Interaction between 2 extracellular loops influences the activity of the cystic fibrosis transmembrane conductance regulator chloride channel

Steven D. Broadbent, Wuyang Wang, Paul Linsdell

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7 Citations (Scopus)

Résumé

Activity of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is thought to be controlled by cytoplasmic factors. However, recent evidence has shown that overall channel activity is also influenced by extracellular anions that interact directly with the extracellular loops (ECLs) of the CFTR protein. Very little is known about the structure of the ECLs or how substances interacting with these ECLs might affect CFTR function. We used patch-clamp recording to investigate the accessibility of cysteine-reactive reagents to cysteines introduced throughout ECL1 and 2 key sites in ECL4. Furthermore, interactions between ECL1 and ECL4 were investigated by the formation of disulfide crosslinks between cysteines introduced into these 2 regions. Crosslinks could be formed between R899C (in ECL4) and a number of sites in ECL1 in a manner that was dependent on channel activity, suggesting that the relative orientation of these 2 loops changes on activation. Formation of these crosslinks inhibited channel function, suggesting that relative movement of these ECLs is important to normal channel function. Implications of these findings for the effects of mutations in the ECLs that are associated with cystic fibrosis and interactions with extracellular substances that influence channel activity are discussed.

Langue d'origineEnglish
Pages (de-à)390-396
Nombre de pages7
JournalBiochemistry and Cell Biology
Volume92
Numéro de publication5
DOI
Statut de publicationPublished - 2014

Note bibliographique

Publisher Copyright:
© 2014 Published by NRC Research Press.

ASJC Scopus Subject Areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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