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Matrix metalloproteinase 3 (stromelysin) activates the precursor for the human matrix metalloproteinase 9
Y Ogata1, J J Enghild, H Nagase
1Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66103.
Abstract:
Matrix metalloproteinase 9 (MMP-9), also known as 92-kDa gelatinase/type IV collagenase, is secreted from neutrophils, macrophages, and a number of transformed cells in zymogen form. Here we report that matrix metalloproteinase 3 (MMP-3/stromelysin) is an activator of the precursor of matrix metalloproteinase 9 (proMMP-9). MMP-3 initially cleaves proMMP-9 at the Glu40-Met41 bond located in the middle of the propeptide to generate an 86-kDa intermediate. Cleavage of this bond triggers a change in proMMP-9 that renders the Arg87-Phe88 bond susceptible to the second cleavage by MMP-3, resulting in conversion to an 82-kDa form. alpha 2-Macroglobulin binding studies of partially activated MMP-9 demonstrate that the 82-kDa species is proteolytically active, but not the initial intermediate of 86 kDa. This stepwise activation mechanism of proMMP-9 is analogous to those of other members of the MMP family, but the action of MMP-3 on proMMP-9 is the first example of zymogen activation that can be triggered by another member of the MMP family. The results imply that MMP-3 may be an effective activator of proMMP-9 in vivo.
Insights
Matrix metalloproteinase 3 (MMP-3) activates matrix metalloproteinase 9 (MMP-9) precursor (proMMP-9) through a two-step cleavage process. This MMP-3 mediated activation generates active MMP-9, suggesting a novel in vivo activation pathway.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Matrix metalloproteinase 9 (MMP-9) is a key enzyme involved in extracellular matrix degradation.
- MMP-9 is secreted as an inactive zymogen (proMMP-9) by various cell types.
- Activation of proMMP-9 is crucial for its biological function but the precise mechanisms are not fully understood.
Purpose of the Study:
- To investigate the role of matrix metalloproteinase 3 (MMP-3) in the activation of matrix metalloproteinase 9 (MMP-9).
- To elucidate the specific cleavage sites and intermediates involved in MMP-3 mediated proMMP-9 activation.
Main Methods:
- In vitro enzymatic assays using purified proMMP-9 and MMP-3.
- Analysis of cleavage products by size and proteolytic activity.
- alpha 2-Macroglobulin binding assays to assess MMP-9 activity.
Main Results:
- MMP-3 directly cleaves proMMP-9 at the Glu40-Met41 bond, generating an 86-kDa intermediate.
- Further cleavage by MMP-3 at the Arg87-Phe88 bond converts the intermediate to an 82-kDa active form of MMP-9.
- The 82-kDa form exhibits proteolytic activity, while the 86-kDa intermediate does not.
Conclusions:
- MMP-3 acts as a direct activator of proMMP-9 through a stepwise proteolytic mechanism.
- This represents the first identified instance of MMP-3 activating another MMP zymogen.
- The findings suggest MMP-3 may play a significant role in regulating MMP-9 activity in vivo.