Eph proteins belong to the superfamily of transmembrane Tyr kinase receptors. They were initially identified in human carcinomas, in which they are significantly overexpressed. One example of a process regulated by ephrin–Eph signalling is developmental cell sorting at tissue compartment boundaries, through which two separate cellular populations sharing a stable border can emerge from initially intermingled populations. Another important ephrin–Eph signalling-mediated process discussed here is axon guidance in neurons, which leads to the collapse or immobilization of axonal growth cones. Cancer, synaptic plasticity and many physiological processes such as vasculogenesis involve short-distance cell–cell communication and also rely on ephrin–Eph signalling. 
All Eph receptors are composed of the following domains: an extracellular globular ligand-binding domain; a Cys domain (comprising sushi and epidermal growth factor (EGF)-like motifs); fibronectin domains; a transmembrane domain; an intracellular Tyr kinase domain adjacent to a sterile alpha motif (SAM); and a PDZ domain.  Eph receptors have been classified into EphA or EphB subfamilies (there are nine EphA and five EphB rodent members in current genomic databases) depending on whether they preferentially bind to membrane-anchored (glycophosphatidylinositol (GPI)-linked) or transmembrane ephrin ligands, referred to as ephrin-As and ephrin-Bs, respectively. Signals generated by ephrin binding to Eph receptors involve their interaction with specific intracellular proteins, including non-catalytic region of Tyr kinase adaptor protein 1 (Nck1) and Nck2, phosphoinositide 3-kinase (PI3K), Src family kinases, Vav2, Vav3 and ephexin. In turn, these effectors are coupled to Rho GTPases such as Rac1 and RhoA, which can modulate the cytoskeleton.

References

1.Kania A, Klein R. Nat Rev Mol Cell Biol. 2016;17(4):240–256.