Leffers H, Nielsen M S, Andersen A H, Honoré B, Madsen P, Vandekerckhove J, Celis J E
Institute of Medical Biochemistry, Aarhus University, Denmark.
Exp Cell Res. 1993 Dec;209(2):165-74. doi: 10.1006/excr.1993.1298.
Proteins (IEF's 1120, 8118, 8120) sharing similarity to the bovine Rho GDP dissociation inhibitor (GDI) have been identified in the human two-dimensional-gel database of keratinocyte proteins. Molecular cloning of the corresponding cDNAs showed that IEF 8118 is the human homolog of bovine GDI while IEF 8120 is a distinct although related protein. All available information indicates the IEF 1120 is a derivative of IEF 8120. The cDNAs coding for IEF's 8118 and 8120 were recombined into vaccinia virus and expressed in differentiated human keratinocytes and their effect on the actin cytoskeleton was assessed by immunofluorescence using TRITC-phalloidin. The results showed that overexpression of both GDI proteins leads to rounding up of the cells and loss of stress fibers and focal contact sites. In addition, the cell to cell adhesion belts gradually disappeared, an effect that was particularly pronounced in infected cells overexpressing IEF 8120. Taken together, the results imply that Rho GDI's play a role in modulating the activity of the Rho proteins as their overexpression mimics phenotypic changes associated with the inactivation of these proteins.
在人类角质形成细胞蛋白质二维凝胶数据库中，已鉴定出与牛Rho GDP解离抑制剂（GDI）具有相似性的蛋白质（IEF's 1120、8118、8120）。相应cDNA的分子克隆表明，IEF 8118是牛GDI的人类同源物，而IEF 8120是一种虽相关但不同的蛋白质。所有现有信息表明IEF 1120是IEF 8120的衍生物。将编码IEF's 8118和8120的cDNA重组到痘苗病毒中，并在分化的人类角质形成细胞中表达，使用TRITC - 鬼笔环肽通过免疫荧光评估它们对肌动蛋白细胞骨架的影响。结果表明，两种GDI蛋白的过表达都会导致细胞变圆、应力纤维和粘着斑位点丧失。此外，细胞间粘附带逐渐消失，这种效应在过表达IEF 8120的感染细胞中尤为明显。综上所述，结果表明Rho GDI在调节Rho蛋白的活性中发挥作用，因为它们的过表达模拟了与这些蛋白失活相关的表型变化。
