Ephrin-B3 （EFNB3） which belongs to the ephrin gene family is essential in brain development as well as in its maintenance. EFNB3 binds to， and induces the collapse of， commissural axons/growth cones in vitro. EFNB3 loosely binds Eph receptors located on bordering cells， leading to contact-dependent bidirectional signaling into neighboring cells. The EPH and EPH-related receptors comprise the largest subfamily of receptor protein-tyrosine kinases and are implicated in mediating developmental events， mostly in the nervous system.
