Figure 8.

Proposed signal transduction cascade of PAR-1, PAR-2 and PAR-3 in Adult HCAECs. In adult HCAECs, PAR-1 and PAR-2 couple to both G_q and G_12/13 to regulate the signaling pathways that phosphorylate eNOS and cause NO production. A Ca²⁺-dependent-mediated mechanism, which is coupled to G_q, leads to the phosphorylation of eNOS-Ser-1177 and causes an increase in NO production. A ROCK-dependent pathway, which is coupled to G_12/13, leads to eNOS-Thr-495 phosphorylation and a decrease in NO production. PAR-3 activation is coupled to G_12/13 and the ROCK signaling pathway, which leads to a suppression of NO production via phosphorylation of eNOS-Thr-495. (A color version of this figure is available in the online journal.)