Cytoskeleton Coordination in Neuronal Morphogenesis

神经元形态发生中的细胞骨架协调

• 批准号: 6620690
• 负责人: W. James Nelson
• 金额: $ 32.05万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-12-15 至 2005-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6620690
• 关键词: actins; axon; biological signal transduction; cadherins; cell cell interaction; cytoskeleton; dendrites; fluorescence microscopy; gene expression; growth cones; histogenesis; laboratory rat; membrane structure; microtubule associated protein; microtubules; neuronal guidance; protein binding; protein protein interaction; protein structure function; tissue /cell culture

DESCRIPTION (provided by applicant): A characteristic feature of neuronal morphogenesis is the formation of long, branched membrane extensions, termed neurites, which seek out and form highly selective connections between neurons. Our long-term objective is to understand how cytoskeletal networks specify complex changes in membrane dynamics required for neurite extension, and how signaling pathways regulate this behavior. Changes in actin and microtubule cytoskeleton assembly and organization are important in neurite outgrowth, and cadherins and the protein adenomatous polyposis coli (APC) are well placed to play key roles in coordinating these changes. Cadherin cell-cell adhesion proteins are involved in axonal path finding, the initiation of contacts between neurite extensions, and synapse function. Cadherins are linked to the actin cytoskeleton by beta- and alpha-catenin, and this complex is essential for cadherin function in adhesion. APC also binds cytoplasmic beta-catenin and targets beta-catenin for degradation thereby regulating another function of beta-catenin in controlling gene expression in response to Wnt signaling. APC protein binds to microtubules, stimulates microtubule assembly and bundling in vitro, accumulates in protein clusters at the plus-end of microtubules at the tips of epithelial and neuronal membrane extensions, and is enriched in axonal growth cones and at synapses. Binding of beta-catenin to APC in microtubule-associated clusters at the plasma membrane decreases membrane outgrowth indicating another function for beta-catenin in regulating cellular morphogenesis through APC. Our working hypothesis is that microtubule-associated APC clusters at the cortex locally regulate cytoskeletal re-organization during neurite outgrowth and contact formation, and that APC clusters are in turn regulated by Wnt signaling and signals from the cadherin complex at the cell surface. This hypothesis will be tested: 1). Identify and characterize proteins in cortical APC clusters, and determine their role in APC cluster formation; 2). Characterize the function of membrane-attached APC clusters in microtubule assembly and formation of neurite extensions; and 3). Identify and characterize signaling pathways from Wnt and cadherins that regulate APC cluster function. The significance of these proposed studies is they will provide novel understanding of how cytoskeletal restructuring is controlled in locally defined, subcellular domains in order to specify neurite outgrowth and cell-cell contacts in response to extracellular signals.

描述（由申请人提供）：神经元的特征 形态发生是长的、分支的膜延伸的形成，称为 神经突，在神经元之间寻找并形成高度选择性的连接。 我们的长期目标是了解细胞骨架网络如何指定 神经突延伸所需的膜动力学的复杂变化，以及如何 信号通路调节这种行为。肌动蛋白和微管的变化 细胞骨架的组装和组织对于神经突的生长很重要，并且 钙粘蛋白和蛋白质腺瘤性结肠息肉病 (APC) 非常适合 在协调这些变化方面发挥关键作用。钙粘蛋白细胞间粘附 蛋白质参与轴突路径寻找、接触的启动 神经突延伸和突触功能之间。钙粘蛋白与 肌动蛋白细胞骨架由β-和α-连环蛋白组成，这种复合物是必不可少的 用于粘附中钙粘蛋白的功能。 APC 还结合细胞质 β-连环蛋白 以β-连环蛋白为目标进行降解，从而调节 β-连环蛋白响应 Wnt 信号传导控制基因表达。 APC 蛋白质与微管结合，刺激微管组装和捆绑 体外，在微管正端的蛋白质簇中积累 上皮和神经元膜延伸的尖端，并且富含轴突 生长锥和突触。 β-连环蛋白与 APC 的结合 质膜上的微管相关簇减少了膜 生长表明β-连环蛋白在调节细胞中的另一个功能 通过 APC 进行形态发生。我们的工作假设是 皮层微管相关的 APC 簇局部调节细胞骨架 神经突生长和接触形成期间的重组，并且 APC 簇依次受到 Wnt 信号和钙粘蛋白信号的调节 细胞表面的复合物。该假设将被检验：1）。识别并 表征皮质 APC 簇中的蛋白质，并确定它们在 APC 中的作用 集群形成； 2）。表征膜附着 APC 的功能 微管组装中的簇和神经突延伸的形成；和3）。 识别并表征 Wnt 和钙粘蛋白的信号通路 调节APC簇功能。这些拟议研究的意义在于 他们将为细胞骨架重组的过程提供新的理解 在局部定义的亚细胞域中进行控制，以指定神经突 响应细胞外信号的生长和细胞间接触。