Conformational change of the extracellular parts of the CFTR protein during channel gating.
Cell Mol Life Sci
; 75(16): 3027-3038, 2018 08.
Article
in En
| MEDLINE
| ID: mdl-29441426
ABSTRACT
Cystic fibrosis can be treated by potentiators, drugs that interact directly with the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel to increase its open probability. These substances likely target key conformational changes occurring during channel opening and closing, however, the molecular bases of these conformational changes, and their susceptibility to manipulation are poorly understood. We have used patch clamp recording to identify changes in the three-dimensional organization of the extracellularly accessible parts of the CFTR protein during channel opening and closing. State-dependent formation of both disulfide bonds and Cd2+ bridges occurred for pairs of cysteine side-chains introduced into the extreme extracellular ends of transmembrane helices (TMs) 1, 6, and 12. Between each of these three TMs, we found that both disulfide bonds and metal bridges formed preferentially or exclusively in the closed state and that these inter-TM cross-links stabilized the closed state. These results indicate that the extracellular ends of these TMs are close together when the channel is closed and that they separate from each other when the channel opens. These findings identify for the first time key conformational changes in the extracellular parts of the CFTR protein that can potentially be manipulated to control channel activity.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Conformation
/
Ion Channel Gating
/
Chlorides
/
Cystic Fibrosis Transmembrane Conductance Regulator
Type of study:
Prognostic_studies
Limits:
Animals
/
Humans
Language:
En
Journal:
Cell Mol Life Sci
Journal subject:
BIOLOGIA MOLECULAR
Year:
2018
Document type:
Article
Affiliation country: