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Cambridge Institute for Medical Research


Basic and translational research into thrombosis, haemophilia and antitrypsin deficiency

General audience summary:
Blood must be able to flow to deliver nutrients and signals to cells throughout the body. When blood vessels rupture, clots must form quickly to limit bleeding, but overgrowth of clots can cause thrombosis. We study the structure of proteins that regulate blood clotting, and use these insights to devise therapies for disorders including haemophilia, heart attacks, stroke, and deep vein thrombosis.

Strategic CIMR themes: Rare Genetic Diseases, Protein Folding and Quality Control

Research Group members:  Fatma Isik Ustok


Haemostasis (blood coagulation) is a complex process under tight regulatory control, with dysregulation resulting in bleeding or thrombosis. The main focus of my lab is to develop a structural understanding of these regulatory mechanisms, with the expectation that such information will help improve therapies for the prevention and treatment of diseases such as haemophilia, deep vein thrombosis, pulmonary embolism, heart attack and stroke. Our basic research into haemostasis centres on the two molecular engines of clot formation: the intrinsic Xase complex and the prothrombinase complex. These complexes are homologous and consist of a protease component and a cofactor. The Xase complex is composed of factor (f) IXa and fVIIIa, and as the name suggests, its function is to convert the zymogen fX to the active protease fXa. The prothrombinase complex produces thrombin from prothrombin, and is composed of fXa and fVa. Haemophilia is caused by deficiencies in either fIX or fVIII, and thrombosis is caused by excessive thrombin formation. We have recently solved the crystal structure of the prothrombinase complex from the venom of the Australian brown snake Pseudonaja textilis, and work is on-going to determine how it relates to human prothrombinase and the Xase complex. In addition to this basic research, we have active translational projects in the field of thrombosis and haemophilia. In collaboration with Trevor Baglin from Addenbrooke’s Trust we invented a first-in-class antithrombotic agent and founded XO1 Ltd in 2013. We also have a company, ApcinteX, developing a novel haemostatic agent to treat bleeding disorders, such as haemophilia.

Another major project in the lab is to determine the molecular basis of serpin polymerisation. We have revolutionised the field with crystal structures of intact serpin dimers and trimers that revealed unexpected and extensive domain swaps. Importantly, we have compelling structural data on how the common Z-mutation results in the misfolding and polymerisation of α1-antitrypsin. This insight has led to the founding of Z Factor Ltd to identify compounds that rescue folding and to prevent onset of the lung and liver manifestations of antitrypsin deficiency.


Key publications: 

Baglin, TP, Langdown, J, Frasson, R & Huntington, JA. Discovery and characterization of an antibody directed against exosite I of thrombin. J. Thromb. Haemost. 14, 137–142 (2016).

Lechtenberg, B.C., Murray-Rust, T.A., Johnson, D.J., Adams, T.E., Krishnaswamy, S., Camire, R.M. and Huntington, J.A. Crystal structure of the prothrombinase complex from the venom of Pseudonaja textilis. Blood 122, 2777–2783 (2013)

 Li, W. and Huntington, J.A. Crystal structures of protease nexin-1 in complex with heparin and thrombin suggest a 2-step recognition mechanism. Blood 120, 459–467 (2012).

 Yamasaki, M., Sendall, T.J., Pearce, M.C., Whisstock, J.C. and Huntington, J.A. Molecular basis of α1-antitrypsin deficiency revealed by the structure of a domain-swapped trimer. EMBO Rep. 12, 1011–1017 (2011).

Professor of Molecular Haemostasis

Contact Details

Takes PhD students
Available for consultancy


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