Phosphatase activities of TI loop mutants.

<p><i>(</i><b><i>A</i></b><i>)</i> Representative currents traces of Ci-VSP WT and denoted mutants that were co-expressed with KCNQ2/KCNQ3 potassium channels in <i>Xenopus</i> oocytes. Channel currents were recorded in response to a depolarization pulse from a holding potential of −80 to+80 mV for the indicated time interval. <i>(</i><b><i>B</i></b><b>–</b><b><i>C</i></b><i>)</i> From the resulting current traces, maximal and minimal current amplitudes (I<sub>max</sub> and I<sub>min</sub>) were determined during the depolarization phase at+80 mV. Inhibition ratios calculated with the values of I<sub>min</sub> and I<sub>max</sub> are plotted with the corresponding time durations required for each mutant to inhibit the channel currents to 50% (τ<sub>50%</sub>). Inhibition ratio of 0.5 (corresponding to 50%) is highlighted as dashed line.</p>