Regulation of cargo transport during neuronal development and disease

项目总结 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 神经元内的隔间和蛋白质和细胞器的精确亚细胞定位。神经元 分区需要像动蛋白-1这样的马达将特定的货物运送到 神经元。神经元尤其依赖于多样化和高保真的货物运输，因为它们高度 两极分化，结构复杂。运输方面的缺陷是人类多种发育和疾病的基础 神经退行性疾病。已知Kinesin-1可以调节多种货物的长途运输，但 在发育过程中决定货物选择和交付的特异性的机制很差 明白了。Kinesin-1(由KLc1-4基因编码)轻链(KLC)亚基的货物结合运动蛋白是 可能与特异性有关，但它们所调节的发育过程尚不清楚。这是一个关键的 知识鸿沟，因为人类KLC2和KLC4基因突变会导致很早就出现痉挛性截瘫 开始了。对该领域的一个重大挑战和该项目的长期目标是了解这些机制 控制货物运输和定位，因为神经元在自然环境中发育，在那里它们必须 整合多种细胞外线索。我们建立了一个模型，在这个模型中我们可以看到神经元的动力学 在完整的斑马鱼胚胎中，货物在发育中的感觉神经元内运输。脊椎动物感觉神经元 伸展不同的中央轴突和外周轴突，形成感觉回路。我们发现了其独特的功能 神经发育过程中的个体KLC，包括在形成轴突茎杆、轴突分支、指导方面的作用 以及开发过程中的维护和在电路功能中的作用。在目标1中，我们将确定机制 KLC4通过它来调节轴突的分支和区域化，以及细胞器运输的货物。在……里面 目的2确定KLC2在轴突发育和货物运输中的功能和机制 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 并将识别和确定与单个KLC相互作用的适配器的功能。澄清 调节神经元区划、货物选择和运输以及轴突的分子信号 生长和分支是理解人类发育障碍、神经退行性疾病的关键 疾病，以及轴突损伤后可能发生再生的条件。我们的实验将 揭示这种机制，从而可能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.