[Expressed in platelets and vascular endothelia by human F2R Gene (GPCR1 Family), 425-aa 47-kDa (precursor) Coagulation Factor II Receptor is a 7-transmembrane G-protein coupled high affinity activated thrombin receptor that stimulates phosphoinositide hydrolysis in the cellular thrombotic response. F2R appears to play a role in platelet activation and vascular development. Receptor phosphorylation probably mediates desensitization prior to uncoupling and internalization. Activated protein C uses EPCR as a coreceptor for cleavage of Coagulation Factor II Receptor on endothelia. Proteolytic cleavage of F2R generates a new N-terminus that functions as a tethered ligand. (NCI) ( NCI )]