Vries R G, Flynn A, Patel J C, Wang X, Denton R M, Proud C G
Department of Biosciences, University of Kent at Canterbury, Canterbury, CT2 7NJ, United Kingdom.
J Biol Chem. 1997 Dec 26;272(52):32779-84. doi: 10.1074/jbc.272.52.32779.
The effects of heat shock on the regulation of the cap-binding initiation factor 4E (eIF4E) and its inhibitory binding protein, 4E-BP1, have been examined in Chinese hamster ovary cells and in cardiac myocytes. Heat shock increased the association between eIF4E and 4E-BP1, and this was associated with a dephosphorylation of 4E-BP1. These effects did not appear to be due wholly to decreased activity of the p70 S6 kinase pathway, which is implicated in the control of 4E-BP1, and they were not mediated by the stress-activated p38 microtubule-associated protein kinase pathway. Increased binding of 4E-BP1 to eIF4E correlated with a decrease in the amount of eIF4G which co-purified with the latter. This could account for the previously observed impairment of eIF4F function during heat shock, and, since heat shock protein mRNAs are believed to be relatively cap-independent, could provide a mechanism for the selective up-regulation of the synthesis of heat shock proteins and other stress proteins during heat shock.
在中国仓鼠卵巢细胞和心肌细胞中，研究了热休克对帽结合起始因子4E（eIF4E）及其抑制性结合蛋白4E - BP1调控的影响。热休克增加了eIF4E与4E - BP1之间的结合，这与4E - BP1的去磷酸化有关。这些效应似乎并非完全归因于参与4E - BP1调控的p70 S6激酶途径活性降低，并且它们不是由应激激活的p38微管相关蛋白激酶途径介导的。4E - BP1与eIF4E结合增加与和后者共纯化的eIF4G量减少相关。这可以解释先前观察到的热休克期间eIF4F功能受损的现象，并且由于热休克蛋白mRNA被认为相对不依赖帽结构，这可以为热休克期间热休克蛋白和其他应激蛋白合成的选择性上调提供一种机制。
