matrix metalloproteinase-14 (matrixin-14, membrane-type matrix metalloproteinase 1, MMP14, MTMMP1, MT1MMP, MMP- X1, MT1-MMP)
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Function
- seems to specifically activate progelatinase A
- precursor is cleaved by a furin endopeptidase
- endopeptidase activity
- activates progelatinase A by cleavage of the propeptide at 37-Asn-|-Leu-38
- other bonds hydrolyzed include 35-gly-|-Ile-36 in the propeptide of collagenase 3, & 341-Asn-|-Phe-342, 441-Asp-|-Leu-442 & 354-Gln-|-Thr-355 in the aggrecan interglobular domain
Structure
- conserved Cys present in the cysteine-switch motif binds the catalytic Zn+2, thus inhibiting the enzyme
- dissociation of the Cys from the Zn+2 upon the activation-peptide release activates the enzyme
- belongs to the peptidase M10A family
- contains 4 hemopexin-like domains
Compartment
- membrane, melanosome
- identified by mass spectrometry in melanosome fractions from stage 1 to stage 4
Expression
stromal cells of colon, breast, & head & neck
Pathology
- may thus trigger invasion by tumor cells by activating progelatinase A on the tumor cell surface