Proteoglycans (PGs) are a family of proteins composed of different polypeptide chains containing glycosaminoglycan (GAG) modifications. They vary in their cellular locations and have diverse structure and functions. NG2 is a proteoglycan found in the nervous system，comprising a large integral membrane PG with a core protein of 300 kDa and at least one covalently attached chondroitin sulfate (CS) GAG chain. In the CNS this protein is expressed mainly on the surfaces of developing and adult oligodendrocyte precursor cells，but is also associated with developing chondrocytes，cardiomyocytes，pericytes and several human tumours. NG2 also stimulates alpha-4，beta-1 integrin-mediated adhesion and spreading by recruiting and activating a signaling cascade through CDC42，ACK1 and BCAR1. May activate FAK and ERK1/ERK2 signaling cascades.