Cell adhesion, signal transduction and cytoskeletal regulation in Drosophila

果蝇的细胞粘附、信号转导和细胞骨架调节

• 批准号: 7906599
• 负责人: Mark A. Peifer
• 金额: $ 8.16万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-31 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7906599
• 关键词: Actins; Address; Adherens Junction; Adhesions; Adult; Affect; Animal Model; Animals; Apical; Area; Autoimmune Process; Biological; Biological Models; Cadherins; Cell Adhesion; Cell Shape; Cells; Complex; Coupled; Coupling; Cues; Cytoskeleton; Data; Development; Developmental Biology; Disease; Drosophila genus; Embryo; Embryonic Development; Event; Filopodia; Foundations; Genetic; Heart Diseases; Homeostasis; Homologous Gene; Inherited; Link; Maintenance; Mechanics; Mediating; Modeling; Morphogenesis; Movement; Neoplasm Metastasis; Normal Cell; Organ; Play; Positioning Attribute; Process; Protein Tyrosine Kinase; Proteins; Receptor Protein-Tyrosine Kinases; Regulation; Role; Signal Transduction; Site; Skin; Staging; Structure; System; Testing; Textbooks; Time; Tissues; Work; Wound Healing; afadin; base; cell behavior; constriction; fly; insight; research study; scaffold; tool; tumor

DESCRIPTION (provided by applicant): The coordination of cell adhesion and cytoskeletal regulation is critical for tissue and organ assembly during embryogenesis, and also during wound repair and tissue homeostasis in adults. Disruption of cell adhesion is a critical step in tumor metastasis, and plays a role in skin and heart diseases. We have developed a model system to study coupling of cell adhesion and regulation of the actin cytoskeleton, using the fruit fly Drosophila. Tools available in this system allow us to combine very powerful genetic approaches with the ability to study cell biological events in the context of intact animals, often in real time. Work in many labs provided a static "textbook" model for how the core cadherin:catenin complex at adherens junctions (AJs) mediates adhesion and links adhesive junctions to actin. However, cells in embryos and adults are far from static. Further, certain key features of the textbook model have been called into question. Our current challenge is to revise this model, revealing how adhesion and cytoskeletal regulation are coordinated and regulated to enable the remarkably diverse cell behaviors found in developing embryos. Here we address two broad unanswered questions in this area, each providing the basis for one of our Specific Aims. Aim 1 Define mechanisms by which AJs are connected to the actin cytoskeleton and explore how these affect apical constriction, AJ remodeling and other processes. The canonical model suggests that there is a direct mechanical connection between AJs and actin, mediated by linked interactions between cadherins, ?-catenin, ??catenin, and actin. However, recent work called this into question. Defining whether and how AJs are linked to the actin cytoskeleton is a key question for our field. We hypothesize that a direct mechanical connection is critical in robust cell shape changes like those of apical constriction. Based on our preliminary data, we further hypothesize that Canoe and Rap1 help mediate this link. We will test this hypothesis, examining mechanisms by which Cno and Rap1 act, and exploring whether they play a more general role in apical constriction and AJ remodeling events. Aim 2 Define mechanisms by which adhesion and actin dynamics are coordinately regulated. To accomplish the complex cell behaviors of morphogenesis, cells must closely coordinate adhesion and actin dynamics. Defining mechanisms by which this occurs is a key task for the field. We identified critical roles for the tyrosine kinase Abl and the actin regulator Ena in morphogenesis. We use them as a model for understanding mechanisms coordinating cell adhesion and cytoskeletal regulation. We hypothesize actin regulators like Ena are stored in an inactive state at AJs. We hypothesize that Abl regulates actin assembly at AJs and nearby by regulating Ena localization and/or function, acting as a scaffold, and influencing actin directly. We hypothesize that Ena helps generate distinct actin structures using different domains and partners, and that Ena is integrated with other actin regulators in filopodia. We will test these hypotheses.

描述（由申请人提供）：细胞粘附和细胞骨架调节的协调对于胚胎发生过程中的组织和器官组装以及成人的伤口修复和组织稳态过程中至关重要。细胞粘附的破坏是肿瘤转移的关键步骤，并且在皮肤和心脏疾病中发挥着作用。我们开发了一个模型系统，利用果蝇来研究细胞粘附和肌动蛋白细胞骨架调节的耦合。该系统中可用的工具使我们能够将非常强大的遗传方法与在完整动物的背景下研究细胞生物学事件的能力（通常是实时的）结合起来。许多实验室的工作提供了静态“教科书”模型，说明粘附连接 (AJ) 处的核心钙粘蛋白：连环蛋白复合物如何介导粘附并将粘附连接与肌动蛋白连接。然而，胚胎和成体中的细胞远非静态。此外，教科书模型的某些关键特征也受到了质疑。我们当前的挑战是修改这个模型，揭示粘附和细胞骨架调节是如何协调和调节的，以实现发育中胚胎中发现的极其多样化的细胞行为。在这里，我们解决了该领域两个广泛的未解答问题，每个问题都为我们的一个具体目标提供了基础。目标 1 定义 AJ 连接到肌动蛋白细胞骨架的机制，并探索这些机制如何影响顶端收缩、AJ 重塑和其他过程。 规范模型表明，AJ 和肌动蛋白之间存在直接的机械连接，由钙粘蛋白、β-连环蛋白、β-连环蛋白和肌动蛋白之间的相互作用介导。然而，最近的研究对此提出了质疑。定义 AJ 是否以及如何与肌动蛋白细胞骨架连接是我们领域的一个关键问题。我们假设直接机械连接对于细胞形状的稳健变化（例如顶端收缩的变化）至关重要。根据我们的初步数据，我们进一步假设 Canoe 和 Rap1 有助于调节这种联系。我们将检验这一假设，检查 Cno 和 Rap1 的作用机制，并探讨它们是否在心尖收缩和 AJ 重塑事件中发挥更普遍的作用。目标 2 定义协调调节粘附和肌动蛋白动力学的机制。为了完成形态发生的复杂细胞行为，细胞必须密切协调粘附和肌动蛋白动力学。定义发生这种情况的机制是该领域的一项关键任务。我们确定了酪氨酸激酶 Abl 和肌动蛋白调节因子 Ena 在形态发生中的关键作用。我们使用它们作为理解协调细胞粘附和细胞骨架调节机制的模型。我们假设像 Ena 这样的肌动蛋白调节因子以非活性状态存储在 AJ 中。我们假设 Abl 通过调节 Ena 定位和/或功能、充当支架并直接影响肌动蛋白来调节 AJ 及其附近的肌动蛋白组装。我们假设 Ena 有助于使用不同的域和伙伴生成不同的肌动蛋白结构，并且 Ena 与丝状伪足中的其他肌动蛋白调节因子整合。我们将测试这些假设。