Thrombomodulin

Protein involved in blood coagulation

Thrombomodulin is an integral membrane protein expressed on the surface of endothelial cells. It plays a crucial role in the coagulation system by serving as a cofactor in the thrombin-mediated activation of protein C, which is an important anticoagulant pathway.

Structure

Thrombomodulin is a type I transmembrane protein composed of 557 amino acids. It has a large extracellular domain, a single transmembrane domain, and a short cytoplasmic tail. The extracellular domain contains several distinct regions, including a lectin-like domain, six epidermal growth factor (EGF)-like repeats, and a serine/threonine-rich domain.

Function

Thrombomodulin binds to thrombin, forming a complex that activates protein C. Activated protein C (APC) then degrades factor Va and factor VIIIa, which are essential cofactors in the coagulation cascade. This process effectively reduces the generation of thrombin and limits blood clotting.

Clinical Significance

Mutations in the gene encoding thrombomodulin (THBD) can lead to various coagulation disorders. Deficiency or dysfunction of thrombomodulin is associated with an increased risk of thrombosis and other cardiovascular diseases. Additionally, thrombomodulin levels can be altered in conditions such as sepsis, inflammation, and cancer.

Related Pages

• Coagulation
• Thrombin
• Protein C
• Endothelial cells
• Thrombosis
• Cardiovascular diseases