Fig. 3

Mutation S652 L alters Ca²⁺-dependent inactivation over a broad voltage range. a, b Voltage-dependence of Ca²⁺-dependent inactivation of WT_L vs S652L_L (A) and WT_S vs S652L_S (B). The fraction of remaining currents was determined at the end of 250 ms (r₂₅₀) upon depolarizations to different test potentials resulting in a typical U-shaped dependence of voltage. Data are presented as mean ± SEM (> 3 independent transfections); n-numbers are given in parenthesis. c, d f values over a broad voltage range for WT_L vs S652L_L (C) and WT_S vs S652L_S (D). f is defined as the difference between r₂₅₀ values of I_Ba and I_Ca at each voltage step and indicates the strength of CDI. CDI of S652 L_L and S652L_S was more pronounced at negative potentials. At higher potentials CDI remained unchanged for the long mutant but was significantly reduced for S652L_S. Statistics: two-way ANOVA of f values followed by Bonferroni post hoc test, *p < 0.05, **p < 0.01, ***p < 0.001 compared to WT. Data are presented as mean ± SEM (> 3 independent transfections)