FIGURE 2.

Efficacy of small molecule correctors enhanced by disruption of R⁵⁵³XR⁵⁵⁵ in F508del-CFTR (processing). A, representative Western blots illustrating processing of F508del-CFTR and F508del-KXK-CFTR (transiently transfected) in the presence of Corr4a (10 μm) or VRT-325 (10 μm). The core-glycosylated form is denoted by the closed triangle, and the complex-glycosylated form is denoted by the open triangle. B, representative Western blot obtained using the Odyssey infrared imaging system from LI-COR Biosciences. F508del-CFTR and F508del-KXK-CFTR stable cell lines were treated with 10 μm VRT-325. The core-glycosylated form is denoted by the closed triangle, and the complex-glycosylated form is denoted by the open triangle. Actin was detected using an anti-β-actin antibody to serve as an loading control. C, the bar graph shows the mean of several experiments (n = 5) where VRT-325 treatment in F508del-CFTR and F508del-KXK-CFTR significantly increased the Band C/(B+C) percentage. The solid bracket represents the change in immature to mature protein in VRT-325-treated F508del-CFTR when compared with vehicle. The stippled bracket represents the change in immature to mature protein in VRT-325-treated F508del-KXK-CFTR when compared with vehicle. D, the bar graph shows the mean of several experiments (n = 5) where VRT-325 treatment in F508del-CFTR and F508del-KXK-CFTR significantly increased the Band C/B ratio, normalized using β-actin as a loading control. The solid bracket represents the change in immature to mature protein in VRT-325-treated F508del-CFTR when compared with vehicle. The stippled bracket represents the change in immature to mature protein in VRT-325-treated F508del-KXK-CFTR when compared with vehicle. *, p < 0.05, **, p < 0.01, ***, p < 0.001 Unpaired Student's t test statistical analyses were employed.