This proteoglycan is a major component of extracellular matrix of cartilagenous tissues. A major function of this protein is to resist compression in cartilage. It binds avidly to hyaluronic acid via an N-terminal globular region. May play a regulatory role in the matrix assembly of the cartilage. Interacts with FBLN1 and COMP. Two globular domains, G1 and G2, comprise the N-terminus of the proteoglycan, while another globular region, G3, makes up the C-terminus. G1 contains Link domains and thus consists of three disulfide-bonded loop structures designated as the A, B, B' motifs. G2 is similar to G1. The keratan sulfate (KS) and the chondroitin sulfate (CS) attachment domains lie between G2 and G3. Contains mostly chondroitin sulfate, but also N-linked and O-linked (about 40) oligosaccharides. The keratan sulfate contents differ considerably between adult and fetal bovine proteoglycans. Belongs to the aggrecan/versican proteoglycan family.