Allosteric ENaC Regulation

变构 ENaC 调节

• 批准号: 8628315
• 负责人: OSSAMA B KASHLAN
• 金额: $ 33.33万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-10 至 2019-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8628315
• 关键词: ASIC channel; Acidic Region; Address; Affect; Aldosterone; Apical; Binding; Binding Sites; Blood Pressure; C-terminal; Cell surface; Chemicals; Cleaved cell; Cues; Data; Distal; Electrostatics; Environment; Epithelial; Extracellular Domain; Extracellular Fluid; Family; Family member; Fingers; Gene Family; Goals; Gray unit of radiation dose; Health; Human; Ion Channel; Kidney; Ligand Binding; Ligands; Location; Mechanical Stress; Membrane; Modeling; Molecular; Molecular Conformation; Molecular Structure; Na(+)-K(+)-Exchanging ATPase; Nephrons; Peptide Hydrolases; Peptides; Play; Process; Proteolysis; Protons; Recruitment Activity; Regulation; Reporting; Role; Site; Sodium; Sodium Channel; Sodium Chloride; Structural Models; Structure; Surface; Taste Perception; Testing; Thumb structure; Tongue; Work; Wrist; apical membrane; base; blood pressure regulation; crosslink; design; epithelial Na+ channel; extracellular; member; predictive modeling; public health relevance; research study; shear stress

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 and it responds to several environmental cues including Na+, Cl-, protons, proteases and shear stress. How these channels respond to these extracellular cues is poorly understood. The goal of this proposal is to determine the molecular mechanisms of ENaC regulation by external Na+ and proteases. They combine to create specific pools of channels that are constitutively active, and others that are recruited only when extracellular Na+ concentrations are low. The proposed studies based on structural models will determine molecular mechanisms of regulation by both factors. Binding sites for Na+ and an inhibitory peptide will be defined, as well as dynamic changes induced upon binding of Na+ or an inhibitory peptide. Experiments will test whether an acidic pocket hosts a Na+ inhibitory binding site, and a region adjacent to the acidic pocket hosts the binding site for an inhibitory peptide. For either effector to induce changes in channel activity, they must induce local conformational changes upon binding that propagate to the channel pore. Experiments are proposed to trap functional conformations of the channel using chemical crosslinks and electrostatic effects. A mechanistic understanding of how extracellular factors regulate ENaC will inform our understanding of ENaC functional regulation and how related channels may sense their environments.

上皮Na+通道（ENaC）在细胞外液容量和血液的调节中起关键作用