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Updated: May 1, 2026

Functional Reconstitution and Channel Activity Measurements of Purified Wildtype and Mutant CFTR Protein
Published on: March 9, 2015
State-dependent blocker interactions with the CFTR chloride channel: implications for gating the pore
1Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada, paul.linsdell@dal.ca.
Tetracyanoplatinate (Pt(NO2)4(2-)) ions block cystic fibrosis transmembrane conductance regulator (CFTR) channels, reducing chloride flow and altering channel gating. This suggests Pt(NO2)4(2-) interacts with a single site within the CFTR pore.
Area of Science:
- Ion channel physiology
- Molecular biophysics
- Cystic fibrosis research
Background:
- Chloride permeation through CFTR channels is crucial for cellular function.
- Cytoplasmic anions can block CFTR channels, but their effects on gating are less understood.
Purpose of the Study:
- Investigate the state-dependent block of CFTR by cytoplasmic Pt(NO2)4(2-) ions.
- Determine how Pt(NO2)4(2-) affects channel permeation and gating kinetics.
Main Methods:
- Utilized patch clamp recording techniques.
- Employed site-directed mutagenesis to probe blocker-pore interactions.
- Performed experiments at varying extracellular chloride concentrations.
Main Results:
- Pt(NO2)4(2-) caused voltage-dependent open-channel block, reducing current amplitude.
- Pt(NO2)4(2-) decreased channel open probability by increasing interburst closed times.
- Mutations affecting Pt(NO2)4(2-) interaction altered both permeation and gating, indicating a single binding site.
Conclusions:
- Pt(NO2)4(2-) binds within the CFTR pore, blocking chloride permeation and influencing channel gating.
- The results provide insights into the CFTR channel gate location and operation.
- Pt(NO2)4(2-) may also interfere with channel closure, potentially increasing activity.
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