Thrombin-dependent MMP-2 activity is regulated by heparan sulfate.
Like most metalloproteases, matrix metalloprotease 2 (MMP-2) is synthesized as a zymogen. MMP-2 propeptide plays a role in inhibition of catalytic activity through a cysteine-zinc ion pairing, disruption of which results in full enzyme activation. A variety of proteases have been shown to be involved in the activation of pro-MMP-2, including metalloproteases and serine proteases. In the previous study we showed that MMP-2 activation occurred via specific cleavages of the propeptide by thrombin followed by intermolecular autoproteolytic processing for full enzymatic activity. Thrombin also degraded MMP-2, but this degradation was reduced greatly under cell-associated conditions with a concomitant increase in activation, prompting us to elucidate the molecular mechanisms underlying thrombin-mediated MMP-2 activation. In the present study we demonstrate that heparan sulfate is essential for thrombin-mediated activation of pro-MMP-2. Binding of heparan sulfate to thrombin is primarily responsible for this activation process, presumably through conformational changes at the active site. Furthermore, interaction of MMP-2 with exosites 1 and 2 of thrombin is crucial for thrombin-mediated MMP-2 degradation, and inhibition of this interaction by heparan sulfate or hirudin fragment results in a decrease in MMP-2 degradation. Finally, we demonstrated interaction between exosite 1 and hemopexin-like domain of MMP-2, suggesting a regulatory role of hemopexin-like domain in MMP-2 degradation. Taken together, our experimental data suggest a novel regulatory mechanism of thrombin-dependent MMP-2 enzymatic activity by heparan sulfate proteoglycans.
Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea. k4119@yonsei.ac.kr
Bon-Hun
BH
Koo
Jung Ho
JH
Han
Young Il
YI
Yeom
Doo-Sik
DS
Kim
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000166:cytology; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D006466:Hemopexin / Q000737:chemistry; D006497:Heparan Sulfate / Q000737:chemistry*; D006801:Humans; D020014:K562 Cells; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D009154:Mutation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013917:Thrombin / Q000737:chemistry*
D006466:Hemopexin; D006497:Heparan Sulfate; D020778:Matrix Metalloproteinase 2; D013917:Thrombin