Structure, Function and Regulation of Bombesin Receptors

铃蟾肽受体的结构、功能和调节

• 批准号: 6104221
• 负责人: James F. Battey
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON DEAFNESS AND OTHER COMMUNICATION DISORDERS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6104221
• 关键词: G protein; autism; bombesin; gastrin releasing peptide; gene targeting; genetic regulation; guanine nucleotide binding protein; human genetic material tag; human tissue; laboratory mouse; neuropeptide receptor; phenotype; phospholipase C; phosphorylation; protein structure function; receptor coupling; site directed mutagenesis

Mammalian bombesin-like neuropeptides, gastrin releasing peptide (GRP) and neuromedin B (NMB), mediate a diverse range of biological responses in normal tissues, and stimulate the growth of some lung, pancreatic, and prostate carcinomas. Our laboratory cloned and characterized three structurally and pharmacologically distinct human bombesin receptors: the gastrin- releasing peptide receptor (GRP-R, or bb2); the neuromedin B receptor (NMB-R, or bb1); and bombesin receptor subtype 3 (BRS-3, or bb3). All three receptors are members of the G-protein coupled receptor superfamily, coupling to heterotrimeric G-proteins that activate phospholipase C. Several advances in our understanding of the function and regulation of these receptors has occurred within the last year: (1) we have used gene targeting strategies to create mice which lack the GRP-R, and progressed in our efforts to generate similar mice that lack BRS-3. Mice lacking GRP-R do not exhibit bombesin-induced satiety, implicating the GRP-R as a regulator of appetite. As these mice age, we hypothesize that GRP-R targeted mice will become obese. (2) We have developed a protocol that allows us to generate uncoupled receptors embedded in a normal biological membrane. This preparation allows us to reconstitute coupling to purified G- proteins, examining the selectivity and enzymology of receptor- catalyzed nucleotide exchange on heterotrimeric GTP-binding proteins. Using this assay, we show that phosphorylation of serines and threonines in the C-terminal domain of the GRP-R inhibits coupling to heterotrimeric G-proteins thereby establishing that ligand-stimulated receptor phosphorylation is the switch that turns off receptor signalling.

哺乳动物bombesin样神经肽，胃蛋白 释放肽（GRP）和神经蛋白B（NMB），介导A 正常组织中的生物反应范围不同，并且 刺激某些肺，胰腺和前列腺的生长 癌。我们的实验室克隆并描述了三个 在结构和药理上截然不同的人类孟买 受体：胃释放肽受体（GRP-R或BB2）； 神经蛋白B受体（NMB-R或BB1）；和孟买 受体亚型3（BRS-3或BB3）。这三个受体都是 G蛋白耦合受体超家族的成员，耦合 到激活磷脂酶C的异三聚体G蛋白。几个 我们对理解功能和调节的进步 这些受体发生在过去的一年中：（1）我们已经使用过 基因靶向策略，以创建缺乏GRP-R的小鼠，并且 我们努力产生缺乏BRS-3的类似小鼠的努力。 缺乏GRP-R的小鼠不会表现出孟买引起的饱腹感， 将GRP-R视为食欲的调节剂。作为这些老鼠 年龄，我们假设GRP-R靶向小鼠将肥胖。 （2）我们开发了一个协议，使我们能够生成 嵌入正常生物膜中的未偶联受体。 这种准备使我们能够重建耦合到纯化的g- 蛋白质，检查受体的选择性和酶学 催化的核苷酸交换在异三聚体GTP结合上 蛋白质。使用该测定法，我们表明丝氨酸的磷酸化 GRP-R的C末端结构域中的急氨酸抑制 耦合到异构三聚体G蛋白，从而确定 配体刺激的受体磷酸化是转弯的开关 关闭受体信号传导。