Rokutan K, Miyoshi M, Teshima S, Kawai T, Kawahara T, Kishi K
Department of Nutrition, School of Medicine, The University of Tokushima, Tokushima 770-8503, Japan.
Am J Physiol Cell Physiol. 2000 Nov;279(5):C1506-15. doi: 10.1152/ajpcell.2000.279.5.C1506.
Phenylarsine oxide (PAO) forms a stable ring complex with vicinal dithiols that can be reversed with 2,3-dimercaptopropanol (DMP) but not by dithiothreitol (DTT) or 2-mercaptoethanol (2-ME). PAO at 2 microM or higher inhibited heat shock protein 70 (HSP70) induction within minutes in cultured guinea pig gastric mucosal cells exposed to heat (43 degrees C) for 30 min. PAO did not affect the nuclear translocation and phosphorylation of heat shock factor 1 (HSF1) induced by heat stress, but it completely blocked the binding activity of HSF1 to the heat shock element (HSE), leading to the block of expression of HSP70 mRNA and accumulation of HSP70 in the cells. These inhibitions were completely reversed with 2 microM DMP but not with 0.1 mM DTT or 1 mM 2-ME, suggesting specific interactions between PAO and vicinal dithiol-containing molecules. Thioredoxin (Trx) reversed the inhibition of the binding activity of HSF1 in whole cell extracts prepared from PAO-treated, heat-stressed cells. Our results suggest that PAO may react with vicinal-containing molecules including Trx and specifically block the interaction between HSF1 and HSE.
苯胂化氧（PAO）与邻二硫醇形成稳定的环状复合物，该复合物可用2,3-二巯基丙醇（DMP）逆转，但不能被二硫苏糖醇（DTT）或2-巯基乙醇（2-ME）逆转。在培养的豚鼠胃黏膜细胞中，2微摩尔或更高浓度的PAO在细胞暴露于热（43℃）30分钟后的几分钟内抑制热休克蛋白70（HSP70）的诱导。PAO不影响热应激诱导的热休克因子1（HSF1）的核转位和磷酸化，但它完全阻断了HSF1与热休克元件（HSE）的结合活性，导致细胞中HSP70 mRNA表达受阻和HSP70积累。这些抑制作用用2微摩尔DMP可完全逆转，但用0.1毫摩尔DTT或1毫摩尔2-ME则不能逆转，这表明PAO与含邻二硫醇的分子之间存在特异性相互作用。硫氧还蛋白（Trx）可逆转在经PAO处理、热应激的细胞制备的全细胞提取物中HSF1结合活性的抑制。我们的结果表明，PAO可能与包括Trx在内的含邻二硫醇的分子发生反应，并特异性地阻断HSF1与HSE之间的相互作用。
