Function of a membrane-localized nuclear receptor

长期目标是了解核激素受体（NHR）是如何定向到血浆的 细胞膜对信号的反应以及它在非核信号转导系统中的功能。 虽然类固醇信号传导的经典观点认为这些激素结合细胞内受体， 配体激活的转录因子，大量的证据表明，类固醇也可以通过非 细胞表面的基因组机制。我们已经确定了一个C。线虫NHR，DPR-1，可能通过 这种基于膜的信号传导系统，提供用于解剖膜的第一遗传系统， 基于NHR信号系统。在存在小的亲脂性分子（dauer信息素或 DPR-1从细胞质移动到质膜。道蒙引发了另一种选择， 发育停滞状态，dauer幼虫。dpr-1基因的缺失突变减弱了 对dauer信息素的反应，并加速退出dauer状态，和DPR- 1触发不适当的dauer发展，并抑制退出dauer状态。Dauer监管 DPR-1在细胞膜上的再定位需要通过这一途径。拟议的研究将测试 DPR-1通过质膜信号转导系统调节dauer形成的假说。 目的1将研究影响DPR-1响应于dauer信息素的重定位的参数， 分析了dpr-1的基本功能，测试了DPR-1的冗余伙伴，并评估了它们之间的关系 DPR-1和Dauer通路之间的联系目标2将确定所需的结构元件和部件， DPR-1信号传导和膜缔合，测试其靶向膜时的信号传导功能， 核，检查DPR-1在Dauer幼虫中膜粘性形式的基础，并研究 DPR-1和其他蛋白质之间的物理相互作用。目标3将检查DPR-1是否响应于 在异源细胞中的dauer信息素，以及DPR-1亲属和dauer调节NHR，NPR-1和NHR-1是否是DPR-1亲属和dauer调节NHR，NHR-1亲属， 12、与膜结合在一起的条件下有利于女儿。Aim 4将启动RNAi筛选， 鉴定负责DPR-1重新定位的组分及其协同作用的基因。的 阐明NHR发挥作用的新途径可能会促进我们对许多问题的理解。 发育缺陷和激素对正常人体生理和各种人类 病理学

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-1in dauer larvae, and investigate physical interactions between DPR-1 and other proteins. Aim 3 will examine whether DPR-1responds 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-1and 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.