BK channel regulation by auxiliary LRR proteins

辅助 LRR 蛋白对 BK 通道的调节

• 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
• 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

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）：大电导率，钙激活钾（BK）通道是钾通道家族的独特成员，该家族具有最大的单个通道电导率，并通过电压和胞质游离CA2+双重激活。 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.我们最近确定了一种新型的BK通道辅助亚基，这是一种富含亮氨酸的重复（LRR），其中含有膜蛋白LRC26，该膜蛋白LRC26在通道激活中的电压依赖性中引起前所未有的大型负移位（〜-150 mV），通过大大增强电压轴承的接近频道的频道和频道之间的交通，甚至可以在频道中均匀地构成频道的轴承激活，该通道均匀的轴承激活均匀的轴承均匀轴承均匀的轴承激活，该通道均匀的轴承均匀的轴承激活速度均匀的频道激活速度激活。可激发和不可驱行的细胞中的静息电压和钙水平。我们还鉴定了三个LRRC26类似的寄生虫蛋白，这些蛋白会修改BK通道的激活对不同扩展的电压依赖性。 LRRC26及其寄生的LRR蛋白在结构和功能上与subunits不同，因此被共同指定为BK通道家庭？ - subunits。三个特定的目的旨在确定这些辅助机制的BK通道调节的生理相关性和分子机制？ - subunits：1）确定人体组织和细胞中BK通道的生理和功能表达？ 2）确定？ - 亚基的BK通道调制的生化机制； 3）确定subunits调节功能的翻译后调节。将进行分子生物学，生化和电生理实验，以实现所提出的目标。总体而言，该赠款应用中提出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制的基本分子机制。拟议的研究的发现将建立一个新的BK通道辅助亚基家族的生理相关性，并对控制LRRC26的分子机制及其旁系同源物的独特能力，在转移电压依赖性的电压依赖性方面具有深入的理解。因此，这些研究将为理解和探索无处不在表达的BK通道的多种生理功能提供新的分子基础，并有助于创建新型试剂和治疗剂，以合理地操纵BK通道活动。 公共卫生相关性：拟议研究的发现将为理解和探索无处不在表达的BK Channel多样化的生理功能提供新的分子基础，并有助于创建新型试剂和治疗学以合理地操纵BK通道活动。