Plasminogen Activator Inhibitor

Plasminogen Activator Inhibitor (PAI) refers to proteins that regulate fibrinolysis by inhibiting plasminogen activators. The most studied PAI is plasminogen activator inhibitor-1 (PAI-1), a key regulator of blood clot dissolution and other physiological processes such as tissue remodeling and wound healing.

Key Types of Plasminogen Activator Inhibitors
PAI-1 (Plasminogen Activator Inhibitor-1):

The most abundant and biologically significant PAI.
A serine protease inhibitor (serpin) that inhibits tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA).
Synthesized by endothelial cells, hepatocytes, adipocytes, and platelets.
PAI-2 (Plasminogen Activator Inhibitor-2):

Primarily expressed in monocytes and macrophages.
Less abundant and plays a role in pregnancy and inflammation.
PAI-3 (Protein C Inhibitor):

Affects thrombin activation and anticoagulation pathways.