serpin family B member 2, plasminogen activator inhibitor 2
Plasminogen activator inhibitor-2 (PAI-2/PLANH2, also called placental PAI, monocyte arg-serpin, or urokinase inhibitor) is a serine protease inhibitor that belongs to the ovalbumin family of serpins (ov-serpins). It is an effective inhibitor of urinary plasminogen activator (urokinase or uPA) and is involved in cell differentiation, tissue growth and regeneration. Ov-serpins are a family of closely related proteins, whose members can be secreted (ovalbumin), cytosolic (leukocyte elastase inhibitor, LEI), or targeted to both compartments (plasminogen activator inhibitor 2, PAI-2). It also characterized by N- and C-terminal extensions, the absence of a signal peptide, and a Ser rather than an Asn residue at the penultimate position. The ov-serpins corresponds to clade B of the serpin superfamily. In general, SERine Proteinase INhibitors (serpins) exhibit conformational polymorphism shifting from native to cleaved, latent, delta, or polymorphic forms. Many serpins, such as antitrypsin and antichymotrypsin, function as serine protease inhibitors which regulate blood coagulation cascades. Non-inhibitory serpins perform many diverse functions such as chaperoning proteins or transporting hormones. Serpins are of medical interest because mutants can cause blood clotting disorders, emphysema, cirrhosis, and dementia. A classification based on evolutionary relatedness has resulted in the assignment of serpins to 16 clades designated A-P along with some orphans.
Comment:depending on the conformational state, RCL is surface accessible in the active form or buried and inserted as the central beta strand in the inactive form
Structure:2ARQ_A: Human plasminogen activator inhibitor-2 deletion mutant RCL, solvent-exposed
Jiyao W et al.(2023). "The conserved domain database in 2023.",