PDGFB [MD313]

PDGF is a mitogen for mesenchyme- and glia-derived cells. It consists of two disulfide-bonded polypeptide chains, A and B, and occurs as three isoforms: PDGF AA, AB and BB. The three isoforms bind, with different affinities, to two receptor types, and, which are structurally related and endowed with protein-tyrosine kinase domains. Ligand binding induces activation of the receptor kinases by formation of receptor dimmers: the A subunit of PDGF binds only to receptors with high affinity, whereas the B subunit can bind to both and receptors. Evidence suggests that PDGF may function as a neurotrophic factor. Receptors for PDGFA are expressed in oligodendrocyte progenitor cells whereas receptors for PDGFB are expressed on neurons. These facts suggest that the different isoforms of PDGF may regulate growth and differentiation of different cell types in the developing central nervous system through paracrine and autocrine routes.