TFF-petides and their mechanisms of action during cell migration

三叶因子是最近在哺乳动物和非洲爪哇中发现的一类分泌型多肽，在成年哺乳动物中主要在胃肠道组织中表达。对TFF功能的研究已经证实，TFFs是在上皮修复的早期过程中发挥作用的运动原，当细胞从受损区域的边缘快速迁移到剥脱区以重建上皮连续性时。在这个项目中，将研究三叶肽诱导迁移的细胞和分子机制。首先，将通过生化分析和免疫荧光显微镜来分析转移因子对钙粘附素-连环蛋白黏附复合体在迁移过程中的影响。其次，应注意顶端糖蛋白如DF3/MUC1是否作为TFf受体发挥作用，以及TFf与这些糖蛋白结合是否是钙粘连蛋白-连环蛋白系统的调节环节。此外，三叶肽的运动活性是否也是由基侧受体介导的，还应予以关注。第三，利用差异基因分析(cDNA微阵列)和高分辨率2D-凝胶电泳法，对TFF诱导的基因表达变化和信号蛋白的翻译后修饰进行鉴定和测试，以确定它们与诱导细胞迁移的相关性。

Trefoil factors (TFFs) represent a family of secreted polypeptides recently identified in mammalians and Xenopus that in adult mammalian organisms are expressed mainly in tissues of the gastrointestinal tract. Studies of TFF function have identified TFFs as motogens acting in early processes of epithelial restitution when cells rapidly migrate from the margins of the damaged region over the denuded area to reestablish epithelial continuity. In this project the cellular and molecular mechanisms responsible for the induction of migration by trefoil peptides shall be examined. First, the influence of TFFs on the cadherin-catenin adhesion complex during migration will be analyzed by biochemical analysis and immunofluorescence microscopy. Second, it shall be adressed whether apical glycoproteins such as DF3/MUC1 play a role as TFF receptors and whether binding of TFF to these glycoproteins is a regulatory link to the cadherin-catenin system. Furthermore, it shall be adressed whether the motogenic activity of trefoil peptides is also mediated by basolateral receptors. Third, employing differential cDNA analysis (cDNA arrays) and high-resolution 2D-gelelectrophoresis, TFF induced changes in gene expression and posttranslational modifications of signaling proteins shall be identified and tested for their relevance in induction of cell migration.