MOLECULAR PROPERTIES OF CARDIAC ADRENERGIC RECEPTORS

我们请求支持一项旨在阐明 在分子水平上， β肾上腺素能受体。 儿茶酚胺，如 去甲肾上腺素和肾上腺素在荷尔蒙分泌中至关重要， 控制整个流通。 这些化合物通过刺激 膜结合酶腺苷酸环化酶，其依次由 与特定的β-肾上腺素能受体结合。 虽然我们的动力 研究一直希望阐明基本的生物化学 肾上腺素能控制循环的基础过程，它已经成为 越来越清楚的是，研究β受体的最佳模型 环化酶系统是简单的、同质的细胞群体。 因此，许多 我们的工作都是用这种简单的模型系统进行的。 这一建议 三个密切相关的主要目标，所有这些目标都涉及主要重点， β-肾上腺素能受体作为一种方法，以获得更多的了解 生理过程的正常和异常荷尔蒙控制。 这些目标是：1）获得关于 β-肾上腺素能受体的生物化学性质，包括完整的 从cDNA克隆推导的氨基酸序列以及 整个基因; 2）了解受体的功能方式 为了翻译激动剂配体在所述细胞外表面上的结合， 细胞激活鸟嘌呤核苷酸调节蛋白， 质膜内的腺苷酸环化酶。 会来做这项工作 在人工膜中进行重构研究，其中纯化的 受体和纯化的效应物组分重新结合， 互动研究。 3)为了了解受体的功能 在质膜中，例如通过共价键， 在核一级， 受体的细胞基因的转录。 主要重点将 对腺苷酸环化酶的脱敏问题， β-肾上腺素能刺激 这种脱敏是一种常见的结果， β-肾上腺素能和其他类型的 激动剂 这些研究将提供第一个全面的图片， 腺苷酸环化酶偶联受体的功能模式，其中 关于受体结构的详细信息提供了 了解受体功能和受体调节。

We request support for a program in basic research directed at elucidating at a molecular level the nature and mode of functioning of the Beta-adrenergic receptors for catecholamines. Catecholamines such as norepinephrine and epinephrine are of vital importance in the hormonal control of the entire circulation. These compounds act via stimulation of the membrane-bound enzyme adenylate cyclase which is in turn mediated by binding to specific Beta-adrenergic receptors. Although the impetus to our studies has been the desire to shed light on the basic biochemical processes underlying adrenergic control of the circulation, it has become increasingly clear that the best models for study of the Beta-receptor cyclase system are simple, homogeneous cell populations. Accordingly, much of our work is conducted with such simple model systems. This proposal has three major intimately linked goals, all involving primary focus on the Beta-adrenergic receptor as an approach to gaining increased understanding of the normal and abnormal hormonal control of physiological processes. These goals are: 1) to obtain detailed molecular information about the biochemical nature of the Beta-adrenergic receptor including the complete amino acid sequence as deduced from cDNA clones as well as the sequence of the entire gene; 2) to understand the way in which the receptor functions to translate the binding of an agonist ligand on the outer surface of the cell into activation of the guanine nucleotide regulatory protein and the enzyme adenylate cyclase within the plasma membrane. This will be done by performing reconstitution studies in artificial membranes wherein purified receptor and purified effector components are reunited and their functional interactions studied. 3) To understand the way in which receptor function is regulated both in the plasma membrane, as for example by covalent modification, and at the nuclear level in terms of the rate of transcription of the cellular gene for the receptor. The major focus will be on the problem of desensitization of adenylate cyclase to Beta-adrenergic stimulation. Such desensitization is a common result of the therapeutic application of Beta-adrenergic and other types of agonists. These studies will provide the first comprehensive picture of the mode of functioning of an adenylate cyclase-coupled receptor in which detailed information about receptor structure provides the basis for understanding receptor function and receptor regulation.