Plasminogen activator inhibitor-2

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



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

Interactions
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.