Structure and regulation of synaptic architecture

描述(由申请人提供)： 这项建议描述了一套研究途径，将用于开发一个独立的突触结构调节研究计划。主要的科学目标是了解信号转导通路和肌动蛋白细胞骨架调节因子之间的关系如何控制果蝇突触的细胞结构。神经元必须将胞吐作用、胞内囊泡和蛋白质运输、内吞作用、细胞黏附、形态变化和局部蛋白质合成紧密联系起来，才能实现适当的连接和突触活动。细胞骨架将所有这些过程连接在一起，但还不知道是如何进行的。一个关键的信号响应性肌动蛋白结合蛋白是Wiskott-Aldrich综合征蛋白，它通过CDC42和SH3结构域蛋白下游的Arp2/3复合体激活肌动蛋白细丝成核。NWK是一种保守的神经元黄蜂激活蛋白，定位于突触周围活动区。在没有NWK的情况下，果蝇会出现温度敏感型癫痫发作，突触圈大小和神经递质释放减少，神经肌肉接头过度生长。因此，NWK是通过WASP对Arp2/3复合体进行突触调节的一个很好的候选者。NWK-WASP相互作用参与突触生长因子信号复合体的内体运输，但肌动蛋白聚合在这一过程中的作用尚不清楚。这一提议的科学目标是(1)确定保守的NWK相互作用蛋白如何在内体运输中发挥其功能；(2)获得周围活动区内细胞和内体结构的高分辨率图像，周围活动区是突触的一个专门亚域，参与突触小泡的循环以及细胞黏附和突触生长，以深入了解它们的功能。这项提议的训练目标是开发电子断层扫描技术，用于高分辨率成像涉及突触生长的亚细胞结构域。突触生长调控不当是许多神经疾病的特征，包括癫痫、阿尔茨海默病和智力低下。WRP是一种与NWK同源的人类基因，其突变与遗传性儿童智力低下有关。因此，阐明受NWK调控的保守的亚细胞转运途径和结构将有助于解释人类疾病，并为治疗提供新的靶点。

DESCRIPTION (provided by applicant): This proposal describes a set of research avenues that will be used to develop an independent research program in regulation of synaptic architecture. The primary scientific goal is to understand how the relationship between signal transduction pathways and actin cytoskeleton regulators controls cellular structures in Drosophila synapses. Neurons must intimately link exocytosis, intracellular vesicle and protein transport, endocytosis, cell adhesion, morphological change and local protein synthesis to achieve appropriate connectivity and synaptic activity. The cytoskeleton links all these processes together but it is not known how. One key signal-responsive actin-binding protein is WASp (Wiskott-Aldrich Syndrome protein), which activates actin filament nucleation by the Arp2/3 complex downstream of Cdc42 and SH3 domain proteins. Nwk (Nervous Wreck) is a conserved neuronal WASp-activating protein that localizes to synaptic periactive zones. In the absence of Nwk, flies suffer from temperature-sensitive seizures, have reduced synaptic bouton size and neurotransmitter release, and exhibit overgrowth of the neuromuscular junction. Therefore, Nwk is an excellent candidate for synaptic regulation of the Arp2/3 complex via WASp. Nwk- WASp interactions are involved in endosomal traffic of synaptic growth factor signaling complexes but the function of actin polymerization in this process is not understood. The scientific goals of this proposal are (1) to determine how a conserved Nwk-interacting protein contributes to its function in endosomal traffic; and (2) to obtain high resolution images of endocytic and endosomal structures in periactive zones, a specialized subdomain of the synapse involved in both recycling of synaptic vesicles and in cell adhesion and synaptic growth, to gain insight into their function. The training goals of this proposal are to develop electron tomography techniques for high resolution imaging of subcellular domains involved in synaptic growth. Misregulation of synaptic growth is a hallmark of many neurological diseases, including epilepsy, Alzheimer's disease and mental retardation. Mutations in WRP, a human homolog of NWK, have been linked to inherited childhood mental retardation. Therefore, elucidation of the conserved subcellular trafficking pathways and structures regulated by NWK will help interpret human diseases and provide new targets for therapies.