The MMP9 gene (MMP3 stands for: Matrix Metallopeptidase 9) is a protein-coding gene located on chromosome 20q13.12.
Proteins of the matrix metalloproteinase (MMP) family are involved in the degradation of the extracellular matrix in normal physiological processes such as embryonic development, reproduction and tissue remodeling as well as in disease processes such as arthritis and metastasis. Most MMPs are secreted as inactive proproteins that are activated when cleaved by extracellular proteinases. The enzyme encoded by this gene degrades type IV and V collagens. Studies in rhesus monkeys indicate that the enzyme is involved in IL-8-induced mobilization of hematopoietic progenitor cells from the bone marrow, and studies in mice suggest a role in tumor-associated tissue remodeling.