Fig. 5

Electrophysiological characterization of the NBCe1 ⁴⁸³SST-GFS/⁷⁵⁴D-E/⁷⁹⁸V-S/⁸⁰⁰A-T/⁸⁰³I-R mutant (A+B+C). The mutant ⁴⁸³SST-GFS/⁷⁵⁴D-E/⁷⁹⁸V-S/⁸⁰⁰A-T/⁸⁰³I-R construct (NBCe1 Mutant A+B+C), which lost Na⁺-driven base transport and whose magnitude of Cl⁻-driven base transport approximated AE1, was studied electrophysiologically using whole-cell patch clamping. Unlike electrogenic wt-NBCe1 (b, e, h), the measured I–V curves of the mutant construct (c, f, i) under the various study conditions did not differ from those obtained in mock-transfected cells (a, d, g) demonstrating that the mode of transport of the mutant construct was electroneutral