Watabe-Uchida M, Uchida N, Imamura Y, Nagafuchi A, Fujimoto K, Uemura T, Vermeulen S, van Roy F, Adamson E D, Takeichi M
Department of Biophysics, Faculty of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, USA.
J Cell Biol. 1998 Aug 10;142(3):847-57. doi: 10.1083/jcb.142.3.847.
alphaE-catenin, a cadherin-associated protein, is required for tight junction (TJ) organization, but its role is poorly understood. We transfected an alphaE-catenin-deficient colon carcinoma line with a series of alphaE-catenin mutant constructs. The results showed that the amino acid 326-509 domain of this catenin was required to organize TJs, and its COOH-terminal domain was not essential for this process. The 326-509 internal domain was found to bind vinculin. When an NH2-terminal alphaE-catenin fragment, which is by itself unable to organize the TJ, was fused with the vinculin tail, this chimeric molecule could induce TJ assembly in the alphaE-catenin-deficient cells. In vinculin-null F9 cells, their apical junctional organization was impaired, and this phenotype was rescued by reexpression of vinculin. These results indicate that the alphaE-catenin-vinculin interaction plays a role in the assembly of the apical junctional complex in epithelia.
αE连环蛋白是一种与钙黏着蛋白相关的蛋白质，对于紧密连接（TJ）的组织形成是必需的，但其作用仍知之甚少。我们用一系列αE连环蛋白突变体构建体转染了αE连环蛋白缺陷的结肠癌细胞系。结果表明，该连环蛋白的326 - 509氨基酸结构域是组织紧密连接所必需的，而其COOH末端结构域对这一过程并非必不可少。发现326 - 509内部结构域可与纽蛋白结合。当一个本身无法组织紧密连接的NH2末端αE连环蛋白片段与纽蛋白尾部融合时，这种嵌合分子可在αE连环蛋白缺陷细胞中诱导紧密连接组装。在缺乏纽蛋白的F9细胞中，其顶端连接组织受损，而通过重新表达纽蛋白可挽救这种表型。这些结果表明，αE连环蛋白 - 纽蛋白相互作用在上皮细胞顶端连接复合体的组装中起作用。
