Thromb Haemost 2017; 117(09): 1688-1699
DOI: 10.1160/TH17-02-0102
Coagulation and Fibrinolysis
Schattauer GmbH

Latency transition of plasminogen activator inhibitor type 1 is evolutionarily conserved

Agnieszka Jendroszek
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Malene S. Sønnichsen
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Andrés C. Muñoz
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Kato Leyman
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Anni Christensen
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Steen Vang Petersen
2   Department of Biomedicine, Aarhus University, Denmark
,
Tobias Wang
3   Department of Bioscience-Zoophysiology, Aarhus University, Denmark
,
Christian Bendixen
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Frank Panitz
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Peter A. Andreasen
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
,
Jan K. Jensen
1   Department of Molecular Biology and Genetics, Aarhus University, Denmark
› Author Affiliations

Financial support: The project was funded by the Danish National Research Council (FNU 12041-26101).
Further Information

Publication History

Received: 13 February 2017

Accepted after major revision: 11 May 2017

Publication Date:
08 November 2017 (online)

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Summary

Plasminogen activator inhibitor type 1 (PAI-1) is a central regulator of fibrinolysis and tissue remodelling. PAI-1 belongs to the serpin super-family and unlike other inhibitory serpins undergoes a spontaneous inactivation process under physiological conditions, termed latency transition. During latency transition the solvent exposed reactive centre loop is inserted into the central β–sheet A of the molecule, and is no longer accessible to reaction with the protease. More than three decades of research on mammalian PAI-1 has not been able to clarify the evolutionary advantage and physiological relevance of latency transition. In order to study the origin of PAI-1 latency transition, we produced PAI-1 from Spiny dogfish shark (Squalus acanthias) and African lungfish (Protopterus sp.), which represent central species in the evolution of vertebrates. Although human PAI-1 and the non-mammalian PAI-1 variants share only approximately 50 % sequence identity, our results showed that all tested PAI–1 variants undergo latency transition with a similar rate. Since the functional stability of PAI–1 can be greatly increased by substitution of few amino acid residues, we conclude that the ability to undergo latency transition must have been a specific selection criterion for the evolution of PAI-1. It appears that all PAI-1 molecules must harbour latency transition to fulfil their physiological function, stressing the importance to further pursue a complete understanding of this molecular phenomenon with possible implication to pharmacological intervention. Our results provide the next step in understanding how the complete role of this important protease inhibitor evolved along with the fibrinolytic system.

Supplementary Material to this article is available online at www.thrombosis-online.com.