Novel insights into the regulation of coagulation by factor V isoforms, tissue factor pathway inhibitorα, and protein S

Factor V (FV) is a regulator of both pro‐ and anticoagulant pathways. It circulates as a single‐chain procofactor, which is activated by thrombin or FXa to FVa that serves as cofactor for FXa in prothrombin activation. The cofactor function of FVa is regulated by activated protein C (APC) and protein S. FV can also function as an anticoagulant APC cofactor in the inhibition of FVIIIa in the membrane‐bound tenase complex (FIXa/FVIIIa). In recent...