Figure 7.

The wild-type and mutants of the β2e subunit show differential effects on Ca_V2.2 and Ca_V1.3 current inhibition by PIP₂ depletion. (A) Current inhibition of Ca_V2.2 channels with mutant β2e subunits by Dr-VSP activation. The currents in test pulses to +10 mV for 10 ms before (a) and after (b) the depolarizing pulse (+120 mV) are superimposed on nontransfected cells (control) and Dr-VSP-transfected cells. (B) Summary of Ca_V2.2 current inhibition (%) by Dr-VSP. For control, n = 4–5; for Dr-VSP, n = 4–5. ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001, compared with wild-type; error bar, ± SEM. (C) Inhibition of Ca_V1.3 currents with different mutant β2e subunits by Dr-VSP. The currents in test pulses to −10 mV for 10 ms before (a) and after (b) the depolarizing pulse (+120 mV) are superimposed on nontransfected cells (control) and Dr-VSP-transfected cells. (D) Summary of current inhibition of Ca_V1.3 channels by Dr-VSP-induced PIP₂ depletion. For control, n = 3–5; for Dr-VSP, n = 4–5. ^∗p < 0.05; ^∗∗∗p < 0.001, compared with the wild-type; error bar, ± SEM. To see this figure in color, go online.