Figure 2. Elk1 has a mode shift to... | Rockefeller University Press

Figure 2.

$Figure 2. Elk1 has a mode shift to voltage gating that is lost upon patch excision. (A) Elk1 currents are shown for a series of 1-s voltage steps from a holding potential of −100 mV (left) or after a 1-s step to 60 mV to elicit mode shift (right). G-V data were taken from isochronal tail currents at −100 mV (arrows). (B) G-V plots for −100-mV hold (squares) and 60-mV prepulses (circles) in the on-cell (black; n = 18) and excised (red; n = 19) configurations. Curves are single Boltzmann fits; mode shifts (ΔV50 between 60-mV prepulse and −100-mV hold) are reported in Table 2. (C) Voltage protocol for measuring the time course of mode shift. A series of 10 60-mV voltage steps increasing in duration from 200 ms to 2 s were given to activate channels and induce mode shift as estimated by time course of tail currents recorded at −100 mV after the steps. Top and bottom panels depict the 1st and 10th sweeps, respectively. (D) Example tail current traces recorded on cell or excised with voltage protocols shown in C. Only the first and last sweeps are shown for clarity, and data were normalized for display; the dotted line shows the zero current level. (E) Tail current time course measured as fractional amplitude remaining at 60 ms plotted as a function of 60-mV prepulse length (n = 34 on cell and 39 excised). The curve for on-cell data are a single-exponential fit with a time constant of 505 ms. All data points show mean ± SEM.$

Elk1 has a mode shift to voltage gating that is lost upon patch excision. (A) Elk1 currents are shown for a series of 1-s voltage steps from a holding potential of −100 mV (left) or after a 1-s step to 60 mV to elicit mode shift (right). G-V data were taken from isochronal tail currents at −100 mV (arrows). (B) G-V plots for −100-mV hold (squares) and 60-mV prepulses (circles) in the on-cell (black; n = 18) and excised (red; n = 19) configurations. Curves are single Boltzmann fits; mode shifts (ΔV₅₀ between 60-mV prepulse and −100-mV hold) are reported in Table 2. (C) Voltage protocol for measuring the time course of mode shift. A series of 10 60-mV voltage steps increasing in duration from 200 ms to 2 s were given to activate channels and induce mode shift as estimated by time course of tail currents recorded at −100 mV after the steps. Top and bottom panels depict the 1st and 10th sweeps, respectively. (D) Example tail current traces recorded on cell or excised with voltage protocols shown in C. Only the first and last sweeps are shown for clarity, and data were normalized for display; the dotted line shows the zero current level. (E) Tail current time course measured as fractional amplitude remaining at 60 ms plotted as a function of 60-mV prepulse length (n = 34 on cell and 39 excised). The curve for on-cell data are a single-exponential fit with a time constant of 505 ms. All data points show mean ± SEM.