How are soluble MMPs produced?

MMPs are secreted as proenzymes and once they are exposed to the external environment become activated through proteolytic cleavage of the N-terminal domain. The soluble MMPs include MMP-1,-2,-3,-7,-8, -9,-10,-11,-12,-13, -19, -20,-22,-21,-22, -26, -27,-and -28. MMP-1 and MMP-8 can be activated by the proteolytic removal of the propeptide by stromelysin-1 and also by matrilysin. A soluble form of MT3-MMP is created by alternative mRNA splicing. MMP13, and MMP20 are thought to be produced from alternative polyadenylation. Production of MMP-11 is determined to be highest in fibroblasts.