title: Cell surface binding of TIMP-2 and pro-MMP-2/TIMP-2 complex.
abstract: Tissue inhibitor of metalloproteinases (TIMP-2) is a low molecular weight proteinase inhibitor capable of inhibiting activated matrix metalloproteinases (MMPs). TIMP-2 is found both free and in a 1:1 stoichiometric complex with the pro-enzyme form of MMP-2 (pro-MMP-2/TIMP-2 complex). We have measured the binding of recombinant TIMP-2 to intact HT-1080 and MCF-7 cells. HT-1080 cells in suspension bound 125I-labeled rTIMP-2 with a Kd of 2.5 nM and 30,000 sites/cell. Monolayers of MCF-7 cells were similarly found to bind [125I]rTIMP-2 with a Kd of 1.6 nM and 25,000 sites/cell. Specific binding of MMP-2 alone to HT-1080 cells was not observed; however, pro-MMP-2/TIMP-2 complex was capable of binding to the surface of HT-1080 cells in a TIMP-2-dependent manner. Binding of rTIMP-2 was not competed by the presence of TIMP-1. These results suggest that rTIMP-2 alone binds directly to the cell surface of HT-1080 and MCF-7 cell lines, and TIMP-2 is capable of localizing MMP-2 to the surface of HT-1080 cells via interaction with a specific binding site.
authors.affiliation: Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20892, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Emmert-Buck
authors.forename: H P
authors.initials: HP
authors.lastname: Emonard
authors.forename: M L
authors.initials: ML
authors.lastname: Corcoran
authors.forename: H C
authors.initials: HC
authors.lastname: Krutzsch
authors.forename: J M
authors.initials: JM
authors.lastname: Foidart
authors.forename: W G
authors.initials: WG
authors.lastname: Stetler-Stevenson
mesh_terms: D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D018093:Gelatinases / Q000378:metabolism*; D006801:Humans; D020778:Matrix Metalloproteinase 2; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D011485:Protein Binding; D011498:Protein Precursors / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2
chemical_list: D011498:Protein Precursors; D011506:Proteins; D011994:Recombinant Proteins; D019716:Tissue Inhibitor of Metalloproteinase-2; D018093:Gelatinases; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2