(A) SH-SY5Y cells were pre-treated with 4,5,6,7-tetrabromobenzotriazole (TBB: 5 µM) for 3 h, and then treated with thapsigargin (Tg: 10 µM) for 18 h and Western blotting analysis was performed. TBB inhibited ER stress-induced GRP78 expression. *p<0.05 (B) SH-SY5Y cells were pre-treated with 4,5,6,7-tetrabromobenzotriazole (TBB: 5 µM) for 3 h, and then treated with thapsigargin (Tg: 10 µM) for 4 h and Western blotting analysis was performed using ATF6 antibody. (C) Densitometric analysis of p90ATF6. (D) Densitometric analysis of p50 ATF6. TBB did not affect ER stress-induced ATF6 cleavage. n = 2–3/group. Results are expressed as the means ± S.E.