Role of E-cadherin’s N-glycans in tissue morphogenesis

进化保守的E-cadherin（果蝇中的猎枪）是上皮细胞粘附分子的原型，它一方面负责同型和钙依赖性细胞-细胞粘附，另一方面通过与β -连环蛋白（果蝇中的犰狳）和α -连环蛋白形成三聚体复合物与皮质肌动球蛋白细胞骨架相连。除了这种通用的三聚体配合物外，e -钙粘蛋白还存在于数百个分子的超分子配合物中，这些分子可能参与粘附也可能不参与三聚体配合物。e -钙粘蛋白位于上皮细胞间力传递的中心位置，在细胞机械通讯中起着关键作用。考虑到e -钙粘蛋白在粘附、皮质连接和机械转导中相互交织的功能，机械转导的分子机制一直难以研究。基于低n -糖基化的E-cadherin在聚集、皮质相互作用和细胞间通讯的某些方面受到损害的研究结果，我们提出系统地研究在果蝇胚胎组织形态发生过程中，n -糖基化位点的一系列E-cadherin突变对E-cadherin功能的贡献。这些突变的表型将通过既定的分子和功能分析来研究e -钙粘蛋白的移动性、复合物的形成、连接机制、粘附、细胞信号传导。利用高分辨率显微镜和DNA-paint单分子定位技术研究其纳米结构的表型。

The evolutionary conserved E-cadherin (shotgun in Drosophila) is the prototype of a cell adhesion molecule in epithelia, which on the one side is responsible for homotypic and Calcium dependent cell-cell adhesion and on the other is connected to the cortical actomyosin cytoskeleton by forming a trimeric complex with beta-catenin (armadillo in Drosophila) and alpha-catenin. Beside such generic trimeric complexes, E-cadherin is found in super-molecular complexes of several hundred molecule, which may or may not be engaged in adhesion and trimeric complexes. Being centrally positioned at the force transmission between epithelial cells, E-cadherin plays a pivotal role in mechanical cell communication. The molecular mechanism of mechanotransduction has been difficult to investigate given the intertwined E-cadherin functions in adhesion, cortical link and mechanotransduction. Based on findings that hypo-N-glycosylated E-cadherin is impaired in clustering, cortical interactions and certain aspects of cell-cell communication, we propose to systematically investigate the contributions of N-glycans to the functions of E-cadherin in a physiological setting during tissue morphogenesis in Drosophila embryos by a series of E-cadherin mutations at N-glycosylation sites. The phenotype of these mutations will be investigated by established molecular and functional assays for E-cadherin mobility, complex formation, mechanics of junctions, adhesion, cell signalling. The phenotypes in nano-structure will be investigated by high resolution microscopy and DNA-paint single molecular localization.