ArticleHelicase-DependentRNADecayIlluminatedbyaCryo-EMStructureofaHumanNuclearRNAExosome-MTR4ComplexGraphicalAbstractHighlightsdStructureofahumannuclearexosome-MTR4-RNAcomplexat3.45A˚overallresolutiondDNA-RNAchimeratranslocationstrandcanstalltheMTR4helicasedMtr4helicaseactivitiesarestimulatedinyeastandhumanexosomesdMutualexclusivityamongexosomecofactorsimpliesasequentialprocessforRNAdecayAuthorsEva-MariaWeick,M.RhyanPuno,KurtJanuszyk,JohnC.Zinder,MichaelA.DiMattia,ChristopherD.LimaCorrespondencelimac@mskcc.orgInBriefThecryo-EMstructureofthehumannuclearexosome-Mtr4complexloadedwithanRNAsubstraterevealsmechanisticinsightstohowthehelicaseunwindsstructuredRNAsubstratestopromotedegradation.Weicketal.,2018,Cell173,1663–1677June14,2018ª2018ElsevierInc.https://doi.org/10.1016/j.cell.2018.05.041ArticleHelicase-DependentRNADecayIlluminatedbyaCryo-EMStructureofaHumanNuclearRNAExosome-MTR4ComplexEva-MariaWeick,1,4M.RhyanPuno,1,3,4KurtJanuszyk,1,4JohnC.Zinder,1,2,4MichaelA.DiMattia,1,3andChristopherD.Lima1,3,5,*1StructuralBiologyProgram,SloanKetteringInstitute,MemorialSloanKetteringCancerCenter,NewYork,NY10065,USA2Tri-InstitutionalTrainingPrograminChemicalBiology,MemorialSloanKetteringCancerCenter,NewYork,NY10065,USA3HowardHughesMedicalInstitute,1275YorkAvenue,NewYork,NY10065,USA4Theseauthorscontributedequally5LeadContact*Correspondence:limac@mskcc.orghttps://doi.org/10.1016/j.cell.2018.05.041SUMMARYTheribonucleolyticRNAexosomeinteractswithRNAhelicasestodegradeRNA.Tounderstandhowthe30to50Mtr4helicaseengagesRNAandthenuclearexosome,wereconstituted14-subunitMtr4-contain-ingRNAexosomesfromSaccharomycescerevisiae,Schizosaccharomycespombe,andhumanandshowthattheyunwindstructuredsubstratestopromotedegradation.WeloadedahumanexosomewithanoptimizedDNA-RNAchimerathatstallsMTR4duringunwindinganddetermineditsstructuretoanoverallresolutionof3.45A˚bycryoelectronmicroscopy(cryo-EM).ThestructurerevealsanRNA-engagedhelicaseatopthenon-catalyticcore,withRNAcapturedwithinthecentralchannelandDI...
