Regulation of ENaC by sgk1

sgk1 对 ENaC 的调节

• 批准号: 7154117
• 负责人: CECILIA M CANESSA
• 金额: $ 34.11万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7154117
• 关键词: Address; Agonist; Aldosterone; Applications Grants; Binding; Biochemical; Biological Assay; Blood Pressure; Cell Line; Cell Nucleus; Cell membrane; Cells; Colon; Condition; Cytosol; Development; Diagnosis; Disease; Distal; Distal convoluted renal tubule structure; Epithelial; Epithelial Cells; Epithelium; Genus Cola; Glucocorticoids; High Blood Pressure; Hormones; In Vitro; Insulin; Kidney; Kinetics; Lipids; Localized; Maintenance; Mediating; Membrane; Membrane Proteins; Messenger RNA; Modeling; Molecular; Nature; Noise; Phosphorylation; Phosphotransferases; Physiological; Post-Translational Protein Processing; Probability; Proteins; Rate; Rattus; Regulation; Renal tubule structure; Retrieval; Role; Serum; Signal Pathway; Signal Transduction; Sodium; Sodium Channel; Stimulus; System; Techniques; Tetracycline Control; Tissues; Vasopressins; Work; apical membrane; basolateral membrane; design; epithelial Na+ channel; extracellular; genetic regulatory protein; patch clamp; protein protein interaction; research study; response; stem; tool; trafficking

DESCRIPTION (provided by applicant): Sodium reabsorption in the distal tubule of the kidney is essential for maintenance of extracellular volume and blood pressure. Aldosterone, vasopressin and insulin stimulate sodium reabsorption by upregulating the activity of ENaC. There is growing evidence that sgkl (serum- and glucocorticoid-induced kinase) mediates the effects of these hormones; however, the signaling pathways employed by sgkl and the molecular mechanisms that modify ENaC activity have not been elucidated. Our working hypothesis stems from a model in which sgkl localizes predominantly at the basolateral membrane of epithelial cells in close proximity with incoming agonists such as insulin or AVP. Phosphorylation of sgkl by these and/or other stimuli to date unknown triggers a signal cascade that reaches the apical membrane to increase the abundance and/or activity of ENaC. The specific aims of this grant proposal are to: 1) Identify the mechanism underlying the effects of sgkl on ENaC in particular, to investigate changes in the traffic of channels, insertion and/or retrieval from the apical membrane, and changes in channel kinetics. 2) Determine the contribution of sgkl to aldosterone, vasopressin and insulin responses, and 3) To identify molecules that by associating with sgkl tether it to membranes, modulate its activity or constitute substrates of the sgkl-signaling cascade. We have developed tools and designed biochemical (turnover of ENaC subunits, phosphorylation assays, modified Ras recruitment system) and electrophysiological (patch-clamp studies and blocker-induced noise analysis) experiments to be conducted in vitro (A6 cell lines modified to express various forms of sgkl and siRNAs under the control of tetracycline) and in rat tissues that together will elucidate the proposed aims. The central role of sgkl in the integration of many signaling pathways makes it a candidate to mediate sodium retention associated with hypertensive disorders. Therefore, understanding the molecular mechanisms of this signaling pathway has potential implications for the diagnosis and development of new treatment strategies for the correction of high blood pressure.

描述（由申请人提供）：肾脏远端小管中的钠重吸收对于维持细胞外体积和血压至关重要。醛固酮，加压素和胰岛素通过上调ENAC的活性刺激钠的重吸收。越来越多的证据表明SGKL（血清和糖皮质激素诱导的激酶）介导了这些激素的作用。但是，尚未阐明SGKL使用的信号传导途径和修饰ENAC活性的分子机制。我们的工作假设源于一个模型，在该模型中，SGKL主要在上皮细胞的基底外侧膜定位，与传入的激动剂（如胰岛素或AVP）非常接近。这些和/或其他刺激对SGKL的磷酸化至今未知触发了一个信号级联，该信号级联到达顶端膜以增加ENAC的丰度和/或活性。该赠款提案的具体目的是：1）确定SGKL尤其是ENAC的影响的机制，以调查渠道，插入和/或从顶部膜的插入和/或检索的变化，以及动力学通道动力学的变化。 2）确定SGKL对醛固酮，加压素和胰岛素反应的贡献，以及3）确定通过与SGKL将其链接到膜的分子，调节其活性或构成SGKL-Signaling Cascad的底物。 We have developed tools and designed biochemical (turnover of ENaC subunits, phosphorylation assays, modified Ras recruitment system) and electrophysiological (patch-clamp studies and blocker-induced noise analysis) experiments to be conducted in vitro (A6 cell lines modified to express various forms of sgkl and siRNAs under the control of tetracycline) and in rat tissues that together will elucidate the proposed aims. SGKL在许多信号通路的整合中的核心作用使其成为介导与高血压疾病相关的钠保留率的候选者。因此，了解该信号通路的分子机制对校正高血压的新治疗策略的诊断和发展具有潜在的影响。