cCAMP Regulation of Aquaporin 5

cCAMP 对水通道蛋白 5 的调节

• 批准号: 6818100
• 负责人: Venkataramana K Sidhaye
• 金额: $ 5.03万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6818100
• 关键词: SDS polyacrylamide gel electrophoresis; autoradiography; confocal scanning microscopy; cyclic AMP; immunoprecipitation; membrane channels; membrane proteins; phosphorylation; postdoctoral investigator; protein degradation; respiratory epithelium; stimulant /agonist; tissue /cell culture; ubiquitin; water channel

DESCRIPTION (provided by applicant): Aquaporins (AQPs) are water specific membrane channel proteins. AQP5, located in the apical membrane of airway submucosal glands, bronchial epithelium, and type I pneumocytes, likely participates in generation of airway surface secretions. Regulation of AQP5 expression is complex and modulated by a variety of stress conditions, including osmolality and viral infections. AQP5 knockout mice have reduced airway gland secretions and increased bronchoconstriction compared to wild type. Changes in AQP5 expression may alter secretions, and play an important role in the airway physiology. In cultured lung epithelial cells, we observed that short-exposures to cAMP decrease AQP5 protein levels and modify its cellular distribution. Beta-agonists, a mainstay of asthma therapy, stimulate the formation of cAMP, and lead to smooth muscle relaxation, but effect on total airway secretions is not defined. We hypothesize that beta-agonists alter AQP5 expression and subcellular trafficking and can thereby alter airway surface liquid. We will investigate the following aims. Aim#1 : To determine how acute cAMP and beta-agonist stimulation decrease AQP5 expression by investigating mechanisms of protein degradation including changes in ubiquitination. Aim#2: To determine the effects of acute exposure to cAMP and beta-agonist stimulation on AQP5 protein trafficking using immunofluorescence of wild-type and mutant AQP5 constructs.

描述（由申请人提供）：水通道蛋白（AQP）是水特异性膜通道蛋白。 AQP5 位于气道粘膜下腺、支气管上皮和 I 型肺细胞的顶膜中，可能参与气道表面分泌物的产生。 AQP5 表达的调节很复杂，并受到多种应激条件的调节，包括渗透压和病毒感染。与野生型相比，AQP5 敲除小鼠气道腺体分泌减少，支气管收缩增加。 AQP5 表达的变化可能会改变分泌物，并在气道生理学中发挥重要作用。在培养的肺上皮细胞中，我们观察到短时间暴露于 cAMP 会降低 AQP5 蛋白水平并改变其细胞分布。 β-激动剂是哮喘治疗的主要药物，可刺激 cAMP 的形成，并导致平滑肌松弛，但对气道总分泌物的影响尚不清楚。我们假设 β 激动剂改变 AQP5 表达和亚细胞运输，从而改变气道表面液体。我们将研究以下目标。目标#1：通过研究蛋白质降解机制（包括泛素化的变化）来确定急性 cAMP 和 β 激动剂刺激如何降低 AQP5 表达。目标#2：使用野生型和突变型 AQP5 构建体的免疫荧光来确定急性暴露于 cAMP 和 β 激动剂刺激对 AQP5 蛋白运输的影响。