SUBUNITS INTERACTION IN THE FUNCTION OF BK CHANNELS

BK 通道功能中的亚基相互作用

• 批准号: 8020026
• 负责人: Jianmin Cui
• 金额: $ 32.59万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-15 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8020026
• 关键词: Active Sites; Affect; Amino Acid Sequence; Amino Acids; Binding; Calcium-Activated Potassium Channel; Characteristics; Chemicals; Coupled; Coupling; DNA Sequence Rearrangement; Data; Disease; Electrophysiology (science); Epilepsy; Event; Family; Foundations; Generalized Epilepsy; Genes; Goals; Health; Hypertension; Ion Channel; Kidney; Kinetics; Link; Mediating; Membrane; Methods; Modeling; Modification; Molecular; Molecular Target; Muscle Contraction; Mutagenesis; Mutation; Nature; Phenotype; Physiological; Physiological Processes; Potassium Channel; Process; Property; Proteins; Publications; Renal function; Role; Signal Transduction; Smooth Muscle; Synaptic Transmission; Time; Tissues; Transmembrane Domain; Work; base; extracellular; improved; insight; large-conductance calcium-activated potassium channels; novel; sensor; voltage

DESCRIPTION (provided by applicant): Our long-term goal is to understand the physiological and pathophysiological role of the BK-type voltage and Ca2+-activated K+ channels. BK channels modulate physiological processes that involve Ca2+ signaling in many tissues, such as muscle contraction, renal function and neural transmission. These channels are composed of the pore-forming, voltage- and Ca2+ -sensing a subunit that is encoded by a single Slo1 gene and four types of auxiliary ¿ subunit (¿1-4). Each of these ¿ subunits modulates functional properties of the Slo1 channel with distinct characteristics and tissue-specific expression. Thus, ¿ subunits help to define the phenotypes and physiological roles of BK channels in various tissues. To achieve our long-term goal, it is necessary to study the molecular mechanism of the interaction between Slo1 and the ¿ subunits. Previous publications and our preliminary data demonstrate that, although all four types of ¿ subunit share similar structural features, the mechanisms of their modulation of Slo1 channels differ in two key aspects: 1) they target different molecular components and processes in Slo1 that are important in channel gating, and 2) they have different amino acids or motifs (active sites) that are critical for altering gating of Slo1 channels. Based on these preliminary results, we will use the methods of electrophysiology, mutagenesis, chemical modification and kinetic modeling to achieve the following specific aims: I. To identify the molecular targets of ¿ subunits modulation in Slo1 channels. II. To identify the active sites of ¿ subunits. III. To examine if ¿ subunits affect the interaction between the membrane-spanning and the cytosolic domains that is critical for BK channel gating. Aim III will establish a link between the ¿ subunit association, as studied in Aims I and II, with a structural mechanism of BK channel gating that has been revealed recently. This study will identify amino acids and structural motifs important for BK channel gating and reveal the nature of the interactions between Slo1 and ¿ subunits. It will lay the foundation for understanding the molecular basis of BK channel related pathological conditions, such as epilepsy and hypertension, and provide the target and rationale for their treatment. ¿ subunits of K+ channels with transmembrane segment, such as the KCNE family and BK ¿ subunits modulate the gating properties of their respective a subunits, which are key to the physiological roles of these channels. Our preliminary studies suggest that some of these ¿ subunits may affect channel gating through common mechanisms. Therefore, this study will provide insights to these common mechanisms of K+ channel function. PUBLIC HEALTH RELEVANCE: This study will identify amino acids and structural motifs important for BK channel gating and reveal the nature of the interactions between Slo1 and ¿ subunits. It will lay the foundation for understanding the molecular basis of BK channel related pathological conditions, such as epilepsy and hypertension, and provide the target and rationale for their treatment.

描述（由申请人提供）：我们的长期目标是了解 BK 型电压和 Ca2+ 激活的 K+ 通道的生理和病理生理作用。 BK 通道调节许多组织中涉及 Ca2+ 信号传导的生理过程，例如肌肉收缩、肾功能和神经传递。这些通道由成孔、电压和 Ca2+ 感应亚基组成，该亚基由单个 Slo1 基因和四种类型的辅助 ¿ 亚基 (¿1-4) 编码。这些亚基中的每一个都以独特的特征和组织特异性表达来调节 Slo1 通道的功能特性。因此，¿ 亚基有助于定义 BK 通道在各种组织中的表型和生理作用。为了实现我们的长期目标，有必要研究Slo1和¿亚基之间相互作用的分子机制。之前的出版物和我们的初步数据表明，尽管所有四种类型的¿亚基具有相似的结构特征，但它们对Slo1通道的调节机制在两个关键方面有所不同：1）它们针对Slo1中对通道门控很重要的不同分子成分和过程，2）它们具有不同的氨基酸或基序（活性位点），这些氨基酸或基序对改变Slo1通道的门控至关重要。基于这些初步结果，我们将利用电生理学、诱变、化学修饰和动力学建模的方法来实现以下具体目标： I.确定Slo1通道中¿亚基调节的分子靶点。二.识别 ¿ 亚基的活性位点。三．检查 ¿ 亚基是否影响跨膜结构域和胞质结构域之间的相互作用，这对于 BK 通道门控至关重要。正如目标 I 和 II 中所研究的那样，目标 III 将在 ¿ 亚基关联与最近揭示的 BK 通道门控结构机制之间建立联系。这项研究将鉴定对 BK 通道门控重要的氨基酸和结构基序，并揭示 Slo1 和 ¿ 亚基之间相互作用的本质。它将为了解癫痫和高血压等BK通道相关病理状况的分子基础奠定基础，并为其治疗提供目标和原理。具有跨膜片段的 K+ 通道亚基，例如 KCNE 家族和 BK 亚基调节各自 a 亚基的门控特性，这是这些通道的生理作用的关键。我们的初步研究表明，其中一些亚基可能通过常见机制影响通道门控。因此，本研究将为 K+ 通道功能的这些常见机制提供见解。 公共健康相关性：这项研究将鉴定对 BK 通道门控重要的氨基酸和结构基序，并揭示 Slo1 和 ¿ 亚基之间相互作用的本质。它将为了解癫痫和高血压等BK通道相关病理状况的分子基础奠定基础，并为其治疗提供目标和原理。