see?touch?Metabolismofplants代謝生理Chapter1WatermetabolismofplantsChapter2MineralnutritionofplantsChapter3PhotosynthesisChapter4Plant

respirationGrowthanddevelopmentofplants發育生理see?touch?GrowthDevelopmentlighttemperaturewatermechanicaldamagegasgravitydiseaseGrowthanddevelopmentofplants發育生理:irreversible;celldivisionandelongation:structureandfunction;differentiation5.1

Environmentalstimulationsandextracellularsignals5.2Receptorandtransmembranesignaltransduction5.3Intracellularsignalmoleculesandsecondarymessengers5.4ReversiblephosphorylationofproteinsChapter5Signaltransduction轉導

ofplantcellSignals?Receptor?SignalenlargementReactions?Geneexpression(spatialandtemporal)5.1EnvironmentalstimulationsandextracellularsignalsEnvironmentalstimulationslighttemperaturewatermechanicaldamagegasgravitydisease

ExtracellularsignalsSignaltransductionbetweendifferentorgans,inplantPhysicalsignals(electricsignal)Electricwave:vascular,apoplast,symplastChemicalsignals(hormones,oligosaccharides寡糖)Drought:ABAandclosureofstomaPlantdefenseSecondarymessengerSignalsinthecellPrimarymessengerEnvironmentalstimulationsandextracellularsignalsCharacteristicsofreceptorSpecificityHighaffinityReversibility

Receptor?Onthesurfaceofcell(ororganelle)5.2ReceptorandtransmembranesignaltransductionSpecificallyrecognizeandcombinechemicalsignals(ligand配體)EnlargeandtransfersignalsStartbiochemicalreactionsProteinsCellsurfacereceptorsIon-channel-linkedreceptorGprotein-linkedreceptorEnzyme-linkedreceptor

TransmembranesignaltransductionGprotein-linkedreceptorsignaltransduction Gprotein:heterotrimeric異源三聚體

GTPbindingprotein3subunitsGTPase:activeandinactiveOnthecytosolsideofmembrane(inactive)Signalenlargement:primarysecondary

outsideinside5.3Intracellularsignalmoleculesandsecondmessengers5.3.1CalciumandcalciumbindingproteinsCalciumhomeostasis(鈣穩態)inthecellCWCytosol<0.1mmol/L100xhigherCalciumpoolTransmembraneCalciumTransportationLittlechangeincalciumhomeostasisinthecell

CalciumbindingproteinsCalmodulin鈣調蛋白,CaMSinglepeptide,148AAresidues,pI=4.0,heatstableDumbbell美籍華人張槐耀(1967)在動物細胞中發現nCa2++CaM

nCa2+.

CaM*(1<n<4)m(nCa2+.

CaM*)+EnzymeActivityEnzyme: Ca2+-ATPase Ca2+channel NADkinase Proteinkinase

CDPK=Calcium-dependentproteinkinase5.3.2DAG(二酯酰甘油)andIP3(三磷酸肌醇)lighthormonesIP3/Ca2+DAG/PKCDoublemessengersystem5.3.3OthersignalmoleculescAMP,cGMP,H+,Ascorbicacid,GSH,H2O2,NO5.4ReversiblePhosphorylationofProteinsProteinProtein-PiNTPNDPProteinkinaseH2OPiProteinphosphataseSiginalcascade:kinase-kinase-kinase……5.4.1Proteinkinase(PK)Largefamily:2~3%ofplantgenesSerine/Threonine-KinaseTyrosine-KinaseHistidine-Kinase

CDPK:Calcium-dependentproteinkinaseNCPKcatalyticdomainSelf-inhibitivedomainCaM-likedomainCa2+ATPase,Ionchannel,etc.5.4.2Proteinphosphatase(PP)Serine/Threonine-PPTyrosine-PPHistidine-PPReversiblephosphorylationofproteinsisrelatedtogeneexpression!SummarySummaryCross-talkamongdifferentsignaltransd