Fig. 2.

Anion permeabilities of selectivity filter variants. (A) Example current–voltage relationships for PKA-phosphorylated CFTR variants under biionic conditions in inside-out excised patches. The patch pipette contained 150 mM chloride, and the perfusion solution contained 150 mM of the indicated anion. Three mM ATP was included in the perfusion solution. Membrane potentials are indicated using physiological convention. Corresponding voltage families are in SI Appendix, Fig. S3. (B) Permeabilities of anions relative to chloride for the wild-type CFTR and selectivity filter variants. Data represent means and SE for 3 to 7 patches. Statistical significance was tested by one-way ANOVA (ns: not significant, *P < 0.05, ****P < 10⁻⁴).