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A more recent version of this article appeared on December 14, 2007
Papers In Press, published online ahead of print October 15, 2007
J. Biol. Chem, 10.1074/jbc.M706290200
Submitted on July 31, 2007
Accepted on October 15, 2007
Proteolysis of the membrane type-1 matrix metalloproteinase (MT1-MMP) prodomain: Implications for a two-step proteolytic processing and activation
Vladislav S. Golubkov, Alexei V. Chekanov, Sergey A. Shiryaev, Alexander E. Aleshin, Boris I. Ratnikov, Katarzyna Gawlik, Ilian Radichev, Khatereh Motamedchaboki, Jeffrey W. Smith, and Alex Y. Strongin
Cancer Research Center, Burnham Institute for Medical Research, La Jolla, CA 92037
Corresponding Author: strongin{at}burnham.org
MT1-MMP exerts its enhanced activity in multiple cancer types. Understanding the activation process of MT1-MMP is essential for designing novel and effective cancer therapies. Like all of the other MMPs, MT1-MMP is synthesized as a zymogen the latency of which is maintained by its inhibitory prodomain. Proteolytic processing of the prodomain transforms the zymogen into a catalytically active enzyme. A sequential, two-step activation process is normally required for MMPs. Our in silico modeling suggests that the prodomain of MT1-MMP exhibits a conserved three helix-bundled structure and a bait loop region linking helixes 1 and 2. We hypothesized and then confirmed that in addition to furin cleavage there is also a cleavage at the bait region in the activation process of MT1-MMP. A two-step sequential activation of MT1-MMP is likely to include the MMP-dependent cleavage at either P47GDL50 or P58QSL61 or at both sites of the bait region. This event results in the activation intermediate. The activation process is then completed by a proprotein convertase cleaving the inhibitory prodomain at the R108RKR111Y112 site, where Y112 is the N-terminal residue of the mature MT1-MMP enzyme. Our findings suggest that the most efficient activation results from a two-step mechanism that eventually is required for the degradation of the inhibitory prodomain and the release of the activated, mature MT1-MMP enzyme. These findings shed more light on the functional role of the inhibitory prodomain and on the proteolytic control of MT1-MMP activation, a crucial process that may be differentially regulated in normal and cancer cells.

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[Abstract]
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Copyright © 2007 by the American Society for Biochemistry and Molecular Biology.
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