A small rab GTPase is distributed in cytoplasmic vesicles in non polarized cells but colocalizes with the tight junction marker ZO-1 in polarized epithelial cells.
A small rab GTPase is distributed in cytoplasmic vesicles in non polarized cells but colocalizes with the tight junction marker ZO-1 in polarized epithelial cells.
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DOI：
10.1083/jcb.124.1.101
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发表时间：
1994-01
期刊：
影响因子：
--
通讯作者：
Louvard D
中科院分区：
文献类型：
--
作者：
Zahraoui A;Joberty G;Arpin M;Fontaine JJ;Hellio R;Tavitian A;Louvard D
小分子rab/Ypt 1/Sec 4 GTdR家族参与真核细胞生物合成和内吞途径中的膜运输沿着调控。极化上皮细胞具有形态和功能上不同的顶侧和基底侧表面，由紧密连接分开。这些结构的建立和维持需要将膜蛋白和脂质递送到这些结构域。在这项工作中，我们已经从人肠道cDNA文库中分离出一个cDNA克隆，编码一个小的GT3，rab 13，密切相关的酵母Sec 4蛋白。对极化Caco-2细胞的共聚焦显微镜分析显示rab 13蛋白与紧密连接标记ZO- 1共定位。组织的冷冻切片证实rab 13定位于各种上皮细胞的连接复合物区域，包括肠、肾、肝和内皮细胞。这种定位需要紧密连接的组装和完整性。通过在低Ca 2+介质中孵育破坏紧密连接诱导rab 13的重新分布。在缺乏紧密连接的细胞中，发现rab 13与分散在整个细胞质中的囊泡相关。在转染的L细胞中由E-钙粘蛋白启动的细胞-细胞接触不将rab 13募集到所得的粘附蛋白样连接复合物。Rab 13参与极化运输，在装配和/或紧密连接的活动进行了讨论。
Small rab/Ypt1/Sec4 GTPase family have been involved in the regulation of membrane traffic along the biosynthetic and endocytic pathways in eucaryotic cells. Polarized epithelial cells have morphologically and functionally distinct apical and basolateral surfaces separated by tight junctions. The establishment and maintenance of these structures require delivery of membrane proteins and lipids to these domains. In this work, we have isolated a cDNA clone from a human intestinal cDNA library encoding a small GTPase, rab13, closely related to the yeast Sec4 protein. Confocal microscopy analysis on polarized Caco-2 cells shows that rab13 protein colocalized with the tight junction marker ZO- 1. Cryostat sections of tissues confirm that rab13 localized to the junctional complex region of a variety of epithelia, including intestine, kidney, liver, and of endothelial cells. This localization requires assembly and integrity of the tight junctions. Disruption of tight junctions by incubation in low Ca2+ media induces the redistribution of rab13. In cells devoid of tight junctions, rab13 was found associated with vesicles dispersed throughout the cytoplasm. Cell- cell contacts initiated by E-cadherin in transfected L cells do not recruit rab13 to the resulting adherens-like junction complexes. The participation of rab13 in polarized transport, in the assembly and/or the activity of tight junctions is discussed.