Allosteric ENaC Regulation

变构 ENaC 调节

基本信息

批准号：
8803794
负责人：
OSSAMA B KASHLAN
金额：
$ 33.5万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
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/8803794
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 model building predictive modeling research study shear stress

项目摘要

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 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.

描述（申请人提供）：上皮Na+通道（ENaC）在细胞外液容量和血压的调节中发挥关键作用。 ENaC 属于感知外部环境的离子通道家族，它对多种环境信号做出反应，包括 Na+、Cl-、质子、蛋白酶和剪切应力。人们对这些通道如何响应这些细胞外信号知之甚少。该提案的目标是确定外部 Na+ 和蛋白酶调节 ENaC 的分子机制。它们结合起来创建了持续活跃的特定通道库，以及仅在细胞外 Na+ 浓度较低时才招募的其他通道库。基于结构模型的拟议研究将确定这两个因素调节的分子机制。将定义Na+和抑制肽的结合位点，以及Na+或抑制肽结合时诱导的动态变化。实验将测试酸性口袋是否含有Na+抑制结合位点，以及酸性口袋附近的区域是否含有抑制肽的结合位点。对于任一效应器要诱导通道活性变化，它们必须在结合时诱导局部构象变化，并传播到通道孔。提出实验利用化学交联和静电效应捕获通道的功能构象。对细胞外因子如何调节 ENaC 的机制理解将有助于我们理解 ENaC 功能调节以及相关通道如何感知其环境。