Figure 3. Activation properties of Ca_V2.2/β₃ channels co-expressed with the wild-type α₂δ-1or its proteolysis mutations.

A) Left, voltage dependence of activation of Ca_V2.2/β₃ channels co-expressed with wild-type α₂δ-1 (filled circles), its proteolysis mutants (E944Q, P4 and P6) or without any α₂δ subunit (open circles). Maximum conductance (G_max) plotted data were derived from Fig. 2B. The mean data were fitted with Boltzmann functions, the V_½ values of which are given in Table 1. Right, comparison of the mean half-activation voltage (V_1/2) for Ca_V2.2/β₃ channels co-expressed with the P6 proteolysis mutation or without the α₂δ subunit (n = 6–8). B) Mean time to peak and time constants of activation (τ_act) obtained by fitting the rising phase of I_Ba at +10 mV with a single exponential, for Ca_V2.2/β₃ channels co-expressed with wild-type α₂δ-1, its proteolysis mutants, or without any α₂δ subunit (n = 11–25).