Importance, localization and functional properties of the cell-associated form of plasminogen activator in mouse peritoneal macrophages.
In inflammatory macrophages, plasminogen activator exists in two active forms, a soluble form released into the extracellular medium and a cell-associated form. This communication describes some properties of the cellular form of plasminogen activator, in intact macrophages and in cell lysates. Cellular plasminogen activator is a membrane protein, associated with the outer face of the plasma membrane; in intact macrophages, it participates in the activation of exogenous plasminogen and, thus, has to be considered as an ectoenzyme. A plasminogen activator activity can be detected in cell lysates (macrophage monolayers lysed in 0.1% Triton X-100) only when plasmin production is followed by the use of small synthetic substrates because a soluble inhibitor, released during extraction, blocks plasmin fibrinolytic activity. In these lysates, plasminogen activator molecules exist as high molecular weight unstable complexes exhibiting a high affinity for plasminogen.
D000818:Animals; D002478:Cells, Cultured; D003979:Diazonium Compounds / Q000494:pharmacology; D005260:Female; D005342:Fibrinolysis; D007700:Kinetics; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D010960:Plasminogen Activators / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism; D013425:Sulfanilic Acids / Q000494:pharmacology; D013864:Thioglycolates / Q000494:pharmacology
D003979:Diazonium Compounds; D013425:Sulfanilic Acids; D013864:Thioglycolates; D010960:Plasminogen Activators; C000469:diazobenzenesulfonic acid