Platelet-derived growth factor receptors exhibit tyrosine-protein kinase activity and have been implicated in the control of cell proliferation, survival and migration. PDGF receptors, PDGFR-alpha and PDGFR-beta, have 5 extracellular immunoglobulin-like domains and an intracellular tyrosine kinase domain. Upon binding a PDGF, the receptors form homo-and heterodimers. Dimerization of the receptors results in phosphorylation in the complex. More than 10 different SH2-domain-containing molecules have been shown to bind to different autophosphorylation sites in the PDGF-alpha and beta receptors. PDGF alpha receptors are expressed in oligodendrocyte progenitor cells and PDGF beta receptors are expressed on neurons.