Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of 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 which are activated when cleaved by extracellular proteinases. The enzyme encoded by this gene degrades type IV and V collagens. Studies in rhesus monkeys suggest that the enzyme is involved in IL-8-induced mobilization of hematopoietic progenitor cells from bone marrow, and murine studies suggest a role in tumor-associated tissue remodeling. Thrombospondins, intervertebral disc proteins, regulate the effective levels of matrix metalloproteinases (MMPs) 2 and 9, which are key effectors of ECM remodeling. Matrix metalloproteinase-1 (MMP-1) is also known as interstitial collagenase and fibroblast collagenase. MMP­1 is expressed by fibroblasts, keratinocytes, endothelial cells, monocytes and macrophages. MMP-1 breaks down the interstitial collagens, types I, II, and III. MMP­1 can degrade a broad range of substrates including types I, II, III, VII, VIII, and X collagens as well as casein, gelatin, myelin basic protein, L­Selectin, pro­TNF, IL­1β, IGF­BP3, IGF­BP5, pro MMP­2 and pro MMP­9.