Figure 5.

Regulation of eIF2α phosphorylation and protein synthesis by interferons. 2fTGH, U4A (A, C) or U1A (B) cells were stimulated with either IFN-α2b or IFN-γ for the indicated time periods. Total protein extracts were subjected to immunoblotting with the indicated antibodies. (D) 2fTGH and U1A cells were left untreated or treated with IFN-α2b in the absence or presence of 0.5 μg ml⁻¹ actinomycin D (Act D) for 2 h. Cells were subjected to [³⁵S]-methionine labelling for 1 h. (E) PKR^+/+ and PKR^−/− MEFs were left untreated or treated with IFN-γ for 2 h followed by [³⁵S]-methionine labelling for an additional hour. (D,E) The graphs show the levels of incorporation of radioactivity into protein as percentages of the corresponding control (CON) values. The data are from three independent experiments performed in duplicate. eIF, eukaryotic initiation factor 2; IFN, interferon; MEF, mouse embryonic fibroblasts 2; PKR, dsRNA-dependent protein kinase; WCE, whole-cell extracts.