Intermediate filaments and the initiation of desmosome assembly.
Intermediate filaments and the initiation of desmosome assembly.
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DOI：
10.1083/jcb.101.2.506
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发表时间：
1985-08
期刊：
影响因子：
--
通讯作者：
Goldman RD
中科院分区：
文献类型：
--
作者：
Jones JC;Goldman RD
桥粒连接是上皮细胞，特别是表皮角质形成细胞粘附的重要组成部分。为了深入了解桥粒的结构和功能，在原代小鼠表皮（PME）细胞培养系统中研究了桥粒的形态发生。当这些细胞在约0.1 mM Ca 2+中生长时，它们不含桥粒。当培养基中的Ca 2+水平升高至约1.2 mM Ca 2+时，它们被诱导形成桥粒。PME细胞在培养基中含有低水平的Ca 2+，然后处理的间接免疫荧光抗体直接针对桥粒斑蛋白（桥粒斑蛋白），显示离散的荧光斑点主要集中在核周区域的模式。使用角蛋白和桥粒斑蛋白抗体的双标记免疫荧光显示，含有桥粒斑蛋白的斑点和张力原纤维的细胞质网络（中间丝束[IFB]）位于同一个核区。在切换到更高水平的Ca 2+后1小时内，斑点向细胞表面移动，主要是细胞-细胞接触区域，而不是游离细胞表面。这种重组发生在张力原纤维也向与相邻细胞接触的细胞表面移动的同时。一旦桥粒斑蛋白点到达细胞表面，它们似乎聚集形成桥粒。这些免疫荧光观察结果已被证实的免疫金超微结构定位。初步的生物化学和免疫学研究表明，桥粒斑蛋白出现在全细胞蛋白提取物和Triton高盐不溶性残留物中（即，主要由IFB组成的细胞骨架制剂），其由维持在含有低和正常Ca 2+水平的培养基中的PME细胞制备。这些结果表明，某些桥粒成分是预先在PME细胞的细胞质中。这些组件经历了一个戏剧性的重组，这平行的IFB再分配的变化，诱导桥粒形成。重组取决于细胞外Ca 2+水平和细胞与细胞接触的建立。此外，数据表明，桥粒不作为IFB的制定组织中心。事实上，我们假设IFB和预制桥粒组件的细胞表面的运动是一个重要的启动事件桥粒形态发生。
The desmosome junction is an important component in the cohesion of epithelial cells, especially epidermal keratinocytes. To gain insight into the structure and function of desmosomes, their morphogenesis has been studied in a primary mouse epidermal (PME) cell culture system. When these cells are grown in approximately 0.1 mM Ca2+, they contain no desmosomes. They are induced to form desmosomes when the Ca2+ level in the culture medium is raised to approximately 1.2 mM Ca2+. PME cells in medium containing low levels of Ca2+, and then processed for indirect immunofluorescence using antibodies directed against desmoplakins (desmosomal plaque proteins), display a pattern of discrete fluorescent spots concentrated mainly in the perinuclear region. Double label immunofluorescence using keratin and desmoplakin antibodies reveals that the desmoplakin-containing spots and the cytoplasmic network of tonofibrils (bundles of intermediate filaments [IFB]) are in the same juxtanuclear region. Within 1 h after the switch to higher levels of Ca2+, the spots move toward the cell surface, primarily to areas of cell-cell contact and not to free cell surfaces. This reorganization occurs at the same time that tonofibrils also move toward cell surfaces in contact with neighboring cells. Once the desmoplakin spots have reached the cell surface, they appear to aggregate to form desmosomes. These immunofluorescence observations have been confirmed by immunogold ultrastructural localization. Preliminary biochemical and immunological studies indicate that desmoplakin appears in whole cell protein extracts and in Triton high salt insoluble residues (i.e., cytoskeletal preparations consisting primarily of IFB) prepared from PME cells maintained in medium containing both low and normal Ca2+ levels. These findings show that certain desmosome components are preformed in the cytoplasm of PME cells. These components undergo a dramatic reorganization, which parallels the changes in IFB redistribution, upon induction of desmosome formation. The reorganization depends upon both the extracellular Ca2+ level and the establishment of cell-to-cell contacts. Furthermore, the data suggests that desmosomes do not act as organizing centers for the elaboration of IFB. Indeed, we postulate that the movement of IFB and preformed desmosomal components to the cell surface is an important initiating event in desmosome morphogenesis.