title: Inhibition of plasminogen activator release from transformed chicken fibroblasts by a protease inhibitor.
abstract: Chicken embryo fibroblasts (CEF) transformed by Rous sarcoma virus (RSV) exhibit increases in both a cell-associated and a secreted form of plasminogen activator (PA). The mechanism whereby the membrane-bound, cell-associated form of PA is processed to an extracellular, soluble form has been examined in cultures of chicken fibroblasts transformed by a temperature-sensitive mutant of RSV. We report that chymostatin, a protease inhibitor of limited specificity, inhibits the release of PA from tsRSVCEF while causing accumulation of cell-associated PA. Chymostatin's effect on PA release is specific, reversible and appears to be due to its anti-proteolytic capacity. Chymostatin does not inhibit cellular protein synthesis or interfere in the assay used to measure PA. A chymostatin-sensitive protease activity has been found in a membrane fraction isolated from tsRSVCEF.
mesh_terms: D000818:Animals; D001358:Avian Sarcoma Viruses; D002448:Cell Adhesion / Q000187:drug effects; D002462:Cell Membrane / Q000201:enzymology; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D002642:Chick Embryo; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D009842:Oligopeptides / Q000494:pharmacology*; D010960:Plasminogen Activators / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism; D012636:Secretory Rate / Q000187:drug effects; D012995:Solubility
chemical_list: D009842:Oligopeptides; D011506:Proteins; C002101:chymostatin; D010960:Plasminogen Activators; D002918:Chymotrypsin