title: Characterization of the AB loop region of TIMP-2. Involvement in pro-MMP-2 activation.
abstract: Tissue inhibitor of metalloproteinases-2 (TIMP-2) is unique as it is the only member of the TIMP family that is involved in the cellular activation of promatrix metalloproteinase-2 (pro-MMP-2) by virtue of forming a trimolecular complex with membrane type 1 matrix metalloproteinase (MT1-MMP) on the cell surface. TIMP-4 is similar in structure to TIMP-2 but is unable to support the activation of the proenzyme. Several reports have highlighted the importance of the TIMP-2 C-terminal domain in the pro-MMP-2 activation complex; however, very little is known about the role of the extended AB loop of TIMP-2 in this mechanism even though it has been shown to interact with MT1-MMP. In this study we show by mutagenesis and kinetic analysis that it is possible to transfer the MT1-MMP binding affinity of the TIMP-2 AB loop to TIMP-4 but that its transplantation into TIMP-4 does not endow the inhibitor with pro-MMP-2 activating activity. However, transfer of both the AB loop and C-terminal domain of TIMP-2 to TIMP-4 generates a mutant that can activate pro-MMP-2 and so demonstrates that both these regions of TIMP-2 are important for the activation process.
authors.affiliation: Department of Oncology, Cambridge University, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 2XY, United Kingdom.
authors.forename: Magdalini
authors.initials: M
authors.lastname: Rapti
authors.forename: Vera
authors.initials: V
authors.lastname: Knaüper
authors.forename: Gillian
authors.initials: G
authors.lastname: Murphy
authors.forename: Richard A
authors.initials: RA
authors.lastname: Williamson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D053511:Matrix Metalloproteinase 14; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D051379:Mice; D008969:Molecular Sequence Data; D050506:Mutant Chimeric Proteins / Q000138:chemical synthesis / Q000235:genetics / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000235:genetics; D011506:Proteins / Q000737:chemistry / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000138:chemical synthesis / Q000235:genetics / Q000502:physiology; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000737:chemistry* / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4
chemical_list: D004792:Enzyme Precursors; D053511:Matrix Metalloproteinase 14; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D050506:Mutant Chimeric Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D019716:Tissue Inhibitor of Metalloproteinase-2; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4; C507096:Mmp14 protein, mouse