Figure 4. Rim1 promotes Ca_v2.2 channel recovery from G-protein inhibition.

A, Representative normalized Ba²⁺ current traces elicited at +10 mV and +30 mV before (I_Control) and after 10 μM DAMGO application (I_DAMGO) for Ca_v2.2/β₃/α₂δ_1b channels (top panel). Corresponding traces showing the amount of current that is present in I_DAMGO (I_{DAMGO wo unbinding}) are also shown (middle panel) and used to calculate I_{G-protein unbinding}, the time dependence of G-protein dissociation from the channel (bottom panel). I_{G-protein unbinding} was fitted with a mono-exponential function (red dashed lines) in order to determine the time constant of recovery from G-protein inhibition (τ_recovery) and the maximal extent of recovery (RI_max). B, Legend as in (A) but for cells expressing Ca_v2.2/β₃/α₂δ_1b/Rim1 channels. Corresponding mean values of τ_recovery (C) and RI_max (D) for Ca_v2.2/β₃/α₂δ_1b (filled symbols) and Ca_v2.2/β₃/α₂δ_1b/Rim1 channels (open symbols) as a function of membrane potential. RI_max values were significantly increased in the presence of Rim1 for all potential values studied.