Membrane-mediated Synthesis of Tissue Factor (Thromboplastin) in Cultured Fibroblasts

Abstract

Abstract A potent procoagulant synthesized by cultured human skin fibroblasts has been identified as tissue factor (factor III, thromboplastin), since it binds factor VII and is blocked by a specific antitissue factor antibody. Fibroblast tissue factor is, at least in part, a labile superficial, membrane-associated substance the synthesis of which is mediated by cell adhesion but is inhibited by actinomycin-D and puromycin. Tissue factor production is related to the shape change that occurs as the cells spread on the floor of the culture vessel, but tissue factor is not synonymous with the configuration on the cell surface responsible for cell adhesion. These observations suggest that cell membranes may play a significant role in hemostasis and thrombosis by virtue of their tissue factor content.