Related Experiment Video

Updated: Sep 13, 2025

In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes
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In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes

Published on: August 13, 2012

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Structure of CFTR bound to (R)-BPO-27 unveils a pore-blockage mechanism

Paul G Young1,2, Karol Fiedorczuk1, Jue Chen3,4

  • 1Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY, USA.

Nature Communications
|August 1, 2025
PubMed

Insights

Selective inhibition of the cystic fibrosis transmembrane conductance regulator (CFTR) is key for treating diseases like secretory diarrhea and ADPKD. The compound (R)-BPO-27 blocks the CFTR chloride pore, uncoupling ion flow from ATP hydrolysis.

Area of Science:

  • Molecular biology
  • Structural biology
  • Pharmacology

Background:

  • Hyperactivation of the cystic fibrosis transmembrane conductance regulator (CFTR) is implicated in secretory diarrhea and autosomal dominant polycystic kidney disease (ADPKD).
  • Selective CFTR inhibition presents a therapeutic avenue for these conditions.
  • (R)-BPO-27 is a promising candidate inhibitor of CFTR.

Purpose of the Study:

  • To elucidate the molecular mechanism of CFTR inhibition by (R)-BPO-27.
  • To determine the structural basis for (R)-BPO-27's inhibitory action.

Main Methods:

  • Cryo-electron microscopy (cryo-EM) was used to determine the structure of CFTR bound to (R)-BPO-27.
  • Biochemical assays were performed to assess ATP hydrolysis and chloride transport.
  • Analysis of NBD dimerization and separation was conducted.

Main Results:

  • A 2.1 Å cryo-EM structure of CFTR bound to (R)-BPO-27 was obtained.
  • (R)-BPO-27 directly occludes the chloride-conducting pore, uncoupling pore occlusion from ATP hydrolysis.
  • Inhibitor binding is dependent on NBD separation, with inhibition rate inversely correlating with NBD dimerization probability.

Conclusions:

  • The findings clarify the mechanism of (R)-BPO-27 as a CFTR inhibitor, distinct from competition with ATP.
  • The structure provides a molecular basis for the rational design of improved CFTR inhibitors.
  • Understanding the NBD dimerization dependence offers insights into CFTR gating regulation.

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