Molecular Mechanisms of Presynaptic Assembly

描述（由申请人提供）：将大脑发展成一个功能单元无疑是大自然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背后的机制。更具体地说，本应用程序中概述的实验旨在了解突触的发育。化学突触是神经交流不可或缺的功能单位。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。对突触分子结构及其维护的深入了解，即使不能治愈神经系统疾病，尤其是像阿尔茨海默氏症这样的退行性疾病，至少也能帮助我们理解神经系统疾病。为了了解突触组装的分子框架，我们利用秀丽隐杆线虫，这是非常适合制作转基因和敲除动物。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结构。首先，跨膜蛋白SYG-1指定突触前位点的位置。接下来，SYG-1招募两个关键支架分子SYD-1和SYD-2，这两个分子对突触的形成至关重要。最后，这些支架蛋白招募包括突触囊泡在内的许多成分。现在我们已经建立了突触前组装的分子框架，我们想要对这个框架的发展获得机制上的见解。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受分子内和分子间调控。在目标2中，我们建议对这一调控进行遗传和生化测试。最后，SYD-2已被证明直接与kif1a相互作用，kif1a是一种将突触囊泡从细胞体运输到突触的激酶。在AIM 3中，我们建议验证SYD-2对于突触上KIF1A的囊泡货物卸载很重要的预测。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有可能比我们历史上任何时候都活得更长。然而，晚年往往与退行性疾病有关，尤其是神经系统疾病。如果我们想充分利用我们的晚年，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。本应用程序中提出的研究向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.