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Membrane-type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane proteinase that degrades the pericellular extracellular matrix (ECM) and is expressed in many migratory cells, including invasive cancer cells. MT1-MMP has been shown to localize at the migration edge and to promote cell migration; however, it is not clear how the enzyme is regulated during the migration process. Here, we report that MT1-MMP is internalized from the surface and that this event depends on the sequence of its cytoplasmic tail. Di-leucine (Leu571-572 and Leu578-579) and tyrosine573 residues are important for the internalization, and the mu2 subunit of adaptor protein 2, a component of clathrin-coated pits for membrane protein internalization, was found to bind to the LLY573 sequence. MT1-MMP was internalized predominantly at the adherent edge and was found to colocalize with clathrin-coated vesicles. The mutations that disturb internalization caused accumulation of the enzyme at the adherent edge, though the net proteolytic activity was not affected much. Interestingly, whereas expression of MT1-MMP enhances cell migration and invasion, the internalization-defective mutants failed to promote either activity. These data indicate that dynamic turnover of MT1-MMP at the migration edge by internalization is important for proper enzyme function during cell migration and invasion.

Original publication

DOI

10.1083/jcb.200108112

Type

Journal

J Cell Biol

Publication Date

24/12/2001

Volume

155

Pages

1345 - 1356

Keywords

Animals, CHO Cells, Cell Movement, Clathrin-Coated Vesicles, Cricetinae, Cytoplasm, Humans, Matrix Metalloproteinase 1, Matrix Metalloproteinases, Metallothionein, Protein Transport, Recombinant Fusion Proteins, Recombinant Proteins, Tissue Inhibitor of Metalloproteinase-2, Transfection, Transferrin