4p5q
Human EphA3 Kinase domain in complex with quinoxaline derivatives
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] Publication Abstract from PubMedThe X-ray crystal structures of the catalytic domain of the EphA3 tyrosine kinase in complex with two type I inhibitors previously discovered in silico (compounds A and B) were used to design type I1/2 and II inhibitors. Chemical synthesis of about 25 derivatives culminated in the discovery of compounds 11d (type I1/2), 7b, and 7g (both of type II), which have low-nanomolar affinity for Eph kinases in vitro and a good selectivity profile on a panel of 453 human kinases (395 nonmutant). Surface plasmon resonance measurements show a very slow unbinding rate (1/115 min) for inhibitor 7m. Slow dissociation is consistent with a type II binding mode in which the hydrophobic moiety (trifluoromethyl-benzene) of the inhibitor is deeply buried in a cavity originating from the displacement of the Phe side chain of the so-called DFG motif as observed in the crystal structure of compound 7m. The inhibitor 11d displayed good in vivo efficacy in a human breast cancer xenograft. Pyrrolo[3,2-b]quinoxaline Derivatives as Types I and II Eph Tyrosine Kinase Inhibitors: Structure-Based Design, Synthesis, and in Vivo Validation.,Unzue A, Dong J, Lafleur K, Zhao H, Frugier E, Caflisch A, Nevado C J Med Chem. 2014 Jul 30. PMID:25076195[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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