Promotes attachment of chondrocytes, fibroblasts, and osteoblasts. This binding is mediated (at least for chondrocytes and fibroblasts) by the integrin alpha(2)beta(1). May play an important role in the regulation of chondrocyte growth and proliferation. Mostly monomeric. Interacts with collagen type II (By similarity). Cartilage. Belongs to the small leucine-rich proteoglycan (SLRP) family. SLRP class IV subfamily.