Solubilizing mutations used to crystallize one CFTR domain attenuate the trafficking and channel defects caused by the major cystic fibrosis mutation.
Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) Cl(-) channel. F508del, the most frequent CF-causing mutation, disrupts both the processing and function of CFTR. Recently, the crystal structure of the first nucleotide-binding domain of CFTR bearing F508del (F508del-NBD1) was elucidated. Although F508del-NBD1 shows only minor conformational changes relative to that of wild-type NBD1, additional mutations (F494N/Q637R or F429S/F494N/Q637R) were required for domain solubility and crystallization. Here we show that these solubilizing mutations in cis with F508del partially rescue the trafficking defect of full-length F508del-CFTR and attenuate its gating defect. We interpret these data to suggest that the solubilizing mutations utilized to facilitate F508del-NBD1 production also assist folding of full-length F508del-CFTR protein. Thus, the available crystal structure of F508del-NBD1 might correspond to a partially corrected conformation of this domain.
Pissarra
Luísa S
LS
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisboa, 1749-016 Lisboa, Portugal.
Farinha
Carlos M
CM
Xu
Zhe
Z
Schmidt
André
A
Thibodeau
Patrick H
PH
Cai
Zhiwei
Z
Thomas
Philip J
PJ
Sheppard
David N
DN
Amaral
Margarida D
MD
D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D003550:Cystic Fibrosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009711:Nucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D012995:Solubility; D013237:Stereoisomerism; D013997:Time Factors
D009711:Nucleotides; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator