Fluorescence assay for simultaneous quantification of CFTR ion-channel function and plasma membrane proximity

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• The cystic fibrosis transmembrane conductance regulator (CFTR) is a crucial anion channel protein.
• CFTR dysfunction causes cystic fibrosis (CF), a genetic disorder.
• Current CFTR therapies include potentiators and correctors.

Purpose of the Study:

• To develop a novel image-based fluorescence assay for simultaneous measurement of CFTR function and membrane localization.
• To characterize CFTR mutations and evaluate drug efficacy.
• To investigate CFTR molecular mechanisms and inform precision therapy development.

Main Methods:

• Development of a rapid, image-based fluorescence assay.
• Monitoring F508del-CFTR variant and assessing rescue effects.
• Characterization of 62 CF-causing mutations.
• Profiling drug effects using approved potentiator VX-770.

Main Results:

• The assay accurately estimates CFTR ion-channel function and membrane proximity.
• Measurements correlate well with existing electrophysiology and biochemical data.
• VX-770 treatment effects on rare CFTR mutations were profiled.
• Mechanistic hypotheses for VX-770 action were proposed.

Conclusions:

• The developed assay is a valuable tool for investigating CFTR molecular mechanisms.
• The assay allows accurate inferences on CFTR gating and permeation.
• This two-dimensional characterization can guide the development of precision CF therapies.