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Crystal Structure of the EphA4-ephrinB2 complex
Structural highlights
FunctionEFNB2_HUMAN Cell surface transmembrane ligand for Eph receptors, a family of receptor tyrosine kinases which are crucial for migration, repulsion and adhesion during neuronal, vascular and epithelial development. Binds promiscuously Eph receptors 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. Binds to receptor tyrosine kinase including EPHA4, EPHA3 and EPHB4. Together with EPHB4 plays a central role in heart morphogenesis and angiogenesis through regulation of cell adhesion and cell migration. EPHB4-mediated forward signaling controls cellular repulsion and segregation from EFNB2-expressing cells. May play a role in constraining the orientation of longitudinally projecting axons.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe EphA4 tyrosine kinase cell surface receptor regulates an array of physiological processes and is the only currently known class A Eph receptor that binds both A and B class ephrins with high affinity. We have solved the crystal structure of the EphA4 ligand binding domain alone and in complex with (1) ephrinB2 and (2) ephrinA2. This set of structures shows that EphA4 has significant conformational plasticity in its ligand binding face. In vitro binding data demonstrate that it has a higher affinity for class A than class B ligands. Structural analyses, drawing on previously reported Eph receptor structures, show that EphA4 in isolation and in complex with ephrinA2 resembles other class A Eph receptors but on binding ephrinB2 assumes structural hallmarks of the class B Eph receptors. This interactive plasticity reveals EphA4 as a structural chameleon, able to adopt both A and B class Eph receptor conformations, and thus provides a molecular basis for EphA-type cross-class reactivity. Structural plasticity of eph receptor A4 facilitates cross-class ephrin signaling.,Bowden TA, Aricescu AR, Nettleship JE, Siebold C, Rahman-Huq N, Owens RJ, Stuart DI, Jones EY Structure. 2009 Oct 14;17(10):1386-97. PMID:19836338[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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