CA2+DEPENDENT K+CHANNELS: ALLOSTERIC GATING

CA2 依赖 K 通道：变构门控

基本信息

批准号：
8841806
负责人：
Jianmin Cui
金额：
$ 37.43万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-04-01 至 2017-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8841806
关键词：
Address Affect Amino Acids Binding Binding Sites Biological Assay Charge Coupled Couples Coupling Cryoelectron Microscopy Dissection Electrostatics Epilepsy Event Foundations Goals Hypertension Impaired cognition Ion Channel Ion Channel Gating Ionic Strengths Ischemia Knowledge Lead Ligand Binding Ligands Measures Mediating Membrane Metal Binding Site Methods Modeling Molecular Molecular Conformation Monitor Muscle Contraction Nature Neurons Output Paroxysmal Dyskinesias Peptides Physiological Positioning Attribute Potassium Channel Probability Process Proteins Publishing Relative (related person)Roentgen Rays Schizophrenia Stimulus Structure Synaptic Transmission Trauma base circadian pacemaker disulfide bond innovation insight interfacial large-conductance calcium-activated potassium channels novel research study sensor therapeutic development therapeutic target voltage

项目摘要

DESCRIPTION (provided by applicant): Our long-term goal is to understand the molecular mechanisms of BK channel activation. BK-type K+ channels are activated by voltage, intracellular Ca2+ and Mg2+. These channels are important in modulating muscle contraction, neural transmission and circadian pacemaker output. Recently, the voltage sensor, Ca2+ and Mg2+ 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. It has become apparent that a knowledge gap presented by this question is a critical barrier for understanding BK channel activation. Recent studies and our preliminary results lead to a general hypothesis for answering this question: interactions between the voltage sensor domain (VSD) and the cytosolic domain (CTD), and this interfacial alignment couples the ligand binding site on the CTD to the opening of the activation gate. We propose the following specific aims to examine three key aspects of this hypothesis. 1. To demonstrate that the electrostatic interactions affect the VSD-CTD alignment. 2. To demonstrate that the VSD-CTD alignment is coupled to the activation gate. 3. To show that the VSD-CTD interactions mediate coupling of Ca2+ binding to gate opening. We have developed innovative methods to measure VSD-CTD alignment and the coupling of this alignment to the activation gate. This study will identify amino acids and structural motifs important for BK channel activation and reveal the nature of the interactions among structural domains during this molecular process. A prevalent model proposed for ion channel activation by intracellular ligands is that ligand binding alters the conformation of the cytosolic domain, which pulls a peptide linker to open the activation gate. The results of our proposed study will show that in BK channels Mg2+ and Ca2+ may also activate the channel by pushing the voltage sensor via an electrostatic interaction involving the residues in different structural domains, which provides a novel mechanism of ligand dependent gating that may be shared by many other ion channels. BK channels are being pursued as therapeutic targets for neuronal ischemia, trauma and cognitive decline, and recent studies show that BK channels are associated with hypertension, schizophrenia, epilepsy and paroxysmal dyskinesia. The dissection of the molecular events during BK channel gating in this study will help identify specific targets for the development of therapeutics in addition to providing insights into the principles of ion channel gating.

描述（由申请人提供）：我们的长期目标是了解 BK 通道激活的分子机制。 BK 型 K+ 通道由电压、细胞内 Ca2+ 和 Mg2+ 激活。这些通道对于调节肌肉收缩、神经传递和昼夜节律起搏器输出非常重要。最近，BK 通道中的电压传感器、Ca2+ 和 Mg2+ 结合位点已被确定。然而，位于不同结构域的传感器和激活门之间耦合的结构基础仍然难以捉摸。 BK 通道门控这一关键步骤的一个核心问题是这些不同的结构域如何相互作用以介导传感器和激活门之间的耦合。很明显，这个问题所带来的知识差距是理解 BK 通道激活的关键障碍。最近的研究和我们的初步结果得出了回答这个问题的一般假设：电压传感器域（VSD）和胞质域（CTD）之间的相互作用，并且这种界面排列将CTD上的配体结合位点与激活门。我们提出以下具体目标来检验该假设的三个关键方面。 1. 证明静电相互作用影响VSD-CTD排列。 2. 证明 VSD-CTD 排列与激活门耦合。 3.表明VSD-CTD相互作用介导Ca2+结合与门打开的耦合。我们开发了创新方法来测量 VSD-CTD 对准以及该对准与激活门的耦合。这项研究将鉴定对 BK 通道激活重要的氨基酸和结构基序，并揭示该分子过程中结构域之间相互作用的本质。细胞内配体激活离子通道的一个流行模型是配体结合改变胞质结构域的构象，从而拉动肽接头以打开激活门。我们提出的研究结果将表明，在 BK 通道中，Mg2+ 和 Ca2+ 也可以通过涉及不同结构域中的残基的静电相互作用推动电压传感器来激活通道，这提供了一种可以共享的配体依赖性门控的新机制通过许多其他离子通道。 BK 通道被视为神经元缺血、创伤和认知能力下降的治疗靶点，最近的研究表明 BK 通道与高血压、精神分裂症、癫痫和阵发性运动障碍有关。本研究中对 BK 通道门控过程中分子事件的剖析除了提供对离子通道门控原理的见解之外，还将有助于确定治疗药物开发的具体靶点。

项目成果

期刊论文数量（39）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Activation of Slo1 BK channels by Mg2+ coordinated between the voltage sensor and RCK1 domains.

DOI：
10.1038/nsmb.1507
发表时间：
2008-11
期刊：
NATURE STRUCTURAL & MOLECULAR BIOLOGY
影响因子：
16.8
作者：
Yang, Huanghe;Shi, Jingyi;Zhang, Guohui;Yang, Junqiu;Delaloye, Kelli;Cui, Jianmin
通讯作者：
Cui, Jianmin

Interaction between residues in the Mg2+-binding site regulates BK channel activation.