ENZYME CATALYSIS AND REGULATION
Regulation of Membrane-type-1 Matrix Metalloproteinase Activity by Its Cytoplasmic Domain*

https://doi.org/10.1074/jbc.M910220199Get rights and content
Under a Creative Commons license
open access

Membrane-type-1 matrix metalloproteinase (MT1-MMP) has transmembrane and cytoplasmic domains, which target it to invasive fronts. We analyzed the role of the cytoplasmic tail by expressing wild type MT1-MMP and three mutants with progressively truncated C termini in human Bowes melanoma cells. We examined gelatinase A activation and the localization and processing of recombinant proteins in stable cell clones using gelatin zymography, immunoblotting, and immunofluorescence. Cell invasion was analyzedin vitro by Matrigel invasion assays. Gelatinase A was activated in all cell clones. However, the localization of MT1-MMP to the leading edge of migrating cells and cell invasion through Matrigel were strongly enhanced only in cells expressing either wild type or truncated MT1-MMP lacking 6 C-terminal amino acid residues (Δ577). Truncations of 10 or 16 amino acid residues in the cytoplasmic domain (Δ567 and Δ573, respectively) disturbed MT1-MMP localization. The expression of wild type and Δ577 MT1-MMPs induced also their cleavage to 43-kDa cell surface forms and the release of soluble, ∼20-kDa N-terminal fragments containing the catalytic center. A synthetic MMP inhibitor but not a gelatinase inhibitor prevented the processing, suggesting that autocatalytic cleavage occurs. Purified soluble MT1-MMP was also autoproteolytically processed to 43- and 20-kDa forms in vitro. Our results indicate that the cytoplasmic domain has an important role in cell invasion by controlling both the targeting and degradation/turnover of MT1-MMP.

Cited by (0)

Published, JBC Papers in Press, March 20, 2000, DOI 10.1074/jbc.M910220199

*

This work was supported by the Academy of Finland, the Sigrid Juselius Foundation, Biocentrum Helsinki, the Helsinki University Hospital Fund, the Novo Nordisk Foundation, the Finnish Cancer Foundation, the Emil Aaltonen Foundation, the Farmos Research and Science Foundation, and the University of Helsinki.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

A fellow of the Academy of Finland.

§

A fellow of the Finnish Cancer Institute.