In tight junctions, claudins regulate the interactions between occludin, tricellulin and marvelD3, which, inversely, modulate claudin oligomerization
In tight junctions, claudins regulate the interactions between occludin, tricellulin and marvelD3, which, inversely, modulate claudin oligomerization
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DOI：
10.1242/jcs.114306
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发表时间：
2013-01-15
影响因子：
4
通讯作者：
Blasig, Ingolf Ernst
中科院分区：
文献类型：
--
作者：
Cording, Jimmi;Berg, Johanna;Blasig, Ingolf Ernst
紧密连接密封上皮和内皮的细胞旁间隙，形成组织间室之间的重要屏障，由紧密连接相关的奇迹蛋白（TAMPs）和cladin组成。TAMPs的功能及其与cladin的相互作用尚不清楚。因此，我们在活体无紧密连接的人胚胎肾-293细胞中研究了TAMPs occludin、tricellulin和marvelD3之间的结合及其与claudin的相互作用。与claudin和occludin相比，tricellulin和marvelD3在细胞接触处没有富集，这表明两个对立细胞膜之间缺乏亲同性的反式相互作用。然而，通过荧光共振能量转移测量，occludin、marvelD3和tricellulin在一个质膜上表现出亲同性的顺式相互作用。MarvelD3还与occludin和tricellulin发生异亲性顺式相互作用。经典的claudin-1至-5可能与TAMPs发生顺式寡聚，而非经典的claudin-11则没有。Claudin-1和-5改善了细胞间接触处occludin和tricellulin的富集。通过光漂白后的荧光恢复研究，低流动性的claudin-1降低了高流动性的occludin和tricellulin的膜迁移率。与TAMPs共转染claudin-1导致该claudin的紧密连接链网络改变为更生理的形态，通过冷冻断裂电子显微镜描绘。这些结果证明了紧密连接蛋白之间的多边相互作用，其中cladin决定了TAMPs的功能，反之亦然，并为紧密连接组装提供了更深入的见解。
Tight junctions seal the paracellular cleft of epithelia and endothelia, form vital barriers between tissue compartments and consist of tight-junction-associated marvel proteins (TAMPs) and claudins. The function of TAMPs and the interaction with claudins are not understood. We therefore investigated the binding between the TAMPs occludin, tricellulin, and marvelD3 and their interaction with claudins in living tight-junction-free human embryonic kidney-293 cells. In contrast to claudins and occludin, tricellulin and marvelD3 showed no enrichment at cell-cell contacts indicating lack of homophilic trans-interaction between two opposing cell membranes. However, occludin, marvelD3 and tricellulin exhibited homophilic cis-interactions, along one plasma membrane, as measured by fluorescence resonance energy transfer. MarvelD3 also cis-interacted with occludin and tricellulin heterophilically. Classic claudins, such as claudin-1 to -5 may show cis-oligomerization with TAMPs, whereas the non-classic claudin-11 did not. Claudin-1 and -5 improved enrichment of occludin and tricellulin at cell-cell contacts. The low mobile claudin-1 reduced the membrane mobility of the highly mobile occludin and tricellulin, as studied by fluorescence recovery after photobleaching. Co-transfection of claudin-1 with TAMPs led to changes of the tight junction strand network of this claudin to a more physiological morphology, depicted by freeze-fracture electron microscopy. The results demonstrate multilateral interactions between the tight junction proteins, in which claudins determine the function of TAMPs and vice versa, and provide deeper insights into the tight junction assembly.