Fig. 6.

PIEZO1 transitions between a pressure-gated and a voltage-gated mode. a PIEZO1 R2482K mutant was subjected to pressure stimulations at increasing voltages (from 10 to 80 mV) with a deactivation of 2 s. After an initial deactivation, PIEZO1 at voltages >40 mV undergoes a reactivation phase. b A saturating pressure pulse at 80 mV was applied to force the channel to reactivate and switch to a voltage-gated mode. Following a 2 s deactivation period at 5 mV (to prevent the inactivation gate from closing), a family of 1 s steps at increasing voltages (in absence of pressure) was applied, showing that PIEZO1 R2482H/K can be activated by voltage. c The mean time, constant of activation (±SEM) for mutant R2482K, is plotted against increasing voltages (n = 10). d wild-type PIEZO1 undergoes reactivation in the presence of the gating modifier Yoda1 (5 μM) in the intracellular solution. The same voltage/pressure protocol was applied as in a. e PIEZO1 can be activated by voltage in presence of Yoda1 (5 μM) intracellularly in absence of externally applied pressure. The same protocol was applied as in b. f The kinetic of activation decreased at more depolarized voltages as it occurs in voltage-gated ion channels (n = 5). g Conductance–voltage relationships for PIEZO1 R2482K (red, n = 10), R2482H (blue, n = 8), wt +Yoda1 5 μM (black, n = 5) in voltage-gated mode were fitted to a Boltzmann equation. The data are displayed as mean ± SEM. h Proposed model for gating transitions of PIEZO1. Bottom left: PIEZO1 inactivation gate opens during outward permeation (+Δμ) and application of pressure (ΔP) (red inactivation gate partially tilted upward). A persistent depolarization can overcome inactivation and induce a reactivation of the channel (inactivation gate completely open) and a switch to a voltage-gated mode (orange). Deactivation of the channel at voltages close to 0 leads to channel closure. Further depolarization causes a movement of gating charges and opening of the channel. Inward permeation (−Δμ) brings the inactivation gate back into the pore and allows the channel to switch back to a pressure-gated mode. Further, pressure-mediated inward permeation leads the channel into an inactive state (inactivation gate tilted toward the center of the pore). Such transition is reversible and mediated further by outward permeation