Organization and function of the interface between cadherin and the cytoskeleton

钙粘蛋白与细胞骨架之间界面的组织和功能

• 批准号: RGPIN-2016-06612
• 负责人: Tepass, Ulrich
• 金额: $ 3.93万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710325
• 关键词: Organization; function; interface; between; cadherin

Cadherins are multifunctional adhesion receptors involved in animal development and tissue homeostasis. We are particularly interested in the role cadherins play in epithelia, the major tissue type found in animals. Cadherins link cells together at prominent contact points called adherens junctions. When cadherins do not function normally, epithelia collapse or develop abnormal shapes, which is often lethal to the animal. Cadherins can only function when they are linked to the cytoskeleton of a cell. This linkage is crucial to form and maintain adherens junctions. Moreover, adherens junctions and the cytoskeleton have to cooperate to shape and maintain tissues. Cadherins bind to several cytoplasmic factors including -Catenin, a protein that we have studied in recent years, and that is the major linker between cadherin and the cytoskeleton. The importance of the linkage between cadherin and the cytoskelton is highlighted by the fact that loss of -Catenin causes the same defects as loss of cadherin. However, the interface between cadherin/-Catenin and actin is very complex as not only -Catenin can bind to the actin filaments of the cytoskeleton, but has also several binding partners that can bind to actin. Much remains to be learned about how this interface operates to regulate epithelial development and stability. We have recently identified a new -Catenin binding partner called Girdin that localizes to adherens junctions in the fruit fly Drosophila, the experimental model that we study, and in mammalian cells as was shown by a collaborator. Girdin can directly bind to actin. When Girdin is lost, actin organization is disrupted at adherens junctions and epithelia adopt abnormal shapes. The first aim of our proposed work is to develop a detailed understanding of how Girdin interacts with -Catenin and what specific contributions Girdin makes to the function of adherens junctions and the organization of the actin cytoskeleton in epithelial cells. In a second aim we will explore the interactions between adherens junctions and the second major component of the cytoskeleton, microtubules. The ends of microtubules are linked to adherens junctions, an association presumed to be important for adherens junction formation and stability, but a detailed understanding of exactly how microtubules interact with adherens junctions and why this is important for normal epithelial development is outstanding. In order to gain an entry point and develop tools to study this association we will explore the function of a factor called PLEKHA7 in mammals and CG34383 in Drosophila. Work in mammalian cell culture suggests that PLEKHA7 links the ends of microtubules to cadherin and that compromising this link disrupts adherens junctions. An analysis of CG34383 in Drosophila will give us the unprecedented opportunity to investigate how this protein contributes to epithelial development in the context of a whole animal.

钙粘蛋白是一种多功能的粘附受体，参与动物的发育和组织的稳态。我们特别感兴趣的是钙粘蛋白在上皮细胞中的作用，上皮细胞是动物中发现的主要组织类型。钙粘蛋白在称为粘附连接的突出接触点处将细胞连接在一起。当钙粘蛋白不能正常发挥功能时，上皮细胞会塌陷或形成异常形状，这通常对动物是致命的。 钙粘蛋白只有在与细胞骨架连接时才能发挥作用。这种连接对于形成和维持粘附连接至关重要。此外，粘附连接和细胞骨架必须合作以形成和维持组织。钙粘蛋白结合几种细胞质因子，包括-连环蛋白，我们近年来研究的一种蛋白质，是钙粘蛋白和细胞骨架之间的主要接头。钙粘蛋白和细胞粘附素之间的联系的重要性突出的事实是，-连环蛋白的损失导致相同的缺陷作为钙粘蛋白的损失。然而，钙粘蛋白/-连环蛋白和肌动蛋白之间的界面非常复杂，因为不仅-连环蛋白可以结合到细胞骨架的肌动蛋白丝，而且还有几个可以结合到肌动蛋白的结合伴侣。关于这个界面如何调节上皮的发育和稳定性，还有很多东西有待了解。 我们最近发现了一个新的-连环蛋白结合伙伴称为Girdin，定位于果蝇，我们研究的实验模型，并在哺乳动物细胞中的adherens连接，如合作者所示。Girdin可以直接与肌动蛋白结合。当Girdin丢失时，粘附连接处的肌动蛋白组织被破坏，上皮细胞呈现异常形状。我们提出的工作的第一个目的是开发一个详细的了解Girdin如何与-连环蛋白的相互作用和什么具体的贡献Girdin使粘附连接的功能和组织的肌动蛋白细胞骨架在上皮细胞。 在第二个目标中，我们将探讨粘附连接和细胞骨架的第二个主要组成部分，微管之间的相互作用。微管末端与粘附连接相连，这种联系被认为对粘附连接的形成和稳定性很重要，但对微管与粘附连接的确切相互作用以及为什么这对正常上皮发育很重要的详细了解是突出的。为了获得一个切入点，并开发工具来研究这种关联，我们将探索一种名为PLEKHA 7的因子在哺乳动物中的功能和CG 34383在果蝇中的功能。在哺乳动物细胞培养中的工作表明，PLEKHA 7将微管末端连接到钙粘蛋白，并且破坏这种连接会破坏粘附连接。对果蝇中CG 34383的分析将为我们提供前所未有的机会，以研究这种蛋白质如何在整个动物的背景下促进上皮发育。