Calreticulin represses E-cadherin gene expression in Madin-Darby canine kidney cells via slug
Calreticulin represses E-cadherin gene expression in Madin-Darby canine kidney cells via slug
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DOI：
10.1074/jbc.m607240200
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发表时间：
2006-10-27
影响因子：
4.8
通讯作者：
Ihara, Yoshito
中科院分区：
文献类型：
--
作者：
Hayashida, Yasushi;Urata, Yoshishige;Ihara, Yoshito
钙网蛋白 (CRT) 是内质网中的多功能 Ca2+ 结合分子伴侣。在哺乳动物中，CRT 的表达水平在各种器官和组织中显着不同，这表明 CRT 在每种细胞类型中发挥着特定的作用。在本研究中，我们关注CRT在肾脏中的功能，其中CRT的总体表达量相当低，并通过基因转染建立了过表达CRT的肾上皮细胞来源的Madin-Darby犬肾细胞。我们证明，在CRT过表达的细胞中，形态发生明显改变，原有的极化上皮细胞表型被破坏。此外，与对照相比，CRT 过表达细胞通过 Matrigel (R) 包被的 Boyden 小室孔的迁移能力增强。与对照相比，CRT 过表达细胞中 E-钙粘蛋白的表达在蛋白质和转录水平上显着受到抑制。另一方面，间充质蛋白标志物，如N-钙粘蛋白和纤连蛋白的表达上调。我们还发现，CRT 的过表达通过改变 Ca2+ 稳态来上调 E-钙粘蛋白启动子的抑制子 Slug 的表达，这导致 Slug 与 E-钙粘蛋白启动子中的 E-box 元件的结合增强。因此，我们得出结论，CRT 通过改变细胞内的 Ca2+ 稳态来调节 Slug/E-cadherin 通路，从而调节细胞表型的上皮-间质转化样变化，这表明 CRT 在上皮细胞的细胞间相互作用中具有新的功能。
Calreticulin (CRT) is a multifunctional Ca2+-binding molecular chaperone in the endoplasmic reticulum. In mammals, the expression level of CRT differs markedly in a variety of organs and tissues, suggesting that CRT plays a specific role in each cell type. In the present study, we focused on CRT functions in the kidney, where overall expression of CRT is quite low, and established CRT-overexpressing kidney epithelial cell-derived Madin-Darby canine kidney cells by gene transfection. We demonstrated that, in CRT-overexpressing cells, the morphology was apparently changed, and the original polarized epithelial cell phenotype was destroyed. Furthermore, CRT-overexpressing cells showed enhanced migration through Matrigel (R)-coated Boyden chamber wells, compared with controls. E-cadherin expression was significantly suppressed at the protein and transcriptional levels in CRT-overexpressing cells compared with controls. On the other hand, the expression of mesenchymal protein markers, such as N-cadherin and fibronectin, was up-regulated. We also found that the expression of Slug, a repressor of the E-cadherin promoter, was up-regulated by overexpression of CRT through altered Ca2+ homeostasis, and this led to enhanced binding of Slug to the E-box element in the E-cadherin promoter. Thus, we conclude that CRT regulates the epithelial-mesenchymal transition-like change of cellular phenotype by modulating the Slug/E-cadherin pathway through altered Ca2+ homeostasis in cells, suggesting a novel function of CRT in cell-cell interaction of epithelial cells.