組蛋白的泛素化與去泛素化專家講座

Histoneubquitination&deubquitination組蛋白的泛素化與去泛素化專家講座第1頁Thestructureofnucleosome組蛋白是一個(gè)11-15KDa堿性蛋白，與DNA相互作用組成核小體。關(guān)鍵組蛋白尾巴伸出來，受到廣泛修飾。組蛋白的泛素化與去泛素化專家講座第2頁Ubquitin泛素(ubiquitin，Ub)是高度保守、含76個(gè)氨基酸蛋白質(zhì)，分子量為8.5kDa，在真核生物體內(nèi)廣泛存在。泛素分子氨基端1-72位點(diǎn)氨基酸殘基形成一個(gè)緊密球狀結(jié)構(gòu)，緊靠羧基端4個(gè)氨基酸殘基是隨機(jī)盤繞（random-coiled）。組蛋白的泛素化與去泛素化專家講座第3頁Ubiquitination&Deubiquitination泛素化修飾就是底物賴氨酸殘基位點(diǎn)與泛素分子羧基末端相互結(jié)合過程。因?yàn)榉核乇旧?個(gè)賴氨酸位點(diǎn),也可與另一個(gè)泛素相結(jié)合,所以單泛素化底物蛋白,可作為Seed，結(jié)合多個(gè)泛素，形成了多泛素化修飾。組蛋白的泛素化與去泛素化專家講座第4頁GENES&DEVELOPMENT17:2733–2740.byColdSpringHarborLaboratoryPressHistoneUbiquitination組蛋白的泛素化與去泛素化專家講座第5頁HistoneubiquitinationPrimarymonoubiquitinationreversible，regulatedbyubiquitinaseanddeubquitinaseHistonemodificationscrosstalkInvolvedinmultiplecellularevents---geneexpressionregulation、DNA

damageresponseandrepair、femaleXchromosomeinactiveandsoon組蛋白的泛素化與去泛素化專家講座第6頁除了單泛素化，H2A/H2AX在DNA損傷時(shí)可發(fā)生K63位多泛素化組蛋白的泛素化與去泛素化專家講座第7頁負(fù)責(zé)H2A/H2B泛素化與去泛素化酶H2A-specificCommontoH2A/H2BH2B-specific組蛋白的泛素化與去泛素化專家講座第8頁HistoneubiquitinaseOneE1(activating),mutipleE2(conjugating),substrate-specificE3(ligase)SchematicdepictionofhistoneubiquitinationMethods.Jul;54(3):315–325.E3主要有兩大類:HECT(homologoustotheE6-APcarboxylterminus)結(jié)構(gòu)域家族，經(jīng)過與泛素形成催化作用所必需硫酯鍵發(fā)揮作用RING(reallyinterestingnewgene)結(jié)構(gòu)域家族，為E2和底物提供居留位點(diǎn)從而使E2催化泛素轉(zhuǎn)移到底物上組蛋白的泛素化與去泛素化專家講座第9頁

Histonedeubiquitinatingenzyme（DUBs）H2AdeubiquitinationUSP16：HOXgenesilencing,DNAdamagerepair

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

Ubp10（Dot4）：Sir-mediatedtelomericandrDNAsilencing組蛋白的泛素化與去泛素化專家講座第10頁FunctionofHistoneUbiquitinationTranscriptionregulationDNAdamageresponseinactiveXchromosome：H2Aubchromatinboundaryintegrity：H2BubstemcellmaintenanceanddifferentiationHistoneUbiquitinationandDeubiquitinationinTranscription,DNADamageResponse,andCancer.FrontOncol,2(26),CaoJ&YanQ,組蛋白的泛素化與去泛素化專家講座第11頁Regulationofcellcycleprogression

—chromosomesegregationduringmitosisUbp-M(USP16)candeubiqutinateH2A.Duringthecellcycle,Ubp-Missequentiallyphosphorylatedanddephosphorylated,potentiallybythecdc-2/cyclinBcomplex.Ubp-MisessentialforSer-10H3phosphorylationmediatedbytheAuroraBkinaseandisrequiredforchromosomesegregationduringmitosis.組蛋白的泛素化與去泛素化專家講座第12頁CellReports,Volume10,Issue2,,226-238/10.1016/j.celrep..12.021DNAdamagerepairATM:ataxiatelangiectasiamutatedDSB:DNAdouble-strandbreakRNF:Ringfingerligase（E3）DDR:DNAdamageresponse53BPI：p53bindingprotein1組蛋白的泛素化與去泛素化專家講座第13頁TranscriptionregulationH2A與H2B單泛素化與轉(zhuǎn)錄調(diào)整相關(guān):H2Aub與基因緘默相關(guān),H2Bub與基因活化相關(guān)【CHIP-on-chip試驗(yàn)證實(shí)ubH2A在衛(wèi)星區(qū)，ubH2B在轉(zhuǎn)錄活化基因主體】H2A/H2B泛素化機(jī)制：co-transcriptionmechanismH2B泛素化與去泛素化循環(huán)與轉(zhuǎn)錄起始及延伸有親密關(guān)系組蛋白的泛素化與去泛素化專家講座第14頁ubH2A&silence

H2A-specificE3：Ring1B，2A-HUB，與轉(zhuǎn)錄緘默相關(guān)Ring1B存在于3種不一樣轉(zhuǎn)錄抑制復(fù)合物PRC1,BCoR及E2F6.com-1中2A-HUB與N-CoR/HDAC1/3complex聯(lián)絡(luò)，定位于chemokinegenes開啟子處，阻斷FACT招募組蛋白的泛素化與去泛素化專家講座第15頁a.HistoneH2AMonoubiquitinationRepressesTranscriptionbyH3K4methylationisessentialforpreinitiationcomplex(PIC)formation.UbiquitylationofH2Adoesinhibitpreinitiationcomplexformation,notinadirectwaybutindirectlybypreventingH3K4methylation.DeubiquitylationofhistoneH2AbyUSP21activatestranscriptionalinitiationviatrans-histonecrosstalkwithH3K4di-andtri-methylation.Fig.1–Modeloftranscriptionalinitiationfromchromatintemplate.InhibitingPICformation組蛋白的泛素化與去泛素化專家講座第16頁b.HistoneH2AMonoubiquitinationRepressesTranscriptionby

2A-HUB:aH2A–specificubiquitinligase,catalyzesmonoubiquitinationofH2AatK119H2AmonoubiquitinationactstopreventFACTrecruitmentatthetranscriptionalpromoterregion,blockingRNApolymeraseIIreleaseattheearlystageofelongation.MolecularCell,MGRosenfeld,1(29),InhibitingRNAPIITranscriptionalElongationFACT:facilitateschromatintranscription二聚體，包含SPT16和SSRP1，能從核小體中置換出H2A/H2B二聚體，進(jìn)而促使染色體介導(dǎo)轉(zhuǎn)錄延伸抑制得到釋放組蛋白的泛素化與去泛素化專家講座第17頁Fig.1.ThediverseactivitiesofH2Bub1.

H2Bmonoubiquitylationanddeubiquitylationcandirectlymodulatethechromatinstatebyalteringnucleosomestability,promotingpartialnucleosomedisassemblyandreassembly,andregulatingchromatinhigher-orderstructure.modulatechromatinindirectlythroughthebindingorrepulsionofspecificreaders,whichcallintoactionaplethoraofproteinsandproteincomplexeswithdiversebiochemicalactivities.ThedirectandindirectmechanismsarenotmutuallyexclusiveE.g.relaxationofhigher-orderchromatinstructureisexpectedtofacilitatetheaccessofH2Bub1readers注：H2Bub1即對(duì)K120進(jìn)行泛素化G.Fuchs,M.Oren/BiochimicaetBiophysicaActa1839()694–701H2B組蛋白的泛素化與去泛素化專家講座第18頁H2BUbiquitinationRequiresEarlyStepsinTranscriptionElongation(Co-Transcription)

1.酸性激活蛋白GAL4招募H2B特異泛素酶復(fù)合物到開啟子區(qū)2.在與PAF、BUR（對(duì)Rad6Ser120磷酸化）、延伸形式RNAP2（其CTDSer5被Kin28磷酸化）作用下，泛素酶復(fù)合物對(duì)H2BK120位進(jìn)行泛素化（co-transcription）組蛋白的泛素化與去泛素化專家講座第19頁ModelfortheregulationofchromatindynamicsbyH2Bubiquitinationanddeubiquitinationduringtranscriptionelongation.Rad6andBre1associatewiththePaf1complexandtravelwiththeelongatingformofRNAPol(iandii)Rad6/Bre1-mediatedH2Bub1stabilizesthenucleosomeinfrontofthepolymerasetocounteractanytorsionalstressandmightactsasa“checkpoint”tocoordinatetranscription-coupledevents,suchas,allowingthebindingofSpt16/FACTandrestrictingCtk1bindingtochromatin.泛素化穩(wěn)定(B)In(i),Ubp8,acomponentoftheSAGAsub-complexthattravelswithRNAPolII,removestheconjugatedubiquitintodestabilizethenucleosome.(ii)ThisfacilitatesnucleosomedisassemblybySpt16/FACT.(iii)DeubiquitinationbyUbp8allowsassociationofCtk1withchromatinforthephosphorylationofserine2inRNAPolIICTD.去泛素化不穩(wěn)定(C)In(i),nucleosomesarereassembledbehindtheelongatingRNAPolIIlikelybythestep-wiseinitialadditionofH3-H4bySpt6followedbytheadditionofH2A-H2BbySpt16/FACT.(ii)Rad6/Bre1-mediatedH2Bub1stabilizesthenucleosometofacilitatenucleosomereassemblyandtopreventanybacktrackingbyRNAPolII.(iii)StablenucleosomealsopreventsanypromiscuoustranscriptionthatmightoccurbythebindingofTBPtocrypticTATA-likesequenceswithinthecodingregion.組蛋白的泛素化與去泛素化專家講座第20頁RNAP2前方H2B泛素化，檢驗(yàn)轉(zhuǎn)錄偶聯(lián)事件H2B去泛素化，核小體解體，允許RNAP2繼續(xù)前行RNAP2經(jīng)過后，核小體H2B泛素化，發(fā)生重組，預(yù)防未知位點(diǎn)轉(zhuǎn)錄起始regulationofchromatindynamicsbyH2Bubiquitinationanddeubiquitinationduringtranscriptionelongation.組蛋白的泛素化與去泛素化專家講座第21頁Histonemodificationscrosstalk

組蛋白修飾間是相關(guān)，它們聯(lián)合或者次序地發(fā)揮作用來調(diào)控轉(zhuǎn)錄。組蛋白的泛素化與去泛素化專家講座第22頁Figure7.Thetrans-histonecrosstalkbetweenhistoneH2BubiquitinationandH3K4/K79methylationinbuddingyeast.COMPASS:complexassociatedwithSet1Epigenetics5:6,460-468;August16,;?LandesBioscienceH2BMonoubiquitinationIsaPrerequisiteforLys-4H3andLys-79H3Methylation組蛋白的泛素化與去泛素化專家講座第23頁crosstalkbetweenH2BUbiquitination&H3K4methylation1.酸性激活蛋白GAL4招募H2B特異泛素酶復(fù)合物到開啟子區(qū)2.在與PAF、BUR（對(duì)Rad6Ser120磷酸化）、延伸形式RNAP2（其CTDSer5被Kin28磷酸化）作用下，泛素酶復(fù)合物對(duì)H2BK120位進(jìn)行泛素化（co-transcription）3.H2B泛素化是招募CPS35必須，Cps35是COMPASS甲基化酶復(fù)合體一個(gè)組分，COMPASS能介導(dǎo)H3K4二甲基化或三甲基化組蛋白的泛素化與去泛素化專家講座第24頁參考文件[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