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. 2009 Dec 14;107(5):2313–2318. doi: 10.1073/pnas.0911868107

Fig. 2.

Fig. 2.

A206stop retains hallmark properties of Hv channels. (A) Depolarization-induced increases pHin in tsA201 cells transfected with A206stop. BCECF ratio images recorded at the times indicated by the arrows are shown at the top. BCECF ratios were calibrated as described in (Fig. S4. pHin/pHout was 6.0/7.0). The timing of the test pulse is indicated below. (B) Zinc sensitivity of A206stop. 500-ms test pulses were applied from 0 mV to 150 mV in 10-mV increments. The current density at 130 mV was significantly reduced with in the presence of 100 μM zinc (20.5 ± 4.8 pA/pF vs. 1.9 ± 0.1 pA/pF, n = 3, mean ± SD). pHin/pHout was 6.0/7.0. Similar zinc sensitivity was observed in I209stop (Fig. S5). (C) Ion selectivity tested with 20 mM Na+ or K+ in the external solution. The external solution was changed in the sequence shown in the figure. Depolarizing step was applied to 100 mV from a holding potential of −80 mV. Tail currents were outward throughout this series of experiments, indicating that Na+ and K+ do not permeate. Outward tail currents were not observed when pHout was 6.5 (bottom). pHin/pHout was 5.3/8.0. (D) pHout dependence of the activation kinetics of A206stop current is shown by plotting t1/2 values for outward currents elicited by depolarizing steps (500 ms) against membrane potential. Activation times were compared between pHout 8.0 and 7.0 (n = 5). The pH of the pipette solution (pHin) was 6.0. (E) pHin dependence of the activation kinetics of A206stop currents. t1/2 values during 2-s depolarizing steps were compared between pHin 6.5 and 5.3. pHout was fixed to 7.5.