Arrestin Interactions During LH Receptor Desensitization

LH 受体脱敏过程中抑制蛋白的相互作用

• 批准号: 6526893
• 负责人: Regina D Horvat
• 金额: $ 2.49万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-23 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6526893
• 关键词: CHO cells; G protein; SDS polyacrylamide gel electrophoresis; adenylate cyclase; arrestins; autoradiography; biological signal transduction; cyclic AMP; enzyme linked immunosorbent assay; guanine nucleotide exchange factors; hormone receptor; immunoaffinity chromatography; immunoprecipitation; luteinizing hormone; mitogen activated protein kinase; postdoctoral investigator; posttranslational modifications; protein sequence; receptor binding; receptor sensitivity; western blottings

The luteinizing hormone (LH) receptor is a seven transmembrane spanning receptor coupled to G proteins, most typically Gs, which activates adenylyl cyclase to transduce a second messenger signal. Signal transduction by the LH receptor is tempered by a molecular mechanism known as desensitization. Although desensitization of the LH receptor may involve attenuation of receptor function, G protein function, or the downstream effector, the inability of receptors to activate their respective G-protein due to associations with arrestin molecules appears to be a key event leading to receptor desensitization. Recent studies from our laboratory have elucidated various proteins necessary for beta-arrestin interaction with the LH receptor and a potential new role for beta-arrestins in signal transduction. I hypothesize that within an intact cell ARF nucleotide-binding site opener (ARNO) activates ADP ribosylation factor 6 (ARF6) which leads to the release of beta-arrestin-1 from its membrane docking site. Once released, beta-arrestin-1 binds to the activated LH receptor and inhibits further signaling through heterotrimeric G proteins. The arrestin-receptor complex then recruits Src and/or Grb-2 to initiate a different signaling pathway, the Akt signaling pathway. To test this hypothesis, I propose three specific aims to clarify the molecular mechanisms involved in the release of and signal transduction via beta- arrestin following activation of the LH receptor.

黄体生成素 (LH) 受体是一种与 G 蛋白（最典型的是 Gs）偶联的七次跨膜受体，它激活腺苷酸环化酶以转导第二信使信号。 LH 受体的信号转导受到称为脱敏的分子机制的调节。尽管 LH 受体脱敏可能涉及受体功能、G 蛋白功能或下游效应子的减弱，但由于与抑制蛋白分子的结合，受体无法激活各自的 G 蛋白似乎是导致受体脱敏的关键事件。我们实验室最近的研究阐明了 β-arrestin 与 LH 受体相互作用所需的各种蛋白质，以及 β-arrestin 在信号转导中的潜在新作用。我推测，在完整细胞内，ARF 核苷酸结合位点开启子 (ARNO) 会激活 ADP 核糖基化因子 6 (ARF6)，从而导致 β-arrestin-1 从其膜对接位点释放。一旦释放，β-arrestin-1 就会与激活的 LH 受体结合，并通过异三聚体 G 蛋白抑制进一步的信号传导。然后，抑制蛋白-受体复合物招募 Src 和/或 Grb-2 来启动不同的信号传导途径，即 Akt 信号传导途径。为了检验这一假设，我提出了三个具体目标，以阐明 LH 受体激活后 β-抑制蛋白的释放和通过 β-抑制蛋白进行信号转导所涉及的分子机制。