Cell surface GPI-bound ligand for Eph receptors, a family of receptor tyrosine kinases which are crucial for migration, repulsion and adhesion during neuronal, vascular and epithelial development. Binds promiscuously Eph receptors residing on adjacent cells, leading to contact-dependent bidirectional signaling into neighboring cells. Plays an important role in angiogenesis and tumor neovascularization. The recruitment of VAV2, VAV3 and PI3-kinase p85 subunit by phosphorylated EPHA2 is critical for EFNA1-induced RAC1 GTPase activation and vascular endothelial cell migration and assembly. Exerts anti-oncogenic effects in tumor cells through activation and down-regulation of EPHA2. Activates EPHA2 by inducing tyrosine phosphorylation which leads to its internalization and degradation. Acts as a negative regulator in the tumorigenesis of gliomas by down-regulating EPHA2 and FAK. Can evoke collapse of embryonic neuronal growth cone and regulates dendritic spine morphogenesis (By similarity). Monomer. Homodimer. Forms heterodimers with EPHA2. Binds to the receptor tyrosine kinases EPHA2, EPHA3, EPHA4, EPHA5, EPHA6 and EPHA7. Also binds with low affinity to EPHA1 (By similarity). Undergoes proteolysis by a metalloprotease to give rise to a soluble monomeric form. N-Glycosylation is required for binding to EPHA2 receptor and inducing its internalization. Belongs to the ephrin family.