Membrane type-1 matrix metalloprotease-independent activation of pro-matrix metalloprotease-2 by proprotein convertases.
Matrix metalloprotease-2 is implicated in many biological processes and degrades extracellular and non-extracellular matrix molecules. Matrix metalloprotease-2 maintains a latent state through a cysteine-zinc ion pairing which, when disrupted, results in full enzyme activation. This pairing can be disrupted by a conformational change or cleavage within the propeptide. The best known activation mechanism for pro-matrix metalloprotease-2 occurs via cleavage of the propeptide by membrane type-1 matrix metalloprotease. However, significant residual activation of pro-matrix metalloprotease-2 is seen in membrane type-1 matrix metalloprotease knockout mice and in fibroblasts treated with metalloprotease inhibitors. These findings indicate the presence of a membrane type-1 matrix metalloprotease-independent activation mechanism for pro-matrix metalloprotease-2 in vivo, which prompted us to explore an alternative activation mechanism for pro-matrix metalloprotese-2. In this study, we demonstrate membrane type-1 matrix metalloprotease-independent propeptide processing of matrix metalloprotease-2 in HEK293F and various tumor cell lines, and show that proprotein convertases can mediate the processing intracellularly as well as extracellularly. Furthermore, processed matrix metalloprotease-2 exhibits enzymatic activity that is enhanced by intermolecular autolytic cleavage. Thus, our experimental data, taken together with the broad expression of proprotein convertases, suggest that the proprotein convertase-mediated processing may be a general activation mechanism for pro-matrix metalloprotease-2 in vivo.
Koo
Bon-Hun
BH
Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, 134 Sinchon-Dong Seodaemun-Gu, Seoul 120-749, South Korea. k4119@yonsei.ac.kr
Kim
Hee-Hyun
HH
Park
Michael Y
MY
Jeon
Ok-Hee
OH
Kim
Doo-Sik
DS
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D018093:Gelatinases / Q000378:metabolism*; D006801:Humans; D053511:Matrix Metalloproteinase 14 / Q000502:physiology*; D008969:Molecular Sequence Data; D045702:Proprotein Convertase 5 / Q000502:physiology; D043484:Proprotein Convertases / Q000502:physiology*; D012697:Serine Endopeptidases / Q000502:physiology
D004792:Enzyme Precursors; C080654:PCSK6 protein, human; D045702:Proprotein Convertase 5; D043484:Proprotein Convertases; D012697:Serine Endopeptidases; D018093:Gelatinases; C069860:progelatinase; D053511:Matrix Metalloproteinase 14