Regulation of Membrane-type-1 Matrix Metalloproteinase Activity by Its Cytoplasmic Domain

Abstract

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 analyzed in 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 (⌬577). Truncations of 10 or 16 amino acid residues in the cytoplasmic domain (⌬567 and ⌬573, respectively) disturbed MT1-MMP localization. The expression of wild type and ⌬577 MT1-MMPs induced also their cleavage to 43-kDa cell surface forms and the release of soluble, ϳ20-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.

MT1-MMP protects breast carcinoma cells against type I collagen-induced apoptosis

“…MMP-14 was expressed as a 60-kDa mature form and a 43-kDa autoproteolytic degradation product, demonstrating that the enzyme was active (Lehti et al, 2000). When incubated in 3D COL1 gels, MMP-14 expressing cells displayed a significantly reduced apoptosis (Figure 2d).…”

Membrane-Type 1 Matrix Metalloproteinase Stimulates Cell Migration through Epidermal Growth Factor Receptor Transactivation

“…Several lines of evidence suggest that MT1-MMP -dependent proteolysis of both extracellular matrix components (2,3) and cell surface adhesion receptors (4-6) plays an essential role in tumor growth, invasion, and angiogenesis. The overexpression of MT1-MMP enables tumor cell growth in otherwise growthrestrictive, three-dimensional extracellular matrices (7) and promotes cell migration of a number of cancer (8)(9)(10) and endothelial cell lines (11)(12)(13). The short cytoplasmic sequence of MT1-MMP also contributes to the induction of cell migration by the enzyme (9, 10, 13) possibly through activation of the extracellular signal-regulated protein kinase (ERK) cascade (14), endocytosis and trafficking of the enzyme (15,16), and interaction with tyrosine phosphorylated caveolin-1 (17).…”

Membrane Type 1 Matrix Metalloproteinase (MT1-MMP) Ubiquitination at Lys581 Increases Cellular Invasion through Type I Collagen

“…Recent evidence showed that the MT1-MMP ICD is pivotal for the MT1-MMP-driven cellular invasion in a number of tumor cell lines (24,26,55,56) as well as in primary endothelial cells (57). ICD deletion mutants exhibit no effect on MT1-MMP cell surface proteolytic activity but reduce MT1-MMPdriven cell migration, thus establishing a link between the ICD and the proteolytic activity of the enzyme, its localization, as well as efficient cellular migration (24,26,56,57).…”

“…MT1-MMP has a 20-amino acid intracellular domain (ICD) that is involved in a plethora of cellular functions that includes the regulation of cell migration, invasion, the induction of intracellular signaling pathways, and the intracellular traffic of the proteinase (23)(24)(25)(26)(27)(28)(29). MT1-MMP was shown to be endocytosed by a clathrin-dependent internalization pathway, although additional means of internalization have been described (25,30,31).…”