Structure and Mechanism of the Kinesin-3 Motor KIF1A

我们的目标是确定驱动蛋白-3马达KIF 1A的结构和功能机制， 产生力并沿着沿着移动，并定义KIF 1A相关的结构基础。 人类疾病。微管（MT）转运系统调节重要的真核生物活动， 包括神经元细胞分裂、神经元迁移和亚细胞货物的运输。 KIF 1A是MT相关运动蛋白驱动蛋白-3家族的成员，是一种关键的介导因子， 这些活动作为MT的主要发电机加上在神经元中的末端定向运动。KIF1A 货物包括分裂的脑干细胞的细胞核和突触囊泡前体以及致密的核心 轴突终末的小泡。毫不奇怪，它的功能障碍与越来越多的 神经发育和神经退行性疾病称为KIF 1A相关 神经系统疾病（KAND）。不幸的是，这些疾病仍然知之甚少，部分原因是 因为KIF 1A的分子机制尚不清楚。例如，虽然大多数突变 由于KIF 1A的运动域中存在高分辨率结构，因此不存在KIF 1A-MT复合物的高分辨率结构。 此外，目前还不清楚为什么Kif 1A是超进程的，但很容易在负荷下放弃。在 这个建议，我们将结合联合收割机冷冻电子显微镜，单分子荧光， 基于光学镊子的力测量与创新的蛋白质工程，以确定为什么 KIF 1A是一个弱但超进行性的马达，定义了KIF 1A-MT的高分辨率结构 复合物作为KIF 1A的机械化学循环的函数，并确定结构缺陷 KIF 1A基因突变引起的疾病这些研究将为KAND提供新的认识 并阐明治疗干预的分子靶点。

Our goal is to define the structural and functional mechanism by which the kinesin-3 motor KIF1A generates force and moves along microtubules, and to define the structural basis of KIF1A-related human diseases. The microtubule (MT) transport system regulates essential eukaryotic activities, including neuronal cell division, neuronal migration and the transport of subcellular cargoes. KIF1A, a member of the kinesin-3 family of MT-associated motor proteins, is a key mediator of these activities as the major generator of MT plus-end-directed motility in neurons. KIF1A’s cargoes include nuclei in dividing brain stem cells and synaptic vesicle precursors and dense core vesicles in axon terminals. Not surprisingly, its dysfunction is implicated in a growing number of neurodevelopmental and neurodegenerative disorders referred to as KIF1A-associated neurological disorder (KAND). Unfortunately, these diseases remain poorly understood, in part because KIF1A’s molecular mechanism remains unclear. For example, while most mutations occur in KIF1A’s motor domain, high-resolution structures of the KIF1A-MT complex do not exist. In addition, it remains unknown why Kif1A is superprocessive but easily gives up under load. In this proposal, we will combine cryo-electron microscopy, single-molecule fluorescence, and optical tweezers-based force measurements with innovative protein engineering to determine why KIF1A is a weak but superprocessive motor, define high-resolution structures of the KIF1A-MT complex as a function of KIF1A’s mechanochemical cycle and determine the structural defects caused by disease mutations in KIF1A. These studies will provide a new understanding of KAND and elucidate molecular targets for therapeutic interventions.