Rescue of rare CF folding mutants by allosteric corrector combination. (a) PM density of the indicated CFTR2 mutants alone and after VX-809 or 3C treatment expressed as percentage of WT-CFTR in CFBE41o- (n = 3). The domain localizations of the mutations are indicated. (b,c) Effect of VX-809 or 3C treatment on the expression pattern of CFTR2 mutants in CFBE41o- determined by immunoblot (b) and densitometric quantification (c, n = 6 for R31C, E92K, R347P, D614G, L1077P; n = 3 for P67L, L206W, S492F, V520F, S1235R). Uncropped immunoblots are presented in Supplementary Figure 11. (d,e) Effect of VX-809 or 3C on the Isc of CFTR2 mutants in CFBE41o-. Representative traces are shown in d. Mutant function (n = 3), expressed as percentage of WT function, is depicted in e. Data in a, c and e were normalized with mutant CFTR2 mRNA abundance (Supplementary Fig. 8a) and are means ± SEM of the indicated number of independent experiments.