Article

Correction of both NBD1 energetics and domain interface is required to restore ΔF508 CFTR folding and function.

Department of Physiology, McGill University, Montréal, Quebec H3E 1Y6, Canada.
Cell (impact factor: 32.4). 01/2012; 148(1-2):150-63. DOI:10.1016/j.cell.2011.11.024 pp.150-63
Source: PubMed

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.

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Keywords

CFTR misfolding
 
CFTR-coupled domain assembly
 
cystic fibrosis transmembrane conductance regulator
 
distinct structural deficiencies
 
drug target
 
first nucleotide-binding domain
 
limited success
 
membrane-spanning domain 2
 
multidomain membrane proteins
 
multidomain proteins
 
mutant channel degradation
 
NBD1 energetics
 
structure-based combination corrector therapies
 
thermodynamic instability
 
thermodynamically
 
transport function
 
wild-type-like folding
 
ΔF508 CFTR corrector molecules
 
ΔF508 destabilizes NBD1
 
ΔF508-NBD1 energetic