2qo7
Human EphA3 kinase and juxtamembrane region, dephosphorylated, AMP-PNP bound
Structural highlights
DiseaseEPHA3_HUMAN Defects in EPHA3 may be a cause of colorectal cancer (CRC) [MIM:114500. FunctionEPHA3_HUMAN Receptor tyrosine kinase which binds promiscuously membrane-bound ephrin 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. Highly promiscuous for ephrin-A ligands it binds preferentially EFNA5. Upon activation by EFNA5 regulates cell-cell adhesion, cytoskeletal organization and cell migration. Plays a role in cardiac cells migration and differentiation and regulates the formation of the atrioventricular canal and septum during development probably through activation by EFNA1. Involved in the retinotectal mapping of neurons. May also control the segregation but not the guidance of motor and sensory axons during neuromuscular circuit development.[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 PubMedEphrin receptors (Eph) affect cell shape and movement, unlike other receptor tyrosine kinases that directly affect proliferative pathways. The kinase domain of EphA3 is activated by ephrin binding and receptor oligomerization. This activation is associated with two tyrosines in the juxtamembrane region; these tyrosines are sites of autophosphorylation and interact with the active site of the kinase to modulate activity. This allosteric event has important implications both in terms of understanding signal transduction pathways mediated by Eph kinases as well as discovering specific therapeutic ligands for receptor kinases. In order to provide further details of the molecular mechanism through which the unphosphorylated juxtamembrane region blocks catalysis, we studied wild-type and site-specific mutants in detail. High-resolution structures of multiple states of EphA3 kinase with and without the juxtamembrane segment allowed us to map the coupled pathway of residues that connect the juxtamembrane segment, the activation loop, and the catalytic residues of the kinase domain. This highly conserved set of residues likely delineates a molecular recognition pathway for most of the Eph RTKs, helping to characterize the dynamic nature of these physiologically important enzymes. Autoregulation by the juxtamembrane region of the human ephrin receptor tyrosine kinase A3 (EphA3).,Davis TL, Walker JR, Loppnau P, Butler-Cole C, Allali-Hassani A, Dhe-Paganon S Structure. 2008 Jun;16(6):873-84. PMID:18547520[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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