A single gene product, claudin-1 or -2, reconstitutes tight junction strands and recruits occludin in fibroblasts.
A single gene product, claudin-1 or -2, reconstitutes tight junction strands and recruits occludin in fibroblasts.
复制标题
单个基因产物Claudin -1或-2，在成纤维细胞中重构紧密结合的连接链和新兵。
DOI：
10.1083/jcb.143.2.391
复制
发表时间：
1998-10-19
影响因子：
7.8
通讯作者：
Tsukita, S
中科院分区：
文献类型：
--
作者：
Furuse, M;Sasaki, H;Fujimoto, K;Tsukita, S
三种完整的膜蛋白Clau-din-1、-2和occludin被认为是紧密连接(TJ)链的组成部分。为了检测它们形成TJ链的能力，将它们的cDNA导入缺乏TJ的小鼠L成纤维细胞中。免疫荧光显微镜显示，标记了claudin-1和-2的两个标记分子都高度集中在细胞接触部位，通过亲和性相互作用形成平面。在这些接触部位的冷冻断裂复制品中，发现了与原位TJ链网络相似的发达的链网络，并用抗FLAG单抗进行了特异性标记。在戊二醛固定的样品中，Claudin-1诱导的链与原生质(P)面的大部分是连续的结构，而Claudin-2诱导的链在P面处不连续，在细胞外(E)面上有互补的凹槽，被颗粒链占据。尽管occludin通过其亲和性相互作用也以斑点的形式集中在细胞接触部位，但冷冻断裂复制品只鉴定出少量标记有抗occludin mAb的短链。然而，当occludin与claudin-1共转染时，它以平面的形式集中在细胞接触部位，并被整合到基于claudin-1的发育良好的链中。这些结果表明，Claudin-1和-2是TJ链形成的主要原因，而occludin是TJ链某些功能的辅助蛋白。
Three integral membrane proteins, clau- din-1, -2, and occludin, are known to be components of tight junction (TJ) strands. To examine their ability to form TJ strands, their cDNAs were introduced into mouse L fibroblasts lacking TJs. Immunofluorescence microscopy revealed that both FLAG-tagged claudin-1 and -2 were highly concentrated at cell contact sites as planes through a homophilic interaction. In freeze-fracture replicas of these contact sites, well-developed networks of strands were identified that were similar to TJ strand networks in situ and were specifically labeled with anti-FLAG mAb. In glutaraldehyde-fixed samples, claudin-1–induced strands were largely associated with the protoplasmic (P) face as mostly continuous structures, whereas claudin-2–induced strands were discontinuous at the P face with complementary grooves at the extracellular (E) face which were occupied by chains of particles. Although occludin was also concentrated at cell contact sites as dots through its homophilic interaction, freeze-fracture replicas identified only a small number of short strands that were labeled with anti-occludin mAb. However, when occludin was cotransfected with claudin-1, it was concentrated at cell contact sites as planes to be incorporated into well- developed claudin-1–based strands. These findings suggested that claudin-1 and -2 are mainly responsible for TJ strand formation, and that occludin is an accessory protein in some function of TJ strands.