FIGURE 3.

The N-terminal domain of VDAC1 is required for mutant SOD1 interaction with VDAC1 and inhibition of channel conductance. (A,B) Currents passing through bilayer-reconstituted recombinant N-terminally truncated VDAC1 (ΔN-VDAC1) were recorded in response to voltage step from 0 to 10 mV (A) or –10 mV (B) before and 15–20 min after the addition of 40 μg/ml (final concentration) of SOD1^WT. (C) Relative conductance of ΔN-VDAC1 as a function of voltage in a step from 60 to –60 mV before (▲) and after addition of SOD1^WT (Δ). Relative conductance (conductance/maximal conductance) was determined as the average steady-state conductance at a given voltage normalized to the conductance at 10 mV, taken as the maximal conductance. (D) Histogram of VDAC1 current amplitudes at 10 mV before and after addition of SOD1^WT. (E–H) Similar experiments as in (A–D), except that mutant SOD1^G93A was used. (I–L) Similar experiments as in (A–D), except that mutant SOD1^G85R was used.