Structure and Mechanism of the Kinesin-3 Motor KIF1A

我们的目标是确定Kinesin-3马达KIF1A的结构和功能机制 产生力并沿微管移动，并定义与KIF1A相关的结构基础 人类疾病。微管(MT)运输系统调节真核生物的基本活动， 包括神经元细胞分裂、神经元迁移和亚细胞货物的运输。 KIF1A是MT相关马达蛋白中Kinesin-3家族的成员，是MT相关的 这些活动是神经元中MT+末端定向运动的主要产生者。KIF1A的 货物包括分裂脑干细胞的核、突触小泡前体和致密核 轴突终末的小泡。不足为奇的是，它的功能障碍与越来越多的 被称为KIF1A相关的神经发育和神经退行性疾病 神经性障碍(KAND)。不幸的是，在一定程度上，人们对这些疾病仍然知之甚少。 因为KIF1A的分子机制尚不清楚。例如，虽然大多数突变 如果KIF1A-MT复合体发生在KIF1A的运动域，则不存在KIF1A-MT复合体的高分辨率结构。 此外，目前尚不清楚为什么Kif1a是超级性的，但在负荷下很容易放弃。在……里面 这项提议，我们将结合冷冻电子显微镜，单分子荧光，和 利用创新的蛋白质工程技术进行基于光钳的测力，以确定原因 KIF1A是一种弱但超前的马达，定义了KIF1A-MT的高分辨率结构 络合物作为KIF1a机械力化学循环的函数，并确定结构缺陷 由KIF1A中的疾病突变引起。这些研究将提供对Kand的新理解 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.