Study of Cell Adhesion through an Analysis of Myosin 7

人体抵御感染的第一道防线是循环中的白细胞 检测并对组织损伤做出反应。这些细胞迅速向损伤部位移动。 使用一种变形虫类型的运动性。这场运动的特点是形成了 广泛分布，细胞与周围底物之间的低亲和力接触。这个 由白细胞产生的阿米巴粘连由许多相同的 通过缓慢移动形成的紧密组织、高亲和力的粘合剂 成纤维细胞(局灶性接触)，但这些分子的组织和调节 在阿米巴细胞中是不同的。确定共享的不同机制 黏附分子在阿米巴细胞中使用，而成纤维细胞是关键 了解细胞迁移是如何快速实现的。 在细胞外基质之间提供动态连接的细胞黏附机制 受体和肌动蛋白细胞骨架在整个进化过程中都是保守的。一个 一种高度保守的非传统肌球蛋白，肌球蛋白VII(M7)在 在网囊阿米巴中发现了阿米巴样粘连。这样做的目的是 该项目是为了确定M7阿米巴粘连的作用。第一个问题将是 讨论了M7如何针对粘连部位，这是了解的关键一步 这种马达蛋白与细胞黏附机制之间的关系。这个 保守的M7尾部结构域对M7定位、膜动力学的贡献 并将对细胞黏附进行系统的研究。然后，基本域将是 用作探针以识别结合配对(最有可能是其他黏附分子或 监管机构)。下一个问题是，是否需要M7运动才能发挥其作用 阿米巴样粘连。M7通过被动连接黏附参与黏附 组件到细胞骨架，或者它可能需要在以下部位产生张力 粘附力。表达M7运动突变体(强或弱结合肌动蛋白)的细胞将 确定M7与肌动蛋白相互作用的循环是否对其 在阿米巴粘连中的作用。对M7的运动特性的体外分析也将是 执行以确定它是否具有作为锚或运输工具的潜力 马达。这项研究的结果将为我们提供对分子基础的基本新见解。 阿米巴粘连和肌球蛋白如何促进这种关键类型的粘连 促进细胞快速迁移。

The body's first line of defense against infection is the circulating white blood cells that detect and respond to tissue damage. These cells move rapidly towards the site of injury using an amoeboid type of motility. This movement is characterized by the formation of broadly distributed, low affinity contacts between the cell and surrounding substrate. The amoeboid adhesions generated by leukocytes are composed of many of the same components as the tightly organized, high affinity adhesions formed by slowly moving fibroblastic cells (focal contacts), but the organization and regulation of these molecules is distinct in amoeboid cells. Identifying the distinct mechanisms by which shared adhesion molecules are employed in amoeboid cells versus fibroblastic cells is key to understanding how rapid cell migration is achieved. The cell adhesion machinery that provides a dynamic link between extracellular matrix receptors and the actin cytoskeleton has been conserved throughout evolution. An unexpected role for a highly conserved unconventional myosin, myosin VII (M7), in amoeboid adhesion has been discovered in the amoeba Dictyostelium. The goal of this project is to define the role of M7 amoeboid adhesion. The first question that will be addressed is how M7 is targeted to adhesion sites, a critical step towards understanding the relationship between this motor protein and the cell adhesion machinery. The contribution of the conserved M7 tail domains to M7 localization, membrane dynamics and cellular adhesion will be systematically investigated. Essential domains will then be used as probes to identify binding partners (most likely other adhesion molecules or regulators). The next question is whether M7 motor activity is required for its role in amoeboid adhesion. M7 could participate in adhesion by passively linking adhesion components to the cytoskeleton or it could be required to generate tension at sites of adhesion. Cells expressing M7 motor mutants (either strong or weak actin binding) will be characterized to determine if cycles of M7 interaction with actin are necessary for its role in amoeboid adhesion. An in vitro analysis of the motor properties of M7 will also be performed to determine if it has the potential to function as an anchor or a transport motor. The results of this study will provide basic new insights into the molecular basis of amoeboid adhesion and how a myosin contributes to this critical type of adhesion to promote rapid cell migration.