Decorin is a member of the small, leucine-rich proteoglycan (SLRP) family along with biglycan. Found in the interterritorial region of cartilage, decorin interacts with collagen and other matrix proteins to regulate the cartilaginous matrix. It has been shown to interact with fibronectin, thrombospondin, C1q, epidermal growth factor receptor (EGFR), and TGF-β. It is believed that decorin also plays a role in the cell cycle of chondrocytes.