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 MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. The encoded protein degrades type IV collagen, fibronectin, fibrinogen, casein, vitronectin, alpha 1-antitrypsin, alpha 2-macroglobulin, and insulin-like growth factor-binding protein 1, and activates MMP9 by cleavage. The protein differs from most MMP family members in that it lacks a conserved C-terminal protein domain.