Plasminogen activator inhibitor-2

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Serpin peptidase inhibitor, clade B (ovalbumin), member 2
Protein SERPINB2 PDB 1by7.png
PDB rendering based on 1by7.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols SERPINB2 ; HsT1201; PAI; PAI-2; PAI2; PLANH2
External IDs OMIM173390 MGI97609 HomoloGene20571 GeneCards: SERPINB2 Gene
RNA expression pattern
PBB GE SERPINB2 204614 at tn.png
More reference expression data
Species Human Mouse
Entrez 5055 18788
Ensembl ENSG00000197632 ENSMUSG00000062345
UniProt P05120 P12388
RefSeq (mRNA) NM_001143818 NM_001174170
RefSeq (protein) NP_001137290 NP_001167641
Location (UCSC) Chr 18:
63.87 – 63.9 Mb
Chr 1:
107.51 – 107.54 Mb
PubMed search [1] [2]

Plasminogen activator inhibitor-2 (placental PAI) 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]

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Further reading[edit]


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

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