Immunoglobulin (Ig)-like domain of the chondroitin sulfate proteoglycan core protein (CSPG), aggrecan
The members here are composed of the immunoglobulin (Ig)-like domain of the chondroitin sulfate proteoglycan core protein (CSPG), aggrecan. In CSPGs, the Ig-like domain is followed by hyaluronan (HA)-binding tandem repeats, and a C-terminal region with epidermal growth factor-like, lectin-like, and complement regulatory protein-like domains. Separating these N- and C-terminal regions is a nonhomologous glycosaminoglycan attachment region. In cartilage, aggrecan forms cartilage link protein stabilized aggregates with HA. These aggregates contribute to the tissue's load bearing properties. Aggrecan has a wide distribution in connective tissue and extracellular matrices. Members of the vertebrate HPLN (hyaluronan/HA and proteoglycan binding link) protein family are physically linked adjacent to CSPG genes.