Plasminogen activator inhibitor-2

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Template:Infobox gene Plasminogen activator inhibitor-2 (placental PAI), a serine protease inhibitor of the serpin superfamily, is a coagulation factor that inactivates tPA and urokinase. It is present in most cells, especially monocytes/macrophages. PAI-2 exists in two forms, a 60-kDa extracellular glycosylated form and a 43-kDa intracellular form.

Fibrinolysis (simplified). Blue arrows denote stimulation, and red arrows inhibition.

It is present only at detectable quantities in blood during pregnancy, as it is produced by the placenta, and may explain partially the increased rate of thrombosis during pregnancy. The majority of expressed PAI-2 remains unsecreted due to the presence of an inefficient internal signal peptide.


Plasminogen activator inhibitor-2 (SerpinB2) has been reported to bind a series of intracellular and extracellular proteins. Whether SerpinB2's physiological function is inhibition of the extracellular protease urokinase and/or whether SerpinB2 has intracellular activities remains controversial. At least one of SerpinB2's physiological functions may involve regulation of adaptive immunity.[1]

See also

Further reading


  1. Schroder WA, Major L, Suhrbier A (2011). "The role of SerpinB2 in immunity". Crit. Rev. Immunol. 31 (1): 15–30. PMID 21395508. doi:10.1615/critrevimmunol.v31.i1.20. 

External links

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