Thrombomodulin, also known as THBD(CD141), is an integral membrane protein which reduces blood coagulation by converting thrombin to an anticoagulant enzyme from a procoagulant enzyme. Thrombomodulin is expressed on the surface of endothelial cells and serves as a cofactor for thrombin. It is also expressed on human mesothelial cell, monocyte and a dendritic cell subset. Thrombomodulin functions as a cofactor in the thrombin-induced activation of protein C in the anticoagulant pathway by forming a 1:1 stoichiometric complex with thrombin. Thrombomodulin also regulates C3b inactivation by factor I. Mutations in the thrombomodulin gene have also been reported to be associated with atypical hemolytic-uremic syndrome.