通过膜受体的信号传递

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1、通过膜受体的信号传递途径SIGNALTRANSDUCTIONTHROUGHMEMBRANERECPTORS生物化学教研室吴映雅QUESTIONHowdovariouscellsinanmulticellurorganismcoordinatewitheachother?Howanextracellularsignal,suchasahormone,influenceintracellularevents?Cellsignaling细胞信号传递:Cellsuseavarietyofdifferentreceptor(受体）proteinsto

2、receiveandrespondtosignalsfromtheexternalenvironment.Thebindingofthesignalingmolecule（suchasahormone，growthfactor，orneurotransmitter（激素、生长因子、神经递质等））tothereceptorresultsinacascadeofenzymaticreactions（级联酶促反应）insidethecellthatconstitutestheappropriateresponsetothesignal.Defin

3、ition通过质膜受体及第二信使的信号传导(Ⅰ)SignalTransductionThroughPlasmaMembraneReceptorandSecondMessenger(Ⅰ)Whenanexternalsignal,suchasahormone,bindsareceptorproteinontheplasmamembrane.Theconformation（构象）ofthereceptormoleculeundergoesachange,transducingthemessageintothecellthroughaspecifi

4、cpathway,performingitsregulatoryfunction.外部信号分子（如：激素）与受体结合，受体构象改变,再通过特异的途径将信息传递到细胞内,实现调节功能。（一）cAMP-蛋白激酶途径cAMP-ProteinkinasePathway----（腺苷酸环化酶体系）adenylatecyclasesystemSomeHormonesgothroughthispathway:eg:Glucagon(胰高血糖素)Adrenalin/Epinephrine(肾上腺素)Antidiuretin(抗利尿激素,ADH)信息传递简

5、式：HormoneMembranereceptorG-proteinACcAMPPKAFunctionalproteinBiologicaleffectP腺苷酸环化酶Adenylatecyclase蛋白激酶AProteinkinaseAResultchangesincAMPlevels,activatingtargetproteinssuchasproteinkinaseA（蛋白激酶A）.改变cAMP浓度，激活蛋白激酶ATheMainCharacteristic(主要特征)：1.受体、G蛋白和腺苷酸环化酶Receptor，G-Protein

6、andAdenylateCyclaseA.Receptor(受体)：Cellsurfacereceptorsarespecificproteins.Signalmoleculefitsbindingsiteonitscomplementaryreceptor;othersignalsdonotfit.信号分子只与特异受体结合Sevenmembrane-spanningαhelicsreceptorB.TrimericG-Protein（三聚体G蛋白）-subunit-subunit-subunitReceptorandThetrime

7、ricG-proteinGDP+GTPGTPGDPPiGTPGDP+PiStimulatoryGProtein(激活型G蛋白)RssGDPGTPGDP5’-AMPPhosphodiesteraseACcAMPATPPpisGTP+ActivatePKAPhospho-rylationofcellularproteinsbyPKAcausesthecellularresponseGiRiRiInhibitoryGProtein(抑制型G蛋白)IGDPGTPGDPIGTP+ACATPcAMPPpi2.cAMP和蛋白激酶A

8、cAMPandProteinkinaseAcAMPcAMP(cyclicAMP)isanucleotidesecondmessengerthatparticipatesinman