NG2, also known as CSPG4, MCSP, and AN2, is a 400-500 kDa transmembrane chondroitin sulfate proteoglycan (CSPG) that is expressed on glial cell progenitors known as O2A cells or NG2 glia. It binds to the extracellular matrix proteins Laminin, Tenascin, and Collagens II, V, and VI as well as to the growth factors basic FGF and PDGF-AA. NG2 associates with PDGF R alpha and the AMPA R subunit GluR2. It is upregulated on microglial cells during inflammation and contributes to the induction of inflammatory mediators. NG2 is also expressed on vascular mural cells and capillaries. It promotes vascular endothelial cell (EC) migration and angiogenesis through interactions with Galectin-3 and Integrin alpha 3 beta 1 on EC, Plasminogen, and Angiostatin. NG2 is also expressed on a variety of tumors where it contributes to tumor cell adhesion, motility, and invasion.