Troyanovsky S M, Eshkind L G, Troyanovsky R B, Leube R E, Franke W W
Division for Cell Biology, German Cancer Research Center, Heidelberg.
Cell. 1993 Feb 26;72(4):561-74. doi: 10.1016/0092-8674(93)90075-2.
To examine the potential of cytoplasmic portions ("tails") of desmosomal cadherins for assembly of desmosome plaque structures and anchorage of intermediate filaments (IFs), we transfected cultured human A-431 carcinoma cells, abundant in desmosomes and cytokeratin IFs, with constructs encoding chimeric proteins in which the transmembranous region of connexin 32 had been fused with tails of desmocollin (Dsc) or desmoglein (Dsg). The results show that the tail of the long splice form a of Dsc, but not its shorter splice form b, contains sufficient information to recruit desmoplakin and plakoglobin to connexon membrane paracrystals (gap junctions) and to form a novel kind of plaque at which cytokeratin IFs attach. By contrast, chimeras containing a Dsg tail, which accumulated in the plasma membrane, showed a dominant-negative effect: they not only were unable to form gap junction structures and plaques but also led to the disappearance of all endogenous desmosomes and the detachment of IFs from the plasma membrane.
为了研究桥粒钙黏蛋白的细胞质部分（“尾部”）组装桥粒斑结构以及锚定中间丝（IFs）的潜力，我们用编码嵌合蛋白的构建体转染了富含桥粒和细胞角蛋白IFs的培养人A - 431癌细胞，这些嵌合蛋白中连接蛋白32的跨膜区域与桥粒芯蛋白（Dsc）或桥粒芯糖蛋白（Dsg）的尾部融合。结果表明，Dsc长剪接形式a的尾部而非较短的剪接形式b的尾部，包含足够的信息来将桥粒斑蛋白和桥粒斑珠蛋白募集到连接子膜副晶体（间隙连接）并形成一种新型的斑，细胞角蛋白IFs附着于此斑上。相比之下，含有Dsg尾部且积聚在质膜中的嵌合体表现出显性负效应：它们不仅无法形成间隙连接结构和斑，还导致所有内源性桥粒消失以及IFs从质膜上脱离。
