Refining a structural model of ENaC

完善 ENaC 的结构模型

• 批准号: 8564819
• 负责人: OSSAMA B KASHLAN
• 金额: $ 2.51万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8564819
• 关键词: ASIC channel; Aldosterone; Bile Acids; Binding; Blood Pressure; Blood Vessels; Cations; Cell surface; Characteristics; Chickens; Cleaved cell; Color; Cues; Cysteine; Data; Distal; Disulfides; Environment; Epithelial; Epithelial Cells; Epithelium; Extracellular Domain; Extracellular Fluid; Extracellular Structure; Family; Family member; Fingers; Gene Family; Goals; Health; Homologous Protein; Human; Ion Channel; Kidney; Location; Lung; Mechanics; Modeling; Mucociliary Clearance; Mutation; Nephrons; Peptide Hydrolases; Peptides; Play; Process; Proteins; Protons; Regulation; Relative (related person); Reporting; Research Design; Site; Smooth Muscle Myocytes; Sodium; Sodium Channel; Sodium Chloride; Stimulus; Stretching; Structural Models; Structure; Taste Perception; Testing; Thumb structure; Tongue; Transmembrane Domain; airway surface liquid; apical membrane; base; blood pressure regulation; comparative; crosslink; disulfide bond; epithelial Na+ channel; extracellular; improved; member; mouse ASIC1 protein; novel; public health relevance; research study; response; shear stress

DESCRIPTION (provided by applicant): The epithelial Na+ channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. ENaC responds to several environmental cues including Na+, Cl-, protons, proteases and shear stress. The ENaC extracellular domains interact with the extracellular environment to sense these cues. Having an accurate model of ENaC structure is therefore critical to understanding ENaC regulation by extracellular factors. Acid sensing ion channel 1 (ASIC1) is the only protein homologous to ENaC whose structure has been reported. The ENaC subunit extracellular domains are largely homologous the corresponding ASIC1 domains, except for the so called finger domain where ENaC subunits have a large insertion. The ENaC finger domain has been implicated in the channel's response to Na+, proteases, and shear stress. The goal of this proposal is to improve upon a structural model of the extracellular domains of the ENaC ? subunit. The proposed studies will investigate the structural interactions that involve a stretch of residues that includes two cysteines in the finger domain insertion. We will then use this information to refine a structural model of the ENaC ? subunit. We previously hypothesized that these two finger domain cysteines formed a disulfide bridged pair, but our preliminary data contradicts this notion. Experiments are proposed to define specific interactions between these cysteines and other specific sites in the channel, and between these cysteines and an inhibitory peptide. We will derive distance constraints from our data and combine them with constraints based on homology to ASIC1 and on other available data to refine a model of the ENaC ? subunit extracellular domains. We will then assess our model by developing novel hypotheses of function to test.

描述(申请人提供)：上皮Na+通道(ENaC)在调节细胞外液容量和血压方面起着关键作用。ENAC属于感知外部环境的离子通道家族。ENAC响应多种环境信号，包括Na+、Cl-、质子、蛋白水解酶和切应力。ENaC胞外区与胞外环境相互作用，以感知这些信号。因此，拥有准确的ENaC结构模型对于了解细胞外因子对ENaC的调控至关重要。酸敏感离子通道1(ASIC1)是已报道的唯一与ENaC同源的蛋白质。ENaC亚基的胞外结构域与相应的ASIC1结构域基本同源，除了所谓的Finger结构域，其中ENaC亚基有一个大的插入。ENaC指状域与通道对Na+、蛋白水解酶和切应力的反应有关。这项建议的目标是改进ENaC？胞外区的结构模型。亚单位。拟议的研究将调查涉及一段残基的结构相互作用，该残基包括指状域插入中的两个半胱氨酸。然后，我们将使用这些信息来改进ENaC的结构模型。亚单位。我们之前假设这两个指状域的半胱氨酸形成了一个二硫键桥接对，但我们的初步数据与这一概念相矛盾。建议通过实验来确定这些半胱氨酸和通道中其他特定位置之间的特定相互作用，以及这些半胱氨酸和抑制性多肽之间的特定相互作用。我们将从我们的数据中推导出距离约束，并将它们与基于ASIC1同源性和其他可用数据的约束相结合，以完善ENaC？亚单位胞外区。然后，我们将通过开发新的函数假设来测试我们的模型。