Requirement of the F-actin-binding activity of l-afadin for enhancing the formation of adherens and tight junctions
Requirement of the F-actin-binding activity of l-afadin for enhancing the formation of adherens and tight junctions
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DOI：
10.1111/gtc.12566
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发表时间：
2018-03-01
期刊：
影响因子：
2.1
通讯作者：
Takai, Yoshimi
中科院分区：
文献类型：
--
作者：
Sakakibara, Shotaro;Maruo, Tomohiko;Takai, Yoshimi
顶端连接复合体由极化上皮细胞中的粘附连接（AJs）和紧密连接（TJs）组成，它们彼此连接以形成片层。肌动蛋白丝（F-肌动蛋白）与AJs和TJs相关，并需要形成和维持这种复合物。l-Afadin是一种F-肌动蛋白结合蛋白，其通过与细胞粘附分子nectin结合而定位于AJs，并调节AJs和TJ的形成。然而，L-阿法丁的F-肌动蛋白结合活性对顶端连接复合物形成的作用仍然未知。我们在此产生了培养的EpH 4小鼠乳腺上皮细胞，其中afadin被遗传消融。在Ca 2+开关试验中，阿法丁缺陷细胞中AJs和TJ的形成均显著受损。在afadin缺陷细胞中l-afadin的再表达完全恢复了AJs和TJ的形成，但是缺乏FAB结构域的l-afadin突变体的再表达没有完全恢复AJs或TJ的形成。这些结果表明，l-阿法丁的F-肌动蛋白结合活性是增强AJs和TJ形成所需的。
The apical junctional complex consists of adherens junctions (AJs) and tight junctions (TJs) in polarized epithelial cells, which are attached to each other to form a sheet. Actin filaments (F-actin) are associated with AJs and TJs and required for the formation and maintenance of this complex. l-Afadin is an F-actin-binding protein, which is localized at AJs through binding to the cell adhesion molecule nectin, and regulates the formation of AJs and TJs. However, the role of the F-actin-binding activity of l-afadin for the formation of the apical junctional complex remains unknown. We generated here the cultured EpH4 mouse mammary epithelial cells in which afadin was genetically ablated. In the Ca2+ switch assay, the formation of both AJs and TJs was markedly impaired in the afadin-deficient cells. Re-expression of l-afadin in the afadin-deficient cells fully restored the formation of both AJs and TJs, but the re-expression of the l-afadin mutant lacking the FAB domain did not completely restore the formation of AJs or TJs. These results indicate that the F-actin-binding activity of l-afadin is required for enhancing the formation of both AJs and TJs.