Figure 1.

Binding specificities of PDGF ligands and receptors. The PDGF isoforms are made up as homo- or heterodimers of antiparallel subunits covalently linked by two S-S bonds. The ligands bind to and dimerize PDGF α and β receptors with specificities depicted in the figure. The receptors have extracellular domains with five immunoglobulin domains. Each receptor has an intracellular, split tyrosine kinase domain.