Fig. 6

Outer, central, and C-domain pocket mutants that reduce inhibitor efficacy also alter channel gating.

A–F Representative traces of currents from HEK-293 cells expressing WT (A), G130W (B), L134W (C), E384A (D), I565W (E), and M573W (F) over a pH range of 10 to 5.0. 1 mM Zn²⁺ (pH 5.5) was applied during the pH 5.5 stimulus as indicated. G Current magnitudes normalized to response to pH 5.0, from experiments as in (A–F) (n = 4-5 cells per construct). Inset: Fitted pH₅₀ curves for WT and mutant channels. pH₅₀s were as follows. WT: pH 5.64, G130W: pH 5.68, L134W: pH 5.43, E384A: pH 5.97, I565W: pH 6.36, M573W: pH 5.43. H Inhibition by 1 mM Zn²⁺ from experiments as in (A–F), (n = 4-5 cells per construct). Significance was determined in (G) using non-parametric two-tailed Mann-Whitney tests to compare cumulative ranks to WT DrOTOP1 at the same pH. Significance was determined in (H) using one-way ANOVA with Dunnett’s correction compared to WT DrOTOP1. All data presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 for all statistical tests. Experiments were performed by holding cells at V_m = −80 mV. Source data are provided as a Source Data file.