Ephrin-A4 (EFNA4)

Ephrin-A4 is a member of the ephrin family of proteins encoded by the EFNA4 gene. It functions as a glycosylphosphatidylinositol (GPI)-anchored ligand for members of the erythropoietin-producing hepatocellular (Eph) receptor tyrosine kinase family—the largest subfamily of receptor tyrosine kinases. Ephrins and their receptors play crucial roles in mediating developmental processes such as neuronal patterning, vascular formation, cell migration, repulsion, adhesion, and immune system interactions. Unlike transmembrane ephrin-B ligands, ephrin-A ligands like Ephrin-A4 are tethered to the membrane via GPI anchors. Ephrin-A/Eph receptor interactions result in contact-dependent bidirectional signaling—forward signaling through the receptor-expressing cell and reverse signaling through the ligand-expressing cell—which regulates cytoskeletal dynamics via small GTPases such as Rho and Ras families. In addition to its developmental functions—especially within nervous system wiring—Ephrin-A4 has been implicated in cancer biology by promoting tumor cell migration and spheroid formation through upregulation of factors like NANOG. alternative splicing can produce soluble forms of Ephrin-A4 that may modulate immune responses by facilitating communication between activated B lymphocytes and dendritic cells.

Other names

EFNA4EFL4EPLG4LERK4LERK-4ephrin A4

As a ligand for Eph receptors, it mediates bidirectional signaling that affects cellular migration and adhesion; no direct drug mechanism is established.