title: Correction of both NBD1 energetics and domain interface is required to restore ΔF508 CFTR folding and function.
abstract: The folding and misfolding mechanism of multidomain proteins remains poorly understood. Although thermodynamic instability of the first nucleotide-binding domain (NBD1) of ΔF508 CFTR (cystic fibrosis transmembrane conductance regulator) partly accounts for the mutant channel degradation in the endoplasmic reticulum and is considered as a drug target in cystic fibrosis, the link between NBD1 and CFTR misfolding remains unclear. Here, we show that ΔF508 destabilizes NBD1 both thermodynamically and kinetically, but correction of either defect alone is insufficient to restore ΔF508 CFTR biogenesis. Instead, both ΔF508-NBD1 energetic and the NBD1-MSD2 (membrane-spanning domain 2) interface stabilization are required for wild-type-like folding, processing, and transport function, suggesting a synergistic role of NBD1 energetics and topology in CFTR-coupled domain assembly. Identification of distinct structural deficiencies may explain the limited success of ΔF508 CFTR corrector molecules and suggests structure-based combination corrector therapies. These results may serve as a framework for understanding the mechanism of interface mutation in multidomain membrane proteins.
authors.affiliation: Department of Physiology, McGill University, Montréal, Quebec H3E 1Y6, Canada.
authors.forename: Wael M
authors.initials: WM
authors.lastname: Rabeh
authors.forename: Florian
authors.initials: F
authors.lastname: Bossard
authors.forename: Haijin
authors.initials: H
authors.lastname: Xu
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Okiyoneda
authors.forename: Miklos
authors.initials: M
authors.lastname: Bagdany
authors.forename: Cory M
authors.initials: CM
authors.lastname: Mulvihill
authors.forename: Kai
authors.initials: K
authors.lastname: Du
authors.forename: Salvatore
authors.initials: S
authors.lastname: di Bernardo
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Liu
authors.forename: Lars
authors.initials: L
authors.lastname: Konermann
authors.forename: Ariel
authors.initials: A
authors.lastname: Roldan
authors.forename: Gergely L
authors.initials: GL
authors.lastname: Lukacs
mesh_terms: D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D009154:Mutation; D017510:Protein Folding; D017434:Protein Structure, Tertiary
chemical_list: C505032:CFTR protein, human; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator