EPH receptor A4 (EPHA4) is a member of the Eph receptor family of receptor tyrosine kinases (RTKs) that interacts with both ephrin-A and ephrin-B ligands, making it one of the most versatile Eph receptors. In mice, Epha4 is highly expressed in the central nervous system, particularly during development, where it regulates axon guidance, neuronal pathfinding, synaptic plasticity, and neural circuit formation. EPHA4 mediates contact-dependent bidirectional signaling, often inducing cell repulsion and boundary formation, which is critical for proper tissue patterning. Beyond development, EPHA4 continues to function in the adult CNS, contributing to synaptic remodeling and neuronal regeneration responses.