The Molecular Architecture of Axons in Health and Disease

项目摘要 有髓轴突中动作电位的启动和传播需要高密度的离子通道 聚集在轴突起始节段(AIS)、Ranvier结节和强大的轴突细胞骨架以帮助轴突 抵抗机械性损伤。人工智能的功能还包括维持神经元的极性和调节 轴突和体树突域。不幸的是，这些结构域和细胞骨架在 疾病或受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、功能和维护的能力仍然很差 明白了。因为任何旨在修复或再生神经系统的治疗方法都必须包括 轴突、AIS和Ranvier结节的重组或保存，对其详细的机械理解 迫切需要结构、组装机制和组成。为此，我们发展了蛋白质组学。 对人工免疫系统和兰维尔结节进行分子解剖的方法；这些实验将产生人工免疫系统 和节点“交互”。为了确定识别出的蛋白质的功能，我们将进行严格的增益和 使用现代分子、成像、遗传学和电生理学方法进行功能丧失研究。建房 基于我们以前的研究成果和我们的发现，节点组装机制收敛于 Ankyrin和Spectrin细胞骨架，我们还将确定这些神秘但必不可少的功能， 使用我们开发的条件基因敲除小鼠模型的细胞骨架蛋白。一起，我们期待着 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 保留轴突功能。

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.