Tachibana K, Nakanishi H, Mandai K, Ozaki K, Ikeda W, Yamamoto Y, Nagafuchi A, Tsukita S, Takai Y
Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita 565-0871, Japan.
J Cell Biol. 2000 Sep 4;150(5):1161-76. doi: 10.1083/jcb.150.5.1161.
We have found a new cell-cell adhesion system at cadherin-based cell-cell adherens junctions (AJs) consisting of at least nectin and l-afadin. Nectin is a Ca(2+)-independent homophilic immunoglobulin-like adhesion molecule, and l-afadin is an actin filament-binding protein that connects the cytoplasmic region of nectin to the actin cytoskeleton. Both the trans-interaction of nectin and the interaction of nectin with l-afadin are necessary for their colocalization with E-cadherin and catenins at AJs. Here, we examined the mechanism of interaction between these two cell-cell adhesion systems at AJs by the use of alpha-catenin-deficient F9 cell lines and cadherin-deficient L cell lines stably expressing their various components. We showed here that nectin and E-cadherin were colocalized through l-afadin and the COOH-terminal half of alpha-catenin at AJs. Nectin trans-interacted independently of E-cadherin, and the complex of E-cadherin and alpha- and beta-catenins was recruited to nectin-based cell-cell adhesion sites through l-afadin without the trans-interaction of E-cadherin. Our results indicate that nectin and cadherin interact through their cytoplasmic domain-associated proteins and suggest that these two cell-cell adhesion systems cooperatively organize cell-cell AJs.
我们在基于钙黏蛋白的细胞间黏附连接（AJs）处发现了一种新的细胞-细胞黏附系统，该系统至少由nectin和l-afadin组成。Nectin是一种不依赖Ca(2+)的同嗜性免疫球蛋白样黏附分子，而l-afadin是一种肌动蛋白丝结合蛋白，它将nectin的细胞质区域连接到肌动蛋白细胞骨架。Nectin的反式相互作用以及nectin与l-afadin的相互作用对于它们与E-钙黏蛋白和连环蛋白在AJs处共定位都是必需的。在这里，我们通过使用稳定表达其各种组分的α-连环蛋白缺陷型F9细胞系和钙黏蛋白缺陷型L细胞系，研究了AJs处这两种细胞-细胞黏附系统之间的相互作用机制。我们在此表明，nectin和E-钙黏蛋白通过l-afadin和α-连环蛋白的COOH末端一半在AJs处共定位。Nectin的反式相互作用独立于E-钙黏蛋白，并且E-钙黏蛋白与α-连环蛋白和β-连环蛋白的复合物通过l-afadin被招募到基于nectin的细胞-细胞黏附位点，而无需E-钙黏蛋白的反式相互作用。我们的结果表明，nectin和钙黏蛋白通过其细胞质结构域相关蛋白相互作用，并表明这两种细胞-细胞黏附系统协同组织细胞间AJs。
