title: Steps involved in activation of the pro-matrix metalloproteinase 9 (progelatinase B)-tissue inhibitor of metalloproteinases-1 complex by 4-aminophenylmercuric acetate and proteinases.
abstract: The precursor of matrix metalloproteinase 9 (pro-MMP-9, progelatinase B) noncovalently binds to tissue inhibitor of metalloproteinases (TIMP)-1 through the C-terminal domain of each molecule. We have isolated the proMMP-9.TIMP-1 complex from the medium of human fibrosarcoma HT-1080 cells and investigated the activation processes of the complex by 4-aminophenylmercuric acetate, trypsin, and matrix metalloproteinase 3 (MMP-3, stromelysin 1). The treatment of the proMMP-9.TIMP-1 complex with 4-aminophenylmercuric acetate or trypsin converts proMMP-9 to lower molecular weight species corresponding to active forms, but no gelatinolytic activity is detected. The lack of enzymic activity results from binding of TIMP-1 to the activated MMP-9. The treatment of the proMMP-9.TIMP-1 complex with a possible physiological proMMP-9 activator, MMP-3, does not reveal any gelatinolytic activity unless the molar ratio of MMP-3 to the complex exceeds 1. This is due to the inhibition of MMP-3 by TIMP-1 forming a ternary proMMP-9.TIMP-1.MMP-3 complex. The formation of the ternary complex weakens the interaction between proMMP-9 and TIMP-1, resulting in partial dissociation of the complex into proMMP-9 and the TIMP-1.MMP-3 complex. When MMP-3 is in excess, the propeptide is completely processed, and the full activity of MMP-9 is detected. Similarly, the proMMP-9.TIMP-1 complex inhibits MMP-1 (interstitial collagenase) and in turn renders the proMMP-9 activable by a catalytic amount of MMP-3. These results suggest that formation of the proMMP-9.TIMP-1 complex regulates extracellular matrix breakdown in tissue by switching the predominant MMP activity from one type to another.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66160-7421, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Ogata
authors.forename: Y
authors.initials: Y
authors.lastname: Itoh
authors.forename: H
authors.initials: H
authors.lastname: Nagase
mesh_terms: D017364:Collagenases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004792:Enzyme Precursors / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; D008666:Metalloendopeptidases / Q000378:metabolism; D010662:Phenylmercuric Acetate / Q000031:analogs & derivatives / Q000494:pharmacology; D011485:Protein Binding; D019714:Tissue Inhibitor of Metalloproteinases; D014357:Trypsin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D004792:Enzyme Precursors; D006023:Glycoproteins; D046911:Macromolecular Substances; D019714:Tissue Inhibitor of Metalloproteinases; C010024:4-aminophenylmercuriacetate; D014357:Trypsin; D017364:Collagenases; D008666:Metalloendopeptidases; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; D010662:Phenylmercuric Acetate