Coagulation factor II thrombin receptor (PAR1) (PAR1)

Coagulation factor II thrombin receptor, commonly known as Protease-activated receptor 1 (PAR1), is a G protein-coupled receptor that serves as the primary mediator of thrombin's cellular effects [1.2.1, 1.3.1]. It is uniquely activated by a proteolytic mechanism where thrombin cleaves the receptor's N-terminus to reveal a tethered ligand that then binds to the receptor's own extracellular loops [1.3.1, 1.3.2]. PAR1 is highly expressed on platelets, where its activation triggers rapid shape change and aggregation, playing a critical role in arterial thrombosis [1.3.1, 1.4.1]. Beyond hemostasis, PAR1 is involved in inflammatory signaling, endothelial barrier regulation, and cancer progression, particularly in tumor metastasis and invasion [1.2.2, 1.3.2]. Pharmacological targeting of PAR1 with antagonists like vorapaxar is used to reduce the risk of thrombotic cardiovascular events in patients with a history of myocardial infarction or peripheral arterial disease [1.4.1, 1.4.2]. However, the clinical utility of these drugs is limited by a significant risk of bleeding, especially intracranial hemorrhage, which restricts their use in patients with a history of stroke or transient ischemic attack [1.4.1, 1.4.3]. Research also explores PAR1 as a potential biomarker and therapeutic target in various cancers, where its overexpression correlates with poor prognosis [1.2.2, 1.2.4]. Overall, PAR1 represents a key link between the coagulation cascade and cellular responses in cardiovascular and malignant diseases [1.3.2, 1.3.4].

Other names

Protease-activated receptor 1PAR-1Thrombin receptorProteinase-activated receptor 1CHTRTRF2R

Competitive antagonism of the protease-activated receptor-1 (PAR1), preventing thrombin-mediated activation and subsequent platelet aggregation and cellular signaling [1.2.1, 1.4.5].