Figure 2.

Structural classes of Eph receptors and ephrins and their binding specificities.

Despite some described high affinity ligand/receptor interactions (red arrows), binding is mostly promiscuous within each of the ephrin/Eph specificity classes (black arrows). In addition, there are two exceptions that show low affinities between members of distinct subclasses (green dashed arrows). Ligands for EphA9 and EphB5 receptors have still not been described. Ligands and receptors have been characterized in mammals (light red), chick (blue) or both (light red/blue).