VX-770 probe potentiates and photolabels WT-CFTR
(A) Structures of ivacaftor (VX-770, 1) and photoaffinity labeling probes VX-770-DIAZ (2) featuring a diazirine, and VX-770-BIOT (3) incorporating a biotin reporter tag.
(B) Representative traces of WT-CFTR dependent chloride efflux (membrane depolarization assay) in HEK293 cells treated with FSK (1μM) +/− VX-770 (1 μM) or VX-770-Biot (1 μM).
(C) Dose-response of VX-770 or VX-770-Biot (0.001-3μM) + FSK (1 μM) (±S.E.M) in WT-CFTR HEK293 cells.
(D) Immunoblots of steady-state expression of WT-CFTR photolabeled with DMSO or VX-770-Biot (0.1μM). CFTR bound: CFTR biotinylated; CFTR unbound: CFTR unbiotinylated; Band C: mature, complex glycosylated CFTR; Band B: immature, core-glycosylated CFTR.
(E) Dose-response of VX-770-Biot on WT-CFTR biotinylated protein expression in HEK293 cells (n = 3).
(F) Bar graphs show the mean (±S.E.M) of the ratio of CFTR bound/CFTR unbound after treatment with VX-770-Biot (0.1 μM) +/− VX-770 (10 μM), SE-02 (10 μM) or SE-03 (10 μM) (n = 3-5). (∗∗p < 0.01)