Figure 3

Nomenclature and structure of mammalian matrix metalloproteinases(MMPs). The mammalian MMP family encompasses 25 members, categorized by different numbers (standard MMP nomenclature) or named depending on their matrix substrates (enzyme nomenclature). Each MMP displays some conserved structural domains, including: i) an N-terminal signal peptide required for secretion; ii) a cleavable pro-domain maintaining enzymatic latency; iii) a catalytic and Zn-binding domain; and iv) a C-terminal hemopexin domain. Optional MMP motifs include a fibronectin-type domain, a vitronectin motif, a furine cleavage site, three head-to-tail cysteine-rich repeats, and (for MT-MMPs) a C-terminal transmembrane domain or GPI anchor occasionally associated with a cytoplasmic domain.