FIG. 5.

eIF2α kinase PEK is required for NF-κB transcriptional activity in response to ER stress. An NF-κB firefly luciferase reporter gene was cotransfected with a Renilla luciferase control plasmid into PEK^+/+ (black bar) or PEK^−/− (white bar) MEF cells. MEF cells were treated with from 0 to 2 μM thapsigargin for 6 h, and the dual luciferase assay was carried out as described in Materials and Methods. To address whether transient expression of PEK in the PEK^−/− MEF cells restored NF-κB transcriptional activity, we cotransfected a PEK expression plasmid with the luciferase genes and subjected these cells to 2 μM thapsigargin (gray bar). Relative NF-κB-luciferase activity is presented in the histogram, which is normalized for PEK^+/+ cells not subjected to thapsigargin treatment.