Motor protein interactions on cytoskeletal networks

描述（由申请人提供）：马达蛋白在细胞内的复杂环境中工作，其中与相同类型的马达，反向马达和细胞骨架景观的相互作用允许远程，双向运输。运动蛋白之间的相互作用以及与细胞骨架的相互作用调节了运动蛋白在体内的行为，并使细胞内货物的靶向运输成为可能。不同类型的运动蛋白通常同时与囊泡货物结合，允许沿微管双向运输，并在微管和肌动蛋白丝之间切换。本研究的目的是通过分析运动蛋白之间的相互作用以及在越来越复杂的体外生理环境中与细胞骨架的相互作用来阐明双向运输的动力学。具体而言，我们提出以下目标：1。目的：探讨在人工货物运输过程中，运动蛋白和动力蛋白相互作用的机理。反向马达的双向运输是通过调节蛋白协调的，还是反向马达之间拉锯战的结果？多个动力蛋白或动力蛋白如何在团队中共同发挥作用？微管相关蛋白（MAPs）在调节双向运输中起什么作用？2. 研究纯化内源性囊泡和内吞货物的双向运输。马达的内源性补体是如何相互作用的？与囊泡结合的效应器对运动功能和协调性有什么影响？3. 建立动力蛋白和动力蛋白双向输送的机械数学模型。数学模型将为实验提供反馈机制，用于测试我们对双向传输的理解并指导进一步的实验。电机之间相互作用的什么机制产生与实验观察一致的结果？未来哪些实验最适合进一步了解双向传输？通过系统地增加体外测定的复杂性，我们可以分离复杂因素（即运动-运动相互作用，细胞骨架网络和map）的影响，并独立理解每个因素。然后，我们可以将这些单独的方面整合到更复杂的分析中，依次纳入细胞环境的各个方面。综合体外实验和数学模型将提供对细胞内运输动力学和调控的理解，这是至关重要的，因为细胞内运输缺陷与人类发育和退行性疾病密切相关。

DESCRIPTION (provided by applicant): Motor proteins operate in a complex environment in the cell where interactions with motors of the same type, oppositely-directed motors, and the cytoskeletal landscape allow long-range, bidirectional transport. Interactions among motor proteins and with the cytoskeleton modulate the behavior of motor proteins in vivo and make possible the targeted trafficking of intracellular cargoes. Motor proteins of different types often associate simultaneously with vesicular cargoes to allow bidirectional transport along microtubules and switching between microtubules and actin filaments. The objective of this study is to elucidate the dynamics of bidirectional transport through analysis of the interactions among motor proteins and with the cytoskeleton in increasingly complex in vitro approximations of the physiological environment. Specifically, we propose the following aims: 1. To investigate the mechanism of interaction between the oppositely-directed motors kinesin and dynein when transporting artificial cargoes. Is bidirectional transport by opposing motors coordinated through regulatory proteins, or the result of a tug-of-war between oppositely-directed motors? How multiple kinesin or dynein do motors function collectively in teams? What role do Microtubule Associated Proteins (MAPs) have in regulating bidirectional transport? 2. To examine bidirectional transport of purified endogenous vesicles and endocytosed cargoes. How does the endogenous complement of motors interact? What influence do the effectors that copurify with the vesicles have on motor function and coordination? 3. To develop a mechanistic, mathematical model of bidirectional transport by kinesin and dynein. A mathematical model will provide a feedback mechanism for the experiments, functioning to test our understanding of bidirectional transport and direct further experiments. What mechanisms of interactions among motors produce results consistent with experimental observations? What future experiments are best suited to further the understanding of bidirectional transport? By systematically increasing the complexity of in vitro assays, we can separate the influence of complicating factors (i.e. motor-motor interactions, cytoskeletal networks, and MAPs) and understand each independently. We can then integrate these individual aspects into more complex assays, sequentially incorporating aspects of the cellular environment. The integrated in vitro experiments and mathematical models will provide an understanding of the dynamics and regulation of intracellular transport, which is critical as defects in intracellular transport are strongly implicated in both developmental and degenerative diseases in humans. PUBLIC HEALTH RELEVANCE: The objective of this study is to elucidate the regulation and dynamics of motor proteins in intracellular transport through analysis of motors in increasingly complex in vitro approximations of the physiological environment. An understanding of intracellular transport is critical as defects are strongly implicated in both developmental and degenerative diseases in humans. For example, a missense mutation in dynactin leads to autosomal dominant motor neuron degeneration and mutations in kinesins have been linked to Charcot-Marie-Tooth Disease Type 2A and Hereditary Spastic Paraplegia.