Freeman M L, Sierra-Rivera E, Voorhees G J, Eisert D R, Meredith M J
Vanderbilt Center for Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Radiat Res. 1993 Sep;135(3):387-93. doi: 10.2307/3578879.
The question of whether depletion of glutathione (GSH) could affect the synthesis of stress proteins was investigated in Hep G2 cells. Cells were exposed to BSO/DEM at 37 degrees C to deplete glutathione. When 95% of the glutathione was depleted cells were washed, and BSO was added to cells previously exposed to BSO/DEM; then the cells were incubated at 37, 38.5, or 39 degrees C for 4 h. Two-dimensional PAGE analysis of GSH-depleted cells incubated at 37 degrees C indicated increased synthesis of heme oxygenase and a polypeptide tentatively identified as hsp-70B'. Depletion of GSH did not affect the cellular concentration of hsp-70 as assessed by Western immunoblotting, yet Northern blot analysis indicated that hsp-70 mRNA was increased in GSH-depleted cells. Incubation of GSH-replete cells at 38.5 degrees C did not appear to enhance the amount of hsp-70 mRNA or the relative rate of hsp-70 synthesis. In contrast, incubation of GSH-depleted cells at 38.5 degrees C elevated steady-state hsp-70 mRNA levels and the rate of hsp-70 synthesis relative to total protein synthesis. Depletion of GSH also increased the relative rate of hsp-70 synthesis at 39 degrees C. These results suggest that the synthesis of stress proteins can be affected by glutathione concentrations.
在Hep G2细胞中研究了谷胱甘肽（GSH）耗竭是否会影响应激蛋白的合成。将细胞在37℃下暴露于丁硫氨酸亚砜胺/二乙胺（BSO/DEM）以耗竭谷胱甘肽。当95%的谷胱甘肽被耗尽时，细胞被洗涤，并且将BSO添加到先前暴露于BSO/DEM的细胞中；然后将细胞在37、38.5或39℃下孵育4小时。对在37℃下孵育的GSH耗竭细胞进行二维聚丙烯酰胺凝胶电泳（PAGE）分析表明，血红素加氧酶和一种暂定为热休克蛋白70B'（hsp-70B'）的多肽的合成增加。通过蛋白质免疫印迹法评估，GSH耗竭并未影响热休克蛋白70（hsp-70）的细胞浓度，但Northern印迹分析表明，在GSH耗竭的细胞中hsp-70信使核糖核酸（mRNA）增加。在38.5℃下孵育GSH充足的细胞似乎并未增加hsp-70 mRNA的量或hsp-70的相对合成速率。相比之下，在38.5℃下孵育GSH耗竭的细胞可提高hsp-70 mRNA的稳态水平以及相对于总蛋白质合成的hsp-70合成速率。GSH耗竭在39℃下也增加了hsp-70的相对合成速率。这些结果表明，应激蛋白的合成可受谷胱甘肽浓度的影响。
