PlGF-3 is an angiogenic factor that belongs to the cysteine-knot superfamily of growth factors. PlGF-3 is expressed exclusively in the placenta. It signals through the VEGFR-1/FLT1 receptor, and stimulates endothelial cell proliferation and migration. PlGF-3 lacks heparin binding affinity. Recombinant Human PlGF-3 is a 45.7 kDa disulfide-linked homodimeric protein of two 203 amino acid polypeptide chains.