细胞内蛋白质的分选和运输-jk

蛋白质的定向运输和分泌IntracellularProteinSorting,Transport,andSecretion,程金科jkcheng生物化学与分子细胞生物学系,细胞与细胞器,细胞器怎么生成？,蛋白质如何形成功能性结构？,新合成的蛋白如何运输到其细胞器或功能性位置？,蛋白质运输通路（Proteintraffickingpathway）,学习目标(掌握和熟悉）,蛋白质靶向运输的基本原理（信号学说）蛋白质到内质网的运输蛋白质到细胞核的运输蛋白质分泌途径和生物学意义5.受体介导胞吞,GnterBlobel&SignalHypothesis（信号学说）,（1999NobelPrizeLaureate）,Thepolypeptidechainpassesthroughanaqueousporeinthetranslocator(转运子).,Signalpeptide,SRPandSRPreceptorinteractwitheachothertodirectattachmentofribosomestothecytosolicsideoftheERmembrane.,Itsatransmembranetransport，ProteinsareimportedintoERbeforecompletesynthesisofthepolypeptidechainthatis,importisaco-translationaltranslocation(共翻译转运).,SignalHypothesis,to,Solubleprotein,signalhypothesis,tranmembraneprotein,Table15-3EssentialCellBiology(GarlandScience2010),信号肽指导蛋白质运输到不同的目的地,三种运输方式：,核孔门控运输,跨膜运输,小泡运输,Figure15-8EssentialCellBiology(GarlandScience2010),核孔的结构,Figure15-9EssentialCellBiology(GarlandScience2010),蛋白质运输到核,核运输受体,核定位信号（positivecharge）,Figure15-10EssentialCellBiology(GarlandScience2010),运输是耗能过程,Mitochondrialuptakesignalisanamphipathichelix,Arg,Lys(+charged),Nterminus,20-50aaresidueslong,hydrophobicresidues,Figure15-11EssentialCellBiology(GarlandScience2010),蛋白质运输到线粒体（跨膜运输）,SignalSequenceBindstoReceptor,Hsp70,COO-,outermembrane,innermembrane,MITOCHONDRIALMATRIX,CYTOSOL,TOM,TIM,receptor,pore,？,为什么需要结合到Hsp伴侣蛋白？,Unfoldedprotein+Hsp,跨膜运输需要unfolding,防止folding保护不被降解,Proteinsareunfolded,ReceptorTransfersProteintoTOM,+,+,+,+,+,+,+,-,-,-,-,-,-,-,Electrochemicalgradient,COO-,3.Hsp70detachesaspolypeptidepassesthroughmembranes,4.Transitsequencecleaved,targetingsequence,protease(peptidase),Proteinfoldsinthematrix,5.MitochondrialHsp70bindsandreleasespolypeptideasitentersthematrix,6.PolypeptidefoldsaidedbyHsp60,Hsp60,ATP,Hsp70,Additionaltargetingsequencesneedtotargetotherlocations,Independentsortingsignalsarerequiredforeverytransportstep!,Example:ATPSynthasesubunitoninnermembrane,核糖体有两种存在方式:,自由型,ER结合型,Figure15-12EssentialCellBiology(GarlandScience2010),内质网附着有核糖体:粗面内质网,Co-translationaltranslocation,Post-translationaltranslocation,Figure15-14EssentialCellBiology(GarlandScience2010),共翻译转运,Figure15-15EssentialCellBiology(GarlandScience2010),运输到ER腔内,Figure15-16EssentialCellBiology(GarlandScience2010),运输到ER膜上,Figure15-17EssentialCellBiology(GarlandScience2010),运输到ER膜上,Figure15-18EssentialCellBiology(GarlandScience2010),小泡运输,Figure15-19aEssentialCellBiology(GarlandScience2010),小泡的形成,Figure15-20EssentialCellBiology(GarlandScience2010),有被小泡的形成,CoatedProteins:,roughER,cis,trans,medial,golgi,COPII,COPI,clathrin,plasmamembrane,Table15-4EssentialCellBiology(GarlandScience2010),有被小泡的类型,Inmostcase,thevesicleisactivelytransportedbymotorproteinsthatmovealongcytoskeletalfibers.,小泡通过微管运输,Motorproteins,Fortheirdiscoveriesofmachineryregulatingvesicletrafficamajortransportsysteminourcells,Figure15-21EssentialCellBiology(GarlandScience2010),小泡的靶向运输：靶细胞器的选择机制,Rab：60个，引导至靶膜SNARE：20个，融合,Rab的选择作用,Figure15-23EssentialCellBiology(GarlandScience2010),蛋白质中内质网中的加工过程,Figure15-24EssentialCellBiology(GarlandScience2010),在内质网中蛋白质需要折叠好后进入小泡,伴侣蛋白帮助蛋白质在内质网中折叠,内质网应急ERstress,细胞凋亡,从高尔基体到细胞外的小泡运输,固有分泌,受调分泌,multiplecomponentsofextracellularmatrixarereleasedfromfibroblastbyconstitutivesecretion,固有分泌途径,Figure15-28EssentialCellBiology(GarlandScience2010),受调的胞吐过程,受调分泌途径,GLUT2摄入葡萄糖,胰岛素分泌,(Ca+-bindingprotein),肉毒肝菌毒素,NeurotransmitterSynapticvesiclesynoptotagmin,Figure15-27EssentialCellBiology(GarlandScience2010),受调分泌的蛋白质,具有受调分泌功能的细胞,激素（Hormone）粘液（mucus）消化酶（digestiveenzymes）,哪些组织细胞有分泌蛋白质的功能？,上皮组织？,结缔组织？,肌肉组织？,神经组织？,肠腔,哪些组织细胞有分泌蛋白质的功能？,上皮组织中的腺上皮细胞,外分泌腺,内分泌腺,外分泌腺细胞：分泌胰酶,胰岛-内分泌腺细胞分泌胰岛素等,上皮组织例1:胰腺,55,蛋白质合成、转运至高尔基体,胰腺外分泌细胞超微结构形态及分泌泡形态细胞中胰酶合成和分泌的过程,糙面内质网,箭头：高尔基体,高尔基体,分泌颗粒的形成,胰腺内分泌细胞分泌胰岛素的调控,正确时间，受调分泌,GLUT2摄入葡萄糖,胰岛素分泌,胰岛素的作用,胰岛素作用靶细胞：脂肪细胞和肌细胞,促进靶细胞摄入大量葡萄糖,例2:小肠上皮组织中有分泌蛋白质功能的细胞,上皮组织,上皮组织例2:粘液分泌细胞（消化道上皮）,分泌细胞外基质,结缔组织,成纤维细胞,疏松结缔组织（HE),例1:成纤维细胞,电镜（成纤维细胞）,1.RER,2.Golgi,固有分泌的方式释放,结缔组织,分泌细胞外基质,例1:成纤维细胞,例2:浆细胞,结缔组织,病原入侵的组织中富含浆细胞,电镜（细胞核内：车轮状）富含RER,（合成分泌抗体）,Mastcell,例3:肥大细胞,结缔组织,消化道，呼吸道管壁的结缔组织中,电镜大量分泌颗粒,分泌组织胺等，也分泌一些蛋白质,例1:神经元,神经组织,（合成结构蛋白和分泌蛋白）,尼氏体,受体介导的胞吞（Endocytosis）,TranscytosisofmaternalIgGimmunoglobulinsacrosstheintestinalepithelialcellsofnewbornmice,biosynthetic-secretorypathway,Vesiculartransport,Endocyticpathway,胞吞小泡的命运,溶酶体,溶酶体及其消化作用,Howaremembrane-boundproteinsdeliveredtolysosomes?,Lodish17-31,Overviewofvesiculartransport,Threeintracellularproteintraffickingpathways:,Summary,Co-translationaltranslocation,biosynthetic-secretorypathway,Post-translationaltranslocation,Endocyticpathway,Figure15-5EssentialCellBiology(GarlandScience2010),Proteinsareimportedintoorganellesbythreemechanisms,Gatedtransport,Transmembranetransport,Vesiculartransport,Targetingsignalsarethepiecesofinformationthatenablethecellulartransportmachinerytocorrectlypositionaproteininsideoroutsidethecell.Thisinformationiscontainedinthepolypeptidechainorinthefoldedprotein.Thecontinuousstretchofaminoacidresiduesinthechainthatenablestargetingarecalledsignalpeptidesortargetingpeptides.Othersignals,knownassignalpatches,arecomposedofpartswhichareseparateintheprimarysequence.Theybecome