PDGF Family

Platelet-derived growth factors (PDGFs) are potent mitogenic and chemotactic proteins that are required for early development and wound healing. Additionally, they may play a pathological role in tumor growth, vascular disease, and fibrotic disease. There are currently four known PDGF proteins encoded by four genes, PDGF-A, PDGF-B, PDGF-C, and PDGF-D. PDGFs are produced by discrete populations of cells and are secreted as disulfide-linked homodimers or heterodimers including PDGF-AA, PDGF-BB, PDGF-CC, PDGF-DD, and PDGF-AB. PDGF dimers act in a primarily paracrine manner by binding to PDGF receptors. There are two known PDGF receptors, PDGF R alpha and PDGF R beta, which can form both heterodimers and homodimers. Ligand binding promotes receptor dimerization, autophosphorylation, and the activation of multiple downstream intracellular signaling cascades that stimulate Actin filament rearrangement, the disruption of gap junction communication, the initiation of gene transcription, and cell survival.