Regulation of Neuronal Motility

神经元运动的调节

• 批准号: 6624130
• 负责人: PAUL FORSCHER
• 金额: $ 38.8万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-08-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6624130
• 关键词: Aplysia; actins; biological signal transduction; cell adhesion; cell motility; fluorescence microscopy; growth cones; intermolecular interaction; microtubules; neural cell adhesion molecules; neurobiology; neuronal guidance; protein kinase; protein protein interaction

DESCRIPTION (provided by applicant): Understanding the molecular events that underlie the process of growth cone guidance and axonal pathfinding in the developing brain are one of the major challenges for Neurobiology. Recently, research in developmental neurobiology has moved decisively into the molecular arena with characterization of molecules that act as extracellular pathfinding cues and specific receptors on growth cones and axons for recognizing these cues. Some of these receptors interact with extracellular components that may serve as spatial cues, others recognize cell adhesion molecules (CAMs) on other cells and still other receptors respond to diffusable chemotropic signals. Neuronal growth cones mediate axon guidance by sensing and responding "intelligently" to these diverse biochemical cues with appropriate changes in their motility and structure. Such effects ultimately involve translation of signals received at the membrane into appropriate changes in cytoskeletal protein dynamics that underlie the growth cone's motility response. In the last decade, there has been intense interest and rapid progress made characterizing the cell surface molecules and ligands involved in growth cone guidance. In addition, the complex web of signal transduction pathways that transmit these signals to downstream effectors has begun to emerge. With all this progress, however, our understanding of how the cytoskeletal machinery is affected by these pathways is still quite limited. This has been in great part due to lack of appropriate bioassays for measuring cytoskeletal protein function in living cells. Recent advances in fluorescent molecular probes and digital imaging have overcome critical limitations in this area. In particular, it is now possible to measure rates of assembly, disassembly and translocation of cytoskeletal proteins in a living cell and correlate cytoskeletal dynamics will the structural changes involved in various forms of motility. Mounting evidence suggests the importance of bi-directional cross talk between dynamic actin and microtubule (MT) cytoskeletal networks in directed cell movements including growth cone guidance. In the neuronal growth cone, a sharp, yet highly dynamic, interface exists between elongating axonal microtubules and peripheral actin networks that support exploratory behavior and provide signals involved in guiding axonal advance. The work proposed here addresses how MTs and actin filaments interact with one another in real time in living growth cones and the functional significance of such interactions. This investigation will provide information fundamental to our understanding the cell biology of growth cone motility since simultaneous analysis of actin filament and MT dynamics has never been achieved a growth cone to date. To reach this goal, multimode Fluorescent Speckle Microscopy (FSM) will be used. Using this technology a full quantitative characterization of how actin filament dynamics affect microtubule behavior, and conversely, how microtubule dynamics affect actin filament behavior will be done. With this knowledge in hand, the more complex problem of how MT and actin filament systems interact and affect one another during growth cone guidance events will be tackled. This will include evaluation of how traction forces that develop in peripheral actin networks bias MT advance, and if tension affects MT polymer dynamics. We will also investigate how protein kinase signaling pathways important in regulation of axon guidance modulate behavior of the cytoskeletal effector machinery during target interaction events. Information gleaned from these studies should have a fundamental impact on our understanding of the cell biology of axon guidance and nerve regeneration.

描述（由申请人提供）：了解分子事件 是生长锥引导和轴突寻路过程的基础 大脑的发育是神经生物学面临的主要挑战之一。最近， 发育神经生物学研究已决定性地进入分子生物学领域 具有细胞外寻路分子特征的竞技场 生长锥和轴突上用于识别这些的线索和特定受体 提示。其中一些受体与细胞外成分相互作用，可能 作为空间线索，其他细胞识别其他细胞粘附分子（CAM） 细胞和其他受体对可扩散的趋化信号做出反应。 神经元生长锥通过感知和响应介导轴突引导 通过适当的改变来“智能地”应对这些不同的生化线索 它们的运动性和结构。这种影响最终涉及到翻译 在膜上接收到的信号转化为细胞骨架的适当变化 生长锥运动反应的蛋白质动力学。在最后 十年来，人们产生了浓厚的兴趣，并取得了快速的进展， 参与生长锥引导的细胞表面分子和配体。在 此外，传输这些信号的信号转导途径的复杂网络 向下游效应器发出的信号已经开始出现。有了所有这些进展， 然而，我们对细胞骨架机制如何受到影响的理解 这些途径仍然相当有限。这在很大程度上是由于缺乏 测量活体细胞骨架蛋白功能的适当生物测定法 细胞。荧光分子探针和数字成像的最新进展 克服该领域的关键限制。特别是，现在可以 测量细胞骨架的组装、拆卸和易位速率 活细胞中的蛋白质和相关的细胞骨架动力学将 涉及各种形式运动的结构变化。越来越多的证据 表明动态肌动蛋白和肌动蛋白之间双向串扰的重要性 定向细胞运动中的微管（MT）细胞骨架网络，包括 生长锥引导。在神经元生长锥中，一个尖锐但高度动态的， 延长的轴突微管和外周肌动蛋白之间存在界面 支持探索行为并提供涉及的信号的网络 引导轴突前进。这里提出的工作解决了 MT 和肌动蛋白如何 细丝在活的生长锥中实时相互作用，并且 这种相互作用的功能意义。这项调查将提供 对于我们理解生长锥细胞生物学至关重要的信息 由于肌动蛋白丝和 MT 动力学的同步分析已经 迄今为止从未实现过增长锥。为了实现这一目标，多模 将使用荧光散斑显微镜（FSM）。充分利用该技术 肌动蛋白丝动力学如何影响微管的定量表征 行为，以及相反，微管动力学如何影响肌动蛋白丝 行为将会被完成。有了这些知识，更复杂的问题 MT 和肌动蛋白丝系统在生长过程中如何相互作用和相互影响 锥体引导事件将得到解决。这将包括评估如何 外周肌动蛋白网络中产生的牵引力会偏向 MT 前进，并且 如果张力影响 MT 聚合物动力学。我们还将研究蛋白质如何 激酶信号通路在轴突引导调节中很重要 靶标相互作用期间细胞骨架效应器的行为 事件。从这些研究中收集的信息应该会产生根本性的影响 关于我们对轴突引导和神经的细胞生物学的理解 再生。