Regulation of Neuronal Motility

神经元运动的调节

• 批准号: 6472486
• 负责人: PAUL FORSCHER
• 金额: $ 36.3万
• 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/6472486
• 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 在大脑中生长锥引导和轴突寻路的过程的基础 大脑发育是神经生物学的主要挑战之一。最近， 发育神经生物学的研究已经决定性地进入了分子水平， 表征作为细胞外寻路分子的竞技场 生长锥和轴突上的信号和特异性受体， 线索其中一些受体与细胞外成分相互作用， 作为空间线索，其他人则识别其他细胞上的细胞粘附分子（CAM）。 细胞和其它受体对可扩散的趋化性信号作出反应。 神经元生长锥通过感知和反应介导轴突导向 “智能地”对这些不同的生化线索进行适当的改变， 它们的运动性和结构。这种影响最终涉及翻译 细胞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。在过去 近十年来，人们对这一问题的浓厚兴趣和迅速进展， 参与生长锥导向的细胞表面分子和配体。在 此外，传递这些信号的信号转导途径的复杂网络 下游效应器的信号已经开始出现。随着所有这些进展， 然而，我们对细胞骨架机制如何受到 这些途径仍然相当有限。这在很大程度上是由于缺乏 适当的生物测定，用于测量细胞骨架蛋白功能， 细胞荧光分子探针和数字成像的最新进展 克服这一领域的严重局限性。特别是， 以测量细胞骨架的组装、分解和移位率， 活细胞中的蛋白质和相关的细胞骨架动力学 涉及各种运动形式的结构变化。越来越多的证据 表明了动态动作和动态动作之间双向串扰的重要性， 微管（MT）细胞骨架网络在定向细胞运动，包括 生长锥引导。在神经生长锥中，一个尖锐的，但高度动态的， 轴突微管与周围肌动蛋白之间存在界面 网络支持探索行为，并提供参与的信号 引导轴突前进这里提出的工作解决如何MT和肌动蛋白 细丝在活的生长锥中以真实的时间相互作用， 这种互动的功能意义。这次调查将提供 我们了解生长锥细胞生物学的基础信息 由于同时分析肌动蛋白丝和MT动力学， 迄今为止还没有一个生长锥。为了实现这一目标，多模 将使用荧光散斑显微镜（FSM）。利用这项技术， 肌动蛋白丝动力学如何影响微管的定量表征 行为，相反，微管动力学如何影响肌动蛋白丝 行为将被完成。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影响 将处理锥形制导事件。这将包括评估如何 在外周肌动蛋白网络中产生的牵引力使MT前进偏置， 如果张力影响MT聚合物动力学。我们还将研究蛋白质 在轴突导向调节中重要激酶信号通路 靶相互作用期间细胞骨架效应器机制的行为 事件从这些研究中收集的信息应该会产生根本性的影响 我们对轴突导向和神经的细胞生物学的理解 再生