Rab14 regulation of claudin-2 trafficking modulates epithelial permeability and lumen morphogenesis.
Rab14 regulation of claudin-2 trafficking modulates epithelial permeability and lumen morphogenesis.
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DOI：
10.1091/mbc.e13-12-0724
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发表时间：
2014-06
影响因子：
3.3
通讯作者：
Wilson JM
中科院分区：
文献类型：
--
作者：
Lu R;Johnson DL;Stewart L;Waite K;Elliott D;Wilson JM
上皮细胞的通透性是由紧密连接蛋白的靶向插入和再循环调节的。Rab 14调节溶酶体靶向的泄漏的claudin，claudin-2，和Rab 14的消耗导致增加的跨上皮阻力和异常的形态发生在三维培养。上皮屏障功能的调节需要有针对性地插入具有不同的选择性渗透特性的紧密连接蛋白。新合成的蛋白质的插入和内化的紧密连接组分的再循环控制极性和连接功能。在这里，我们表明，小GTTRab 14调节紧密连接结构。在Madin-Darby犬肾（MDCK）II细胞中，Rab 14与连接蛋白共定位，Rab 14的敲低导致跨上皮阻力增加。在没有Rab 14的细胞中，claudin-1和occludin的运输有很小的变化。此外，存在泄漏的紧密连接蛋白、紧密连接蛋白-2的大量消耗，但不存在其它紧密连接组分。claudin-2的损失通过抑制溶酶体功能来补充，表明Rab 14将claudin-2从溶酶体导向的途径中分离出来。MDCK I细胞内源性缺乏密蛋白-2，这些细胞中Rab 14的敲低不会导致跨上皮阻力的变化，表明该作用对密蛋白-2运输是特异性的。此外，渗漏的claudins已被证明是上皮形态发生所需的，Rab 14的敲低导致在三维培养中无法形成正常的单腔囊肿。这些结果表明Rab 14参与了来自再循环内体的claudin-2的专门运输。
Epithelial permeability is regulated by targeted insertion and recycling of tight junction proteins. Rab14 regulates the lysosomal targeting of the leaky claudin, claudin-2, and depletion of Rab14 results in increased transepithelial resistance and aberrant morphogenesis in three-dimensional culture. Regulation of epithelial barrier function requires targeted insertion of tight junction proteins that have distinct selectively permeable characteristics. The insertion of newly synthesized proteins and recycling of internalized tight junction components control both polarity and junction function. Here we show that the small GTPase Rab14 regulates tight junction structure. In Madin–Darby canine kidney (MDCK) II cells, Rab14 colocalizes with junctional proteins, and knockdown of Rab14 results in increased transepithelial resistance. In cells without Rab14, there are small changes in the trafficking of claudin-1 and occludin. In addition, there is substantial depletion of the leaky claudin, claudin-2, but not other tight junction components. The loss of claudin-2 is complemented by inhibition of lysosomal function, suggesting that Rab14 sorts claudin-2 out of the lysosome-directed pathway. MDCK I cells lack claudin-2 endogenously, and knockdown of Rab14 in these cells does not result in a change in transepithelial resistance, suggesting that the effect is specific to claudin-2 trafficking. Furthermore, leaky claudins have been shown to be required for epithelial morphogenesis, and knockdown of Rab14 results in failure to form normal single-lumen cysts in three-dimensional culture. These results implicate Rab14 in specialized trafficking of claudin-2 from the recycling endosome.