FIGURE 2.

RIM1 changes the inactivation kinetics of recombinant L-type Ca_V channels. A, representative whole cell currents recorded in HEK-293 cells expressing Ca_V1.2α₁/Ca_Vα₂δ-1 channels, with Ca_Vβ₂ (upper traces) or Ca_Vβ₃ (lower traces) in the absence and presence (black and gray traces, respectively) of RIM1. Peak amplitude of the currents before and after RIM1 co-expression was normalized for comparison. Currents were elicited by 2-s depolarizing pulses from a V_h of −80 to 0 mV. B, comparison of time constant of inactivation (top) and percentage of current remaining at the end of the 2-s voltage step (I_rem) in cells expressing Ca_V1.2α₁/Ca_Vα₂δ-1/Ca_Vβ channels in the absence (solid bars) or presence (open bars) of RIM1. C, representative current traces recorded in HEK-293 cells expressing Ca_V1.3α₁/Ca_Vα₂δ-1 channels together with Ca_Vβ₂ or Ca_Vβ₃ in the absence and presence of RIM1 (as in A). Currents were evoked by 2-s depolarizing pulses from a V_h of −80 to −30 mV. D, comparison of time constant of inactivation (top) and percentage of current remaining at the end of the voltage step in cells expressing Ca_V1.3α₁/Ca_Vα₂δ-1/Ca_Vβ channels in the absence or presence of RIM1 (as in B). *, significant differences (p < 0.05) compared with control without RIM1. Error bars, S.E.