The function of F3 (coagulation factor III, tissue factor, Ensembl gene identifier ENSG00000117525) is as follows. Initiates blood coagulation by forming a complex with circulating factor VII or VIIa. The [TF:VIIa] complex activates factors IX or X by specific limited proteolysis. TF plays a role in normal hemostasis by initiating the cell-surface assembly and propagation of the coagulation protease cascade. {ECO:0000269|PubMed:12652293, ECO:0000269|PubMed:271951}.