ER stress induces phosphorylation of eIF2α and expression of ZTA and LMP1. (A) SAL and ER stress result in increased levels of eIF2α S51 phosphorylation. LCLs were treated with SAL (40μM for 24 hours), TG (50μM for 6 hours), or SAL and TG as described. Western blot analysis for total eIF2α and pS51 eIF2α were performed 24 hours after treatment. (B) ER stress induces ZTA expression in LCLs. LCLs were treated with TG, SAL, or TG + SAL as described and at 6 or 24 hours after treatment, the cells were lysed in 1× RIPA buffer. Equal amounts of protein were analyzed by Western blot for ZTA. (C) Time-course experiment of ZTA and LMP1 protein expression after the induction of ER stress. LCLs were treated with TG and cells were lysed at the indicated times after TG treatment in 1× RIPA buffer. Equal amounts of protein were analyzed by Western blot for ZTA and LMP1.