Two distinct PDGF receptors, the alpha -receptor and the beta -receptor, have been identified. The two receptors are structurally related, with an extracellular portion containing five immunoglobulin-like domains, a single transmembrane region, and an intracellular portion with a protein-tyrosine kinase domain. The alpha -receptor binds both the A and B chains with high affinity whereas the beta -receptor binds only the B-chain with high affinity. Receptor dimerization is induced upon ligand binding.
In addition to being a potent mitogen for cells of mesenchymal origin, PDGF has also been shown to be a potent chemoattractant for mesenchymal cells, mononuclear cells and neutrophils and has been reported to be important in the modification of cellular matrix constituents.