MUTATIONAL ANALYSIS OF ANGIOTENSIN II RECEPTORS

描述：(改编自《调查者摘要》)很好 认识到血管紧张素II(AngII)的中枢作用是 重要参与心血管和体液的调节 动态平衡。血管紧张素转换酶在大脑中的作用包括 行为、内分泌和生理反应 多肽与细胞表面受体的相互作用。主要有两种 血管紧张素Ⅱ受体家族，称为AT1和AT2。诱变 研究和计算机模拟主要集中在AT1受体上， 从而增加了对分子机制的理解 定义AT1配体结合和效应器动作。相比之下，有限的 对AT2亚型进行了诱变和建模研究。 因为这两个亚型只有34%的同源性，所以AT1 突变和建模数据适用于AT2受体IS 目前尚不清楚。因此，在本申请中，一系列 血管紧张素Ⅱ受体突变体，缺失突变，AT1/AT2嵌合体，和点 突变，将被创建和分析，以确定结构 定义AT2受体的配体结合特性的元件。 虽然这些实验主要集中在AT2亚型上，但后来 与AT1受体Will的异同比较 洞察整个血管紧张素Ⅱ受体的配体结合口袋 一家人。此外，因为越来越多的证据表明，受体 二聚化可能在调节受体功能中发挥重要作用 还将研究血管紧张素受体二聚体的可能形成。 具体而言，这项提案将涉及：(1)确定离子对 AT2受体与血管紧张素转换酶Ⅱ的相互作用 亚型特异性表位在血管紧张素Ⅱ结合中的作用； 半胱氨酸残基在二硫键形成中的作用，并作为 两种亚型对还原剂的不同敏感性 二硫苏糖醇；(Iv)鉴定下列结构元素 负责AT2亚型选择性结合；以及(V)调查 血管紧张素Ⅱ受体二聚体的可能形成，同源或 异源的。

DESCRIPTION: (Adapted from the Investigator's Abstract) It is well recognized that the central actions of angiotensin II (AngII) are importantly involved in the regulation of cardiovascular and body fluid homeostasis. Included amongst the actions of AngII in the brain are behavioral, endocrine, and physiological responses that result from the interaction of the peptide with cell surface receptors. There are two main families of AngII receptors, referred to as AT1 and AT2. Mutagenesis studies and computer modeling have primarily focused on the AT1 receptor, thereby leading to increasing understanding of the molecular mechanisms that define AT1 ligand binding and effector actions. In contrast, limited mutagenesis and no modeling studies have been performed on AT2 subtype. Because the two subtypes share only 34% homology, the extent that AT1 mutagenesis and modeling data are applicable to the AT2 receptor is currently unknown. Accordingly, in the present application, a series of AngII receptor mutants, in deletional mutations, AT1/AT2 chimeras, and point mutations, will be created and analyzed in order to identify the structural elements that define the ligand binding properties of AT2 receptors. Although these experiments focus primarily on the AT2 subtype, later comparison of similarities and differences with the AT1 receptor will provide insight into the ligand binding pocket of the entire AngII receptor family. In addition, because there is growing evidence that receptor dimerization may play an important role in modulating receptor function, the possible formation of AngII receptor dimers will also be studied. Specifically, this proposal will address: (i) identifying ion-pair interactions between AT2 receptor and AngII; (ii) the role of subtype-specific epitopes in the binding of AngII; (iii) the role of cysteine residues in the formation of disulfide bridges and as a source for the differing sensitivities of the two subtypes to the reducing agent dithiothreitol; (iv) identifying the structural elements that are responsible for AT2 subtype selective binding; and (v) investigating possible formation of AngII receptor dimers, either homologous or heterologous.