BK channel regulation by auxiliary LRR proteins

辅助 LRR 蛋白对 BK 通道的调节

基本信息

批准号：
8275072
负责人：
Jiusheng Yan
金额：
$ 34.56万
依托单位：
UNIVERSITY OF TX MD ANDERSON CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8275072
关键词：
Amino Acids Applications Grants Auditory Biochemical Biological Brain region Calcium Cells Chimera organism Consensus Coupling Cysteine Dependence Disulfide Linkage Docking Elements Family Frequencies Gated Ion Channel Hair Cells Hormones Human Human Cell Line Hydrophobic Interactions In Situ LIM Domain Leucine-Rich Repeat Maps Membrane Proteins Modification Molecular Molecular Profiling Mutation N-Glycosylation Site Nature Neurons Oxidation-Reduction Pattern Phosphorylation Physiological Physiological Processes Post-Translational Protein Processing Post-Translational Regulation Potassium Potassium Channel Property Proteins Reagent Regulation Research Rest Scanning Side Site Site-Directed Mutagenesis Smooth Muscle Structural Models Surface Tertiary Protein Structure Therapeutic Time Tissues base cell type crosslink design extracellular glycosylation human tissue large-conductance calcium-activated potassium channels leucine-rich repeat protein member neurotransmitter release novel paralogous gene research study sensor voltage

项目摘要

DESCRIPTION (provided by applicant): The large conductance, calcium- and voltage-activated potassium (BK) channel is a unique member of the potassium channel family, which has the largest single channel conductance and is dually activated by voltage and cytosolic free Ca2+. BK channels consist of the pore-forming, voltage- and Ca2+-sensing -subunits (BK) either alone or in association with the tissue-specific regulatory subunits including the four previously known ?-subunits. We recently identified a novel BK channel auxiliary subunit, a leucine-rich repeat (LRR) containing membrane protein LRRC26, which causes an unprecedented large negative shift (~ -150 mV) in voltage dependence of channel activation by greatly enhancing the allosteric coupling between the voltage-sensor activation and the channel's closed-open transition, allowing BK channel activation at even near resting voltages and calcium levels in excitable and non-excitable cells. We have additionally identified three LRRC26- like paralogous proteins that modify the BK channel's voltage dependence of activation to different extents. LRRC26 and its paralogous LRR proteins are structurally and functionally distinct from the ?-subunits and are thus collectively designated as a family of BK channel ?-subunits. Three specific aims are designed to determine the physiological relevance and molecular mechanisms of BK channel regulation by these auxiliary ?-subunits: 1) determine the physiological and functional expression of the BK channel ?-subunits in human tissues and cells; 2) determine the biochemical mechanisms of BK channel modulation by the ?-subunits; 3) determine the posttranslational regulation of the ?-subunits' modulatory functions. Molecular biological, biochemical and electrophysiological experiments will be performed to achieve the proposed aims. Overall, the proposed research in this grant application is designed to systematically investigate these auxiliary LRR proteins for their physiological relevance and the underlying molecular mechanisms of channel modulation. The findings from the proposed studies will establish the physiological relevance of a new family of BK channel auxiliary subunits, and provide an in-depth understanding of the molecular mechanisms governing the LRRC26 and its paralogs' unique capacity in shifting the voltage dependence of a voltage-gated ion channel. These studies will thus offer a new molecular basis for an understanding and exploration of the ubiquitously expressed BK channel's diverse physiological functions, and help in creation of novel reagents and therapeutics to rationally manipulate BK channel activity. PUBLIC HEALTH RELEVANCE: The findings from the proposed research will provide a new molecular basis for an understanding and exploration of the ubiquitously expressed BK channel's diverse physiological functions, and help in creation of novel reagents and therapeutics to rationally manipulate BK channel activity.

描述（由申请人提供）：大电导、钙和电压激活的钾（BK）通道是钾通道家族的独特成员，其具有最大的单通道电导，并且由电压和胞质游离Ca2+双重激活。 BK 通道由成孔、电压和 Ca2+ 感应亚基 (BK) 单独组成或与组织特异性调节亚基（包括四个先前已知的 β 亚基）联合组成。我们最近发现了一种新的 BK 通道辅助亚基，即含有膜蛋白 LRRC26 的富含亮氨酸重复序列 (LRR)，它通过大大增强通道激活之间的变构耦合，导致通道激活的电压依赖性出现前所未有的大负移 (~ -150 mV)。电压传感器激活和通道的关闭-开放转换，允许 BK 通道在可兴奋和不可兴奋细胞中甚至接近静息电压和钙水平下激活。我们还鉴定了三种 LRRC26 样旁系同源蛋白，它们不同程度地改变 BK 通道激活的电压依赖性。 LRRC26 及其旁系同源LRR 蛋白在结构和功能上不同于β-亚基，因此统称为BK 通道β-亚基家族。设计了三个具体目标来确定这些辅助β-亚基调节BK通道的生理相关性和分子机制：1）确定人体组织和细胞中BK通道β-亚基的生理和功能表达； 2)确定β-亚基调节BK通道的生化机制； 3)确定α-亚基调节功能的翻译后调节。将进行分子生物学、生物化学和电生理学实验以实现拟议的目标。总体而言，本次资助申请中拟议的研究旨在系统地研究这些辅助 LRR 蛋白的生理相关性和通道调节的潜在分子机制。拟议研究的结果将建立新的 BK 通道辅助亚基家族的生理相关性，并提供对控制 LRRC26 及其旁系同源物在改变电压依赖性的电压依赖性方面的独特能力的分子机制的深入理解。门控离子通道。因此，这些研究将为理解和探索普遍表达的 BK 通道的多种生理功能提供新的分子基础，并有助于创建新的试剂和疗法来合理操纵 BK 通道活性。公共健康相关性：拟议研究的结果将为理解和探索普遍表达的 BK 通道的多种生理功能提供新的分子基础，并有助于创建新的试剂和疗法来合理操纵 BK 通道活性。