CFTR transmembrane segments are impaired in their conformational adaptability by a pathogenic loop mutation and dynamically stabilized by Lumacaftor

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung



The cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel protein that is defective in individuals with cystic fibrosis (CF). To advance the rational design of CF therapies, it is important to elucidate how mutational defects in CFTR lead to its impairment and how pharmacological compounds interact with and alter CFTR. Here, using a helical-hairpin construct derived from CFTR's transmembrane (TM) helices 3 and 4 (TM3/4) and their intervening loop, we investigated the structural effects of a patient-derived CF-phenotypic mutation, E217G, located in the loop region of CFTR's membrane-spanning domain. Employing a single-molecule FRET assay to probe the folding status of reconstituted hairpins in lipid bilayers, we found that the E217G hairpin exhibits an altered adaptive packing behavior stemming from an additional GXXXG helix?helix interaction motif created in the mutant hairpin. This observation suggested that the misfolding and functional defects caused by the E217G mutation arise from an impaired conformational adaptability of TM helical segments in CFTR. The addition of the small-molecule corrector Lumacaftor exerts a helix stabilization effect not only on the E217G mutant hairpin, but also on WT TM3/4 and other mutations in the hairpin. This finding suggests a general mode of action for Lumacaftor through which this corrector efficiently improves maturation of various CFTR mutants.


Seiten (von - bis)1985-1991
FachzeitschriftJournal of Biological Chemistry
PublikationsstatusVeröffentlicht - 27 Dez. 2019

Externe IDs

Scopus 85079472091
ORCID /0000-0003-2125-4045/work/141545222
ORCID /0000-0002-6209-2364/work/142237620
ORCID /0000-0002-2213-2763/work/142239771



  • cystic fibrosis transmembrane conductance regulator (CFTR), cystic fibrosis, single-molecule biophysics, membrane protein, protein misfolding, helical packing, lumacaftor, pharmacological corrector, single-molecule Förster resonance energy transfer (FRET), SINGLE-MOLECULE FRET, CONDUCTANCE REGULATOR, EXTRACELLULAR LOOP, FOLDING DEFECTS, PROTEIN, DOMAIN, CORRECTORS, RECEPTOR