Fig. 6.

α₂δ-1 is necessary for the USP2-45-induced decrease of Ca_v1.2 currents. a, b Representative whole-cell current traces and corresponding bar graphs showing that USP2-45 failed to regulate Ca_v1.2 channels in the absence of α₂δ-1 subunits (a), whereas USP2-45 still decreases Ca_v1.2 currents in the absence of β₂ (b). tsA-201 cells were transfected with Ca_v1.2/β₂ alone (white circle, (control)) or together with USP2-45 (black circle) in a and Ca_v1.2/α₂δ-1 alone (white square (control)) or together with USP2-45 (black square) in b. As expected because of their known involvement in Ca_v trafficking, the absence of either subunit decreased Ca_v current densities (compared to Fig. 1). The lack of β subunit in particular dramatically decreased Ca_v currents, despite the charge carrier being increased to 20 mM BaCl₂ in order to reliably quantify the decrease caused by USP2-45 on Ca_v1.2/α₂δ-1 channels. The data show the amplitude of the current densities recorded at 20 mV which generates the maximal current in the absence of β. As for prior experiments, 5 mM BaCl₂ was used to record Ca_v1.2/β₂ currents. Currents densities are compared at 10 mV which generates the maximal current in the absence of α₂δ-1. The number of cells is indicated in parentheses. NS non-significant. *p < 0.05 when compared with respective control