OutsidePlasma membraneInside of cellof cellG-protein-linkedCa"CaMIP,DAGPhysiologicalreceptorSignalReceptorNTPreactionProteinProtein-nPiTwo-componentH.OtransmembraneNetworkintracellular signalSignal inputSignal outputtransductiontransductionFig. 7-1 Plant cell signal transduction processes
Fig.7-1 Plant cell signal transduction processes
GravityPhotosynthetic lightPhotoperiodPhotomorphogeniclightHumidityFigure 7-2TemperatureHerbivoresWindCOSH4(ethylene)PathogensOnFigure 18.1ParasitesExternal signalsthataffectplantgrowthanddevel-Soilmicroorganismsopmentincludemanyaspectsoftheplant'sphysicalSoil qualitychemical,and biological environments.Someexter-ToxicmineralsandotherWaterstatusnal signalscomefromotherplants.ApartfromalleopathicchemicalsMineralgravitropicsignals,all othersignalsvaryinintensitynutrientsoftenfromminutetominute
Figure 7-2
CDrotainExtraceillardenviviCCvcasEPlasmaOBEYEalmcCteirCPTeTmstadenyiyiactivatingsyntnesistendstoMFPFFigure 7-3
Figure 7-3
(A)(B)Figure14.19Structureof calmodulih.(A)Calmodulincon-32sists oftwo qlobularends separatedbya flexibleαhelixEachglobularendhastwocalcium-binding sites.(B)WhenH2Nthe calcium-calmodulin complex associates witha proteinit literallywraps around it.(FromAlbertset al.1994.)H2NH2N2nmCOOHHOOCNH2COOHCOOHFigure 7-5
Figure 7-5
HormoneProteinEXTRACELLULARDAGPIP2kinaseReceptorSPACECPlasmamembraneCYTOSOLGByGoProteinCellular(inactive)responseGproteinProteinp(active)PhospholipaseCFigure14.18SummarydiagramoftheCa2+CellularIP3events in the inositol-lipid signal trans-responseductionpathwaycoupledto sevenspanning G protein-linkedreceptorsThebindingofhormonetoitsreceptorBound IP3triggers activation oftheα subunit ofIP3rsensitivethe heterotrimeric G protein, whichCa2+channelactivatestheeffector enzymephos-EndoplasmicpholipaseC(PLC).PLCcleavesPIP,inreticulumthemembranetoyieldIP,andDAGorvacuoleIP,diffuses into the cytosol andbinds←to IP-gated calcium channels on the.ERorvacuolarmembrane,causingthe-9areleaseofcalciumintothecytosolCa2+S4fromintracellularstores.Theincrease.--incytosoliccalciumconcentrationleads-?to a cellularresponse.DAGremains in-.3the membraneand activatesprotein6D.kinaseCTheactivated proteinkinase9-Cthenphosphorylatesotherproteins,6leadingto acellularresponse.Inani-mal cellstheinositol-lipidpathwaymayalsobecoupledtoreceptortyroFigure 7-6sinekinases.(FromLodishetal.1995.)
Figure 7-6