Regulation of cargo transport during neuronal development and disease

项目摘要 高度精细和极化的神经元形态的发展需要形成分子上不同的 神经元内的区室和蛋白质和细胞器的精确亚细胞定位。神经元 区室化要求马达如驱动蛋白-1将特定的货物递送到细胞内的不同位点。 neuron.神经元特别依赖于多样化和高保真的货物运输，因为它们的高度依赖性。 两极分化的复杂结构。运输缺陷是多种人类发展和 神经退行性疾病已知驱动蛋白-1介导多种货物的长距离运输，但是， 在发育过程中，确定货物选择和运输特异性的机制很差， 明白驱动蛋白-1的货物结合驱动蛋白轻链（KLC）亚基（由klc 1 -4基因编码）是 可能参与特异性，但它们介导的发育过程尚不清楚。这是一个关键 由于人类klc 2和klc 4基因突变导致痉挛性截瘫疾病， 发病该领域的一个主要挑战和该项目的长期目标是了解这些机制 神经元在自然环境中发育时控制货物运输和定位， 整合多种细胞外信号。我们建立了一个模型，在这个模型中，我们可以成像神经元的动力学， 在完整的斑马鱼胚胎发育中的感觉神经元内的货物运输。脊椎动物感觉神经元 延伸不同的中央和外周轴突以形成感觉回路。我们发现了 单个KLC在神经发育过程中的作用，包括在形成轴突乔木，轴突分支，指导 开发过程中的维护，以及在电路功能中的作用。在目标1中，我们将确定 KLC 4通过其调节轴突分支和区室化，以及其运输的细胞器货物。在 目的2：明确KLC 2在轴突发育和货物运输中的作用及其机制 潜在的人类SPOAN综合征。在目标3中，我们将确定哪些蛋白质结构域赋予KLC功能 特异性，并将鉴定和确定与单个KLC相互作用的衔接子的功能。阐发 调节神经元区室化、货物选择和运输以及轴突的分子信号 生长和分支对于理解人类发育障碍、神经退行性疾病、 疾病，以及轴突损伤后再生可能发生的条件。我们的实验将 揭示这些机制，从而有助于确定疾病治疗的分子靶点。

Project summary Development of highly elaborate and polarized neuronal morphology requires formation of molecularly distinct compartments within neurons and precise subcellular localization of proteins and organelles. Neuronal compartmentalization requires that motors such as kinesin-1 deliver specific cargos to different sites within the neuron. Neurons are especially dependent on diverse and high fidelity cargo transport because of their highly polarized and complex structure. Defects in transport underlie multiple human developmental and neurodegenerative diseases. Kinesin-1 is known to mediate long-distance transport of multiple cargos, but the mechanisms that determine specificity of cargo selection and delivery during development are poorly understood. The cargo-binding kinesin light chain (KLC) subunits of kinesin-1 (encoded by klc1-4 genes) are likely involved in specificity, yet the developmental processes they mediate are not understood. This is a critical knowledge gap, as mutations in human klc2 and klc4 genes cause spastic paraplegia diseases with very early onset. A major challenge to the field and the long term goal of this project is to understand the mechanisms controlling cargo transport and localization as neurons develop in their natural environment, where they must integrate multiple extracellular cues. We established a model in which we can image dynamics of neuronal cargo transport within developing sensory neurons in the intact zebrafish embryo. Vertebrate sensory neurons extend distinct central and peripheral axons to form the sensory circuit. We discovered unique functions for individual KLCs during neural development, including roles in shaping axon arbors, axon branching, guidance and maintenance during development, and roles in circuit function. In Aim 1 we will determine the mechanisms by which KLC4 regulates axon branching and compartmentalization, and the organelle cargos it transports. In Aim 2 we will determine functions of KLC2 in axon development and cargo transport, and mechanisms underlying human SPOAN syndrome. In Aim 3 we will determine which protein domains confer KLC functional specificity and will identify and determine the function of adaptors that interact with individual KLCs. Elucidation of the molecular signals regulating neuronal compartmentalization, cargo selection and transport, and axon growth and branching is critical for understanding human developmental disorders, neurodegenerative disorders, and the conditions under which regeneration after axon injury can occur. Our experiments will uncover such mechanisms and thus may help to identify molecular targets for disease treatment.