Figure 7.

The effects of PI(4,5)P₂ and PI(4)P on Piezo1-mediated MA currents in excised inside-out patches in HEK293 cells transfected with Piezo1. (A) Voltage (upper) and pressure (middle) protocols and representative MA currents (lower). The holding potential was 0 mV, a 3s long voltage step to −60 mV was applied, during which a 200 ms long negative pressure pulse was used to elicit MA currents; 15 s later a second 3 s voltage step to +60 mV was applied during which the MA currents were induced with a −20 mmHg pressure step. The protocol was repeated every 30 s. (A, lower) Individual traces with marks showing peak currents (black square) and the currents at the end of the pressure step (red circle) at −60 mV, and peak currents (blue triangle) at +60 mV, which were plotted in panel B. (B) Representative MA peaks and end currents (as marked in the lower part of A) measured when patches were excised (i/o) into control bath solution (left), or a bath solution containing 10 μM PI(4,5)P₂ and 10 μM PI(4)P (PIPs) (right). At the time periods indicated by the horizontal lines the patch was perfused with 30 μg/ml Poly-lysine (Poly K). (C) Statistical summary of peak MA currents recorded at −60 mV (downward bars) and +60 mV (upward bars) in the cell attached configuration (ca), after excision (i/o), 5 minutes after excision (end), and after application of 30 μg/ml Poly-lysine (PolyK). All data were normalized to the cell-attached current values at +60 mV *p<0.05, ANOVA