Fig. 4.

Two distinct interfaces control the final activation gating transition. (A) Q - V curves for the ILT Shaker mutant in the presence (open circles) or absence (full squares) of 1 mM 4-AP. (B) Q - V (circles) and G - V (squares) curves of the double mutant ILT/F²⁹⁰T (open symbols) and ILT channels (full symbols). (C–D) Gating currents of the R4K mutant (C) and the double mutant R4K/F²⁹⁰T (D) measured with the indicated activation protocol. The currents’ traces at the repolarizing pulses are shown in an expanded time scale (Insets). Capacitive and leak currents were subtracted off-line. (E) Q - V (full circles) and G - V (open squares) curves for the R4K mutant. (F) Q - V (circles) and G - V (squares) curves for the R4K mutation (full symbols) and for the double mutant R4K/F²⁹⁰T (open symbols). The data are representative of four to six independent experiments for each mutant.