MOLECULAR ULTRASTRUCTURE UNDERLYING CELL ADHESION

展示其结构和功能特性的研究 将继续使用各种细胞-细胞外基质附着点，特别是 重视改变细胞黏附的分子机制 转化细胞中的去黏附和侵袭。我们的工作假说 是：1)不同的、特定的细胞表面受体参与 在动态过程中组织细胞对纤维连接蛋白和胶原的附着 细胞黏附和侵袭的过程，2)如纤维连接蛋白等配体可以 有助于调节其受体和细胞骨架的分布， 3)定位的细胞表面蛋白水解酶负责细胞 与接触有关的ECM溶解，从而允许入侵。 最近的研究证明了相变诱导的存在。 降解细胞内纤维连接蛋白和胶原的细胞表面蛋白 联系地点。因此，本提案的近期目标是 使用单抗探针来定位这些转化敏感的， 侵袭相关的蛋白水解酶，以确定蛋白水解酶结构域，以及 扰乱涉及蛋白水解酶的分子相互作用。通过这个，我们计划 确定这些蛋白水解酶在转化细胞侵袭中的可能作用 或者作为肿瘤细胞转移潜能的指标。建议数 研究还将确定电子上可能的胶原蛋白附着位置 微观层面，并确定这种依恋是否通过 胶原蛋白受体。为此，我们将使用原位定位和 抗体抑制方法类似于用于 纤维连接蛋白-受体结合的特征。可能的 纤维连接蛋白和胶原在组织中的调节作用 附着位置和在肿瘤细胞的侵袭之后 通过允许这些分子结合到细胞表面和 使用特定的单抗探针抑制其结合 合成肽。 更具体地说，我们将寻求确定：1)分子结构 和细胞表面蛋白水解酶的生化性质 杂交瘤技术，2)细胞表面蛋白水解酶在 转化和侵袭到纤维连接蛋白和胶原底物，3) 胶原蛋白和细胞表面受体的表达和定位 纤维连接蛋白在不同的附着部位，4)调节作用 纤维粘连蛋白和胶原在粘连部位组织中的作用 转化细胞；5)细胞的体内生物学意义 肿瘤细胞迁移和侵袭中的表面蛋白或受体。

Studies demonstrating the structural and functional specificities of various cell-ECM attachment sites will be continued, with particular emphasis on altered molecular mechanisms of cell adhesion, cell de-adhesion, and invasion in transformed cells. Our working hypotheses are: 1) distinct, specific cell surface receptors are involved in organizing cell attachments to fibronectin and collagen during dynamic processes of cell adhesion and invasion, 2) ligands such as fibronectin can help to regulate the distribution of their receptors and the cytoskeleton, and 3) localized cell surface proteases are responsible for cell contact-related dissolution of the ECM, which permits invasion. Recent studies have demonstrated the existence of transformation-induced cell surface proteases that degrade fibronectin and collagen at cell contact sites. Thus, the immediate goals of the present proposal are to use monoclonal antibody probes to localize these transformation-sensitive, invasion-associated proteases, to identify protease structural domains, and to perturb molecular interactions involving proteases. By this we plan to determine the possible role of these proteases in transformed cell invasion or as indicators of the metastatic potential of tumor cells. The proposed studies will also define possible collagen attachment sites at the electron microscopic level, and determine whether such attachments function via collagen receptors. To do this, we will use in situ localization and antibody inhibition approaches similar to those used for the characterization of the fibronectin-receptor association. Possible regulatory roles of fibronectin and collagen in the organization of attachment sites and in the invasion of the tumor cells will then be studied by allowing these molecules to bind to the cell surface and inhibiting their binding using specific monoclonal antibody probes and synthetic peptides. More specifically, we will seek to determine: 1) the molecular structure and biochemical properties of cell surface proteases by the use of hybridoma technology, 2) the roles of cell surface proteases in transformation and invasion into fibronectin and collagen substrata, 3) the expression and localization of cell surface receptors for collagen and fibronectin at distinct attachment sites, 4) the regulatory roles of fibronectin and collagen in the organization of adhesion sites in transformed cells, and 5) the in vivo biological significance of cell surface proteases or receptors in migration and invasion of tumor cells.