BK channel regulation by auxiliary LRR proteins

辅助 LRR 蛋白对 BK 通道的调节

• 批准号: 9927679
• 负责人: Jiusheng Yan
• 金额: $ 35万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9927679
• 关键词: Affect; Applications Grants; Binding; Binding Sites; Biochemical; Biophysical Process; C-terminal; Calcium; Cardiovascular system; Cell physiology; Cells; Characteristics; Charge; Coupling; Cytoplasmic Tail; Data; Disease; Grant; Human; Investigation; Ion Channel; Ion Channel Protein; Knowledge; Leucine-Rich Repeat; Light; Lobe; Membrane; Membrane Proteins; Methods; Molecular; Mutation; Neurobiology; Peptides; Physiological Processes; Potassium; Prevention; Protein Databases; Proteins; Reagent; Regulation; Reporting; Research; Signal Transduction; Site; Smooth Muscle Myocytes; Structural Models; Structure; Synaptic Transmission; Tail; Testing; Tissues; Transmembrane Domain; base; design; experimental study; extracellular; genetic regulatory protein; large-conductance calcium-activated potassium channels; leucine-rich repeat protein; member; neuronal excitability; novel therapeutics; protein crosslink; rottlerin; sensor; small molecule; stoichiometry; synthetic peptide; unnatural amino acids; voltage; voltage gated channel

PROJECT SUMMARY: Ion channel regulation by variable auxiliary subunits is a major mechanism in generating diversity of ion channel function and thus variability in electrical signaling in different tissues and cells. Large conductance, calcium- and voltage-activated potassium (BK) channels are ubiquitously expressed and critically involved in various cellular and physiological processes including regulation of neuronal excitability and synaptic transmission and control of contractile tone of almost all types of smooth muscle cells. BK channels are diversified in structure and function by the presence of several tissue specific auxiliary β and  subunits. Since our initial identification of the leucine-rich repeat containing (LRRC) membrane protein LRRC26 as the BK channel auxiliary 1 subunit, an increasing number of LRRC proteins, among hundreds of LRRC proteins in the human protein database, have been found to function as regulatory proteins of ion channels. Currently, little is known about the mechanisms underlying ion channel regulation by most regulatory LRRC proteins. The BK channel auxiliary 1 subunit have characteristics of an atypical “all-or-none” modulatory action, an exceptionally large capability in affecting the BK channel’s voltage-gating, a predicted major effect on the allosteric coupling between the voltage sensor activation and channel pore-opening, and a competitive relationship with a small molecule BK channel activator mallotoxin (rottlerin). Based on our previous and current studies, we hypothesize that the auxiliary 1 subunit modulates BK channels via a central intramembrane mechanism and also subsidiary extracellular and intracellular mechanisms. To test our hypothesis and elucidate the molecular mechanisms of BK channel modulation by auxiliary  subunits, we propose to pursue the following 3 specific aims: 1) determine the molecular basis underlying an atypical “all-or- none” action of the 1 subunit on BK channel modulation; 2) determine the molecular mechanisms of BK channel modulation by the 1 subunit involving transmembrane domains; 3) determine the molecular mechanisms of BK channel modulation by the 1 subunit and mallotoxin involving cytoplasmic domains. The proposed research in this grant application is designed to systematically investigate the biochemical and biophysical mechanisms governing BK channel regulation by the auxiliary 1 subunit and mallotoxin. The knowledge obtained in this study could be applicable to ion channel regulation by other regulatory LRRC proteins. The findings from the proposed studies will shed light on mechanisms of BK channel voltage gating and provide in-depth understanding of the 1 subunit’s atypical “all-or-none” action and exceptional capability in modulating BK channel voltage-gating. They will also help in creation of novel therapeutic reagents targeting BK channels in treatment or prevention of neurobiological, cardiovascular, and other types of disorders and diseases.

项目摘要：可变辅助亚基的离子通道调节是一种主要机制 产生离子通道函数的多样性，从而在不同组织中的电信号传导中变异性变化 细胞。大型电导率，钙激活的钾（BK）通道普遍表达 并严格参与各种细胞和物理过程，包括调节神经元 几乎所有类型的平滑肌细胞的兴奋性和突触传播和收缩色调的控制。 BK通道在结构和功能上多样 亚基。由于我们最初鉴定了富含亮氨酸的重复含有（LRRC）膜蛋白 LRRC26作为BK通道辅助1亚基，越来越多的LRRC蛋白 已发现人蛋白数据库中的LRRC蛋白充当离子的调节蛋白 频道。当前，大多数调节的离子通道调控机制知之甚少 LRRC蛋白。 BK通道辅助1亚基具有非典型“全或无”的特征 调节作用，这是影响BK通道电压门控的极大能力，预测 对电压传感器激活和通道孔隙开放和A之间的变构耦合的主要影响 与小分子BK通道激活剂Malotoxin（Rottlerin）的竞争关系。基于我们 以前和当前的研究，我们假设辅助1亚基通过中央调节BK通道 膜内机理以及子公司细胞外和细胞内机制。测试我们的 假设并阐明了通过辅助亚基的BK通道调制的分子机制，我们 提出以下3个特定目的的提议：1）确定非典型“全或 1亚基对BK通道调制的无动作用； 2）确定BK的分子机制 涉及跨膜结构域的1亚基的通道调制； 3）确定分子 1亚基和涉及细胞质结构域的Malotoxin的BK通道调节机制。这 本赠款申请中的拟议研究旨在系统地研究生化和 通过辅助1亚基和malotoxin管理BK通道调节的生物物理机制。这 在这项研究中获得的知识可能适用于其他调节性LRC的离子通道调节 蛋白质。提出的研究的发现将阐明BK通道电压门的机理 并深入了解1亚基的非典型“全有或无名”动作和出色的能力 调节BK通道电压门控。他们还将有助于创建针对性的新型治疗试剂 在治疗或预防神经生物学，心血管和其他类型的疾病中的BK通道以及 疾病。