Figure 4. Cat-1 mRNA accumulation during ER stress requires ATF4 and XBP1, the levels of which depend on eIF2α phosphorylation.
Quantification of Cat-1 mRNA levels in (A) Thapsigargin (Tg)-treated WT, ATF4−/− and XBP1−/− (C) or S/S (eIF2α-WT) and A/A (eIF2α-S51A) MEFs. Results are from qRT-PCR analysis of total RNA using gene-specific primers and were normalized to the 18S ribosomal RNA signal. *P < 0.05 between 0 and 12 h of Tg treatment for ATF4−/− MEFs compared with WT. Results are means ± S.E.M. for three independent experiments. (B and D) Western blot analysis of total cell extracts from the indicated Tg-treated MEFs using antibodies against the the indicated proteins. A -representative gel from three independent experiments is shown. All Tg-treatments were performed in DMEM supplemented with 10 % (v/v) FBS, as described in the Experimental section.