Fig. 2
TM2.6 mutation increases the basal activity of pH-sensitive K2P channels. Current–voltage relationships of a hTASK1 and b mTASK2 channels; wild-type (black) and TM2.6 mutant (red) at extracellular pH 7.4 (filled squares) and pH 9.4 (open squares). Each data point represents the mean ± standard error of the mean, numbers in parentheses represent the number of oocytes tested for each condition. In (b), insets represent normalized current traces recorded at 0 mV. mTASK2 activation time was 91.07 ± 2.27 ms (n = 8) at pH 7.4 (black trace) and 44.98 ± 4.96 ms (n = 8) at pH 9.4 (orange trace). mTASK2 L127N activation time was 39.51 ± 2.25 ms (n = 8) at pH 7.4 (red trace) and 29.41 ± 5.35 ms (n = 5) at pH 9.4 (brown trace). Rightmost panels represent relative current increases, corresponding to the ratio between currents under pH 9.4 perfusion and currents under pH 7.4 perfusion at 0 mV. Mean relative current increases at 0 mV from pH 7.4 to 9.4 were 2.8 ± 0.2 and 1.4 ± 0.1 for wild-type and mutant hTASK1, respectively. Mean relative current increases were 9.8 ± 0.7 and 1.8 ± 0.1 for wild-type and mutant mTASK2, respectively. Currents were recorded 24 h after injection of cRNA (mTASK2 and mTASK2 L127N, 5 ng/oocyte; hTASK1, 2.28 ng/oocyte; hTASK1 L122N, 0.38 ng/oocyte). Each data point represents one oocyte; center lines, medians; open circles, means; box limits, 25th and 75th percentiles; whiskers, standard deviation. Mann–Whitney, **p < 0.01, ***p < 0.001
