组蛋白的泛素化与去泛素化专家讲座

Histoneubquitination&deubquitination组蛋白的泛素化与去泛素化专家讲座第1页Thestructureofnucleosome组蛋白是一个11-15KDa碱性蛋白，与DNA相互作用组成核小体。关键组蛋白尾巴伸出来，受到广泛修饰。组蛋白的泛素化与去泛素化专家讲座第2页Ubquitin泛素(ubiquitin，Ub)是高度保守、含76个氨基酸蛋白质，分子量为8.5kDa，在真核生物体内广泛存在。泛素分子氨基端1-72位点氨基酸残基形成一个紧密球状结构，紧靠羧基端4个氨基酸残基是随机盘绕（random-coiled）。组蛋白的泛素化与去泛素化专家讲座第3页Ubiquitination&Deubiquitination泛素化修饰就是底物赖氨酸残基位点与泛素分子羧基末端相互结合过程。因为泛素本身7个赖氨酸位点,也可与另一个泛素相结合,所以单泛素化底物蛋白,可作为Seed，结合多个泛素，形成了多泛素化修饰。组蛋白的泛素化与去泛素化专家讲座第4页GENES&DEVELOPMENT17:2733–2740.byColdSpringHarborLaboratoryPressHistoneUbiquitination组蛋白的泛素化与去泛素化专家讲座第5页HistoneubiquitinationPrimarymonoubiquitinationreversible，regulatedbyubiquitinaseanddeubquitinaseHistonemodificationscrosstalkInvolvedinmultiplecellularevents---geneexpressionregulation、DNA

damageresponseandrepair、femaleXchromosomeinactiveandsoon组蛋白的泛素化与去泛素化专家讲座第6页除了单泛素化，H2A/H2AX在DNA损伤时可发生K63位多泛素化组蛋白的泛素化与去泛素化专家讲座第7页负责H2A/H2B泛素化与去泛素化酶H2A-specificCommontoH2A/H2BH2B-specific组蛋白的泛素化与去泛素化专家讲座第8页HistoneubiquitinaseOneE1(activating),mutipleE2(conjugating),substrate-specificE3(ligase)SchematicdepictionofhistoneubiquitinationMethods.Jul;54(3):315–325.E3主要有两大类:HECT(homologoustotheE6-APcarboxylterminus)结构域家族，经过与泛素形成催化作用所必需硫酯键发挥作用RING(reallyinterestingnewgene)结构域家族，为E2和底物提供居留位点从而使E2催化泛素转移到底物上组蛋白的泛素化与去泛素化专家讲座第9页

Histonedeubiquitinatingenzyme（DUBs）H2AdeubiquitinationUSP16：HOXgenesilencing,DNAdamagerepair

Xchromosomeinactivation,cellcycleprogression2A-DUB：interactswithPCAFUSP21：regulatorofliverregenerationBAP1：C-terminalhydrolase,repressionofHOXgenesH2BdeubiquitinationUbp8：residewithinSAGA，Transcription

Ubp10（Dot4）：Sir-mediatedtelomericandrDNAsilencing组蛋白的泛素化与去泛素化专家讲座第10页FunctionofHistoneUbiquitinationTranscriptionregulationDNAdamageresponseinactiveXchromosome：H2Aubchromatinboundaryintegrity：H2BubstemcellmaintenanceanddifferentiationHistoneUbiquitinationandDeubiquitinationinTranscription,DNADamageResponse,andCancer.FrontOncol,2(26),CaoJ&YanQ,组蛋白的泛素化与去泛素化专家讲座第11页Regulationofcellcycleprogression

—chromosomesegregationduringmitosisUbp-M(USP16)candeubiqutinateH2A.Duringthecellcycle,Ubp-Missequentiallyphosphorylatedanddephosphorylated,potentiallybythecdc-2/cyclinBcomplex.Ubp-MisessentialforSer-10H3phosphorylationmediatedbytheAuroraBkinaseandisrequiredforchromosomesegregationduringmitosis.组蛋白的泛素化与去泛素化专家讲座第12页CellReports,Volume10,Issue2,,226-238/10.1016/j.celrep..12.021DNAdamagerepairATM:ataxiatelangiectasiamutatedDSB:DNAdouble-strandbreakRNF:Ringfingerligase（E3）DDR:DNAdamageresponse53BPI：p53bindingprotein1组蛋白的泛素化与去泛素化专家讲座第13页TranscriptionregulationH2A与H2B单泛素化与转录调整相关:H2Aub与基因缄默相关,H2Bub与基因活化相关【CHIP-on-chip试验证实ubH2A在卫星区，ubH2B在转录活化基因主体】H2A/H2B泛素化机制：co-transcriptionmechanismH2B泛素化与去泛素化循环与转录起始及延伸有亲密关系组蛋白的泛素化与去泛素化专家讲座第14页ubH2A&silence

H2A-specificE3：Ring1B，2A-HUB，与转录缄默相关Ring1B存在于3种不一样转录抑制复合物PRC1,BCoR及E2F6.com-1中2A-HUB与N-CoR/HDAC1/3complex联络，定位于chemokinegenes开启子处，阻断FACT招募组蛋白的泛素化与去泛素化专家讲座第15页a.HistoneH2AMonoubiquitinationRepressesTranscriptionbyH3K4methylationisessentialforpreinitiationcomplex(PIC)formation.UbiquitylationofH2Adoesinhibitpreinitiationcomplexformation,notinadirectwaybutindirectlybypreventingH3K4methylation.DeubiquitylationofhistoneH2AbyUSP21activatestranscriptionalinitiationviatrans-histonecrosstalkwithH3K4di-andtri-methylation.Fig.1–Modeloftranscriptionalinitiationfromchromatintemplate.InhibitingPICformation组蛋白的泛素化与去泛素化专家讲座第16页b.HistoneH2AMonoubiquitinationRepressesTranscriptionby

2A-HUB:aH2A–specificubiquitinligase,catalyzesmonoubiquitinationofH2AatK119H2AmonoubiquitinationactstopreventFACTrecruitmentatthetranscriptionalpromoterregion,blockingRNApolymeraseIIreleaseattheearlystageofelongation.MolecularCell,MGRosenfeld,1(29),InhibitingRNAPIITranscriptionalElongationFACT:facilitateschromatintranscription二聚体，包含SPT16和SSRP1，能从核小体中置换出H2A/H2B二聚体，进而促使染色体介导转录延伸抑制得到释放组蛋白的泛素化与去泛素化专家讲座第17页Fig.1.ThediverseactivitiesofH2Bub1.

H2Bmonoubiquitylationanddeubiquitylationcandirectlymodulatethechromatinstatebyalteringnucleosomestability,promotingpartialnucleosomedisassemblyandreassembly,andregulatingchromatinhigher-orderstructure.modulatechromatinindirectlythroughthebindingorrepulsionofspecificreaders,whichcallintoactionaplethoraofproteinsandproteincomplexeswithdiversebiochemicalactivities.ThedirectandindirectmechanismsarenotmutuallyexclusiveE.g.relaxationofhigher-orderchromatinstructureisexpectedtofacilitatetheaccessofH2Bub1readers注：H2Bub1即对K120进行泛素化G.Fuchs,M.Oren/BiochimicaetBiophysicaActa1839()694–701H2B组蛋白的泛素化与去泛素化专家讲座第18页H2BUbiquitinationRequiresEarlyStepsinTranscriptionElongation(Co-Transcription)

1.酸性激活蛋白GAL4招募H2B特异泛素酶复合物到开启子区2.在与PAF、BUR（对Rad6Ser120磷酸化）、延伸形式RNAP2（其CTDSer5被Kin28磷酸化）作用下，泛素酶复合物对H2BK120位进行泛素化（co-transcription）组蛋白的泛素化与去泛素化专家讲座第19页ModelfortheregulationofchromatindynamicsbyH2Bubiquitinationanddeubiquitinationduringtranscriptionelongation.Rad6andBre1associatewiththePaf1complexandtravelwiththeelongatingformofRNAPol(iandii)Rad6/Bre1-mediatedH2Bub1stabilizesthenucleosomeinfrontofthepolymerasetocounteractanytorsionalstressandmightactsasa“checkpoint”tocoordinatetranscription-coupledevents,suchas,allowingthebindingofSpt16/FACTandrestrictingCtk1bindingtochromatin.泛素化稳定(B)In(i),Ubp8,acomponentoftheSAGAsub-complexthattravelswithRNAPolII,removestheconjugatedubiquitintodestabilizethenucleosome.(ii)ThisfacilitatesnucleosomedisassemblybySpt16/FACT.(iii)DeubiquitinationbyUbp8allowsassociationofCtk1withchromatinforthephosphorylationofserine2inRNAPolIICTD.去泛素化不稳定(C)In(i),nucleosomesarereassembledbehindtheelongatingRNAPolIIlikelybythestep-wiseinitialadditionofH3-H4bySpt6followedbytheadditionofH2A-H2BbySpt16/FACT.(ii)Rad6/Bre1-mediatedH2Bub1stabilizesthenucleosometofacilitatenucleosomereassemblyandtopreventanybacktrackingbyRNAPolII.(iii)StablenucleosomealsopreventsanypromiscuoustranscriptionthatmightoccurbythebindingofTBPtocrypticTATA-likesequenceswithinthecodingregion.组蛋白的泛素化与去泛素化专家讲座第20页RNAP2前方H2B泛素化，检验转录偶联事件H2B去泛素化，核小体解体，允许RNAP2继续前行RNAP2经过后，核小体H2B泛素化，发生重组，预防未知位点转录起始regulationofchromatindynamicsbyH2Bubiquitinationanddeubiquitinationduringtranscriptionelongation.组蛋白的泛素化与去泛素化专家讲座第21页Histonemodificationscrosstalk

组蛋白修饰间是相关，它们联合或者次序地发挥作用来调控转录。组蛋白的泛素化与去泛素化专家讲座第22页Figure7.Thetrans-histonecrosstalkbetweenhistoneH2BubiquitinationandH3K4/K79methylationinbuddingyeast.COMPASS:complexassociatedwithSet1Epigenetics5:6,460-468;August16,;©LandesBioscienceH2BMonoubiquitinationIsaPrerequisiteforLys-4H3andLys-79H3Methylation组蛋白的泛素化与去泛素化专家讲座第23页crosstalkbetweenH2BUbiquitination&H3K4methylation1.酸性激活蛋白GAL4招募H2B特异泛素酶复合物到开启子区2.在与PAF、BUR（对Rad6Ser120磷酸化）、延伸形式RNAP2（其CTDSer5被Kin28磷酸化）作用下，泛素酶复合物对H2BK120位进行泛素化（co-transcription）3.H2B泛素化是招募CPS35必须，Cps35是COMPASS甲基化酶复合体一个组分，COMPASS能介导H3K4二甲基化或三甲基化组蛋白的泛素化与去泛素化专家讲座第24页参考文件[1]HigashiM,InoueS,ItoT.CorehistoneH2Aubiquitylationandtranscriptionalregulation[J].Experimentalcellresearch,,316(17):2707-2712.[2]GattiM,PinatoS,MaiolicaA,etal.RNF168PromotesNoncanonicalK27UbiquitinationtoSignalDNADamage[J].Cellreports,,10(2):226-238.[3]WeakeVM,WorkmanJL.Histoneubiquitination:triggeringgeneactivity[J].Molecularcell,,29(6):653-663.[4]ChandrasekharanMB,HuangF,SunZW.HistoneH2Bubiquitinationandbeyond:Regulationofnucleosomestability,chromatindynamicsandthetrans-histoneH3methylation[J].Epigenetics,,5(6):460-468.[5]FuchsG,OrenM.WritingandreadingH2Bmonoubiquitylation[J].BiochimicaetBiophysicaActa(BBA)-GeneRegulatoryMechanisms,,1839(8):69