Structural Basis for Recognition of Urokinase-type Plasminogen Activator by Plasminogen Activator

Plasminogen activator inhibitor-1 (PAI-1), together with its physiological target urokinase-type plasminogen activator (uPA), plays a pivotal role in fibrinolysis, cell migration, and tissue remodeling and is currently recognized as being among the most extensively validated biological prognostic factors in several cancer types. PAI-1 specifically and rapidly inhibits uPA and tissuetype PA (tPA). Despite extensive structural/functional studies on these two reactions, the underlying structural mechanism has remained unknown due to the technical difficulties of obtaining the relevant structures. Here, we report a strategy to generate a PAI-1� uPA(S195A) Michaelis complex and present its crystal