Tissue factor – activated factor VII complex (TF-FVIIa complex)

The Tissue factor – activated factor VII (TF-FVIIa) complex is the primary initiator of the extrinsic pathway of blood coagulation [1.2.2, 1.3.5]. It forms when transmembrane tissue factor (TF), exposed upon vascular injury or induced on cells like monocytes, binds to circulating activated factor VII (FVIIa) [1.3.1, 1.3.4]. This complex acts as a serine protease, often referred to as the extrinsic tenase, which proteolytically activates factors X and IX [1.1.4, 1.2.5]. This activation leads to a burst of thrombin generation and subsequent fibrin clot formation [1.1.2, 1.4.2]. Beyond its role in hemostasis, the TF-FVIIa complex triggers intracellular signaling through the cleavage of protease-activated receptor 2 (PAR2) [1.2.4, 1.3.5]. This signaling pathway influences various pathophysiological processes, including inflammation, angiogenesis, and tumor metastasis [1.2.3, 1.2.4]. In clinical practice, recombinant FVIIa is used as a bypassing agent to treat hemophilia patients with inhibitors [1.3.2, 1.4.1]. Conversely, inhibitors of the complex or its regulator, tissue factor pathway inhibitor (TFPI), are under investigation for treating thrombosis and bleeding disorders [1.3.3, 1.4.2]. Additionally, the high expression of TF in certain cancers makes the complex a target for antibody-drug conjugates in oncology [1.2.3, 1.3.3].

Other names

Extrinsic tenase complexCoagulation factor III – activated factor VII complexTF-FVIIa complexCD142-FVIIa complexTissue factor – activated coagulation factor VII complex

The TF-FVIIa complex initiates the coagulation cascade by proteolytically activating Factor X and Factor IX [1.1.4]. Drugs targeting this complex either inhibit its enzymatic activity to prevent thrombosis or enhance its activity (directly or by inhibiting its natural inhibitor, TFPI) to promote hemostasis in bleeding disorders [1.3.4, 1.4.2].