Molecular Mechanisms of Presynaptic Assembly

描述(申请人提供)：将大脑发育成一个功能单位无疑是自然界最伟大的工程壮举之一。这个项目的目的是帮助我们理解这一发展过程的基础机制。更具体地说，本申请中概述的实验旨在了解突触的发育。化学突触是神经通讯不可缺少的功能单位。虽然我们对突触的各种功能方面了解很多，但我们对突触形成的分子机制知之甚少。对突触的分子结构及其维护的洞察将至少带给我们理解，如果不能治愈神经疾病，特别是阿尔茨海默氏症等退行性疾病。为了了解突触组装的分子结构，我们利用线虫，这是非常容易制造转基因和基因敲除动物的。我们系统地研究并揭示了线虫体内突触前组装的三层分子层次。首先，跨膜蛋白SYG-1规定了突触前部位的位置。接下来，SYG-1招募了两个关键的支架分子SYD-1和SYD-2，这两个分子对突触的形成至关重要。最后，这些支架蛋白招募了许多成分，包括突触小泡。现在我们已经建立了一个突触前组装的分子框架，我们想要从机制上深入了解这个框架的发展。在目标1中，我们将描述SYG-1和SYD-1之间的相互作用。初步证据表明，SYD-2是分子内和分子间调节的。在目标2中，我们建议从遗传学和生物化学的角度测试这一调控。最后，SYD-2已被证明与KIF1 A直接相互作用，KIF1 A是一种将突触小泡从细胞体运输到突触的激动素。在AIM 3中，我们建议验证SYD-2在突触从KIF1A卸载囊泡货物中起重要作用的预测。我们生活在这样一个时代，预防措施和先进的医疗技术使我们能够比我们历史上的任何时候活得更长。然而，晚年往往与退行性疾病有关，特别是神经疾病。如果我们想最大限度地利用晚年生活，了解并最终治愈神经退行性疾病对我们来说是至关重要的。本申请中提出的研究朝着实现这一目标迈出了一小步。

DESCRIPTION (provided by applicant): Development of the brain into a functional unit is undoubtedly one of the greatest engineering feats of nature. Aim of this project is to contribute to our understanding of the mechanisms that underlie this developmental process. More specifically, experiments outlined in this application aim to understand development of synapses. Chemical synapses are functional units that are indispensable for neural communication. Although we know much about the various functional aspects of synapses, we know very little about the molecular mechanisms that underlie synapse formation. Insights gained into the molecular architecture of synapses and its maintenance will take us at least towards understanding, if not curing neural diseases, especially degenerative diseases such as Alzheimer's. In order to understand the molecular framework of synaptic assembly, we utilized C. elegans, which is very amenable to making transgenic and knockout animals. We have systematically investigated and uncovered a three-layer molecular hierarchy of presynaptic assembly in vivo in C. elegans. First, a transmembrane protein, SYG-1 specifies the location of presynaptic sites. Next, SYG-1 recruits two key scaffold molecules SYD-1 and SYD-2 that are essential for synapse formation. Finally, these scaffold proteins recruit numerous components including synaptic vesicles. Now that we have established a molecular framework of presynaptic assembly, we would like to gain mechanistic insights into the development of this framework. In Aim 1, we will characterize the interaction between SYG-1 and SYD-1. Preliminary evidence indicates that SYD-2 is intra- and inter-molecularly regulated. In Aim 2, we propose to genetically and biochemically test this regulation. Finally, SYD-2 has been shown to directly interact with KIF1 A, a kinesin that transports synaptic vesicles from the cell body to the synapses. In AIM 3, we propose to test the prediction that SYD-2 is important for unloading of vesicular cargo from KIF1A at the synapses. We live in a time when preventive measures and sophisticated medical technology have made it possible for us to live longer than at any time during our history. However, later years of life are often associated with degenerative diseases, especially neurological ones. If we are to get most out of later years of our life, it will be essential for us to understand and eventually cure neurodegenerative diseases. Research proposed in this application takes a small step towards achieving this goal.