Fig 1: IER3IP1 suppression decreases the UPR activation(A) mRNA levels of IRE1a, Perk and Atf6 in IER3IP1 KD cells. 4 days after infection with IER3IP1 shRNA lentivirus, mRNA levels of IRE1a, Perk and Atf6 in IER3IP1 KD cells were determined by qRT-PCR. *P<0.05, **P<0.01 compared to control group. Values are mean ± SEM. (B) Effect of IER3IP1 suppression on the IRE1a arm of the UPR. 4 days after IER3IP1 KD in MIN6 cells, phosphorylation of IRE1a, Bip, sXBP-1 and uXBP-were determined by Western blot. The loaded proteins in the two “- or +” lines were the same but from the different plates. (C) mRNA levels of downstream targets of sXBP-1 in IER3IP1 KD cells. 4 days after IER3IP1 KD in MIN6 cells, mRNA levels of downstream targets of sXBP-1, Erdj4, p58IPK, EDEM and Sec61a, were determined by qRT-PCR. Values are mean ± SEM. (D) Effect of IER3IP1 suppression on the Perk arm of the UPR. 4 days after IER3IP1 KD in MIN6 cells, phosphorylation of Perk and eIF2a, and ATF4 were determined by Western blot. The loaded proteins in the two “- or +” lines were the same but from the different plates. (E) IER3IP1 KD decreases UPR activation induced by ER stress in MIN6. 4 days after IER3IP1 KD, MIN6 cells were treated with 10 µg/ml tunicamycin (TC) or 1 µM thapsigargin (TG) for 6 hours. Then the expression levels of Chop, sXBP-1, uXBP-1 and IER3IP1 were determined by Western blot.