The Eph receptors, which bind a group of cell-membrane-anchored ligands known as ephrins, represent the largest subfamily of receptor tyrosine kinases (RTKs). The Eph receptors and their ephrin ligands control a diverse array of cell-cell interactions in the nervous and vascular systems. On ephrin binding, the Eph kinase domain is activated, initiating 'forward' signaling in the receptor-expressing … expand

The Eph receptors, which bind a group of cell-membrane-anchored ligands known as ephrins, represent the largest subfamily of receptor tyrosine kinases (RTKs). The Eph receptors and their ephrin ligands control a diverse array of cell-cell interactions in the nervous and vascular systems. On ephrin binding, the Eph kinase domain is activated, initiating 'forward' signaling in the receptor-expressing cells. Simultaneously, signals are also induced in the ligand-expressing cells a phenomenon referred to as 'reverse' signalling. The extracellular Eph receptor region contains a conserved 180- amino-acid N-terminal ligand-binding domain (LBD) which is both necessary and sufficient for bindings of the receptors to their ephrin ligands. An adjacent cysteine-rich region might be involved in receptor-receptor oligomerization often observed on ligand binding, whereas the next two fibronectin type III repeats have yet to be assigned a clear biological function. The cytoplasmic Eph receptor region contains a kinase domain, a sterile alpha motif (SAM) domain, and a PDZ-binding motif. The ligand-binding domain (LBD) of Eph receptors is unique to this family of RTKs ans shares no significant amino-acid-sequence homology with other known proteins [ PUBMED:9853759 PUBMED:11780069 PUBMED:19525919 ].

The Eph LBD domain forms a compact globular structure which folds into a jellyroll β-sandwich composed of 11 antiparallel β-strands. It has two antiparallel β-sheets, with the usual left-handed twist, packed against each other to form a compact β-sandwich, and a short 3(10) helix [ PUBMED:9853759 PUBMED:11780069 PUBMED:19525919 ].