
Type:Protein
SpeciesReactivity:M
B=Bovine;Ca=Cat;Ch=Chicken;D=Dog;EQ=Equine;GP=GuineaPig;H=Human;M=Mouse;P=Porcine;Pr=Primate;R=Rat;Rb=Rabbit;Y=Yeast;Xe=Xenopus;Ze=Zebrafish;;;;NA-NotApplicable;STP=Step-TactinProteins;AllEphA4,alsoknownasSek,Sek1,Cek8,Hek8,andTyro1,1isamemberoftheEphreceptorfamilywhichbindsmembersoftheephrinligandfamily.Therearetwoclassesofreceptors,designatedAandB.BoththeAandBclassreceptorshaveanextracellularregionconsistingofaglobulardomain,acysteine-richdomain,andtwofibronectintypeIIIdomains.Thisisfollowedbythetransmembraneregionandcytoplasmicregion.Thecytoplasmicregioncontainsajuxtamembranemotifwithtwotyrosineresidues,whicharethemajorautophosphorylationsites,akinasedomain,andaconservedsterilealphamotif(SAM)inthecarboxytailwhichcontainsoneconservedtyrosineresidue.Activationofkinaseactivityoccursafterligandrecognitionandbinding.EphA4hasbeenshowntobindephrin-A5,ephrin-A1,ephrin-A3,ephrin-A2,ephrin-B2,ephrin-B3,andephrin-A4.2,3TheextracellulardomainsofmouseandhumanEphA4sharegreaterthan95%aminoacididentity.Onlymembrane-boundorFcclusteredligandsarecapableofactivatingthereceptorinvitro.Whilesolublemonomericligandsbindthereceptor,theydonotinducereceptorautophosphorylationandactivation.2Invivo,theligandsandreceptorsdisplayreciprocalexpression.3Ithasbeenfoundthatnearlyallreceptorsandligandsareexpressedindevelopingandadultneuraltissue.3TheEph/ephrinfamiliesalsoappeartoplayaroleinangiogenesis.3
References:
1UnifiednomenclatureforEphfamilyreceptorsandtheirligands,theephrins.EphNomenclatureCommittee[letter].Cell,1997,90(3):403-404
2Flanagan,J.G.andP.Vanderhaegen,TheephrinsandEphreceptorsinneuraldevelopment.Annu.Rev.Neurosci.1998,21:309-345
3Pasquale,E.B.,TheEphfamilyofreceptors.Curr.Opin.Cell.Biol.1997,9(5):608-615