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Updated: Feb 15, 2026

Peptide-based Identification of Functional Motifs and their Binding Partners
Published on: June 30, 2013
Angiopoietins bind thrombomodulin and inhibit its function as a thrombin cofactor
Christopher Daly1, Xiaozhong Qian2, Carla Castanaro2
1Regeneron Pharmaceuticals, Inc., 777 Old Saw Mill River Road, Tarrytown, New York, 10591, USA. christopher.daly@regeneron.com.
Angiopoietins (Ang1 and Ang2) bind to thrombomodulin (TM), an endothelial protein, inhibiting its role in blood coagulation. This discovery reveals a new function for angiopoietins in regulating hemostasis.
Area of Science:
- Endothelial biology
- Hemostasis and thrombosis
- Molecular and cell biology
Background:
- Angiopoietin-1 (Ang1) and Angiopoietin-2 (Ang2) are ligands for the Tie2 receptor, crucial for angiogenesis.
- Thrombomodulin (TM) is an endothelial cell surface protein vital for inhibiting coagulation by acting as a cofactor for thrombin-mediated activation of Protein C and TAFI.
Purpose of the Study:
- To identify novel receptors for Ang1 and Ang2.
- To investigate the interaction between angiopoietins and thrombomodulin.
- To elucidate the role of angiopoietins in hemostasis.
Main Methods:
- Expression cloning was used to identify TM as a receptor for Ang1 and Ang2.
- In vitro assays measured the binding of thrombin to TM and the generation of activated Protein C and TAFI.
- In vivo studies analyzed plasma Ang1 levels after thrombin administration in mice and in wound blood.
Main Results:
- Thrombomodulin (TM) was identified as a novel receptor for Ang1 and Ang2.
- Ang1 and Ang2 inhibited thrombin/TM-mediated generation of activated Protein C and TAFI in endothelial cells.
- Ang2 exhibited higher affinity for TM than Ang1, acting as a more potent inhibitor of TM function.
- Plasma Ang1 levels increased after thrombin administration and were elevated in wound blood, suggesting platelet release at injury sites.
Conclusions:
- Angiopoietins (Ang1 and Ang2) bind to thrombomodulin (TM), modulating its anticoagulant function.
- Angiopoietins play a previously unrecognized role in the regulation of hemostasis.
- The interaction between angiopoietins and TM offers new insights into vascular biology and coagulation.
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