Dynamic behavior of paired claudin strands within apposing plasma membranes
Dynamic behavior of paired claudin strands within apposing plasma membranes
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DOI：
10.1073/pnas.0630649100
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发表时间：
2003-04-01
影响因子：
11.1
通讯作者：
Tsukita, S
中科院分区：
文献类型：
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作者：
Sasaki, H;Matsui, C;Tsukita, S
紧密连接（TJ）链是跨越质膜的线性蛋白质聚合物，并且每个TJ链与相邻细胞的并置膜中的另一TJ链横向缔合以形成“成对”TJ链。紧密连接蛋白已被鉴定为TJ链的主要成分，并且当在L成纤维细胞中外源表达时，它们折叠成成对链，其在形态上类似于上皮中的成对TJ链。在这里，我们表明，GFP与claudin-1的融合蛋白也可以在L成纤维细胞中形成类似的配对链，使我们能够直接观察活细胞中真实的单个配对的claudin链。这些成对的链表现出比预期更多的动态行为;它们偶尔会断裂和退火，并以端对侧和侧对侧的方式动态地相互关联。通过单独的成对紧密连接蛋白链的这种行为，链的网络被动态地重组。此外，光漂白分析后的荧光恢复显示，claudin分子在成对链内是不移动的。虽然这些观察结果不一定代表TJ链本身在上皮细胞中，它们提供了重要的信息，TJ链在原位的结构和动力学特性的屏障功能的重大影响，我们。
The tight junction (TJ) strand is a linear proteinaceous polymer spanning plasma membranes, and each TJ strand associates laterally with another TJ strand in the apposing membranes of adjacent cells to form "paired" TJ strands. Claudins have been identified as the major constituents of TJ strands, and when exogenously expressed in L fibroblasts, they polymerize into paired strands, which are morphologically similar to paired TJ strands in epithelia. Here, we show that a fusion protein of GFP with claudin-1 can also form similar paired strands in L fibroblasts, allowing us to directly observe individual paired claudin strands in live cells in real time. These paired strands showed more dynamic behavior than expected; they were occasionally broken and annealed, and dynamically associated with each other in both an end-to-side and side-to-side manner. Through this behavior of individual paired claudin strands, the network of strands was reorganized dynamically. Furthermore, fluorescence recovery after photobleaching analyses revealed that claudin molecules were not mobile within paired strands. Although these observations are not necessarily representative of TJ strands per se in epithelial cells, they provide important information on the structural and kinetic properties of TJ strands in situ with significant implications for barrier function of Us.