The TIMP2 Membrane Type 1 Metalloproteinase “Receptor” Regulates the Concentration and Efficient Activation of Progelatinase A

Abstract

, but residues 418 -474 were not important. A similar pattern was seen using cell membrane-associated MT1 MMP; residues 568 -631 were required for binding and activation of progelatinase A, whereas residues 418 -474 were not. Neither region was required for activation in solution. The addition of TIMP2 to HT1080 membrane preparations expressing MT1 MMP, but depleted of endogenous TIMP2, resulted in potentiation of progelatinase A activation. This effect was dependent upon TIMP2 binding to MT1 MMP rather than at an independent membrane site. Together, the data suggest that TIMP2 forms a receptor with MT1 MMP that regulates the concentration and efficient generation of functionally active gelatinase A.

Type IV Collagen Induces Matrix Metalloproteinase 2 Activation in HT1080 Fibrosarcoma Cells

“…7A). These data are in agreement with previous observations that cell-associated TIMP-2 is required for pro-MMP-2 activation [20,28,53].…”

“…TIMP-2 has previously been demonstrated to play a dual role in pro-MMP-2 activation: at low concentrations, it promotes activation while, at higher concentrations, it completely inhibits this process [20,28,53]. To detect a potential modification of TIMP-2 concentration induced by pro-MMP-2 activating treatments, TIMP-2 concentrations in conditioned media and total cell extracts were quantified by ELISA (Fig.…”

“…Because TIMP-2 was shown to bind to the cell surface by interacting with the active site of MT1-MMP [28,30], we examined the influence of GI129471 on type IV collagen-stimulated TIMP-2 binding and degradation by HT1080 cells. Such synthetic inhibitors have previously been shown to bind to the active site of MMPs [55], thus competing with TIMP-2 for binding to MT1-MMP [28,33,54].…”

“…Such synthetic inhibitors have previously been shown to bind to the active site of MMPs [55], thus competing with TIMP-2 for binding to MT1-MMP [28,33,54]. HT1080 cells plated on type IV collagen were incubated for up to 48 h with or without 1 µM GI129471 and TIMP-2 concentrations in conditioned media and total cell extracts were determined by ELISA (Fig.…”

“…Sato and co-workers have identified MT1-MMP (membrane type 1 MMP or MMP-14): a MMP possessing a hydrophobic C-terminal transmembrane domain, which is considered as a physiological MMP-2 activator [22][23][24][25]. The active form of MT1-MMP, which is generated through a furin-dependent mechanism [26,27], binds TIMP-2 through the interaction of the N-terminal domains of each protein, thereby docking soluble TIMP-2 to the cell surface [20,[28][29][30]. This bimolecular complex subsequently functions as a receptor for the secreted pro-MMP-2, through interactions of their C-terminal domains, thus forming a MT1-MMP/TIMP-2/MMP-2 ternary complex.…”