title: Specific, high affinity binding of tissue inhibitor of metalloproteinases-4 (TIMP-4) to the COOH-terminal hemopexin-like domain of human gelatinase A. TIMP-4 binds progelatinase A and the COOH-terminal domain in a similar manner to TIMP-2.
abstract: The binding properties of the newly described tissue inhibitor of metalloproteinases-4 (TIMP-4) to progelatinase A and to the COOH-terminal hemopexin-like domain (C domain) of the enzyme were examined. We present evidence for the first time of a specific, high affinity interaction between TIMP-4 and the C domain of human gelatinase A and show that TIMP-4 binds both progelatinase A and the C domain in a similar manner to that of TIMP-2. Saturable binding of recombinant C domain to TIMP-4 and to TIMP-2 but not to TIMP-1 was demonstrated using a microwell protein binding assay. The recombinant collagen binding domain of gelatinase A, comprised of the three fibronectin type II-like repeats, did not bind to TIMP-4, indicating that binding is mediated selectively by the C domain. Binding to TIMP-4 was of high affinity with an apparent Kd of 1.7 x 10(-7) M but slightly weaker than that to TIMP-2 (apparent Kd of 0.66 x 10(-7) M). Affinity chromatography confirmed the TIMP-4-C domain interaction and also showed that the complex could not be disrupted by 1 M NaCl or 10% dimethyl sulfoxide, thereby further demonstrating the tight binding. To verify the biological significance of this interaction, binding of full-length progelatinase A to TIMP-4 was investigated. TIMP-4 and TIMP-2 but not TIMP-1 bound specifically to purified TIMP-2-free human recombinant full-length progelatinase A and to full-length rat proenzyme from the conditioned culture medium of ROS 17/2.8 cells. Preincubation of the C domain with TIMP-2 was found to reduce subsequent binding to TIMP-4 in a concentration-dependent manner. Competition between TIMP-2 and TIMP-4 for a common or overlapping binding sites on the gelatinase A C domain may occur; alternatively TIMP-2 may prevent the binding of TIMP-4 by steric hindrance or induction of a conformational change in the C domain. We propose that the binding of progelatinase A to TIMP-4 represents a third TIMP-progelatinase interaction in addition to that of progelatinase A with TIMP-2 and progelatinase B with TIMP-1 described previously. This new phenomenon may be of important physiological significance in modulating the cell surface activation of progelatinase A.
authors.affiliation: Faculty of Dentistry and Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: H F
authors.initials: HF
authors.lastname: Bigg
authors.forename: Y E
authors.initials: YE
authors.lastname: Shi
authors.forename: Y E
authors.initials: YE
authors.lastname: Liu
authors.forename: B
authors.initials: B
authors.lastname: Steffensen
authors.forename: C M
authors.initials: CM
authors.lastname: Overall
mesh_terms: D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D004792:Enzyme Precursors / Q000378:metabolism*; D018093:Gelatinases / Q000737:chemistry / Q000378:metabolism*; D006466:Hemopexin / Q000378:metabolism*; D006801:Humans; D020778:Matrix Metalloproteinase 2; D008666:Metalloendopeptidases / Q000737:chemistry / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D019716:Tissue Inhibitor of Metalloproteinase-2; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4
chemical_list: D004792:Enzyme Precursors; D018093:Gelatinases; D006466:Hemopexin; D020778:Matrix Metalloproteinase 2; D008666:Metalloendopeptidases; D011506:Proteins; D019716:Tissue Inhibitor of Metalloproteinase-2; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4; C069860:progelatinase