Thrombin-dependent MMP-2 activity is regulated by heparan sulfate

Area of Science:

• Biochemistry
• Molecular Biology
• Enzymology

Background:

• Matrix metalloprotease-2 (MMP-2) is a metalloprotease synthesized as an inactive zymogen.
• MMP-2 activation involves propeptide cleavage, often by proteases like thrombin.
• Cell-associated conditions modulate thrombin's effect on MMP-2 activity.

Purpose of the Study:

• To elucidate the molecular mechanisms of thrombin-mediated MMP-2 activation and degradation.
• To investigate the role of heparan sulfate in regulating MMP-2 activity.
• To understand how MMP-2 interacts with thrombin during these processes.

Main Methods:

• Biochemical assays to study enzyme activation and degradation.
• Analysis of protein-protein interactions using specific inhibitors (heparan sulfate, hirudin fragment).
• Investigation of structural interactions between MMP-2 and thrombin.

Main Results:

• Heparan sulfate is essential for thrombin-mediated pro-MMP-2 activation, likely via conformational changes in thrombin.
• MMP-2 degradation by thrombin depends on interactions with thrombin exosites 1 and 2.
• Heparan sulfate and hirudin fragment inhibit MMP-2 degradation by blocking these interactions.
• A direct interaction between thrombin exosite 1 and the MMP-2 hemopexin-like domain was observed.

Conclusions:

• Heparan sulfate plays a critical role in regulating thrombin-dependent MMP-2 activation.
• The hemopexin-like domain of MMP-2 may regulate its degradation by thrombin.
• These findings reveal a novel mechanism involving heparan sulfate proteoglycans in controlling MMP-2 enzymatic activity.