CD141, also known as Thrombomodulin, is a type I membrane glycoprotein and forms a 1:1 stoichiometric complex with thrombin, which activates the protein C. The activated protein C splits the activated cofactors of coagulation mechanism, factor Va and VIIIa, thus reduces the amount of thrombin generated. CD141 is expressed on monocyted, macrophages, a subpopulation of myeloid dendritic cells, vascular endothelial cells, and keratinocytes. It is also involved in embryonic and atherosclerotic plaque development.