Fig. 6

Knockdown FKBP9 activates the IRE1α-XBP1 pathway. a The list of 22 significant transcripts that are regulated by FKBP9 deficiency were classified into 4 categories including PERK-mediated UPR, IRE1-mediated UPR, ERAD and other proteins response to ER stress (Additional file 9: Table S3). b Real-time quantitative PCR analysis for CHAC1, DDIT3, IL6, SEL1L and GPNMB mRNA levels of stable FKBP9-depleted SF-539 and T98G cells. c IB analysis for pIRE1α and XBP1(s) expression in stable FKBP9-depleted and adenovirus-overexpressed SF-539 and T98G cells treated as in Fig. 2a. GAPDH was used as a loading control. d Tumor tissue sections from SF-539-shControl and SF539-shFKBP9 cells were analyzed by IHC using anti-pIRE1α antibody. Scale bar = 50 μm. Magnified insets showed pIRE1α positive stained cells. e, f Colony formation and sphere formation assays were performed in stable FKBP9-depleted SF-539, T98G or U-87 MG cells treated with vehicle or 50 μM 4μ8C. Nestin and Sox2 expression of SF-539 and U-87 MG cells spheres were detected by IB. g Aggresomes in stable FKBP9-depleted SF-539 and T98 cells were analyzed using Aggresome Detection kit by confocal microscopy. MG132 (5 μM for 8 h) was used as a positive control. Fluorescence intensity was quantified by Image J. Data are presented as mean ± SEM from three independent experiments. (*p < 0.05, **p < 0.01, ***p < 0.001)