Function of a membrane-localized nuclear receptor

膜定位核受体的功能

• 批准号: 7050020
• 负责人: Joel H. Rothman
• 金额: $ 29.03万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-05 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7050020
• 关键词: Caenorhabditis elegans; RNA interference; biological signal transduction; biotechnology; cell membrane; developmental genetics; functional /structural genomics; gene mutation; helminth genetics; hormone receptor; hormone regulation /control mechanism; hormone sensitivity /resistance; larva; nuclear receptors; pheromone; protein localization; protein protein interaction; protein structure function

DESCRIPTION (provided by applicant): The long-term goals are to understand how a nuclear hormone receptor (NHR) is directed to the plasma membrane in response to a signal and how it might function in a non-nuclear signal transduction system. While the classical view of steroid signaling holds that these hormones bind intracellular receptors that act as ligand-activated transcription factors, extensive evidence indicates that steroids can also act by a non-genomic mechanism at the cell surface. We have identified a C. elegans NHR, DPR-1, that may act through such a membrane-based signaling system, providing the first genetic system for dissecting a membrane-based NHR signaling system. In the presence of a small lipophilic molecule (dauer pheromone or "daumone") DPR-1 moves from the cytoplasm to the plasma membrane. Daumone triggers an alternative, developmental arrested state, the dauer larva. A deletion mutation of the dpr-1 gene attenuates responsiveness to dauer pheromone and accelerates exit from the dauer state, and overexpression of DPR- 1 triggers inappropriate dauer development and inhibits exit from the dauer state. The dauer regulatory pathway is required for relocalization of DPR-1 to the membrane. The proposed studies will test the hypothesis that DPR-1 regulates dauer formation through a plasma membrane signal transduction system. Aim 1 will investigate parameters that influence relocalization of DPR-1 in response to dauer pheromone, analyze the essential function of dpr-1, test for redundant partners of DPR-1, and assess the relationship between DPR-1 and the dauer pathway. Aim 2 will identify structural elements and components required for DPR-1 signaling and membrane association, test its signaling function when targeted to the membrane and nucleus, examine the basis for a membrane-tenacious form of DPR-1 in dauer larvae, and investigate physical interactions between DPR-1 and other proteins. Aim 3 will examine whether DPR-1 responds to dauer pheromone in heterologous cells and whether DPR-1 relatives and the dauer-regulating NHR, DAF- 12, associate with the membrane under dauer-favoring conditions. Aim 4 will initiate RNAi screens to identify components responsible for relocalization of DPR-1 and genes with which it collaborates. The elucidation of novel pathways through which NHRs function may advance our understanding of many developmental defects and the hormonal influences on normal human physiology and a variety of human pathologies.

描述（由申请人提供）：长期目标是了解核激素受体（NHR）如何响应信号而定向至质膜，以及它如何在非核信号转导系统中发挥作用。虽然类固醇信号传导的经典观点认为这些激素与充当配体激活转录因子的细胞内受体结合，但大量证据表明类固醇也可以通过细胞表面的非基因组机制发挥作用。我们已经鉴定出秀丽隐杆线虫 NHR，DPR-1，它可能通过这种基于膜的信号系统发挥作用，为剖析基于膜的 NHR 信号系统提供了第一个遗传系统。在存在亲脂性小分子（dauer 信息素或“daumone”）的情况下，DPR-1 从细胞质移动到质膜。 Daumone 会触发另一种发育停滞状态，即 dauer 幼虫。 dpr-1基因的缺失突变会减弱对dauer信息素的反应并加速从dauer状态的退出，而DPR-1的过度表达会触发不适当的dauer发育并抑制从dauer状态的退出。 DPR-1 重新定位到膜上需要 dauer 调节途径。拟议的研究将检验 DPR-1 通过质膜信号转导系统调节 dauer 形成的假设。目标 1 将研究影响 DPR-1 响应 dauer 信息素重新定位的参数，分析 dpr-1 的基本功能，测试 DPR-1 的冗余伙伴，并评估 DPR-1 和 dauer 通路之间的关系。目标 2 将鉴定 DPR-1 信号传导和膜关联所需的结构元件和成分，测试其靶向膜和细胞核时的信号传导功能，检查 DPR-1 在多尔幼虫中的膜坚韧形式的基础，并研究物理DPR-1 和其他蛋白质之间的相互作用。目标 3 将检查 DPR-1 是否对异源细胞中的 dauer 信息素作出反应，以及 DPR-1 亲属和 dauer 调节 NHR、DAF-12 是否在有利于 dauer 的条件下与膜相关。目标 4 将启动 RNAi 筛选，以识别负责 DPR-1 重新定位的成分以及与其合作的基因。阐明 NHR 发挥作用的新途径可能会增进我们对许多发育缺陷以及激素对正常人类生理和各种人类病理的影响的理解。