Excitatory Eph receptors and adhesive ephrin ligands

Ephrins are cell surface associated ligands for Eph receptor tyrosine kinas es and are implicated in repulsive axon guidance, cell migration, topograph ic mapping and angiogenesis. During the past year, Eph receptors have been shown to associate with glutamate receptors in excitatory neurons, suggesti ng a role in synapse formation or function. Moreover, ephrin/Eph signaling appears to regulate neural stem cell proliferation and migration in adult m ouse brains. The mode of action of ephrin/Ephs has been expanded from repul sion to adhesion and from cell surface attachment to regulated cleavage.