title: Collagen binding properties of the membrane type-1 matrix metalloproteinase (MT1-MMP) hemopexin C domain. The ectodomain of the 44-kDa autocatalytic product of MT1-MMP inhibits cell invasion by disrupting native type I collagen cleavage.
abstract: Up-regulation of the collagenolytic membrane type-1 matrix metalloproteinase (MT1-MMP) leads to increased MMP2 (gelatinase A) activation and MT1-MMP autolysis. The autocatalytic degradation product is a cell surface 44-kDa fragment of MT1-MMP (Gly(285)-Val(582)) in which the ectodomain consists of only the linker, hemopexin C domain and the stalk segment found before the transmembrane sequence. In the collagenases, hemopexin C domain exosites bind native collagen, which is required for triple helicase activity during collagen cleavage. Here we investigated the collagen binding properties and the role of the hemopexin C domain of MT1-MMP and of the 44-kDa MT1-MMP ectodomain in collagenolysis. Recombinant proteins, MT1-LCD (Gly(285)-Cys(508)), consisting of the linker and the hemopexin C domain, and MT1-CD (Gly(315)-Cys(508)), which consists of the hemopexin C domain only, were found to bind native type I collagen but not gelatin. Functionally, MT1-LCD inhibited collagen-induced MMP2 activation in fibroblasts, suggesting that interactions between collagen and endogenous MT1-MMP directly stimulate the cellular activation of pro-MMP2. MT1-LCD, but not MT1-CD, also blocked the cleavage of native type I collagen by MT1-MMP in vitro, indicating an important role for the MT1-MMP linker region in triple helicase activity. Similarly, soluble MT1-LCD, but not MT1-CD or peptide analogs of the MT1-MMP linker, reduced the invasion of type I collagen matrices by MDA-MB-231 cells as did the expression of recombinant 44-kDa MT1-MMP on the cell surface. Together, these studies demonstrate that generation of the 44-kDa MT1-MMP autolysis product regulates collagenolytic activity and subsequent invasive potential, suggesting a novel feedback mechanism for the control of pericellular proteolysis.
authors.affiliation: C.I.H.R. Group in Matrix Dynamics, Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Tam
authors.forename: Yi I
authors.initials: YI
authors.lastname: Wu
authors.forename: Georgina S
authors.initials: GS
authors.lastname: Butler
authors.forename: M Sharon
authors.initials: MS
authors.lastname: Stack
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Overall
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism*; D004789:Enzyme Activation; D005347:Fibroblasts / Q000378:metabolism; D006466:Hemopexin / Q000378:metabolism*; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D024042:Collagen Type I; D010455:Peptides; D011993:Recombinant Fusion Proteins; D006466:Hemopexin; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2