植物发育生物学1-BR signal tranduction

Exampleforhormonesignaltransductionandhormonalregulatingplantdevelopment:Brassinosteroids(BR)PlantSteroidH[e-mail]2014-09BrassinosteroidsignalingAniceoverview?ReprintedfromGudesblat,G.E.,andRussinova,E.(2011).Plantsgrowonbrassinosteroids.Curr.Opin.PlantBiol.14:530-537withpermissionfromElsevier.BRI1encodesthemainBRreceptor;bri1mutantsareBR-insensitiveClouse,S.D.,Langford,M.,andMcMorris,T.C.(1996).Abrassinosteroid-insensitivemutantinArabidopsisthalianaexhibitsmultipledefectsingrowthanddevelopment.PlantPhysiol.111:671-678.bri1Wild-typeWild-typebri1bri1Inwild-typeplants,rootgrowthisinhibitedbyelevatedBRlevelsTheArabidopsisbri1mutantisverysmall(below)andinsensitivetoexogenousBRTheBRI1receptorisaplasma-membranelocalizedLRR-RLKBRI1Leucine-richrepeat(LRR)Trans-membranedomainKinaseDomainReprintedfromLi,J.,andChory,J.(1997).Aputativeleucine-richrepeatreceptorkinaseinvolvedinbrassinosteroidsignaltransduction.Cell90:929-938,withpermissionfromElsevier;Bishop,G.J.,andKoncz,C.(2002).Brassinosteroidsandplantsteroidhormonesignaling.PlantCell14:S97-110.BRI1isaLeucine-richrepeat–receptorlikekinase(LRR-RK)bri1TheBRI1genewasidentifiedthroughmap-basedcloningThestructureandrelatedmutantsofBRI1Bycontrast,animalsteroidreceptorsareintracellularSteroidsfreelycrossplasmamembraneSteroidreceptorWhenthereceptorbindsthehormone,thecomplexmovesintonucleus,bindsDNAandinitiatestranscriptionLeucine-richrepeatreceptor-likekinases(LRR-RLKs)areprevalentLRR-RLKsareveryabundantinplantandanimalcellsandbindawidevarietyofsignalingmolecules.InplantsLRR-RLKsareinvolvedindevelopmentalsignalingandpathogenresponses.PLANTANIMALBishop,G.J.,andKoncz,C.(2002).Brassinosteroidsandplantsteroidhormonesignaling.PlantCell14:S97-110.TwoadditionalBRreceptorshaverestrictedexpressionpatternsReproducedwithpermissionfromCaño-Delgado,A.,Yin,Y.,Yu,C.,Vafeados,D.,Mora-García,S.,Cheng,J.-C.,Nam,K.H.,Li,J.,andChory,J.(2004).BRL1andBRL3arenovelbrassinosteroidreceptorsthatfunctioninvasculardifferentiationinArabidopsis.Development131:5341-5351.TheBRI1geneisexpressedthroughouttheplant.BRL1andBRL3areprimarilyexpressedinvasculartissues.TheproteinencodedbyBRL1andBRL3canfunctionasreceptorsWhenBRL1orBRL3proteinsareexpressedfromtheBRI1promoter,theyrescuethebriloss-of-functionmutant.bri1loss-of-functionmutantRescuedbyBRL1orBRL3expressedfromBRI1promoterTheBRLgenesmayencodereceptorswithcell-specificfunctions.ReproducedwithpermissionfromCaño-Delgado,A.,Yin,Y.,Yu,C.,Vafeados,D.,Mora-García,S.,Cheng,J.-C.,Nam,K.H.,Li,J.,andChory,J.(2004).BRL1andBRL3arenovelbrassinosteroidreceptorsthatfunctioninvasculardifferentiationinArabidopsis.Development131:5341-5351.ThericeBRLgeneshaveadifferentexpressionpatternthanBRI1Nakamura,A.,Fujioka,S.,Sunohara,H.,Kamiya,N.,Hong,Z.,Inukai,Y.,Miura,K.,Takatsuto,S.,Yoshida,S.,Ueguchi-Tanaka,M.,Hasegawa,Y.,Kitano,H.,andMatsuoka,M.(2006).TheroleofOsBRI1anditshomologousgGenes,OsBRL1andOsBRL3,inrice.PlantPhysiol.140:580-590.ThericeOsBRI1geneispreferentiallyexpressedinshoots.Aloss-of-functionmutantshowsseveredwarfingintheshootbutlittlechangeinrootgrowth,suggestinganorgan-specificroleforOsBRL1andOsBRL3.osbri1osbri1BRI1signalingisnegativelycontrolledbyBKI1Wang,X.,andChory,J.(2006)BrassinosteroidsregulatedissociationofBKI1,anegativeregulatorofBRI1signaling,fromtheplasmamembrane.Science313:1118-1122.ReprintedwithpermissionfromAAASWild-typeArabidopsisBKI1overexpressionLowBRReceptor(BRI1)Inhibitor(BKI1)BKI1wasidentifiedthroughasearchforproteinsthatphysicallyinteractwithBRI1.BindingofBLtoBRI1causesBKI1todissociatefromitReceptor(BRI1)NoBL5minBL10minBLIntheabsenceofBL,BKI1(labeledwithYFP)isattheplasmamembrane.BLcausesBKI1todissociatefromtheplasma-membranelocalizedreceptorandmoveintothecytoplasm.Wang,X.,andChory,J.(2006)BrassinosteroidsregulatedissociationofBKI1,anegativeregulatorofBRI1signaling,fromtheplasmamembrane.Science313:1118-1122.ReprintedwithpermissionfromAAASPPBRI1signalingrequiresactivationbyacoreceptorBAK1;BAK1isalsoaplasma-membraneassociatedkinaseBAK1wasidentifiedbyanactivationscreen–ascreenforplantsthatpartiallyreversethedwarfbri1-5phenotypewhenoverexpressed.ExtracellulardomainCytoplasmicproteinkinasedomainBAK1BRI1BAK1hasacytoplasmicproteinkinasedomainbutasmallerextracellulardomainthatdoesnotbindBR.Summary–BRreceptoractionReceptor(BRI1)LowBRInhibitor(BKI1)BAK1HighBRLowBRlevels–receptorinactiveandinhibitedbyBKI1HighBRlevelsBRI1autophosphorylates,BKI1dissociates,BAK1bindsandenhancesBR1activityPPPPBAK1bindingtoBRI1enhancesBRI1kinaseactivitySignalingdownstreamfromthereceptorTheBRsignal,perceivedattheplasmamembrane,istransducedtothenucleuswhereBR-regulatedgenesareswitchedonoroff.Whathappensbetweenthereceptorandnucleus?BZR1isatranscriptionfactorthatinducesandrepressesgenesBAK1BZR1isaBR-activatedtranscriptionfactorthatturnsOFFBRbiosynthesisgenesBZR1CPDDWF4BR6OXHighBRPPPPBZR2/BES1isatranscriptionfactorthatactivatesgenesBAK1HighBRBZR2/BES1isaBR-activatedtranscriptionfactorthatturnsONBR-inducedgenesGenespromoti