Figure 1.

Shear stress activation of Piezo1 induces rapid mobilization of Ca²⁺ into the ER lumen

(A) Live-cell images of G-CEPIA1er, used to measure changes in [Ca²⁺]_ER, upon the application of 10 dyn/cm² laminar shear for 60 s in untransfected (UT) or siRNA-treated endothelial monolayers as indicated; color-coding scale is shown below; times in seconds; scale bar, 20 μm. Arrow indicates the application of shear stress.

(B) Time-dependent changes of [Ca²⁺]_ER in endothelial monolayers before and after stimulation with 2, 5, and 10 dyn/cm² shear stress for 60 s (highlighted area) as in (A); n = 5-7 cells per group from 3 independent experiments; mean ± SEM.

(C) Rate constants of ER Ca²⁺ rise and decay in (B), mean ± SD; ∗, p < 0.05; ∗∗∗, p < 0.001, ANOVA with Tukey’s post hoc test.

(D) Time-dependent changes of [Ca²⁺]_ER in control and Piezo1-depleted endothelial monolayers upon the application of 10 dyn/cm² shear stress as in (A); n = 6 cells per group from 3 independent experiments; mean ± SEM.

(E) Rate constants of ER Ca²⁺ rise and decay in D, mean ± SD; left, ∗, p < 0.05; ∗∗∗, p < 0.001, Student’s t test.