Protease-activated receptor 1 (PAR-1) (PAR-1)

Protease-activated receptor 1 (PAR-1) is the primary thrombin-activated member of the protease-activated receptor family, which also includes PAR-4 as a thrombin-responsive receptor in humans (Coughlin, 2000). Unlike traditional receptors, PAR-1 is activated through a unique mechanism where thrombin cleaves the N-terminal extracellular domain, revealing a tethered ligand that binds and activates the receptor (UniProt Consortium, 2024). PAR-1 is highly expressed on human platelets and vascular cells, serving as a high-affinity receptor for thrombin to initiate platelet aggregation and vascular remodeling (StatPearls, 2023). Beyond hemostasis, PAR-1 signaling contributes to inflammatory responses, wound healing, and the progression of certain cancers (PubMed, 2021). Clinically, PAR-1 is a significant therapeutic target for preventing atherothrombotic events in patients with a history of myocardial infarction or peripheral arterial disease (FDA, 2014). Drugs like vorapaxar act as competitive antagonists to block the tethered ligand's interaction, effectively inhibiting thrombin-mediated platelet activation while maintaining other pathways of coagulation (PubChem, 2024).

Other names

Coagulation factor II receptorThrombin receptorF2RPAR1CF2R

PAR-1 antagonists function as competitive or allosteric inhibitors that prevent the receptor's tethered ligand, generated by thrombin cleavage, from binding to the receptor's active site, thus blocking intracellular signaling and platelet aggregation (StatPearls, 2023).