Thrombin-Induced Calpain Activation Promotes Protease-Activated Receptor 1 Internalization

Figure 2

Thrombin-induced []i increase is mimicked by PAR1-AP. Cells were serum-deprived for 24 hours prior to stimulation with thrombin or PAR-APs. [Ca²⁺]i was assessed by fluorescence microscopy as described in Methods. (a) PAR1-AP (2.5 μM) induced an increase in [Ca²⁺]i, comparable to thrombin. [Ca²⁺]i was plotted as a function of fluorescence intensity (Arbitrary Fluorescence Units (AFU)) over time (minutes). (b) The graph represents the area under the curves in (a). Thrombin (10 nM) stimulation was used as positive control. Results are expressed as the mean ± SEM of three independent experiments, compared to nonstimulated cells (- Control). Multiple comparison ANOVA and Tukey’s test: α = 0.001 () referred to negative control.

(a)

(b)