Chitaev N A, Troyanovsky S M
Department of Dermatology, Washington University Medical School, St. Louis, Missouri 63110, USA.
J Cell Biol. 1998 Aug 10;142(3):837-46. doi: 10.1083/jcb.142.3.837.
We examined intercadherin interactions in epithelial A-431 cells producing endogenous E-cadherin and recombinant forms of E-cadherin tagged either by myc or by flag epitopes. Three distinct E-cadherin complexes were found. The first is a conventional E-cadherin-catenin complex consisting of one E-cadherin molecule linked either to beta-catenin/alpha-catenin or to plakoglobin/alpha-catenin dimers. The second is a lateral E-cadherin complex incorporating two E-cadherin- catenin conventional complexes combined in parallel fashion via dimerization of the NH2-terminal extracellular domain of E-cadherin. The third complex is likely to contain two E-cadherin-catenin conventional complexes derived from two opposing cells and arranged in an antiparallel fashion. Formation of the antiparallel but not lateral complex strictly depends on extracellular calcium and E-cadherin binding to catenins. Double amino acid substitution Trp156Ala/Val157Gly within the extracellular NH2-terminal E-cadherin domain completely abolished both lateral and antiparallel inter-E-cadherin association. These data support an idea that the antiparallel complex has the adhesion function. Furthermore, they allow us to suggest that antiparallel complexes derive from lateral dimers and this complex process requires catenins and calcium ions.
我们检测了上皮A-431细胞中内源性E-钙黏蛋白以及分别用myc或flag表位标记的重组形式E-钙黏蛋白之间的钙黏蛋白相互作用。发现了三种不同的E-钙黏蛋白复合物。第一种是传统的E-钙黏蛋白-连环蛋白复合物，由一个E-钙黏蛋白分子与β-连环蛋白/α-连环蛋白或桥粒芯蛋白/α-连环蛋白二聚体相连组成。第二种是侧向E-钙黏蛋白复合物，通过E-钙黏蛋白NH2末端胞外结构域的二聚化，以平行方式结合两个传统的E-钙黏蛋白-连环蛋白复合物。第三种复合物可能包含来自两个相对细胞的两个传统E-钙黏蛋白-连环蛋白复合物，并以反平行方式排列。反平行而非侧向复合物的形成严格依赖于细胞外钙以及E-钙黏蛋白与连环蛋白的结合。E-钙黏蛋白胞外NH2末端结构域内的双氨基酸取代Trp156Ala/Val157Gly完全消除了E-钙黏蛋白之间的侧向和反平行结合。这些数据支持了反平行复合物具有黏附功能这一观点。此外，它们使我们能够提出，反平行复合物源自侧向二聚体，且这一复杂过程需要连环蛋白和钙离子。
