Characterization of Aquaporin 2 Interacting Proteins

性状（申请人提供）：加压素（VP）是参与哺乳动物肾脏水重吸收调节的主要抗利尿激素。深入的研究已经确定VP通过将AQP 2水通道从细胞质囊泡募集到集合管主细胞的质膜来发挥功能。VP-AQP 2信号通路的损伤导致尿崩症以及在一些心力衰竭患者中观察到的液体潴留。AQP 2通过复杂的运输途径进行调节。我们的假设是，AQP 2的调节运输需要细胞内移位、胞吐和胞吞过程中直接和间接的蛋白质-蛋白质相互作用。拟议的研究分为三个具体的目标，解决新的AQP 2相互作用蛋白的鉴定和表征，以及调查这些新的蛋白质相互作用的功能意义上的AQP 2在体外和体内运输。该研究将利用多学科方法（分子生物学，细胞生物学，生物化学和免疫细胞化学）和强大的技术（酵母双杂交筛选，结构功能分析，基因转移）来识别和表征新的蛋白质-蛋白质相互作用及其生物学功能。这些研究将提供关于AQP 2运输的分子机制的重要信息，并可能最终为尿浓缩缺陷患者提供更好的治疗方法。

DESCRIPTION (provided by applicant): Vasopressin (VP) is the major antidiuretic hormone involved in the regulation of water reabsorption by mammalian kidney. Intensive studies have established that VP functions by recruiting the AQP2 water channel from cytoplasmic vesicles to the plasma membrane of collecting duct principal cells. The impairment of VP-AQP2 signaling pathways results in diabetes insipidus as well as fluid retention seen in some heart failure patients. AQP2 is regulated through complex trafficking pathways. Our hypothesis is that regulated trafficking of AQP2 requires direct and indirect protein-protein interactions during intracellular translocation, exocytosis as well as endocytosis. The proposed studies are divided into three specific aims addressing identification and characterization of novel AQP2 interacting proteins as well as investigation of the functional significance of these novel protein interactions on AQP2 trafficking in vitro and in vivo. The proposed study will utilize multidisciplinary approaches (molecular biology, cell biology, biochemistry and immunocytochemistry) and powerful technology (yeast two hybrid screen, structural functional analysis, gene transfer) to identify and characterize novel protein-protein interactions and their biologic functions. These studies will provide important information of the poorly understood molecular mechanisms underlying AQP2 trafficking, and may ultimately lead to better therapies for patients with defective urinary concentration.