Growth factor active in angiogenesis, vasculogenesis and endothelial cell growth. Induces endothelial cell proliferation, promotes cell migration, inhibits apoptosis and induces permeabilization of blood vessels. Binds to the FLT1/VEGFR1 and KDR/VEGFR2 receptors, heparan sulfate and heparin (By similarity). Binding to NRP1 receptor initiates a signaling pathway needed for motor neuron axon guidance and cell body migration, including for the caudal migration of facial motor neurons from rhombomere 4 to rhombomere 6 during embryonic development (By similarity). Also binds the DEAR/FBXW7-AS1 receptor (By similarity). Homodimer; disulfide-linked (By similarity). Also found as heterodimer with PGF (By similarity). Interacts with NRP1 (By similarity). Interacts with BSG (By similarity). Secreted but remains associated to cells or to the extracellular matrix unless released by heparin. Belongs to the PDGF/VEGF growth factor family.