The functions of maestro TF. The TF/FVIIa complex initiates activation of FX to FXa (A) or FIX to FIXa (B) localized to an anionic phospholipid-containing membrane (green lipid polar head groups). (C) Nascent TF/FVII/FXa is an important cell modulator via cleavage of PAR2 to expose its tethered ligand in the stimulated form (PAR2a). (D) Newly defined in the current article is an additional TF/FVIIa/FXa function, which initiates FVIII activation. Double arrows indicate multistep processes.