- Paper Report
- Open Access
Cell-associated MT1-MMP degrades collagen type I
- Willemijn van der Laan1
© Biomed Central Ltd 2001
- Received: 26 July 2001
- Accepted: 26 July 2001
- Published: 26 July 2001
- Collagen type I
Membrane-type matrix metalloproteinases (MT-MMPs) are, unlike the other MMPs, attached to the cell surface. A recognized function of MT1-MMP is the activation of gelatinase A (MMP-2). However, MT1-MMP itself may also directly exert proteolytic activity. The severe defects observed in MT1-MMP knockout mice, mainly bony malformations, suggest an important role of MT1-MMP in collagen type I turnover. Previous experiments have investigated MT-MMP activity using recombinant, soluble MT-MMP. In the present paper, however, a cell culture model was used to investigate the collagenolytic capacity of MT1-MMP attached to the cell surface.
The results of this study indicate that MT1-MMP is a potent cell associated interstitial collagenase. Cells over-expressing MT1-MMP degraded collagen type I up to four times more efficiently than the control cells. Tissue inhibitor of matrix metaloproteinases (TIMP)-2, but not TIMP-1 inhibited collagenolysis (TIMP-2, unlike TIMP-1, is an efficient inhibitor of MT1-MMP). Collagenolysis was inhibited by ionomycin, an inhibitor of MT1-MMP maturation.
Immunofluorescence, transfection, tet-off system, 14C-labelled collagen films, gelatin zymography, Western blotting