Function of a Novel Matrix Junction in Endothelial Cells

描述(申请人提供)：血管的管腔内衬有 内皮细胞(ECs)。后者位于基底膜上，其结构 元素包括层粘连蛋白、蛋白多糖和胶原蛋白。ECS与这些服务器进行交互 基质蛋白部分通过被称为整合素的受体。这样的互动是 参与调节包括黏附在内的许多细胞功能， 运动性和基因表达。在成人，血管中的内皮细胞 都是静止的。然而，在伤口愈合和病理条件下 包括癌症和炎症性疾病在内，刺激会激活新的血管 生长，这一过程被称为血管生成。在这个应用程序中，我们的研究是 聚焦于我们最近在内皮细胞中发现的一种新的基质连接。 初步实验表明，内皮细胞组装了一个新的焦点 与微丝和微丝都有联系的接触式结构 细胞骨架中的波形。这种波形蛋白相关的基质黏附(VMA) 在其核心拥有avbeta3整合素异源二聚体和A4层粘连蛋白 细胞外基质中含有亚基的配体。此外，VMA 其特征是含有我们推测涉及的plectin 介导细胞表面对波形蛋白细胞骨架的锚定。这个交叉口 以依赖于生长因子的方式组装，并似乎在EC中发挥作用 迁移和分支形态发生，血管生成的基本要素， 由于针对avbeta3整合素异源二聚体和A4的抗体 层粘连蛋白亚单位抑制这些事件。在目标1中，我们将进一步承诺 VMA分子组成的表征 强调其蛋白质成分是如何相互作用的，以及如何识别 与细胞内波形蛋白细胞骨架锚定有关的分子 浮出水面。在目标2中，我们将研究VMA在生活中的组装动力学 在ECS中，我们表达了绿色荧光标记的VMA蛋白 蛋白。在目标3中，我们将分析虚拟MA的组件(S)在 体内血管生成。这些研究将为我们提供新的视角，了解 整合素/基质在血管生成中的相互作用。

DESCRIPTION (provided by the applicant): The lumen of blood vessels is lined by endothelial cells (ECs). The latter lie on a basement membrane whose structural elements include laminins, proteoglycans and collagens. ECs interact with these matrix proteins, in part, via receptors called integrins. Such interactions are involved in regulating a number of cellular functions including adhesion, motility and gene expression. In the adult, endothelial cells in the vessels are quiescent. However, in wound healing and in pathological conditions including cancer and inflammatory diseases, a stimulus activates new vessel growth, a process called angiogenesis. In this application, our studies are focused on a novel matrix junction that we recently identified in ECs. Preliminary experiments indicate that endothelial cells assemble a novel focal contact-like structure that is associated with both the microfilament and vimentin cytoskeletons. This vimentin-associated matrix adhesion (VMA) possesses, at its core, the avbeta3 integrin heterodimer and an a4 laminin subunit-containing ligand in the extracellular matrix. In addition, the VMA characteristically contains plectin that we hypothesize is involved in mediating cell surface anchorage of the vimentin cytoskeleton. This junction assembles in a growth factor-dependent manner and appears to play a role in EC migration and branching morphogenesis, essential elements of angiogenesis, since antibodies against both the avbeta3 integrin heterodimer and the a4 laminin subunit inhibit these events. In aim 1, we will undertake further characterization of the molecular composition of the VMA with particular emphasis on how its protein components interact and on identification of the molecules involved in anchorage of the vimentin cytoskeleton at the cell surface. In aim 2, we will study the dynamics of assembly of the VMA in living ECs in which we have expressed VMA proteins tagged with green fluorescent protein. In aim 3, we will analyze the function(s) of components of the VMA in angiogenesis in vivo. These studies will provide new insight into the role of integrin/matrix interactions in angiogenesis.