title: Proteolytic cleavage of urokinase-type plasminogen activator by stromelysin-1 (MMP-3).
abstract: Matrix metalloproteinase-3 (MMP-3, or stromelysin-1) specifically hydrolyzes the Glu143-Leu144 peptide bond in 45-kDa single-chain urokinase-type plasminogen activator (scu-PA) and in its two-chain (tcu-PA) derivative, yielding a 17-kDa NH2-terminal domain comprising the u-PA receptor (u-PAR) binding site and a 32-kDa COOH-terminal moiety containing the serine proteinase domain of u-PA. The conversion is completely abolished in the presence of the MMP inhibitors EDTA or 1,10-phenanthroline. Biospecific interaction analysis indicates that binding of MMP-3 occurs through the 32-kDa fragment. The 32-kDa fragment derived from scu-PA (scu-PA-32k) has a specific activity of </=500 IU/mg, but it can be activated with plasmin to a two-chain derivative (tcu-PA-32k) with a specific activity of 79 000 IU/mg. tcu-PA and tcu-PA-32k moieties derived from scu-PA-32k by plasmin or from tcu-PA by MMP-3 have comparable amidolytic activities toward the chromogenic substrate S-2444 (kcat/Km of 110 and 160 mM-1 s-1, respectively) and similar plasminogen activating activities in a coupled chromogenic substrate assay. Specific binding of the 17-kDa NH2-terminal domain to THP-1 monocytoid cells is completely abolished by competition with scu-PA but is not affected by scu-PA-32k (residual binding of 88 +/- 9% (mean +/- SEM; n = 3) with 25-fold molar excess). Thus, MMP-3 removes a functional NH2-terminal u-PAR-binding domain from u-PA without affecting its enzymatic properties.
authors.affiliation: Center for Molecular and Vascular Biology, University of Leuven, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Ugwu
authors.forename: B
authors.initials: B
authors.lastname: Van Hoef
authors.forename: A
authors.initials: A
authors.lastname: Bini
authors.forename: D
authors.initials: D
authors.lastname: Collen
authors.forename: H R
authors.initials: HR
authors.lastname: Lijnen
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D004789:Enzyme Activation; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry / Q000378:metabolism*
chemical_list: C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D019278:Matrix Metalloproteinase 3