G PROTEIN SIGNALING IN THE C ELEGANS NERVOUS SYSTEM

这项提案的长期目标是了解如何 神经递质通过G蛋白偶联受体调节 神经元的活动。我们的研究重点是一种神经递质 调节神经元和肌肉活动的信号通路 线虫的产卵系统。我们已经确定了突变 这扰乱了产卵行为的调节，并利用它们 鉴定和研究编码该G蛋白信号成分的基因 路径。到目前为止，所分析的基因在 哺乳动物的大脑，这表明线虫将被证明是一个有用的模型 以了解人类通过G蛋白进行的神经传递。 这项提议的第一个主要目标是系统地利用 我们开发的分子遗传系统是为了分析这一点 神经递质信号通路。我们将进行饱和 基因筛选以识别尽可能多的信号基因。 我们将对这些基因进行克隆和分子分析。我们的目标是 最终减少我们对G蛋白信号通路的了解 达到生化水平。 这种方法的潜力可以通过以下事实来说明：我们拥有 已经用它来鉴定一种蛋白质，EGL-10，它抑制信号转导 通过线虫产卵系统中的异三聚体G蛋白。 EGL-10是我们在 蠕虫和人类--我们已经命名为“G蛋白的调节器” 信号“(RGS)蛋白。这些RGS蛋白可能调节可能或全部 G蛋白信号通路。 这项提案的第二个主要目的是确定为什么会有这样的 许多RGS蛋白。它们仅仅是多余的，还是每个都有一个 特定的生物功能，也许是因为每种功能都被限制在 与特定的G蛋白或一组G蛋白相互作用？我们会 通过确定遗传功能和表达来研究这一问题 11种虫体RGS蛋白的图谱及生化研究 线虫RGS与G蛋白相互作用的特异性 在试管中。这一分析应该揭示出 RGS蛋白在蠕虫体内调节多种信号通路。因为 许多线虫G蛋白和RGS蛋白与 相应的人类同源物，我们的分析应该有助于 类似的人类信号通路，并指导他们的进一步研究。

The long-term goal of this proposal is to understand how neurotransmitters act through G protein-coupled receptors to modulate the activities of neurons. Our studies focus on a neurotransmitter signaling pathway that regulates activities of the neurons and muscles of the egg-laying system of C. elegans. We have identified mutations that disrupt the regulation of egg-laying behavior and used them to identify and study genes encoding components of this G protein signaling pathway. The genes analyzed so far have close homologs expressed in the mammalian brain, suggesting that C. elegans will prove a useful model for understanding neurotransmission through G proteins in humans. The first major aim of this proposal is to systematically exploit the molecular genetic system we have developed to analyze this neurotransmitter signaling pathway. We will carry out saturating genetic screens to identify as many of the signaling genes as possible. We will clone and molecularly analyze these genes. Our goal is to eventually reduce our understanding of this G protein signaling pathway to a biochemical level. The potential of this approach is illustrated by the fact that we have already used it to identify a protein, EGL-10, that inhibits signaling by a heterotrimeric G protein in the C. elegans egg-laying system. EGL-10 is a prototype for a large family of proteins we identified in worms and humans that we have named the "regulator of G protein signaling" (RGS) proteins. These RGS proteins may regulate may or all G protein signaling pathways. The second major aim of this proposal is to determine why there are so many RGS proteins. Are they simply redundant, or does each have a specific biological function, perhaps because each is restricted to interacting with a particular G protein or set of G proteins? We will examine this issue by determining the genetic functions and expression patterns of the 11 worm RGS proteins and by studying the biochemical specificity of the interactions between C. elegans RGS and G proteins in vitro. this analysis should reveal the logic by which the family of RGS proteins regulates multiple signaling pathways in the worm. Because many C. elegans G proteins and RGS proteins are closely related to corresponding human homologs, our analysis should shed light on analogous human signaling pathways and direct their further study.