CFTR: Molecular mechanisms of ion conduction and gating

D. C. Dawson, M. K. Mansoura, S. S. Smith, D. J. Wilkinson

Research output: Contribution to journalArticle

Abstract

Purpose: CFTR is a Cl channel found in a variety of epithelial cells that is activated by increases in cytosolic cAMP. The primary structure of CFTR can be envisioned as comprising two membrane-spanning domains (MSD1, MSD2) that are presumed to form a Cl-selective pore and three cytosolic domains, the R domain and two nucleotide binding folds (NBF's), that govern the opening and closing of the channels. Methods: The object of the studies presented here was to use mutant CFTR's expressed in Xenopus oocytes to investigate molecular mechanisms for ion conduction and gating. Results: Kinetic analysis of acivation of CFTR constucts bearing mutations in the nucleotide binding folds was consistent with a model in which the activation of CFTR requires ATP hydrolysis at NBF1 and deactivation requires ATP hydroysis at NBF2. Elimination of single serines in the R domain altered CFTR activation in a manner consistent with the existence of both stimulatory and inhibitory phosphorylation sites that regulate channel activity. Ion selectivity determinations indicated that the conduction path contains an anion binding site that exhibits a high affinity for thiocyanate (SCN). A patient mutation (G314E) that introduces a negative charge into the 5th membrane-spanning segment (TM5) of MSD1 markedly reduced SCN binding in the channel suggesting that TM5 may form a portion of the lining of the pore and contribute to the anion binding site. Conclusions: These results provide insights into the relationship between the structure of CFTR and its Cl channel function in health and disease.

Original languageEnglish (US)
JournalInvestigative Ophthalmology and Visual Science
Volume37
Issue number3
StatePublished - Feb 15 1996
Externally publishedYes

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Anions
Nucleotides
Adenosine Triphosphate
Binding Sites
Ions
Mutation
Membranes
Xenopus
Serine
Oocytes
Hydrolysis
Epithelial Cells
Phosphorylation
Health
thiocyanate

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Dawson, D. C., Mansoura, M. K., Smith, S. S., & Wilkinson, D. J. (1996). CFTR: Molecular mechanisms of ion conduction and gating. Investigative Ophthalmology and Visual Science, 37(3).

CFTR : Molecular mechanisms of ion conduction and gating. / Dawson, D. C.; Mansoura, M. K.; Smith, S. S.; Wilkinson, D. J.

In: Investigative Ophthalmology and Visual Science, Vol. 37, No. 3, 15.02.1996.

Research output: Contribution to journalArticle

Dawson, DC, Mansoura, MK, Smith, SS & Wilkinson, DJ 1996, 'CFTR: Molecular mechanisms of ion conduction and gating', Investigative Ophthalmology and Visual Science, vol. 37, no. 3.
Dawson DC, Mansoura MK, Smith SS, Wilkinson DJ. CFTR: Molecular mechanisms of ion conduction and gating. Investigative Ophthalmology and Visual Science. 1996 Feb 15;37(3).
Dawson, D. C. ; Mansoura, M. K. ; Smith, S. S. ; Wilkinson, D. J. / CFTR : Molecular mechanisms of ion conduction and gating. In: Investigative Ophthalmology and Visual Science. 1996 ; Vol. 37, No. 3.
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