Hv1 response to mechanical stimulation in the presence of a pH gradient. (A) Schematic representation of dimeric Hv1 opened by membrane stretch (red arrows) when ΔpHm = pHo − pHi > 0. (B) Proton currents were recorded at a membrane potential sufficiently negative to prevent voltage-dependent channel activation in the absence of mechanical stimulation (between −30 and −20 mV; black). The current was then recorded again at the same voltage but in the presence of negative pressure in the pipette (red). At the end of the pressure step, the voltage was changed to −80 mV. (C) Quantification of the proton current elicited by negative pressure stimulation under conditions described in B. Membrane patches from noninjected cells (NI) displayed no stretch-induced currents. Error bars are SEM (n = 5 for NI, n = 11 for Hv1). Asterisks indicate statistically significant difference: ***, P < 0.0001.
