FIGURE 6.

GADD34 expression during hyperosmotic stress controls the phosphorylation of eIF2α and downstream signaling but not MAP kinase signaling. MEFs were treated for the indicated times with 500 mosmol (A–D) or 600 mosmol (E) medium after infection with lentivirus-expressing shRNAs. A, Western blot of extracts from cells treated with 500 mosmol medium after infection with retroviral particles expressing truncated forms of GADD34 (ΔN active and ΔC inactive). B, Western blot analysis of extracts of cells expressing shRNA against GADD34. C, qRT-PCR analysis of the indicated mRNAs normalized to GAPDH mRNA and shown as -fold change over untreated cells. D and E, caspase 3 activity in cell extracts. Results are the means of triplicate determinations.