Ephrin B3 belongs to the ephrin family. Ephrins are divided into the ephrin-A (EFNA) class, which are anchored to the membrane by a glycosylphosphatidylinositol linkage, and the ephrin-B (EFNB) class, which are transmembrane proteins. Ephrin B3 is important in brain development as well as in its maintenance. It is especially important for forebrain function since its expression levels were particularly high in several forebrain subregions compared to other brain subregions. Ephrin B3 binds to, and induce the collapse of, commissural axons/growth cones in vitro. It may play a role in constraining the orientation of longitudinally projecting axons.