Figure 4
From: Effect of the Brugada syndrome mutation A39V on calmodulin regulation of Cav1.2 channels
CaM lobe mutants differentially shift the voltage dependence of activation for WT and A39V-Cav1.2 channels. A) Current voltage relationships for WT-Cav1.2 channels expressed transiently in tsA-201 cells with Cavβ2a/Cavα2δ and recorded in barium with one of four CaM conditions: CaMWT, CaM12, CaM34, or CaM1234. All experiments were recorded with high calcium buffering intracellularly (10 mM BAPTA). B) Current–voltage relationships for A39V-Cav1.2 channels expressed as in (A) with one of four CaM conditions: CaMWT, CaM12, CaM34, or CaM1234. C) A bar graph displaying the half activation potentials for Cav1.2 channels recorded in barium. WT-Cav1.2 channels recorded with any CaM mutant have a significant leftward shift in the voltage-dependence of activation in barium compared to CaMWT (*p ≤ 0.05 by one-way ANOVA). D) A bar graph displaying the voltage dependence of activation for A39V-Cav1.2 channels recorded in barium. A39V-Cav1.2 channels recorded with CaM12 have a significant leftward shift in the voltage-dependence of activation in barium compared to CaMWT (*p ≤ 0.05 by one-way ANOVA), and CaM1234 (# p ≤ 0.05 by one-way ANOVA).