MMP9

MMP9 (matrix metalloproteinase 9, gelatinase B) is a secreted enzyme that degrades collagen IV and gelatin, the structural components of basement membranes.

Function

MMP9 is secreted as a zymogen by neutrophils, macrophages, and stromal cells and activated by proteolytic cleavage at the membrane or in the extracellular space. Its substrates are basement-membrane collagens and denatured collagen (gelatin), so its physiological roles involve breaking through barriers: wound healing, bone remodeling, immune-cell diapedesis, and endometrial cycling. The enzyme is regulated at three levels - transcription (induced by inflammatory cytokines such as TNF and IL-6), zymogen activation, and inhibition by TIMP tissue inhibitors - and its activity therefore