Fig. 5.

Airn protects IMP2 from ubiquitin–proteasome-dependent degradation, thus maintaining its stability. A Representative blot images and quantitative analysis of IMP2 expression in CFs. B qRT-PCR analysis of IMP2 in CFs. C, D CFs were treated with 20 μg/mL cycloheximide (CHX), harvested at indicated points and analyzed by western blotting. E After MG132 treatment of CFs cultured in HG-medium, the protein level of IMP2 was detected by western blot. F–H IP and ubiquitination assays were conducted to investigate the effect of Airn or HG on ubiquitination of IMP2. I The sequences of WT, K77R and K139R mutants of IMP2. J IP and ubiquitination assays using anti-FLAG antibodies and CFs transfected with plasmids expressing the FLAG-tagged WT, K77R and K139R of IMP2. K RIP assays were performed using anti-FLAG antibodies and CFs transfected with plasmids expressing the FLAG-tagged WT, K77R and K139R of IMP2. Data are presented as means ± SEM. *p < 0.05; **p < 0.01. n = 3 wells