Ephrin receptors and their ligands, the ephrins, mediate numerous developmental processes, particularly in the nervous system. Based on their structures and sequence relationships, 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. The Eph family of receptors are divided into 2 groups based on the similarity of their extracellular domain sequences and their affinities for binding ephrin-A and ephrin-B ligands. Ephrin receptors make up the largest subgroup of the receptor tyrosine kinase (RTK) family. The ligand-activated form of EphB2, which belongs to the Tyr family of protein kinases, interacts with multiple proteins, including GTPase-activating protein (RASGAP) through its SH2 domain. It binds RASGAP through the juxtamembrane tyrosines residues, and also interacts with PRKCABP and GRIP1 This type I membrane protein is expressed in brain, heart, lung, kidney, placenta, pancreas, liver and skeletal muscle. It is preferentially expressed in fetal brain. This protein contains putatively 2 fibronectin type III domains and 1 sterile alpha motif (SAM) domain.