Background：

Cell surface transmembrane ligand for Eph receptors， a family of receptor tyrosine kinases which are crucial for migration， repulsion and adhesion during neuronal， vascular and epithelial development. Binding to Eph receptors residing on adjacent cells leads to contact-dependent bidirectional signaling into neighboring cells. Shows high affinity for the receptor tyrosine kinase EPHB1/ELK. Can also bind EPHB2 and EPHB3. Binds to， and induces collapse of， commissural axons/growth cones in vitro. May play a role in constraining the orientation of longitudinally projecting axons.