ER stress decreases Ucp1 activator, peroxisome proliferator-activated receptor γ (Pparγ) mRNA expression through ERK and JNK pathway in IWAT cells. Pparγ and ER stress marker (Bip, Chop, and X-box binding protein 1 splicing-Xbp1s) mRNA expression in cells treated with (A,C) 100 μM ERK inhibitor (U0126) for 14 h or (B,D) 25 μM JNK inhibitor (SP600125) for 13 h, followed by tunicamycin (1 μM, 12 h). Data are presented as mean ± S.E.M. (error bars). n = 4 in each group. Different letters indicate significant differences (p < 0.05) according to one-way ANOVA followed by Tukey–Kramer multiple comparison test.