Hv1 response to combined electrical and mechanical stimulation. (A) Schematic representation of dimeric Hv1 stimulated by membrane stretch (red arrows). (B) Effect on Hv1 activation: Proton currents were measured in response to membrane depolarization in the absence (black) and presence (red) of negative pressure in the pipette. Holding potential: −80 mV, holding pressure: 0 mmHg. (C) Effect on Hv1 deactivation: Tail currents were measured at −40 mV after a depolarization pulse at 120 mV in the absence (black) and presence (red) of negative pressure in the pipette. Holding conditions and proton concentrations were as in B. Dotted line corresponds to 0 pA. Break in the current axis corresponds to 200 pA. (D) τ_a as a function of applied voltage without pressure stimulation (black circles) and in the presence of −10 mmHg pressure in the pipette (red squares). (E, left) Effect of −10-mmHg-pressure stimulation on τ_a measured at 60 mV; n = 11; ***, P < 0.0001. (right) Effect of −20-mmHg-pressure stimulation on τ_d measured at −40 mV; n = 3; P > 0.05. (F) Effect on G-V curve of negative pressure in the pipette. G-Vs measured at 0 mmHg and −10 mmHg are shown in black and red, respectively. Boltzmann fit parameters are V_1/2 = 60.5 ± 1.5 mV and s = 11.0 ± 0.8 mV for the 0-mmHg condition (n = 10) and V_1/2 = 46.1 ± 1.2 mV and s = 7.5 ± 0.4 mV for the −10-mmHg condition (n = 10). P < 10⁻⁶ and P < 0.002 for differences in V_1/2 and s, respectively. Errors bars are SEM.