Protease-activated receptor type 1 (PAR1)

Protease-activated receptor type 1 (PAR1) is a seven-transmembrane, cell surface receptor that belongs to the G protein-coupled receptor family and is primarily activated by thrombin through a unique proteolytic cleavage mechanism that unmasks a tethered ligand on its N-terminus, leading to intracellular signaling. PAR1 plays a key role in platelet activation, hemostasis, and thrombosis, and is also involved in vascular biology, inflammation, and cell proliferation. It is widely expressed on platelets, endothelial cells, smooth muscle cells, and is upregulated in a number of solid tumors, contributing to cancer invasion, metastasis, and angiogenesis. PAR1 is a validated pharmacological target in cardiovascular disease (notably for antithrombotic therapy), and emerging evidence highlights its relevance as an oncology target. Antagonists targeting PAR1 are approved or in clinical trials for thrombotic disorders and cancer, but bleeding risks remain a significant therapeutic challenge.

Other names

PAR-1Thrombin receptorF2R (gene name)Protease-activated receptor 1

Antagonism/inhibition of PAR1-mediated G protein signaling (e.g., by vorapaxar, atopaxar, PZ-128); Allosteric modulation of GPCR-dependent signaling (pepducin mechanism); Blockage of thrombin or other protease activation of PAR1