Fig. 4.
Most mutations at residue 122 disrupt PKTHPP inhibition, and charged residues are the most disruptive. (A–C) Ussing chamber potassium current records using Fischer rat thyroid cell monolayers transiently expressing rat TASK-3 channels (L122E, L122K, L122T). (D) Ussing chamber concentration response for PKTHPP. (E) Concentration required for 50% inhibition of potassium current (IC50; mean ± 95% confidence; data fitted as in Fig. 3). (F) Basal current levels for each mutant (mean ± S.E.M.; n = at least 3 each). ***P < 0.001, **P < 0.01, and *P < 0.05 relative to wild-type TASK-3.