Mg2+结合通过分子内相互作用耦合到激活门打开的分子过程。具体目的是：1 .阐明细胞质结构域，即AC区域，在Ca2+依赖性门控中的作用。2。研究束缚态Mg2+与电压传感器之间的相互作用。3。研究S6突变对激活门功能和对电压、Ca2+和Mg2+的敏感性的影响。BK通道在人体健康中的作用是基于它们被电压、Ca2+和Mg2+激活，并且BK通道正在作为多种疾病的治疗靶点进行研究。影响电压和Ca2+依赖性激活的BK通道突变与癫痫和阵发性运动障碍有关。本应用旨在通过这些刺激剖析BK通道门控的分子机制，这将为BK通道相关疾病的研究提供深入的见解，并为治疗发展提供坚实的基础。近年来的一些研究为我们提供了钾通道Kv1.2、KvAP和MthK的x射线晶体结构，可以作为BK通道的模型。基于这些结构模型和其他初步结果，将采用包括电生理学、突变、化学修饰、蛋白质生物化学和动力学建模在内的多学科方法来实现具体目标。bk型钾离子通道对脑功能和血液循环至关重要。本研究探讨了BK通道功能的机制。该结果将提高我们对该通道功能障碍引起的疾病如癫痫和高血压的认识，并促进治疗神经缺血、创伤和认知能力下降等各种疾病的药物的开发。

DESCRIPTION (provided by applicant): The broad long-term objective of this proposal is to understand the mechanisms of ion channel gating, a key molecular event that is known to regulate a variety of physiological and pathological processes. Studying the BK-type, voltage, Ca2+ and Mg2+ dependent K+ channel as a model system, the focus of this proposal is to investigate the molecular process in which voltage sensor movements, Ca2+ or Mg2+ binding are coupled to the opening of the activation gate through intramolecular interactions. The specific aims are: I. To elucidate the role of a cytosolic domain, the AC region, in Ca2+ dependent gating. II. To investigate the interactions between the bound Mg2+ and the voltage sensor. III. To examine effects of mutations in S6 on the function of the activation gate and the sensitivity to voltage, Ca2+ and Mg2+. The role of BK channels in human health is based on their activation by voltage, Ca2+ and Mg2+, and BK channels are being pursued as a therapeutic target for various diseases. A BK channel mutation that affects voltage and Ca2+ dependent activation is linked to epilepsy and paroxysmal dyskinesia. This application seeks to dissect the molecular mechanism of BK channel gating by these stimuli, which will provide insights into BK channel related diseases and a solid basis for therapeutic developments. Several studies in recent years have provided us with X-ray crystallographic structures of potassium channels Kv1.2, KvAP, and MthK that can serve as models for BK channels. Based on these structural models and other preliminary results, a multi-disciplinary approach, including electrophysiology, mutation, chemical modification, protein biochemistry and kinetic modeling will be used to achieve the specific aims. The BK-type potassium ion channel is important for brain function and blood circulation. This research investigates the mechanism of BK channel function. The results will improve our understanding of diseases caused by the malfunction of this channel such as epilepsy and hypertension, and facilitate the development of drugs treating various diseases such as neuronal ischemia, trauma and cognitive decline.