BackgroundInformation | Theepidermalgrowthfactorreceptor(EGFR;ErbB-1;HER1inhumans)isthecell-surfacereceptorformembersoftheepidermalgrowthfactorfamily(EGF-family)ofextracellularproteinligands.EGFRisamemberoftheErbBfamilyofreceptors,asubfamilyoffourcloselyrelatedreceptortyrosinekinases:EGFR(ErbB-1),HER2/c-neu(ErbB-2),Her3(ErbB-3)andHer4(ErbB-4).MutationsaffectingEGFRexpressionoractivitycouldresultincancer.EGFRexistsonthecellsurfaceandisactivatedbybindingofitsspecificligands,includingepidermalgrowthfactorandtransforminggrowthfactorα(TGFα).Uponactivationbyitsgrowthfactorligands,EGFRundergoesatransitionfromaninactivemonomericformtoanactivehomodimer.Inadditiontoforminghomodimersafterligandbinding,EGFRmaypairwithanothermemberoftheErbBreceptorfamily,suchasErbB2/Her2/neu,tocreateanactivatedheterodimer.EGFRdimerizationstimulatesitsintrinsicintracellularprotein-tyrosinekinaseactivity.Asaresult,autophosphorylationoffivetyrosine(Y)residuesintheC-terminaldomainofEGFRoccurs. |