Importance of a Factor VIIIc-Like Glycoprotein Expressed in Capillary Endothelial Cells (eFactor VIIIc) in Angiogenesis
Factor VIII is a large, 2,332-residue plasma glycoprotein that acts as a regulatory cofactor in the process of blood coagulation [1–3]. It binds to activated factor IX (factor IXa) in the presence of calcium and negatively charged phospholipids at the surface of activated platelets to form a membrane-associated, proteolytically active complex. Upon complex formation, the Vmax of factor IXa is increased by approximately 200,000-fold, promoting the rapid activation of its substrate, the serine protease factor X. The proteolytic conversion of factor X to its active form, factor Xa, is a central control point in the coagulation cascade, leading to activation of thrombin, formation of a fibrin mesh, and establishment of a stable blood clot. The binding of factor VIIIc and other activated proteins to these membrane surfaces allows for localization of the procoagulation process to sites of vascular damage.
KeywordsAngiogenesis Mannosylphospho dolichol synthase Unfolded protein response ER stress Apoptosis Cell cycle N-linked glycoproteins Tunicamycin Lipid-linked oligosaccharide