PAR1 also known as Thrombin R, F2R is a 7-transmembrane receptor involved in the regulation of thrombotic response. PAR1 plays a crucial role in the regulation of hemostasis and inflammation by mediating the effects of thrombin, a serine protease that is pivotal in platelet aggregation and blood coagulation. Upon activation by thrombin, PAR1 undergoes cleavage, releasing a 41 amino acid peptide that acts as a potent platelet agonist, leading to an increase in cytosolic calcium concentration. This activation is essential for the physiological response to vascular injury, as it promotes platelet activation and aggregation, thereby facilitating clot formation. PAR1 protein is predominantly located on the cell surface, where it can interact with thrombin, but also cycles between the cell surface and an intracellular pool, which is vital for maintaining cellular responsiveness to thrombin.