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(AQPs)是水特有的膜通道蛋白。AQP5位于呼吸道粘膜下腺、支气管上皮和I型肺泡细胞的顶膜上，可能参与了呼吸道表面分泌物的生成。AQP5的表达调控是复杂的，并受到各种应激条件的调节，包括渗透压和病毒感染。与野生型相比，AQP5基因敲除小鼠的气道腺分泌减少，支气管收缩增加。AQP5表达的改变可能会改变分泌物，并在呼吸道生理中发挥重要作用。在培养的肺上皮细胞中，我们观察到短期暴露于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，但对总呼吸道分泌物的影响尚不明确。我们假设，β-激动剂可以改变AQP5的表达和亚细胞转运，从而改变呼吸道表面液体。我们将调查以下目标。目的#1：通过研究蛋白质降解的机制，包括泛素化的变化，确定急性cAMP和β-激动剂刺激如何降低AQP5的表达。目的#2：利用野生型和突变型AQP5结构的免疫荧光，确定急性暴露于cAMP和β-激动剂刺激对AQP5蛋白转运的影响。