MMP-17
MMP-17 (MT4-MMP) is the most atypical of the membrane-type matrix metalloproteinases, being anchored to the outer leaflet by a glycosylphosphatidylinositol (GPI) moiety rather than a transmembrane segment. First cloned from breast carcinoma cells, the enzyme is expressed in keratinocytes, placenta, brain and cells of the immune system, and its catalytic domain shows comparatively weak activity against standard extracellular matrix substrates. Functionally, MMP-17 has been connected with epithelial morphogenesis and with inflammatory signaling, and expression patterns in gastric and breast tumors have been described. The GPI anchor makes MMP-17 a model for studying how lipid-raft association shapes pericellular proteolysis and shedding.
