Molecular Mechanisms of Axonal Transport and Organelle Dynamics

轴突运输和细胞器动力学的分子机制

• 批准号: 10621591
• 负责人: Erika L Holzbaur
• 金额: $ 71.88万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10621591
• 关键词: Active Biological Transport; Affect; Afferent Neurons; Aging; Amyotrophic Lateral Sclerosis; Anabolism; Autophagosome; Axon; Axonal Transport; Cells; Charcot-Marie-Tooth Disease; Complement; Cytoplasm; Cytoskeletal Filaments; Cytoskeletal Modeling; Cytoskeleton; Defect; Development; Disease; Dynein ATPase; Exhibits; Future; Goals; Human; In Vitro; Kinesin; Lead; Length; Membrane; Mitochondria; Modeling; Molecular; Molecular Motors; Morphology; Motor; Motor Neurons; Movement; Nerve Degeneration; Neurons; Organelles; Pattern; Protein Biosynthesis; Proteins; Regulation; Resolution; Scaffolding Protein; Site; Synapses; Synaptic Vesicles; Testing; Time; Vesicle; cell motility; genetic regulatory protein; insight; interest; live cell imaging; meter; presynaptic; reconstitution; single molecule; targeted treatment; therapeutically effective

Molecular motors drive the active transport of organelles along the cellular cytoskeleton. Organelle transport is critically important in neurons, cells that extend axons reaching up to 1m in length. Axons have limited capacity for biosynthesis and degradation, thus axonal transport is required to supply newly synthesized proteins and organelles and to remove aging proteins and dysfunctional organelles. Accumulating evidence supports a cargo-specific model for axonal transport, in which the opposing activities of kinesin and cytoplasmic dynein motors are regulated by a distinct complement of regulatory proteins including scaffolding proteins and activating adaptors. We are interested in the mechanisms that regulate the transport of key organelles including mitochondria, autophagosomes, and synaptic vesicle precursors. We are also interested in the mechanisms that lead to site-specific delivery, such as the targeting of newly synthesized synaptic components to presynaptic sites along the axon. We hypothesize that this delivery is dependent on the localized regulation of cytoskeletal dynamics and organization, which directly affect the initiation and termination of cargo motility. Finally, we are interested in the mechanisms by which molecular motors and cytoskeletal dynamics actively remodel organelle membranes, leading to tubulation, fission and fusion. We tackle these questions using the synergistic approaches of live cell imaging and in vitro reconstitution with single molecule resolution. We will continue to focus on three major goals. Goal 1: Understanding the integrated regulation of organelle transport. Each type of organelle transported along the axon has a distinct pattern of motility that directly relates to its function. We seek to understand the specific mechanisms involved, focusing on essential axonal cargos, such as mitochondria and autophagosomes, testing the model that the cargo-specific, integrated regulation of motors allows for sustained transport over long time scales and distances. In Goal 2, we seek to understand the localized regulation of organelle dynamics within defined axonal zones, such as the delivery of synaptic vesicle precursors to presynaptic sites along the axon. These zones exhibit distinct patterns of cytoskeletal organization and cytoskeletal dynamics. We are interested in the mechanisms that enhance the rate-limiting step of transport initiation and control cargo delivery/retention at specific sites of cellular need. And in Goal 3, we will study organelle remodeling driven by molecular motors and/or cytoskeletal dynamics. Organelles such as mitochondria undergo dramatic remodeling via mechanisms including fission and fusion. We hypothesize that molecular motors and cytoskeletal filaments provide an adaptable toolbox that can be specifically tuned to regulate dynamic organelle morphology. Together, these approaches will provide important new insights into organelle dynamics in neurons. As deficits in axonal transport lead to neurodegeneration, we hope that our progress may provide new opportunities for targeted and effective therapeutic approaches.

分子电动机驱动细胞器沿细胞骨骼的主动运输。细胞器运输 在神经元中至关重要，将轴突延伸到长度为1m的细胞。轴突有限 生物合成和降解的能力，因此需要轴突运输才能提供新合成的 蛋白质和细胞器，并去除老化蛋白质和功能失调的细胞器。积累证据 支持用于轴突运输的特定货物模型，在该模型中 细胞质动力蛋白电动机受调节蛋白的独特补充（包括脚手架）的不同调节 蛋白质和激活适配器。我们对调节密钥运输的机制感兴趣 包括线粒体，自噬体和突触囊泡前体在内的细胞器。我们也很感兴趣 在导致特定地点输送的机制中，例如新合成的突触的靶向 沿轴突沿突触前部位的组件。我们假设这种交付取决于 细胞骨架动力学和组织的局部调节，这直接影响开始和 终止货物运动。最后，我们对分子电动机和 细胞骨架动力学积极重塑细胞器膜，导致裂变，裂变和融合。我们 使用活细胞成像的协同方法和体外重构来解决这些问题 单分子分辨率。我们将继续专注于三个主要目标。目标1：了解 细胞器传输的综合调节。沿轴突运输的每种类型的细胞器都有一个 与其功能直接相关的运动模式。我们试图了解具体机制 涉及的，重点是必需的轴突冠，例如线粒体和自噬体，测试模型 电动机的特定货物，集成的调节允许长时间的运输持续运输 和距离。在目标2中，我们试图了解内部动力学的本地化调节 定义的轴突区域，例如将突触囊泡前体递送到沿着突触前部位 轴突。这些区域表现出细胞骨架组织和细胞骨架动力学的不同模式。我们是 对增强运输启动和控制货物的限制步骤的机制感兴趣 在细胞需求的特定部位输送/保留。在目标3中，我们将研究Organelle重塑驱动 通过分子电机和/或细胞骨架动力学。线粒体等细胞器会发生戏剧性 通过包括裂变和融合在内的机制进行重塑。我们假设该分子电动机和 细胞骨架丝提供了一个适应性的工具箱，可以专门调节以调节动态 细胞器形态。这些方法将共同为Organelle提供重要的新见解 神经元中的动力学。随着轴突运输中的缺陷导致神经变性，我们希望我们的进步 可能为有效且有效的治疗方法提供新的机会。