Receptor tyrosine kinase which binds promiscuously transmembrane ephrin-B family ligands residing on adjacent cells, leading to contact-dependent bidirectional signaling into neighboring cells. The signaling pathway downstream of the receptor is referred to as forward signaling while the signaling pathway downstream of the ephrin ligand is referred to as reverse signaling. May play a role in axon guidance during nervous system development. May also play an important redundant role with other ephrin-B receptors in development and maturation of dendritic spines and synapse formation. More generally, may play a role in targeted cell migration and adhesion. Upon activation by ephrin-B ligands activates the MAPK/ERK and the JNK signaling cascades to regulate cell migration and adhesion respectively (By similarity). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Heterotetramer upon binding of the ligand. The heterotetramer is composed of an ephrin dimer and a receptor dimer. Oligomerization is probably required to induce biological responses (By similarity). Expressed in the embryo in the brain and spinal cord and in the first and fourth visceral arches. Most abundant in adult brain, with lower levels in eye, heart, ovary, oviduct, lung and pharynx. Expressed during early development. Phosphorylated. Autophosphorylation is stimulated by ligands (By similarity). Belongs to the protein kinase superfamily. Tyr protein kinase family. Ephrin receptor subfamily.