A cell-permeable bisaminomethylbithiazole compound that is reported to rescue/correct the folding defect of CFTR ΔF508 mutant via direct interaction and promote proper trafficking/glycosylation and surface expression in both transfected cells and primary airway epithelial cells from ΔF508-homozygous patients, while exhibiting little correcting effect toward N1303K-CFTR, P574H-CFTR, M345T-DRD4 (dopamine receptor 4), or G268V-ABCA1/CD243 /MDR1/ P-gp mutant. Reported to enhance the folding efficiency of both ΔF508 (by 3-fold at 10μM in FRT cells) and wild-type CFTR (by up to 70%), delay the ER-associated degradation of the core-glycosylated ΔF508 (by 30% at 10μM in FRT cells), and increase the stability of low-temperature resuced ΔF508 mutant on the plasma membrane (by 1.7-fold at 10μM in FRT cells). Corr-4a is shown to be more effective than VRT-325/CFcor-325 n restoring forskolin-stimulated CFTR activity in FRT and A549 ΔF508-CFTR transfectants. Unlike VRT-532 Corr-4a does not affect mutant CFTR channel gating activity.
