CONTROL OF EPITHELIAL CELL MOTILITY BY E CADHERIN

钙依赖性粘附介导的细胞-细胞接触 分子，E-钙粘蛋白，强烈影响极性， 上皮细胞的分化。 我们发现E-钙粘蛋白 还抑制上皮细胞的运动。 引人注目的是，这 抑制不需要E-钙粘蛋白介导的粘附，但 相反，似乎涉及细胞内运动的产生- 抑制信号 我们已经确定了E的一部分- 钙粘蛋白胞质片段，即胞膜9 JM）区域， 这是产生这种信号的关键。 我们的总体目标是 识别该信号通路的组成部分，以确定 细胞运动的哪些方面受到信号的抑制，以及 确定在表皮发育过程中该信号的重要性 和伤口愈合 为了定义JM域的边界， 分析JM缺失对细胞运动的影响 JM区域的突变体和显性负性形式。 与JM域交互的组件将通过以下方式标识： 将免疫共沉淀的蛋白质模式与 含有或缺乏该区域的E-钙粘蛋白形式，通过亲和力 用JM结构域融合蛋白进行纯化，并通过使用该方法， 酵母双杂交系统 我们将测试这些JM- 相关成分参与信号通路， 表达显性负性多肽，这些多肽将阻断它们的 与JM结构域结合。 我们将测试是否同性恋E- 钙粘蛋白结合激活MAP激酶。 要定义蜂窝 可能受此信号调节的反应，我们将确定 E-钙粘蛋白是否影响膜皱褶和丝状伪足 扩展名. 最后，要确定这种调节的作用， 运动在皮肤发育和伤口愈合，我们将 建立并分析转基因小鼠， E-cadherin的形式在基底节细胞中特异性表达， 角质细胞总之，这些研究将导致更好的 了解细胞间接触的机制 调节上皮细胞运动。 这些知识将证明 用于促进伤口愈合和控制癌细胞 入侵

Cell-cell contacts mediated by the calcium-dependent adhesion molecule, E-cadherin, strongly affect the polarity and differentiation of epithelial cells. We have found that E-cadherin also suppresses the movement of epithelial cells. Strikingly, this suppression does not require adhesion mediated by E-cadherin, but instead appears to involve generation of an intracellular motility- suppressing signal. We have determined that part of the E- cadherin cytoplasmic segment, the juxtamembrane 9JM) region, is essential for generating this signal. Our overall goals are to identify the components of this signaling pathway, to determine which aspects of cell motility are suppressed by the signal, and to define the importance of this signal during epidermal development and wound-healing. To define the boundaries of the JM domains, we will analyze the effects on cell movement of JM deletion mutants and dominant-negative forms of the JM region. Components that interact with the JM domain will be identified by comparing the pattern of proteins co-immunoprecipitated with forms of E-cadherin that contain or lack this region, by affinity purification with JM domain fusion proteins, and by use of the yeast two-hybrid system. We will test whether these JM- associated components are involved in the signaling pathway by expressing dominant-negative polypeptides that will block their binding to the JM domain. We will test whether homophilic E- cadherin binding activates MAP kinase. To define cellular responses that may be regulated by this signal, we will determine whether E-cadherin affects membrane ruffling and filopodial extension. Finally, to determine the role of this regulation of motility during skin development and wound-healing, we will create and analyze transgenic mice in which dominant-negative forms of E-cadherin are expressed specifically in basal karatinocytes. Together, these studies will result in a better understanding of the mechanisms by which cell-cell contact regulates epithelial cell motility. Such knowledge will prove useful for enhancing wound healing and controlling carcinoma cell invasion.