Calicum, MARCKS, and PIP2 regulation of ENaC

ENaC 的钙、MARCKS 和 PIP2 调节

• 批准号: 9245699
• 负责人: Abdel Ayube Alli
• 金额: $ 13.94万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9245699
• 关键词: Actins; Adaptor Signaling Protein; Alveolar; Amiloride; Apical; Binding; Binding Proteins; Calcium; Calcium Binding; Calmodulin; Calpain; Carrier Proteins; Cell membrane; Cells; Cleaved cell; Colon; Congestive Heart Failure; Cytoplasm; Cytoskeleton; Disease; Distal; Embryo; End stage renal failure; Epithelial; Epithelial Cells; Essential Hypertension; Etiology; F-Actin; Fluid Balance; Health; Homeostasis; Hypertension; Hypotension; Inherited; Injection of therapeutic agent; Kidney; Knock-out; Knockout Mice; Laboratories; Lead; Learning; Liquid substance; LoxP-flanked allele; Lung; MARCKS gene; Mediating; Membrane; Membrane Lipids; Membrane Proteins; Methods; Modeling; Molecular; Mus; Mutation; Names; Nephrons; PKC Phosphorylation Site; Peptide Hydrolases; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phosphorylation; Post-Translational Protein Processing; Probability; Protein Kinase C; Proteolysis; Public Health; Regulation; Reporting; Risk Factors; Role; Sodium; Sodium Channel; Stroke; Testing; apical membrane; aquaporin-2; blood pressure regulation; embryonic stem cell; epithelial Na+ channel; extracellular; in vivo; inorganic phosphate; knock-down; knockout animal; promoter; recombinase; recombinase-mediated cassette exchange; small hairpin RNA; success; tissue culture

DESCRIPTION (provided by applicant): Hypertension is a major public health concern because it is an important risk factor for many other diseases including congestive heart failure, stroke, and end-stage renal disease. The constitutive activation of epithelial sodium channels (ENaC) leads to severe hypertension, while subtle stimulation of ENaC may contribute to essential hypertension. Therefore, understanding the regulation of ENaC is important to understand the etiology of hypertension. Our laboratory was among the first to show that ENaC activity requires binding of phosphatidylinositol bis-phosphate (PIP2) to the amino terminal domain of ENaC subunits. We used a tissue culture model of distal nephron sodium transport and we showed that the PIP2 dependent regulation of ENaC is mediated by an adaptor protein, myristoylated alanine-rich C kinase substrate (MARCKS), that binds PIP2 and increases the local concentration of PIP2 near ENaC and, thereby, activates ENaC. The myristoylated amino terminal domain and the basic effector domain of MARCKS both contribute to its function at the apical plasma membrane. The function of MARCKS can be regulated by posttranslational modifications, association with calcium/calmodulin, and proteolysis so that regulation of MARCKS is also important for regulating ENaC. The aims of this project are to show how MARCKS regulates ENaC in vivo and identify the molecular mechanisms that regulate MARCKS activity at the apical membrane of renal epithelial cells.

描述(申请人提供)：高血压是一个主要的公共卫生问题，因为它是许多其他疾病的重要风险因素，包括充血性心力衰竭、中风和终末期肾脏疾病。上皮性钠通道(ENaC)的结构性激活导致严重高血压，而ENaC的轻微刺激可能导致高血压。因此，了解ENaC的调节对于了解高血压的病因具有重要意义。我们的实验室是最早证明ENaC活性需要磷脂酰肌醇二磷酸(PIP2)与ENaC亚基的氨基末端结构域结合的实验室之一。我们使用了远端肾单位钠转运的组织培养模型，我们证明了PIP2对ENaC的依赖调节是由一种适配蛋白--肉豆蔻酰化富含丙氨酸的C激酶底物(MARCKS)介导的，它与PIP2结合并增加ENaC附近PIP2的局部浓度，从而激活ENaC。MARCKS的肉豆蔻酰化氨基末端结构域和基本效应结构域都参与了它在顶端质膜上的功能。Marcks的功能可以通过翻译后修饰、与钙/钙调蛋白的结合和蛋白分解来调节，因此Marcks的调节在调节ENaC中也是重要的。本项目的目的是展示Marcks如何在体内调节ENaC，并确定调节肾上皮细胞顶膜Marcks活性的分子机制。