Figure 1. K_v3.1b gating current recordings monitor the VSD movement.

(a) Gating currents (Ig) of WT K_v3.1b after depletion of K⁺ and subsequent application of external TEA to block the remaining ionic current. Ig recordings were obtained using the activation pulse protocol shown on top. The holding potential was −120 mV and cells were depolarized in 5-mV increments from −120 mV to +80 mV. Background leak and capacitive currents were subtracted using a –P/4 protocol. Inset shows a scaled-up view of the Ig_off currents obtained by stepping to −90 mV. (b) Pulse protocol to analyse the deactivating Ig_deac currents. (c) Voltage dependence of activating charge movement (QV curve, open triangles), which was obtained by integrating the Ig_off currents from pulse protocols shown in a (data are shown as average±s.e.m., n=6). For comparison, the ionic GV curve from Supplementary Fig. 1 is displayed (grey circles). (d) Voltage dependence of the average time constants±s.e.m. of Ig_ac (τ_Igac, open triangles, n=6) and Ig_deac (τ_Igdeac, black circles, n=6). τ_Igac kinetics were obtained from fitting the Ig_ac current decays (from pulse protocols shown in a) with a single exponential function. τ_Igdeac kinetics were obtained by approximating the Ig_deac current decays (from pulse protocols shown in b) with a double exponential function and represented values are the weighted time constants. As comparison the ionic τ_Iiac and τ_Iideac kinetics (Supplementary Fig. 1) are displayed in grey circles and triangles, respectively.