Modulation of PAR1-dependent ERK1/2 signaling by PAR3 in endothelial cells. Phosphorylation of Thr202/Tyr204-ERK1/2 and Ser473-Akt by P3R (residues 42-54) and P3K (residues 39-54) was determined in the absence and presence of TRAP-peptides TFLLRN or SFLLRN. (A) Time-dependent ERK1/2 phosphorylation by P3R (50 µM) and P3K (50 µM). (B) Phosphorylation of Akt by P3R (50 µM) and P3K (50 µM) over time. (C-D) ERK1/2 phosphorylation at 15 minutes induced by TFLLRN (25 µM) (C) or SFLLRN (25 µM) (D) after pretreatment (1 hour) with P3R (50 µM) or P3K (50 µM). (E, F) Akt phosphorylation at 15 minutes induced by TFLLRN (25 µM) (E) or SFLLRN (25 µM) (F) after pretreatment (1 hour) with P3R (50 µM) or P3K (50 µM). (A-F) Data points represent mean ± SD of at least 3 independent experiments. *P < .05; **P < .01. ns, not significant.