On the self-association potential of transmembrane tight junction proteins
On the self-association potential of transmembrane tight junction proteins
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DOI：
10.1007/s00018-005-5472-x
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发表时间：
2006-02-01
影响因子：
8
通讯作者：
Piontek, J
中科院分区：
文献类型：
--
作者：
Blasig, IE;Winkler, L;Piontek, J
紧密连接通过膜相关链密封细胞间的裂缝，因此，维持重要的器官功能。我们研究了形成链的跨膜紧密连接蛋白的自缔合。调节紧密连接蛋白occludin不同的标签和共转染真核细胞。这些occludins共定位在同一细胞的质膜内，共沉淀，并表现出荧光共振能量转移。标记的链形成紧密连接蛋白-5也共定位在同一细胞的质膜中，并显示荧光共振能量转移。这证明了在完整细胞中闭合蛋白和紧密连接蛋白-5在一个质膜中的自缔合。为了寻找闭合蛋白的二聚化区域，鉴定了其胞质C末端卷曲螺旋结构域的二聚化。在claudin-5中，第二个细胞外环被检测为二聚体。由于跨膜连接粘附分子也被称为二聚化，跨膜紧密连接蛋白的同源二聚化可能作为一个共同的结构特征，在紧密连接组装的假设得到支持。
Tight junctions seal intercellular clefts via membrane-related strands, hence, maintaining important organ functions. We investigated the self-association of strand-forming transmembrane tight junction proteins. The regulatory tight junction protein occludin was differently tagged and cotransfected in eucaryotic cells. These occludins colocalized within the plasma membrane of the same cell, coprecipitated and exhibited fluorescence resonance energy transfer. Differently tagged strand-forming claudin-5 also colocalized in the plasma membrane of the same cell and showed fluorescence resonance energy transfer. This demonstrates self-association in intact cells both of occludin and claudin-5 in one plasma membrane. In search of dimerizing regions of occludin, dimerization of its cytosolic C-terminal coiled-coil domain was identified. In claudin-5, the second extracellular loop was detected as a dimer. Since the transmembrane junctional adhesion molecule also is known to dimerize, the assumption that homodimerization of transmembrane tight junction proteins may serve as a common structural feature in tight junction assembly is supported.