信號分子與信號轉(zhuǎn)導(dǎo)SignalingTransduction02課件

ClassificationofphosphataseaccordingtotheAminoacidsequenceinactivecenterSer/Thr

phosphatase

TyrphosphataseDualspecificity

Ⅱ.Gprotein/smallGproteinguaninenucleotidebindingprotein，Gprotein（鳥苷酸結(jié)合蛋白）亦稱GTP結(jié)合蛋白

asignalmoleculeinvariouspathways,functioningdifferentlyindifferentcellsTwoformsofGproteinGproteinbindingwithGTP:itsactiveform

GTPhydrolysedtoGDP:inactiveform

2typesofGprotein：Hetero-trimerG

protein:（Gα）,β,γ(Gβγ)

bindingwithreceptorwith7transmembrane

dormains，SmallG

protein(21kD）

Theactivation/deactivationcycleforhormonallystimulatedadenylatecyclaseGprotein-coupledreceptors，GPCRs

Ligand-GPCRs–Gprotein-（AC,PLC…)-cellfunction

TheroleofPIP2inintracellularsignalingFactorscontrolsmallGproteinact.Factorincreasingact.：guaninenucleotideexchangefactor(GEF)

guaninenucleotidereleaseprotein(GNRP)Factordecreasingact.：guaninenucleotidedissociationinhibitor(GDI)

GTPaseactivationprotein(GAP)

RasactivationanditsregulatorsGTPGDPRasRasSOSGAPonoffSummaryofSection3ProteinsarethemaincomponentsofsignalingpathwaysProetin

kinasesandphosphotasesaretheswitchinsignalingpathways.GproteinandsmallGproteinarefunctionastheirbindingwithGTP/GDPⅠ.SignalingComplexanditscharacterProteinswon’tseparatedeachotherincells

butaggregated

Proteincomplex-functioninginlife1.Signalingcomplexensurestheefficiency,precision,varietyPriority:①directlycontact，efficency,precision②amplification③collaboration,variety④complex,multiple

2.SignalingcomplexexistsatmembraneandcytoskeletonstructureProteincomplex–

existedinmembranestructureorcellskeletoncompartmentation。3.ComponentsofcomplexchangesdependedonexogenoussignalsDynamicstate:thecomponentsandformationofsignalcomplexdependedonexogenoussignals

Significance:withdrewligand-stopsignaingimmediatelyreutilizationofsignalmolecules,saveenergyⅡ.Dt-protinteraction–mediatedbydomainsCharacterofproteininteractiondomain(PID)①onemoleculecontains≥twoPID②samedomainexistedinvariousproteins,butsequencearenotexactlysame

–bindingspecificity③PID

doesn’thaveenzymeactivity,justbindingPIDrecognizedmotifSrchomology2SH2Tyr-PiSrchomology3SH3ProrichpleckstrinhomologyPHPhospholipidderivationProteintyrosinebindingPTBTyr-PiWWWWProrichDomainanditsrecognizedmotif2.Srchomology2(SH2)domainSrchomology2domain:SH2domianFunction:therecognizedmotifisphosphorylatedtyrosineandneighboringaminoacids

DifferentproteincontainsdifferentSH2-selectivity3.SH3DomainSrchomology2domain:SH3domianFunction:therecognizedmotifisproline-rich(9-10Pro)sequenceⅢ.adaptorproteinsandscaffoldingproteinsadaptorproteinakindofmediatorprotein,Linkone,upstreamprot.,toanother,downstream

role：recruitandorganizethecomplex

Mostadaptorproteinscontaintwodomains,nootherspecialdomain

1.adaptorproteinAdaptorproteinNckSH2CNSH3SH3SH3HGFR,VEGFR,BCR-AblPDGFR,EphB1SLP-76,HPK1,p130casIRS-1,p62doc

CKIg2,WASP,IRS-1,DOCK180,NIKIRS-1,DOCK180,Sos,NIK,Pak1,Pak3,NAP4,WIP,dynamin,synaptojanin、Abl,c-CblAbl,c-Cbl,NAP1,Sam68Section5GeneralSignalPathwaysMediatedbyMembraneReceptors

膜受體介導(dǎo)的基本信號轉(zhuǎn)導(dǎo)通路

3typesofmembraneboundreceptor：Ionchannelreceptor(ICR)G-proteincouplingreceptor(GPCR)Singletransmembranereceptor

(STMR)ICRGPCRSTMR內(nèi)源性配體神經(jīng)遞質(zhì)神經(jīng)遞質(zhì)、激素、趨化因子、外源刺激（味，光）生長因子細(xì)胞因子結(jié)構(gòu)寡聚體形成的孔道單體具有或不具有催化活性的單體跨膜區(qū)段數(shù)目4個7個1個功能離子通道激活G蛋白激活蛋白酪氨酸激酶細(xì)胞應(yīng)答去極化與超極化去極化與超極化調(diào)節(jié)蛋白質(zhì)功能和表達(dá)水平調(diào)節(jié)蛋白質(zhì)的功能和表達(dá)水平，調(diào)節(jié)細(xì)胞分化和增殖Charactersof3typesreceptorsⅠ.IonChannelReceptorstructurallyachannel,openorclosepassthroughion,

ligand-gatedreceptorchannelLigand:neurotransmittermainly

AcetylcholinereceptorAcetylcholineBindingSiteIonchanneloverlooksidelook

TheroleofAcetylcholinIonchannelmemb.electricpotentialchangechemicalsignalformationcellfunctionIonchannel

Cationchannel:AcetylCholine,Glutamicacid,5-Hydroxytrypotamine

Anionchannel:Glycine，γ-aminobutylicacidⅡ.G-proteincouplingreceptor–secondmessenger-targetmoleculesGPCR:

bindingGproteinwithtri-subunitactivateGproteinGPCR

aserpentinereceptor,7transmembraneG蛋白偶聯(lián)區(qū)1.G-proteinactivationinitiatessignalingModeloftransductionviaG-protein：①ligandreceptorbinding②receptoractivatesG-protein③G-proteinact.orinh.targetprtoein④changesecondmessengerlevelordistribution,⑤secondmessengeraffectsitstargetmoleculeconformationalchange

G-proteincycle2.ActivatedG-proteinaltersactivityoftargetmole.活化的G蛋白的α亞基主要作用于生成或水解細(xì)胞內(nèi)第二信使的酶，如AC、PLC等效應(yīng)分子（effector），改變它們的活性，從而改變細(xì)胞內(nèi)第二信使的濃度?？梢约せ預(yù)C的G蛋白的亞基稱為s（s代表stimulate）；反之，稱為i（i代表inhibit）。GáEffectivemole.Messengeincyto.Targetmole.asAC↑c(diǎn)AMP↑PKA↑aiAC↓cAMP↓PKA↓aqPLC↑Ca2+、IP3、DAG↑PKC↑atcGMP-PDE↑c(diǎn)GMP↓Na+Chan.↓Gasubunitanditseffect

3.Glucagonreceptor-AC-cAMP-PKApathwaysAdrenocorticotrophin(ACTH)Melanotrophin(MSH)Corticoliberin(CRH)OlfactionmoleculeDopamineParathyrinAdrenalineProstaglandinE1,E2Glucagon5-HT（1a）、5-HT（2）Histamine（H2receptor）SomatostadinLutropin(LH)TastemoleculeSignalsactsbyAC-cAMP-PKApathways4.AngiotensinIIreceptor-PLC-IP3/DAG-PKCAngiotensinIIreceptorisaGCPR

q

→

PLC-IP3/DAG-PKC

pathwayAcetylCholine[M1]light(fruitfly)5-HT（1c）ATPGastrinreleasingpeptideThyrotropinreleasinghormone(TRH)AdrenergicagonistGlutaminevasopressin-antidiuretichormoneAngiotensinIIgonadotrophinreleasainghormone(GRH)histamine[H1receptor]SignalsactsbyPLC-IP3/DG-PKC此外，由于G蛋白亞型的不同，形成多種其他通路和效應(yīng)，如PDE-cGMP-Na+通道信號轉(zhuǎn)導(dǎo)通路、PLC-IP3-Ca2+/CaM-PK信號轉(zhuǎn)導(dǎo)通路等。Ⅲ.Enzymecouplingreceptor-proteinkinasekinase–proteinkinase–targetmole酶偶聯(lián)受體指那些自身具有酶活性，或者自身沒有酶活性，但與酶分子結(jié)合存在的一類受體。這些受體大多為只有1個跨膜區(qū)段的糖蛋白，亦稱為單跨膜受體。酶偶聯(lián)受體種類繁多，但是以具有PTK活性和與PTK偶聯(lián)的受體居多。常見的酶偶聯(lián)受體：受體型蛋白酪氨酸激酶（receptorstyrosinekinases，RTKs）蛋白酪氨酸激酶偶聯(lián)受體（tyrosinekinase-coupledreceptors，TKCRs）受體型蛋白酪氨酸磷酸酶（receptorstyrosinephosphatases，RTPs）受體型蛋白絲/蘇氨酸激酶（receptorsserine/threonine

kinase，RSTK）受體型鳥苷酸環(huán)化酶（receptorsguanylate

cyclases，RGCs）酶偶聯(lián)受體大部分是生長因子和細(xì)胞因子的受體，它們所介導(dǎo)的信號轉(zhuǎn)導(dǎo)通路主要是那些調(diào)節(jié)蛋白質(zhì)的功能和表達(dá)水平、調(diào)節(jié)細(xì)胞增殖和分化。1.PTKcouplingreceptor:similarmodelPTKcouplingreceptor主要通過蛋白質(zhì)相互作用激活自身或細(xì)胞內(nèi)其他的PTK或絲/蘇氨酸激酶來轉(zhuǎn)導(dǎo)信號。PTK偶聯(lián)受體介導(dǎo)的信號轉(zhuǎn)導(dǎo)途徑的基本模式：①結(jié)合配體后受體形成二聚體或寡聚體；②第一個蛋白激酶被激活。對于具有蛋白激酶活性的受體來說，此步驟是激活受體胞內(nèi)結(jié)構(gòu)域的蛋白激酶活性；對于沒有蛋白激酶活性的受體來說，此步驟是受體通過蛋白質(zhì)-蛋白質(zhì)相互作用激活與它緊密偶聯(lián)的蛋白激酶；③通過蛋白質(zhì)-蛋白質(zhì)相互作用或蛋白激酶的磷酸化修飾激活下游信號轉(zhuǎn)導(dǎo)分子，通常是繼續(xù)活化下游的一些蛋白激酶；④蛋白激酶通過磷酸化修飾激活代謝途徑中的關(guān)鍵酶、反式作用因子等，影響代謝途徑、基因表達(dá)、細(xì)胞運(yùn)動、細(xì)胞增殖等。表皮生長因子受體作用機(jī)制：2.EGFRsignalingpathway:Ras→MAPK表皮生長因子受體（epidermalgrowthfactorreceptor,EGFR）是一個典型的受體型PTK。Ras→MAPK途徑是EGFR的主要信號通路之一。EGFR介導(dǎo)的信號轉(zhuǎn)導(dǎo)過程3.OtherspathwaysthanenzymecoupingreceptorT細(xì)胞抗原受體、B細(xì)胞抗原受體、肥大細(xì)胞表面的IgE受體屬于酶偶聯(lián)受體，它們自身不具備蛋白酪氨酸激酶活性；非受體型的Src家族蛋白酪氨酸激酶和ZAP70家族蛋白酪氨酸激酶是這一類受體的直接信號轉(zhuǎn)導(dǎo)分子。下游分子包括PLCγ、MAPK家族的活化，并有多種銜接蛋白參與。大部分白細(xì)胞介素（interlukin,IL）受體屬于酶偶聯(lián)受體。通過JAK（JanusKinase）-STAT（signaltransducerandactivatoroftranscription）通路轉(zhuǎn)導(dǎo)信號。細(xì)胞內(nèi)有數(shù)種JAK和數(shù)種STAT的亞型存在，分別轉(zhuǎn)導(dǎo)不同的白細(xì)胞介素的信號。白介素介導(dǎo)的信號轉(zhuǎn)導(dǎo)途徑轉(zhuǎn)化生長因子β（transformgrowthfactorβ,TGFβ）受體屬于單次跨膜受體，自身具有蛋白絲氨酸激酶催化結(jié)構(gòu)域。受體活化后通過信號分子Smad介導(dǎo)的途徑調(diào)節(jié)靶基因轉(zhuǎn)錄，影響細(xì)胞的分化。細(xì)胞內(nèi)有數(shù)種Smad存在，參與