The matrix metalloproteinase (MMP) family degrades the extracellular matrix. One member of this family, MMP-1, initiates the breakdown of interstitial collagens. The expression ofMMP-1 is controlled by themitogen activated protein kinase (MAPK) pathway(s) via the activity of acti-vator protein-1 (AP-1) and polyoma enhancing activity-3/ E26 virus (PEA3/ETS) transcription factors through con-sensus binding sites present in the promoter.