Plasminogen Activator Inhibitor 2 (PAI-2)

Plasminogen activator inhibitor 2 (PAI-2), also known as SERPINB2, is a member of the serine protease inhibitor (serpin) superfamily. It primarily functions as an inhibitor of urokinase-type plasminogen activator (uPA) and, to a lesser extent, tissue plasminogen activator (tPA). PAI-2 exists in two main forms: a non-glycosylated intracellular form (~47 kDa) and a glycosylated secreted form (~60 kDa). The protein contains a unique CD-domain between alpha-helices C and D that contributes to its antiapoptotic activity. Unlike many other serpins, it lacks a typical N-terminal signal peptide for secretion; instead, it has an inefficient internal signal sequence. The primary function attributed to PAI-2 is inhibition of uPA-mediated plasminogen activation—an important step in fibrinolysis. Its expression is highly inducible by inflammatory mediators such as TNFα and LPS, especially in macrophages, keratinocytes, fibroblasts, and endothelial cells. Beyond regulating fibrinolysis, it is associated intracellularly with protection against apoptosis induced by tumor necrosis factor or viral infection, implicated in cell differentiation processes for monocytes/macrophages and keratinocytes, and may modulate immune responses. Dysregulation is linked with diseases such as asthma, periodontal disease, pre-eclampsia, and cancer.

Other names

SERPINB2

Suicide substrate inhibition