STRUCTURE AND FUNCTION OF CYTOPLASMIC MOTORS

细胞质马达的结构和功能

• 批准号: 6163013
• 负责人: Thomas S Reese
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6163013
• 关键词: Escherichia coli; actins; axon; cilium /flagellum motility; cytoskeleton; dynein ATPase; intracellular transport; kinesin; membrane structure; microtubules; myosins; neurofilament; neuronal transport; neurons; organelles; protein purification; protein structure function; protoplasm motility

The goal of this project is to understand the distribution and functions of cytoplasmic motors in the axon of neurons. This information is intended to lead to an understanding, at the molecular level, of fast and slow axonal transport as well as the cytoplasmic organization in the axon. Our results showing that kinesin is more tightly bound to organelle surfaces than dynein have led to elaboration of the simple idea that direction of transport depends on anterograde vesicles binding kinesin and retrograde vesicles binding dynein. Since an organelle could retain its particular kinesins while it is being transported down the axon, we propose that up or down regulation of kinesin determines the direction of transport. New types of myosin motors has been discovered attached to the surfaces of squid axonal organelles, and it now appears that there are at least two species of myosin also involved in organelle transport. We have developed antibodies to both of these myosins, and both myosins are associated with organelles. New studies of the organization of the actin substrates for these motors in the axon has showed that parallel actin filaments intertwine with the microtubule bundles, and that they have mixed polarities, suggesting that they might carry organelles both to and from the microtubule bundles. We made a start on defining the mechanism of slow transport. Negatively charged macromolecule assemblies injected into the squid giant axon move in the anterograde direction at rates up to 0.5 um/sec. Of particular interest is that neurofilament proteins as well as actin and microtubule fragments move anterogradely, and that all movements appear to be along some type of intracellular tract. This in vitro assay should make it possible to define the motors for such movements. The bacterial flagellar motor in E. coli has been studied as another example of a motor system than can switch direction of translocation. We are completing a structural study of the cytoplasmic representation of this motor which is expected to provide new information on the

该项目的目标是了解分布和功能 神经元轴突中的细胞质马达。 该信息是 旨在导致在分子水平上理解快速 和缓慢的轴突运输以及细胞质组织 轴突。我们的结果表明驱动蛋白与 细胞器表面比动力蛋白导致了简单的阐述 运输方向取决于顺行囊泡结合的想法 驱动蛋白和逆行囊泡结合动力蛋白。 既然是细胞器 在向下运输时可以保留其特定的驱动蛋白 轴突，我们建议驱动蛋白的上调或下调决定 运输方向。新型肌球蛋白马达已被 发现附着在鱿鱼轴突细胞器的表面，并且它 现在看来至少有两种肌球蛋白也参与其中 在细胞器运输中。 我们已经开发出针对这两种疾病的抗体 肌球蛋白，两种肌球蛋白都与细胞器相关。新研究 轴突中这些马达的肌动蛋白底物的组织 已经表明平行的肌动蛋白丝与微管交织在一起 束，并且它们具有混合极性，这表明它们可能 将细胞器运入和运出微管束。 我们做了一个 首先定义慢速传输的机制。带负电 注入鱿鱼巨轴突的大分子组件在 顺行方向，速率高达 0.5 微米/秒。 特别感兴趣 是神经丝蛋白以及肌动蛋白和微管 碎片顺行移动，所有运动似乎都是沿着 某种类型的细胞内管道。这种体外测定应该能够 可以定义此类运动的电机。 细菌 大肠杆菌中的鞭毛运动已作为另一个例子进行了研究 运动系统可以切换易位方向。我们是 完成该细胞质表征的结构研究 电机有望提供有关