Growth factor that plays an essential role in the regulation of embryonic development, cell proliferation, cell migration, survival and chemotaxis. Potent mitogen for cells of mesenchymal origin. Signaling is modulated by the formation of heterodimers with PDGFB (By similarity). Homodimer; antiparallel disulfide-linked dimer. Heterodimer with PDGFB; antiparallel disulfide-linked dimer. The PDGFA homodimer interacts with PDGFRA homodimers, and with heterodimers formed by PDGFRA and PDGFRB. The heterodimer composed of PDGFA and PDGFB interacts with PDGFRA homodimers, and with heterodimers formed by PDGFRA and PDGFRB (By similarity). The long form contains a basic insert which acts as a cell retention signal. Belongs to the PDGF/VEGF growth factor family.