Mechanism-based corrector combination restores ΔF508-CFTR folding and function

T Okiyoneda, G Veit, JF Dekkers, M Bagdany… - Nature chemical …, 2013 - nature.com
T Okiyoneda, G Veit, JF Dekkers, M Bagdany, N Soya, H Xu, A Roldan, AS Verkman
Nature chemical biology, 2013nature.com
The most common cystic fibrosis mutation, ΔF508 in nucleotide binding domain 1 (NBD1),
impairs cystic fibrosis transmembrane conductance regulator (CFTR)-coupled domain
folding, plasma membrane expression, function and stability. VX-809, a promising
investigational corrector of ΔF508-CFTR misprocessing, has limited clinical benefit and an
incompletely understood mechanism, hampering drug development. Given the effect of
second-site suppressor mutations, robust ΔF508-CFTR correction most likely requires …
Abstract
The most common cystic fibrosis mutation, ΔF508 in nucleotide binding domain 1 (NBD1), impairs cystic fibrosis transmembrane conductance regulator (CFTR)-coupled domain folding, plasma membrane expression, function and stability. VX-809, a promising investigational corrector of ΔF508-CFTR misprocessing, has limited clinical benefit and an incompletely understood mechanism, hampering drug development. Given the effect of second-site suppressor mutations, robust ΔF508-CFTR correction most likely requires stabilization of NBD1 energetics and the interface between membrane-spanning domains (MSDs) and NBD1, which are both established primary conformational defects. Here we elucidate the molecular targets of available correctors: class I stabilizes the NBD1-MSD1 and NBD1-MSD2 interfaces, and class II targets NBD2. Only chemical chaperones, surrogates of class III correctors, stabilize human ΔF508-NBD1. Although VX-809 can correct missense mutations primarily destabilizing the NBD1-MSD1/2 interface, functional plasma membrane expression of ΔF508-CFTR also requires compounds that counteract the NBD1 and NBD2 stability defects in cystic fibrosis bronchial epithelial cells and intestinal organoids. Thus, the combination of structure-guided correctors represents an effective approach for cystic fibrosis therapy.
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