Panniers R, Henshaw E C
Eur J Biochem. 1984 Apr 2;140(1):209-14. doi: 10.1111/j.1432-1033.1984.tb08088.x.
The rate of polypeptide synthesis is inhibited by 80% in Ehrlich cells incubated at 43 degrees C compared to those at 37 degrees C. The regulatory site of translation resides at polypeptide chain initiation. Polypeptide synthesis does not recover at the higher temperature; however, the inhibition is reversed by returning the cells to 37 degrees C. Neither new RNA synthesis or protein synthesis is required for recovery at 37 degrees C, eliminating degradation of mRNA and irreversible denaturation of a protein essential for polypeptide chain initiation. The concentration of 40-S initiation complexes was found to be reduced markedly in heat-shocked cells compared to controls. This was confirmed in the cell-free protein-synthesizing systems prepared from heat-shocked and control cells. Reversible alteration in the activity of components affecting eIF2 function is, therefore, a likely mechanism of regulation in heat-shocked Ehrlich cells. In extracts from heat-shocked cells, Met-tRNA synthetase activity was unaltered compared to control extracts.
与在37℃培养的艾氏腹水癌细胞相比，在43℃培养的艾氏腹水癌细胞中多肽合成速率被抑制了80%。翻译的调控位点位于多肽链起始阶段。在较高温度下多肽合成无法恢复；然而，将细胞恢复到37℃可逆转这种抑制作用。在37℃恢复时既不需要新的RNA合成也不需要蛋白质合成，这排除了mRNA降解以及对多肽链起始至关重要的一种蛋白质的不可逆变性。与对照相比，发现在热休克细胞中40-S起始复合物的浓度显著降低。这在由热休克细胞和对照细胞制备的无细胞蛋白质合成系统中得到了证实。因此，影响eIF2功能的组分活性的可逆改变很可能是热休克艾氏腹水癌细胞中的一种调控机制。在热休克细胞的提取物中，与对照提取物相比，甲硫氨酰-tRNA合成酶活性未改变。
