BK channel regulation by auxiliary LRR proteins

辅助 LRR 蛋白对 BK 通道的调节

• 批准号: 10172982
• 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/10172982
• 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 therapeutic intervention; 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.

项目概述：可变辅助亚基对离子通道的调节是细胞内的一种主要机制。 产生离子通道功能的多样性，从而在不同组织中产生电信号的可变性， 细胞大电导、钙离子和电压激活钾（BK）通道广泛表达 并与各种细胞和生理过程密切相关，包括神经元的调节， 兴奋性和突触传递以及几乎所有类型平滑肌细胞收缩张力的控制。 BK通道的结构和功能是多样化的，因为存在几种组织特异性的辅助β和β受体。 亚单位。自从我们首次鉴定出富含亮氨酸重复序列的膜蛋白（LRRC）以来， LRRC 26作为BK通道辅助β 1亚基，是数百种LRRC蛋白中数量不断增加的一种 LRRC蛋白在人类蛋白质数据库中，已被发现作为离子调节蛋白发挥功能， 渠道目前，对大多数调节性细胞因子对离子通道调节的机制知之甚少。 LRRC蛋白。BK通道辅助亚基BK 1具有非典型的“全或无”特征 调节作用，一个非常大的能力，影响BK通道的电压门控，预测 电压传感器激活和通道孔开放之间的变构耦合的主要影响，以及 与小分子BK通道激活剂mallotoxin（rottlerin）的竞争关系。基于我们 以前和现在的研究，我们假设辅助性的β 1亚基通过一个中枢调节BK通道， 膜内机制以及辅助的细胞外和细胞内机制。来测试我们 假设并阐明了BK通道调节的分子机制的辅助β亚基，我们 建议追求以下3个具体目标：1）确定非典型“全或”的分子基础， 探讨BK 1亚基在BK通道调控中的”无“作用; 2）确定BK通道的分子机制 通过涉及跨膜结构域的EST 1亚基的通道调节; 3）确定分子生物学活性。 BK通道的调节机制，由EST 1亚基和mallotoxin涉及胞质结构域。的 在这项资助申请中提出的研究旨在系统地研究生物化学和生物医学。 生物物理机制支配BK通道调节的辅助EST 1亚基和mallotoxin。的 本研究获得的知识可应用于其他调节性LRRC对离子通道的调节 proteins.这些研究结果将有助于阐明BK通道电压门控的机制 并提供了深入的了解，在EST 1亚基的非典型的“全有或全无”的行动和特殊的能力， 调节BK通道电压门控。它们还将有助于创造新的治疗试剂， BK通道在治疗或预防神经生物学、心血管和其他类型的疾病中的应用， 疾病