Lee Y J, Kim D, Hou Z Z, Corry P M
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan 48073.
J Cell Physiol. 1991 Nov;149(2):202-7. doi: 10.1002/jcp.1041490205.
We investigated whether or not a 50 kDa glycoprotein might play an important role in protein synthesis-independent thermotolerance development in CHO cells. When cells were heated for 10 min at 45.5 degrees C, they became thermotolerant to a heat treatment at 45.5 degrees C administered 12 hr later. The thermotolerance ratio at 10(-3) isosurvival was 4.4. The cellular heat shock response leads to enhanced glycosylation of a 50 kDa protein. The glycosylation of proteins including a 50 kDa glycoprotein was inhibited by treatment with various concentrations of tunicamycin (0.2-2 micrograms/ml). The development of thermotolerance was not affected by treatment with tunicamycin after the initial heat treatment, although 2 micrograms/ml tunicamycin inhibited glycosylation by 95%. However, inhibiting protein synthesis with cycloheximide (10 micrograms/ml) after the initial heat treatment partially inhibited the development of thermotolerance. Nevertheless, there was no further reduction of thermotolerance development by treatment with a combination of 2 micrograms/ml tunicamycin and 10 micrograms/ml cycloheximide. These data suggest that development of thermotolerance, especially protein synthesis-independent thermotolerance, is not correlated with increased glycosylation of the 50 kDa protein.
我们研究了一种50 kDa糖蛋白是否可能在CHO细胞中不依赖蛋白质合成的耐热性发展过程中发挥重要作用。当细胞在45.5℃加热10分钟后，它们对12小时后施加的45.5℃热处理产生了耐热性。10^(-3)等存活度下的耐热比为4.4。细胞热休克反应导致一种50 kDa蛋白质的糖基化增强。用不同浓度的衣霉素（0.2 - 2微克/毫升）处理可抑制包括50 kDa糖蛋白在内的蛋白质的糖基化。初始热处理后用衣霉素处理对耐热性的发展没有影响，尽管2微克/毫升衣霉素可抑制95%的糖基化。然而，初始热处理后用环己酰亚胺（10微克/毫升）抑制蛋白质合成会部分抑制耐热性的发展。尽管如此，用2微克/毫升衣霉素和10微克/毫升环己酰亚胺联合处理并没有进一步降低耐热性的发展。这些数据表明，耐热性的发展，尤其是不依赖蛋白质合成的耐热性，与50 kDa蛋白质糖基化的增加无关。
