1. Figure 2 Initiation, amplification and propagation of coagulation
Figure 2 | Initiation, amplification and propagation of coagulation. Upon vessel wall injury and/or activation of endothelial cells, tissue factor (TF) is exposed to blood and binds to FVII or FVIIa, promoting FVII activation or enhancing its catalytic activity. The TF–FVIIa (extrinsic tenase) complex activates small amounts of FIX and FX. FXa associates with FVa to form the prothrombinase complex, which cleaves FII to generate a small amount of thrombin. This initiation phase is followed by the amplification phase, in which thrombin activates cell-surface (predominately platelet) bound FV and FVIII and platelet-bound FXI. FIXa binds to FVIIIa on negatively charged surfaces (predominately platelet-derived phospholipids), activating FX (intrinsic tenase) and initiating a burst of thrombin generation—the propagation phase. Thrombin has pleotropic functions including feedback inhibition, fibrin formation, platelet activation and signalling through protease activated receptors. a, activated; F, factor.
Kerlin, B. A. & Isermann, B. et al. (2015) The emerging role of coagulation proteases in kidney disease
Nat. Rev. Nephrol. doi: /nrneph