蛋白質(zhì)與疾病孫秉貴浙江大學(xué)醫(yī)學(xué)院神經(jīng)科學(xué)研究所bsun@/sunbgMay19,2015ProteinrelateddiseasesNatRevNeurosci2003,4:49-60ProteinStructureisHierarchicalStructureDeterminesFunctionPrimaryStructure:SequenceTheprimarystructureofaproteinistheaminoacidsequencePrimaryStructure:SequenceTwentydifferentaminoacidshavedistinctshapesandpropertiesSecondaryStructure:,,&loopshelicesandsheetsarestabilizedbyhydrogenbondsbetweenbackboneoxygenandhydrogenatomsSecondaryStructure:

helixSecondaryStructure:sheetbsheetbbuldgeTertiaryStructure:DomainsTertiaryStructure:AProteinFoldThreeDimensionalStructureofProteinsQuaternaryStructure:MultimericProteinsorFunctionalAssembliesMultimericProteinsMacromolecularAssembliesRibosome:

ProteinSynthesisReplisome:DNAcopyingHemoglobin:AtetramerProteinFoldingTheprocessbywhichaproteinacquiresitsnativetridimensionalstructure.Underphysiologicalconditions,eachproteinhasauniquestablefoldedstructure,butinconformationaldisordersthepolypeptidechainadoptsanalternativestructure,associatedwiththepathogenesisofthedisease.RegulationofProteinFoldingintheERManynewlysynthesizedproteinsaretranslocatedintotheER,wheretheyfoldintotheirthree-dimensionalstructureswiththehelpofaseriesofmolecularchaperonesandfoldingcatalysts(notshown).CorrectlyfoldedproteinsarethentransportedtotheGolgicomplexandthendeliveredtotheextracellularenvironment.However,incorrectlyfoldedproteinsaredetectedbyaquality-controlmechanismandsentalonganotherpathway(theunfoldedproteinresponse)inwhichtheyareubiquitinatedandthendegradedinthecytoplasmbyproteasomes.Nature2003,426:884-890MolecularChaperonsHeatshockprotein(Hsp)/熱休克蛋白:

HSP40、HSP70Chaperonins/伴侶素

GroEL、GroESFoldase/折疊酶

Proteindisulfideisomerase(PDI)、Peptidylprolylcis/transisomerase(PPI)HSPsinProteinFoldingThediagramshowstheroleofheat-shockproteinsandachaperonininproteinfolding.

AstheribosomemovesalongthemoleculeofmessengerRNA,achainofaminoacidsisbuiltuptoformanewproteinmolecule.

Thechainisprotectedagainstunwantedinteractionswithothercytoplasmicmoleculesbyheat-shockproteinsandachaperoninmoleculeuntilithassuccessfullycompleteditsfolding.

Source:(/chem/Chemistry/CHEM43/CHEM43/HSP/FUNCTION.HTML)

WhenGoodProteinsGoBadDNAmutationcausestheproductionofaproteinthatcannotfoldwheninitiallyproducedofftheribosomeMutationscausetheproductionofaproteinthatisdestabilizedandthusunfoldseasieroncefoldedStressesduringthelifetimeoftheproteinmodifyitcausingittobedestabilizedandthusunfoldProteinchangesfromonefoldedformintoanother(thisoftenoccurswhenanα-helicalproteinchangesintoaβ-sheetprotein)Mahley,Neuron(2012)ApolipoproteinE(ApoE)

FateofaPolypeptideChainPosttranslationalmodificationofproteinsPosttranslationalmodificationofproteinsSchematicrepresentationofthepathwayleadingtoproteinmisfoldingandaggregationNatRevNeurosci2003,4:49-60TauAcetylationandADNatureCommunicationAmyloidPrecursorProtein(APP)andItsProcessingSelkoeetal,2001A

A

b-secretase(BACE1)Ab1-42Ab1-40Ab1-38GenerationofAβPeptidesfromAmyloidPrecursorProtein(APP)hAPPg-secretase(Presenilin,Nicastrin,Pen-2,Aph-1)FADmutationsA

b-secretase(BACE1)Ab1-42Ab1-40Ab1-38GenerationofAβPeptidesfromAmyloidPrecursorProtein(APP)hAPPA1-42DAEFRHDSGYEVHHQKLVFFAEDVGSNKGAIIGLMVGGVVIA

MoretoxicMorepronetoaggregationA

g-secretase(Presenilin,Nicastrin,Pen-2,Aph-1)Aggregation:FailureofQualityControlAggregation:FailureofQualityControlImpactofaggregationonmechanismsofproteindegradationSolublemisfoldedmonomersanddimerscanberecognizedbyboththeUPSorCMA(chaperone-mediatedautophagy)-relatedchaperones,andsubsequentlydegradedbyeitherofthesetwopathways.InthecaseofCMA,cytosolicproteins(i.e.,a-synuclein)arerecognizedbyachaperone(i.e.,Hsc70),whichdeliversthetargetproteintothelysosomeviaareceptorproteinpresentinthelysosomalmembrane.However,onmorecomplexassembly(oligomerorfibrilformation)ofthetargetprotein,macroautophagyistheonlymechanismavailabletoclearthemoreinsolubleandhighlyorderedaggregates.Ubiquitin-ProteasomeProteolysisUbiquitinisfirstactivatedbytheubiquitin-activatingenzymeE1(A),anubiquitin-carrierprotein,E2,andATP.Theproductofthisreactionisahigh-energyE2ubiquitinthiolesterintermediate(B).Proteinsubstratesarethenubiquitinatedbyeitherbindingofthesubstratetoaspecificubiquitin-proteinligase(E3),andthentheE2-boundactivatedubiquitinistransferreddirectlytotheE3-boundproteinsubstrate.Oralternatively,theactivatedubiquitincanbetransferredfromtheE2totheE3,priortoitsconjugationtotheE3-boundsubstrate(C).Followingconjugationofthefirstubiquitinmoleculetotheproteinsubstrate,additionalubiquitinmoleculescanbeaddedtotheinternallysineresiduesofubiquitintoformapolyubiquitinchainonthesubstrate(D).Theubiquitinatedsubstrateisthenrecognizedanddegradedbythe26Sproteasomecomplex,leadingtothereleaseofshortpeptides(E).Ubiquitinisrecycledviatheactivityofdeubiquitinatingenzymes.AutophagyAutophagyisthebasiccatabolicmechanismthatinvolvescelldegradationofunnecessaryordysfunctionalcellularcomponentsthroughthelysosomalmachineryAggregation:FailureofQualityControlCerebralaggregatesinneurodegenerativediseasesNatRevNeurosci2003,4:49-60AβdepositsinmousemodelsofADModelsfortheToxicMechanismof

MisfoldedAggregatesAtleastfourhypotheseshavebeenproposedtoexplainthemechanismofneurotoxicityassociatedwithproteinmisfoldingandaggregation:activationofanapoptoticsignallingpathway,recruitmentofessentialcellularfactors,formationofionchannelsandtheinductionofoxidativestress.ModelsfortheMechanismofCellularToxicityassociatedwithProteinMisfoldingandAggregationNatRevNeurosci2003,4:49-60DiseasesSchematicRepresentationofMitochondrialCompartmentalizationMitochondrialDysfunctionImmuneContributionsProteinFoldingDiseasesSickleCellAnemia:

HaemoglobinSickle-cellanemiaiscausedbyapointmutationintheβ-globinchainofhaemoglobinAggregateisnottoxictocells,butcausescellstobeelongatedLimitscellsabilitytobindoxygenProteinFoldingDiseasesSickleCellAnemia:

Haemoglobin

Sickle-cellanemiaiscausedbyapointmutationintheβ-globinchainofhaemoglobinAggregateisnottoxictocells,butcausescellstobeelongatedLimitscellsabilitytobindoxygenInsicklecellanemia,theabnormalcellsusuallydieafteronlyabout10to20days.Thebonemarrowcan'tmakenewredbloodcellsfastenoughtoreplacethedyingones.Sicklecellanemiaisaninherited,lifelongdisease.Peoplewhohavethediseasearebornwithit.Theyinherittwogenesforsicklehemoglobin—onefromeachparent.ProteinFoldingDiseasesCysticfibrosis纖維囊腫Cysticfibrosis,orCF,isanautosomalrecessivegeneticdisorderofthesecretoryglandsthatmakemucusandsweat.CFiscausedbyamutationinthegenefortheproteincysticfibrosistransmembraneconductanceregulator(CFTR).Thisproteinisrequiredtoregulatethecomponentsofsweat,digestivefluids,andmucus.CFTRregulatesthemovementofchlorideandsodiumionsacrossepithelialmembranes.CFmainlyaffectsthelungs,pancreas,liver,intestines,andsexorgans.ProteinFoldingDiseasesHuntington’sdisease:

Huntingtinproteininheritedautosomaldominantdisordermotorimpairment,personalitychangespolyglutaminerepeatintheHuntingtinproteinofsomepeoplecausesselfassociationoftheproteininnervecellscytoplsmicinclusionskillingnervecellsPolyglutamine(PolyQ)Repeat>40repeatsinHD舞蹈癥ProteinFoldingDiseasesHuntington’sdisease:

HuntingtinproteinProteinFoldingDiseasesParkinson’sdisease:

alpha-synucleinLewybodiesforminbraincellsKillcellsinpartofbrainthatproducesdopamineLessdopaminemeansmotorcontrollossIsekiE.Neuropathology.2004.24(1):72-8Parkinson’sDiseaseLewyBodyAlpha-synucleinNeuronallossinParkinson’sdiseaseEtiologyofParkinson’sDiseaseEnvironmentaltoxinhypothesis

MPTP

(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine):aneurotoxinprecursortoMPP+,whichcausespermanentsymptomsofParkinson'sdiseasebydestroyingdopaminergicneuronsinthesubstantianigraofthebrain.

Rotenone:

pesticide魚藤酮Paraquat:herbicide百草枯

Maneb:fungicide代森錳

EtiologyofParkinson’sDiseaseGenetichypothesis

SNCA:encodingα-synuclein

PARK2:encodingtheE3ubiquitinligaseparkin

PARK6:encodingPINK1,amitochondrialkinase

PARK7:encodingtheproteinDJ-1

PARK8:encodingleucine-richrepeatkinase2(LRRK2)

PARK9:encodingATP13A2ALS:amyotrophiclateralsclerosisAmytrophiclateralsclerosis.ALSisaprogressivefataldiseasecausedbydegenerationoflowermotorneuronsinthelateralhornofthespinalcordanduppermotorneuronsofthecerebralcortex,resultinginprogressivemotorweaknessSuperoxidedismutase(SOD1)ALS:amyotrophiclateralsclerosisALS:amyotrophiclateralsclerosisLouGehrigALS:amyotrophiclateralsclerosisLouGehrigStephenHawkingProteinFoldingDiseasesAlzheimer’sDisease:

Abprotein,TauOvertimemoreandmoredestabilizedproteinformsandeventuallywithagethereisenoughtoaggregateAggregatedproteinformslongfibersthatwrapthemselvesaroundthebaseofthenervecellsAβplaquetanglesAmyloidPlaquesandNeurofibrillaryTangles(NFT)inADBrainsSciTranslMed.2011StructuralChangesinBrainsofADPatients

Late-onsetADriskallelesbyGWASHoltzmanD,2011AβAccumulationintheBrainIs

DependentonItsProductionand

Clearance

ColdSpringHarbPerspectMed2012,2(6):a006379GeneMutationsAβDP:Aβ-degradingproteaseUPSAutophagyAβ-DegradingProteasesColdSpringHarbPerspectMed2012,2(6):a006379NeuronalProcessesatMultipleLevelsofComplexityAdecreasessynapticglutamatergictransmissionLFRFLTRPLPRTLOROHealthyMouseADMouseNeuronalActivityMeasuredbyEEG(Electroencephalogram)AinducedAberrantSynchronousNeuronalNetworkActivityLRProteinFoldingDiseasesMadCowDisease:

Prion(proteinaceousinfectiousonly)SimilartoAlzheimer’sinthatlongneurofibrillarytanglesformfromaggregatesTheproteinistheinfectiousparticleplayingagameof“aggregationtag”inyourcellsTorrentJ.etal.Biochemistry.200443:22,7162-7170

PrPcPrPscsoluble

+

-enzymedigesting

+

-polypeptidechainα-helicalsegment?-sheetPrionproteinThenativestate(endogenouscellularprionprotein,PrPC)iswater-soluble,presentinginhealthycells,withpossiblefunctionintransmembranetransportorsignaling;Theotherconformationalstate(misfolded,disease-associatedPrPSc(Scmeaningscrapie-associated)isverypoorlywater-solubleandreadilyformsproteinaggregates.動(dòng)物prion病

人類prion病

羊瘙癢病(scrapieofsheepandgoat)

庫(kù)魯病(Kurudisease)

水貂傳染性腦病(transmissibleminkencephalopathy,TMM)克-雅病(Creutzfeld-Jakobdisease,CJD)鹿慢性退行性變(chronicwastingdiseaseofdeer,CWD)格斯特曼綜合征(Grestmann-StrausslerSyndrome,GSS)牛海綿狀腦病(bovinespongiformencephalopathy,BSE)致死性家庭失眠癥(fatalfamilialinsomnia,FFI)

貓海綿狀腦病(felinespongiformencephalopathy,FSE)克-雅病變種(variantCJD,v-CJD)

Prion-associatedDiseasesinHumanandOtherAnimalsStanleyB.PrusinerDr.Prusinercoinedthetermprion,whichcomesfrom"proteinaceousinfectiousparticlethatlacksnucleicacid"(缺乏核酸的蛋白質(zhì)感染因子)torefertoapreviouslyundescribedformofinfectionduetoproteinmisfolding.AUnifyingRoleforPri