Clive D R, Greene J J
Department of Biology and The Institue for Biomolecular Studies, The Catholic University of America, Washington, D.C. 20064, USA.
Cell Biochem Funct. 1996 Mar;14(1):49-55. doi: 10.1002/cbf.638.
Most transcription factors are multimeric complexes whose subunits depend on strict conformation requirements to form the active unit. Among these requirements is the presence of appropriate sulfhydryl interactions that are critical to transcription factor binding to cognate DNA recognition sites. Our experiments now suggest that modulation of these sulfhydryls may involve the action of thiol-modifying oxido-reductases such as protein disulfide isomerase (PDI). Electrophoretic mobility shift titration experiments incorporating different ratios of GSH:GSSG indicated that changes in GSH and GSSG concentrations corresponding to redox potential differences of as little as +/- 15 mV enabled or abolished binding of NF-kappaB and AP1 to their cognate DNA sites. Moreover, this binding range was modulated significantly by the addition of purified protein disulfide isomerase (PDI). Collectively, these results suggest that a reversible oxidation/reduction signalling pathway may exist in the cell whereby localized changes in redox potentials and/or oxido-reductase activity can be functionally relevant in the regulation of critical gene expression events.
大多数转录因子是多聚体复合物，其亚基依赖于严格的构象要求来形成活性单元。这些要求中包括存在适当的巯基相互作用，这对于转录因子与同源DNA识别位点的结合至关重要。我们现在的实验表明，这些巯基的调节可能涉及硫醇修饰的氧化还原酶如蛋白质二硫键异构酶（PDI）的作用。包含不同比例GSH:GSSG的电泳迁移率变动滴定实验表明，对应于低至+/- 15 mV氧化还原电位差异的GSH和GSSG浓度变化能够使或消除NF-κB和AP1与其同源DNA位点的结合。此外，通过添加纯化的蛋白质二硫键异构酶（PDI）可显著调节该结合范围。总体而言，这些结果表明细胞中可能存在可逆的氧化/还原信号通路，由此氧化还原电位和/或氧化还原酶活性的局部变化在关键基因表达事件的调节中可能具有功能相关性。
