A peculiar internalization of claudins, tight junction-specific adhesion molecules, during the intercellular movement of epithelial cells
A peculiar internalization of claudins, tight junction-specific adhesion molecules, during the intercellular movement of epithelial cells
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DOI：
10.1242/jcs.00972
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发表时间：
2004-03-01
影响因子：
4
通讯作者：
Tsukita, S
中科院分区：
文献类型：
--
作者：
Matsuda, M;Kubo, A;Tsukita, S
紧密连接（TJ）密封上皮细胞的细胞间隙，而单个上皮细胞在细胞片层中与相邻细胞相对移动。为了观察活的上皮细胞片层中的TJ，将绿色荧光蛋白（GFP）融合到紧密连接蛋白-3（TJ的主要细胞粘附分子）的N末端，紧密连接蛋白-3在小鼠Eph 4上皮细胞中以约为内源性紧密连接蛋白-3的50%的水平稳定表达。在融合培养条件下，单个细胞在细胞片层内移动，这与TJ的重塑有关。然而，在这种重塑过程中，GFP阳性TJ并没有失去其结构的连续性。当两个相邻细胞之间的Us在该重塑期间长度减少时，GFP-密蛋白-3经常作为颗粒结构与内源性密蛋白一起从GFP阳性TJ被夹断。共培养实验，以及电子显微镜，揭示了两个并列的膜的TJ没有脱离，但共内吞到相邻的细胞之一。有趣的是，其他TJ组分，如occludin，JAM和ZO-1似乎在这种内吞作用之前从claudins中解离。当细胞间运动上调时，促进了claudins的内吞作用。通过损伤细胞层。这些研究结果表明，这种独特的内部化的密封蛋白在TJ的重塑中起着至关重要的作用，并且这种内吞作用的精细调节对于TJ密封上皮细胞的细胞间隙是重要的，上皮细胞在细胞片层内移动对抗相邻细胞。
Tight junctions (TJs) seal the intercellular space of epithelial cells, while individual epithelial cells move against adjacent cells in cellular sheets. To observe TJs in live epithelial cellular sheets, green fluorescent protein (GFP) was fused to the N-terminus of claudin-3 (a major cell adhesion molecule of TJs), which was stably expressed at a level that was approximately 50% of that of endogenous claudin-3 in mouse Eph4 epithelial cells. Under confluent culture conditions, individual cells moved within cellular sheets, which was associated with the remodeling of TJs. However, during this remodeling, GFP-positive TJs did not lose their structural continuity. When Us between two adjacent cells decreased in length during this remodeling, GFP-claudin-3 was frequently pinched off as a granular structure from GFP-positive TJs together with endogenous claudins. Co-culture experiments, as well as electron microscopy, revealed that the two apposed membranes of TJs were not detached, but co-endocytosed into one of the adjacent cells. Interestingly, other TJ components such as occludin, JAM and ZO-1 appeared to be dissociated from claudins before this endocytosis. The endocytosis of claudins was facilitated when the intercellular motility was upregulated. by wounding the cellular sheets. These findings suggest that this peculiar internalization of claudins plays a crucial role in the remodeling of TJs, and that the fine regulation of this endocytosis is important for TJs to seal the intercellular space of epithelial cells that are moving against adjacent cells within cellular sheets.