Figure 2
Biophysical impact of T309I mutation. (A) Representative records in wild type (WT), T309I, and WT/T309I channels (KCNE1 subunit cotransfected); arrows point to the tail current. (B) Average voltage dependence of tail current activation (n = 20, 9, and 16 in WT, T309I, and WT/T309I channels, respectively); the half-maximal activation voltage V1/2 = 8.3 ± 2.2 mV in WT channels and 15.6 ± 2.1 mV in WT/T309I channels; P < 0.05). (C) Activation experimental protocol; the dashed lines—steps used for stimulation only in T309I channels. (D) Representative trace from a non-transfected CHO cell. (E) Average voltage dependence of steady-state activation. (F) Average voltage dependence of the time constant of activation (τact) and time constant of deactivation (τdeact; n = 11 and 9 in WT and WT/T309I channels, respectively); inset: deactivation experimental protocol; *, ** and ***statistical significance between WT and WT/T309I channels at P < 0.05, 0.01 and 0.001, respectively. The stimulation frequency was 0.08 Hz. All graphs were prepared using the software Origin, version 8.5.1.
