蛋白質(zhì)分選下培訓(xùn)講學(xué)

Chapter7ProteinsortingII------free-ribosomesystemsecretorypathway

1.1SynthesisandTargetingofMitochondrial線粒體具有1000多種蛋白質(zhì)，其自身合成的僅十余種，因此大量蛋白質(zhì)是在細(xì)胞質(zhì)中合成的。MatrixOutermembraneIntermembranespaceCrosssectionofmitochondrionInnermembraneMitochondrialProteinsThatAreSynthesizedintheCytosolProteinsAreTargetedtoSub-mitochondrialCompartmentsProteinimportintomitochondriaProteinTransportintoInnerMembraneandIntermembraneSpaceRequiresTwoSignalSequences線粒體轉(zhuǎn)運(yùn)與葉綠體非常相似1.2SorttoChloroplastCompartment葉綠體蛋白轉(zhuǎn)運(yùn)運(yùn)輸機(jī)理與線粒體的相似。如：?都發(fā)生后轉(zhuǎn)譯；?每一種膜上有特定的轉(zhuǎn)位因子；?具有接觸點(diǎn)（contactsite）；?需要能量，同樣利用ATP和質(zhì)子動力勢；?前體蛋白N端有信號序列，使用后被信號肽酶切除。?但兩者的蛋白質(zhì)轉(zhuǎn)運(yùn)體系中除了某些hsp分子相同外，轉(zhuǎn)位因子復(fù)合體是不同的。Importofrubiscosmall(S)subunitsintothechloroplaststroma

轉(zhuǎn)運(yùn)肽內(nèi)囊體膜蛋白轉(zhuǎn)運(yùn)需要兩段信號1.3SynthesisandTargetingofPeroxisomeProteins

核基因合成，后轉(zhuǎn)運(yùn)方式運(yùn)輸C-andN-TerminalTargetingSequencesPTS1PTS21.4ProteinsorttonucleusThenuclearporecomplex0.1um

Sideviewofnuclearpore1.4.1Nuclearproteintransportmechanism

◆nuclearlocalizationsignals,NLS◆nuclearexportsignals,NES◆importin◆exportinMechanismofproteinimportProteinsselectedforimportintonucleushaveanuclearlocalizationsignal(NLS)e.g.-Pro-Pro-Lys-Lys-Lys-Arg-NLSisrecognizedbycytosolicnuclearimportreceptorswhichbindtonuclearporefibrilsextendingintocytosolPoreopensandproteinplusimportreceptorenternucleus.Importreceptorexportedforre-useNuclearlocalizationsignals

Nuclearlocalisationsignal(NLS)Nuclearlocalizationsignals

Nucleoplasminlabelandinjection

NucleoplasminlocationeffectMechanismoftransportthroughnuclearporesNLSneednotcutaftertransport

NuclearimportProteintransportbynucleusporecomplexTransportisselectiveRestricttransportparticleRequireenergyexpendituresaturateddynamicTransportisdoubledirectionImportandexport1.4.2MechanismofexportfromnucleusMostoftrafficmovingoutofnucleusconsistsofdifferenttypesofRNAmoleculesRNAmovesthroughnuclearporeascomplexofribonucleoprotein(RNP):核糖核蛋白顆粒ProteincomponentofRNPcontainsanuclearexportsignal(NES)thatisrecognisedbyexportproteinsmRNAisboundbyhnRNPonlyafterfullysplicedsoonlymatureRNAisexportednuclearRNAandproteinexport

◆mRNAexport●核內(nèi)不均一核糖核蛋白(heterogeneousribonucleoprotein,hnRNP)