Electrophysiological analysis of the GGG/AAA mutants. (A) Position of the Gly₂₁₃-Gly₂₁₄-Gly₂₁₅ mutation is indicated (black bold), as is that of the previous GGG_216–218 mutation in the earlier study (Fujiwara et al., 2012) (gray). (B) Representative current traces of the mutants at 25°C. (C) Accumulated data of activation kinetics of the mutant are shown as the mean ± SEM (n = 5 in the GGG mutant, n = 6 in the AAA mutant, and n = 5 in WT). ***, P < 0.001, paired t test between GGG versus AAA.