简介：ProteinkinaseRAFisstrategicallylocatedinthe'Ras-MAP-kinasesignaltransductionpathway',aprinciplesystemwhichtransmitssignalsfromgrowthfactorreceptorstothenucleus,resultingincellproliferation.GrowthfactorresponsesaremediatedinpartbyactivationofRas,whichinturnactivatesRAFtophosphorylateMEK,itsdownstreamsubstrate.MEKactivatesMAPkinasetoinfluencenuclearevents.itisclear.however,thatanetworkofsignalsotherthanthosecarredbyRasplaysaroleinRAFregulation.Theseorthogonalinfluencesaremediatedbu:serine/threoninekinases,tyrosinekinases,andprotein-proteininteractions.AsafurthercomplicationtotheRAFnetwork,threeisoformsofRAFhavebeenestablishedwhichhavedivergentN-terminalregulatorydomains,Whereasthesedivergentregulatorydomainsimplicateisoform-specificfunctions,noclearevidenceorhypothesisfordistinctfunctionsforindividualisoformshasbeenpresented.Recently,'isoform-specificproteininteractions'havebeenidentifiedamongnumerousproteinsinteractingwithRAF,ThesestudiesmayservetodelineateindependentfunctionsforRAFisoforms.