title: Targeted degradation of PSEUDO-RESPONSE REGULATOR5 by an SCFZTL complex regulates clock function and photomorphogenesis in Arabidopsis thaliana.
abstract: Circadian clocks comprise several regulatory feedback loops that control gene transcription. However, recent evidence has shown that posttranslational mechanisms are also required for clock function. In Arabidopsis thaliana, members of the PSEUDO-RESPONSE REGULATOR (PRR) family were proposed to be components of the central oscillator. Using a PRR5-specific antibody, we characterized changes in PRR5 protein levels in relation to its mRNA levels under various circadian conditions. Under long-day conditions, PRR5 mRNA levels are undetectable at dusk but PRR5 protein levels remain maximal. Upon dark transition, however, PRR5 levels decrease rapidly, indicating dark-induced, posttranslational regulation. We demonstrated that the Pseudo-Receiver (PR) domain of PRR5 interacts directly with the F box protein ZEITLUPE (ZTL) in vitro and in vivo. Analyses of mutants and transgenic plants revealed an inverse correlation between PRR5 and ZTL levels, which depends on the PR domain. These results indicate that PRR5 is negatively regulated by ZTL, which likely mediates its ubiquitination and degradation. Phenotypic analyses of prr5 ztl double mutants showed that PRR5 is required for ZTL functions. ZTL contains a Light-Oxygen-Voltage domain, and its activity may be directly regulated by blue light. Consistent with this notion, we found that blue light stabilizes PRR5, although it does not alter ZTL levels. Together, our results show that ZTL targets PRR5 for degradation by 26S proteasomes in the circadian clock and in early photomorphogenesis.
authors: Laboratory of Plant Molecular Biology, The Rockefeller University, New York, New York 10065-6399, USA.
authors: Takatoshi
authors: T
authors: Kiba
authors: Rossana
authors: R
authors: Henriques
authors: Hitoshi
authors: H
authors: Sakakibara
authors: Nam-Hai
authors: NH
authors: Chua
mesh_terms: D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001683:Biological Clocks / Q000502:physiology* / Q000528:radiation effects; D002940:Circadian Rhythm / Q000528:radiation effects; D015536:Down-Regulation / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D017343:Genes, Plant; D018546:Hypocotyl / Q000528:radiation effects; D008027:Light; D009024:Morphogenesis / Q000528:radiation effects*; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding / Q000528:radiation effects; D011499:Protein Processing, Post-Translational / Q000528:radiation effects*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013489:Suppression, Genetic / Q000528:radiation effects; D013816:Thermodynamics; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C523307:PRR5 protein, Arabidopsis; D012333:RNA, Messenger; D014157:Transcription Factors; C410503:ZTL protein, Arabidopsis; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease
references: Plant Physiol. 1999 Jun;120(2):605-14
references: 10364413
references: Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):4176-9
references: 10097183
references: Genes Dev. 2005 Mar 1;19(5):593-602
references: 15741320
references: Plant Cell. 2005 Mar;17(3):791-803
references: 15705949
references: Methods Enzymol. 2005;393:418-35
references: 15817303
references: Plant Cell Physiol. 2005 Apr;46(4):609-19
references: 15695441
references: Plant Cell Physiol. 2005 May;46(5):686-98
references: 15767265
references: Plant Mol Biol. 2005 Mar;57(5):761-71
references: 15988568
references: Genes Dev. 2005 Jul 1;19(13):1532-43
references: 15998807
references: Science. 2005 Jul 8;309(5732):293-7
references: 16002617
references: J Biol Chem. 2005 Jul 22;280(29):26863-72
references: 15917222
references: Science. 2005 Jul 22;309(5734):630-3
references: 16040710
references: Biochem Soc Trans. 2005 Nov;33(Pt 5):953-6
references: 16246019
references: FEBS Lett. 2006 Feb 20;580(5):1193-7
references: 16457821
references: Plant Physiol. 2006 Mar;140(3):933-45
references: 16428597
references: Plant J. 2006 Jun;46(5):736-46
references: 16709190
references: Plant J. 2006 Jun;46(5):849-60
references: 16709199
references: Science. 2006 Jun 23;312(5781):1809-12
references: 16794082
references: Biosci Biotechnol Biochem. 2007 Feb;71(2):535-44
references: 17284847
references: Biosci Biotechnol Biochem. 2007 Feb;71(2):527-34
references: 17284849
references: Nat Protoc. 2006;1(2):641-6
references: 17406292
references: Plant Cell Physiol. 2007 Jun;48(6):822-32
references: 17504813
references: Cell. 2000 Apr 28;101(3):319-29
references: 10847686
references: Cell. 2000 Apr 28;101(3):331-40
references: 10847687
references: Science. 2000 Aug 4;289(5480):768-71
references: 10926537
references: Plant Cell Physiol. 2000 Sep;41(9):1002-12
references: 11100772
references: Nature. 2001 Mar 22;410(6827):487-90
references: 11260718
references: Science. 2001 Aug 3;293(5531):880-3
references: 11486091
references: Nature. 2001 Dec 6;414(6864):656-60
references: 11740564
references: Plant Cell. 2001 Dec;13(12):2659-70
references: 11752379
references: Plant Cell Physiol. 2002 Jan;43(1):58-69
references: 11828023
references: Curr Biol. 2002 Apr 30;12(9):757-61
references: 12007421
references: Dev Cell. 2002 May;2(5):629-41
references: 12015970
references: Dev Cell. 2002 Jul;3(1):51-61
references: 12110167
references: Plant Cell Physiol. 2002 Aug;43(8):833-43
references: 12198185
references: Nature. 2002 Nov 14;420(6912):178-82
references: 12432393
references: Plant Cell Physiol. 2002 Nov;43(11):1374-85
references: 12461138
references: Nature. 2002 Dec 12;420(6916):673-8
references: 12442174
references: Plant Cell. 2003 Jan;15(1):223-36
references: 12509533
references: Proc Natl Acad Sci U S A. 2003 Apr 15;100(8):4933-8
references: 12665620
references: EMBO J. 2003 Sep 1;22(17):4421-30
references: 12941694
references: Plant Cell. 2003 Nov;15(11):2654-65
references: 14563930
references: Science. 2003 Nov 7;302(5647):1049-53
references: 14605371
references: Planta. 2003 Nov;218(1):159-62
references: 12955513
references: Nature. 2003 Nov 20;426(6964):302-6
references: 14628054
references: Plant Cell Physiol. 2003 Nov;44(11):1119-30
references: 14634148
references: Nature. 2003 Dec 4;426(6966):567-70
references: 14654842
references: Proc Natl Acad Sci U S A. 2004 Mar 2;101(9):3292-7
references: 14978263
references: Plant Cell. 2004 Mar;16(3):769-82
references: 14973171
references: Plant Cell Physiol. 2004 May;45(5):645-50
references: 15169947
references: Plant Cell. 2004 Jun;16(6):1550-63
references: 15155885
references: J Exp Bot. 2004 Sep;55(405):2015-27
references: 15310821
references: Plant J. 2004 Oct;40(2):291-301
references: 15447654
references: J Biol Rhythms. 1997 Jun;12(3):204-17
references: 9181432
references: Development. 1998 Feb;125(3):485-94
references: 9425143
references: FEBS Lett. 1998 Jun 16;429(3):259-62
references: 9662428
references: Proc Natl Acad Sci U S A. 1998 Sep 1;95(18):11020-5
references: 9724822
references: Plant Physiol. 1999 Mar;119(3):909-15
references: 10069829
references: Curr Biol. 2005 Jan 11;15(1):47-54
references: 15649364