SYNAPTIC FUNCTION IN THE NEMATODE C. ELEGANS

描述：(摘自申请者的摘要)拟议研究的目标是 识别和理解突触所需分子的功能 功能。近年来，我们在这一领域取得了很大进展， 已经通过生化手段鉴定了突触蛋白的种类。然而，它是 不清楚这些蛋白质如何在突触中发挥作用，也不清楚 参与这一基本生物过程的蛋白质已被鉴定出来。 我们在线虫中发现了突触功能突变体 优雅女装。其中一些突变存在于已知的突触蛋白中。从 我们建议将重点放在三种蛋白质上，这些蛋白质被认为在 突触小泡的内吞作用。我们将描述其表型。 这些突变体的详细信息，从而测试已提出的 基于生化数据的这些蛋白质的功能。其他突变 在我们的筛查中发现的是编码新蛋白质的基因。我们会 在分子水平上表征这些蛋白质中的一种并确定 该蛋白在突触传递中的作用 详细的表型。目标1.国家科学基金会。有人提出，NSF可能在以下方面发挥作用 胞吐的预对接步骤，在胞吐的融合步骤，或在 融合后前一步，内吞。我们将检验NSF的假设 在后融合步骤中需要；具体地说，它是 囊泡蛋白突触短缩蛋白的内吞作用。目的2.AP2的U2亚基。这个 网状蛋白接头复合体AP2被认为是内吞作用所必需的 突触小泡。然而，目前尚不清楚突触小泡回收是否 仅通过网状蛋白介导的过程发生。也有可能是 Synapse使用AP2的特殊中间亚单位，而不是普遍存在的U2 中等亚基。我们将测试是否需要AP2的U2中等亚基 用于突触小泡内吞。目标3.突触素。已经有人提议 肌醇磷酸酶突触素是细胞内吞作用所必需的 突触小泡，因为它与内吞机制有关。我们 将决定突触的内吞是否需要突触素 质膜中的囊泡成分。另外，我们初步的 研究表明，它可能是囊泡运输所必需的。 突触的前体。我们将测试一个模型，以了解 突触素在囊泡运输中的作用。瞄准4。RIC-7。这个基因的突变 基因干扰胆碱能和GABA能介导的行为。我们将决定 这种新型突触蛋白的超微结构和超微结构研究 生理工具。

DESCRIPTION: (from applicant's abstract) The goal of the proposed research is to identify and understand the function of the molecules required for synaptic function. In recent years we have seen great progress in this field as a number of synaptic proteins have been identified by biochemical means. However, it is not clear how each of these proteins functions in the synapse nor have all of the proteins involved in this fundamental biological process been identified. We have identified synaptic function mutants in the nematode Caenorhabditis elegans. Some of these mutations are in known synaptic proteins. From among these we propose to focus on three proteins which are believed to function in the endocytosis of synaptic vesicles. We will characterize the phenotype of these mutants in detail and thereby test models which have been proposed for the function of these proteins based on biochemical data. Other mutations identified in our screens are in genes encoding novel proteins. We will characterize one of these proteins at a molecular level and determine the function of this protein in synaptic transmission by characterizing the mutant phenotype in detail. Aim 1. NSF. It has been proposed that NSF may function at a pre-docking step of exocytosis, at the fusion step of exocytosis, or at a post-fusion step preceding, endocytosis. We will test the hypothesis that NSF is required at a post-fusion step; specifically, that it is required for the endocytosis of the vesicle protein synaptobrevin. Aim 2. u2 subunit of AP2. The clathrin adaptor complex AP2 is believed to be required for endocytosis of synaptic vesicles. However, it is not clear whether synaptic vesicle recycling occurs solely via a clathrin-mediated process. It is also possible that the synapse uses a specialized medium subunit of AP2 rather than the ubiquitous u2 medium subunit. We will test whether the u2 medium subunit of AP2 is required for synaptic vesicle endocytosis. Aim 3. Synaptojanin. It has been proposed that the inositol phosphatase synaptojanin is required for endocytosis of synaptic vesicles because it is associated with the endocytic machinery. We will determine whether synaptojanin is required for endocytosis of synaptic vesicle components from the plasma membrane. In addition, our preliminary studies indicate that it may be required for the transport of vesicle precursors to the synapse. We will test a model for the mechanism of synaptojanin function in vesicle transport. Aim 4. RIC-7. Mutations in this gene disrupt cholinergic and GABAergic-mediated behaviors. We will determine the function of this novel synaptic protein using ultrastructural and physiological tools.