Thrombomodulin

Thrombomodulin (TM), CD141 or BDCA-3 is an is_associated_with::integral membrane protein expressed on the surface of endothelial cells and serves as a cofactor for is_associated_with::thrombin. It reduces is_associated_with::blood coagulation by converting thrombin to an anticoagulant enzyme from a procoagulant is_associated_with::enzyme. Thrombomodulin is also expressed on human mesothelial cell, monocyte and a dendritic cell subset.

Characterization
In humans, thrombomodulin is encoded by the THBD is_associated_with::gene. The protein has a molecular mass of 74kDa, and consists of a single chain with 5 distinct domains.

Function
Thrombomodulin functions as a cofactor in the is_associated_with::thrombin-induced activation of is_associated_with::protein C in the is_associated_with::anticoagulant pathway by forming a 1:1 stoichiometric complex with thrombin. This raises the speed of protein C activation thousandfold. Thrombomodulin-bound thrombin has procoagulant effect at the same time by inhibiting fibrinolysis by cleaving thrombin-activatable fibrinolysis inhibitor (TAFI,aka carboxypeptidase B2) into its active form.

Thrombomodulin is a glycoprotein on the surface of endothelial cells that, in addition to binding thrombin, regulates C3b inactivation by factor I. Mutations in the thrombomodulin gene (THBD) have also been reported to be associated with atypical hemolytic-uremic syndrome (aHUS).

The is_associated_with::antigen described as BDCA-3 has turned out to be identical to thrombomodulin. Thus, it was revealed that this molecule also occurs on a very rare (0.02%) subset of human is_associated_with::dendritic cells called MDC2. Its function on these cells is unknown.

Interactions
Thrombomodulin has been shown to interact with is_associated_with::thrombin.