Amagai M, Fujimori T, Masunaga T, Shimizu H, Nishikawa T, Shimizu N, Takeichi M, Hashimoto T
Department of Dermatology, Keio University School of Medicine, Japan.
J Invest Dermatol. 1995 Jan;104(1):27-32. doi: 10.1111/1523-1747.ep12613462.
We examined whether classic cadherins play a role in the formation of desmosomes using a mouse keratinocyte, PAMcN390 delta cell, which shows disrupted classic-cadherin-mediated cell adhesion by introduction of a dominant-negative mutant of N-cadherin. The expression of the mutant did not alter that of endogenous E-cadherin or desmoplakin. In control cells with functional classic cadherins, we observed redistribution of desmoplakin to cell-cell borders with insertions of keratin filaments at the contact sites as soon as 2 h after calcium elevation, after an earlier event of E-cadherin translocation to the cell-cell contact sites. In contrast, in the PAMcN390 delta cells, which showed retarded translocation of E-cadherin, the redistribution of desmoplakin and the rearrangement of keratin filaments were delayed as late as 24 h after the calcium elevation. The acquisition of Nonidet P-40 insolubility of desmoplakins also was found to be delayed in the PAMcN390 delta cells. These findings indicate that the disruption of classic cadherin affected the organization of desmosomes upon calcium elevation and suggest that the proper function of classic cadherins is a prerequisite for desmosome assembly in keratinocytes.
我们使用小鼠角质形成细胞PAMcN390δ细胞，研究了经典钙黏着蛋白是否在桥粒形成中发挥作用。通过导入N-钙黏着蛋白的显性负性突变体，该细胞显示经典钙黏着蛋白介导的细胞黏附受到破坏。突变体的表达并未改变内源性E-钙黏着蛋白或桥粒斑蛋白的表达。在具有功能性经典钙黏着蛋白的对照细胞中，我们观察到，在钙浓度升高后2小时，随着E-钙黏着蛋白向细胞间接触位点的早期转位，桥粒斑蛋白重新分布到细胞间边界，在接触位点有角蛋白丝插入。相比之下，在E-钙黏着蛋白转位延迟的PAMcN390δ细胞中，钙浓度升高后24小时，桥粒斑蛋白的重新分布和角蛋白丝的重排仍被延迟。在PAMcN390δ细胞中，还发现桥粒斑蛋白获得不溶于非离子型去污剂NP-40的特性也被延迟。这些发现表明，经典钙黏着蛋白的破坏影响了钙浓度升高时桥粒的组织，并提示经典钙黏着蛋白的正常功能是角质形成细胞中桥粒组装的先决条件。
