The Molecular Architecture of Axons in Health and Disease

项目摘要 有髓轴突中动作电位的起始和传播需要高密度的离子通道 聚集在轴突起始段（AIS），Ranvier节点，和一个强大的轴突细胞骨架，以帮助轴突 抗机械损伤。AIS还具有维持神经元极性和调节 轴突和体树突结构域。不幸的是，这些结构域和细胞骨架的破坏， 疾病或损伤后会严重损害神经系统功能。此外，分子机制 控制AIS、节点和轴突细胞骨架的组装、功能和维护的基因仍然很差 明白由于任何旨在神经系统修复或再生的治疗方法都必须包括 重组或保存轴突，AIS和Ranvier节点，详细的机械理解， 结构、组装机制和组成是迫切需要的。为此，我们开发了蛋白质组学 进行AIS和郎维尔淋巴结分子解剖的方法;这些实验将产生AIS 和节点的相互作用组。“为了确定已鉴定蛋白质的功能，我们将进行严格的增益， 使用现代分子、成像、遗传和电生理学方法进行功能丧失研究。建筑 我们以前的研究成果和我们的发现，节点组装的机制收敛于 锚蛋白和血影蛋白细胞骨架，我们也将确定这些神秘的，但必不可少的， 细胞骨架蛋白质，使用条件敲除小鼠模型，我们已经开发。我们共同期待 这些研究揭示了负责组装，维护和功能的关键分子机制， 轴突这些发现可能揭示可用于修复或治疗的靶点和机制。 保持轴突功能。

Project Summary Action potential initiation and propagation in myelinated axons requires high densities of ion channels clustered at axon initial segments (AIS), nodes of Ranvier, and a robust axonal cytoskeleton to help axons resist mechanicial injury. AIS also function to maintain neuronal polarity and regulate the distinction between axonal and somatodendritic domains. Unfortunately, disruption of these domains and the cytoskeleton during disease or after injury dramatically impairs nervous system function. Furthermore, the molecular mechanisms that control the assembly, function, and maintenance of AIS, nodes, and axonal cytoskeleton remain poorly understood. Since any therapeutic approach aimed at nervous system repair or regeneration must include the reassembly or preservation of axons, AIS and nodes of Ranvier, a detailed mechanistic understanding of their structure, mechanisms of assembly, and composition is urgently needed. To this end we developed proteomic approaches to perform a molecular dissection of AIS and nodes of Ranvier; these experiments will yield AIS and node 'interactomes.' To determine the functions of identified proteins we will perform rigorous gain and loss of function studies using modern molecular, imaging, genetic, and electrophysiological methods. Building on our previous research accomplishments and our discovery that mechanisms of node assembly converge on ankyrin and spectrin cytoskeletons, we will also determine the functions of these enigmatic, yet essential, cytoskeletal proteins using conditional knockout mouse models that we have developed. Together, we expect these studies to reveal key molecular mechanisms responsible for the assembly, maintenance, and function of axons. These discoveries may reveal targets and mechanisms that can be used for therapies to repair or preserve axon function.