Abstract
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-EP1, 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.
Original language | English |
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Pages (from-to) | 32779-32784 |
Number of pages | 6 |
Journal | Journal of Biological Chemistry |
Volume | 272 |
Issue number | 52 |
Publication status | Published - 26 Dec 1997 |
Keywords
- CAP-DEPENDENT TRANSLATION
- EPIDIDYMAL FAT-CELLS
- MESSENGER-RNA CAP
- HELA-CELLS
- PHAS-I
- FACTOR EIF-4E
- 3T3-L1 ADIPOCYTES
- ALPHA-SUBUNIT
- PHOSPHORYLATION
- INSULIN