2p1n is a 6 chain structure with sequence from Arath. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
[SKP1A_ARATH] Involved in ubiquitination and subsequent proteasomal degradation of target proteins. Together with CUL1, RBX1 and a F-box protein, it forms a SCF E3 ubiquitin ligase complex. The functional specificity of this complex depends of the type of F-box protein. In the SCF complex, it serves as an adapter that links the F-box protein to CUL1. SCF(UFO) is required for vegetative and floral organ development as well as for male gametogenesis. SCF(TIR1) is involved in auxin signaling pathway. SCF(COI1) regulates responses to jasmonates. SCF(EID1) and SCF(AFR) are implicated in phytochrome A light signaling. SCF(ADO1), SCF(ADO2), SCF(ADO3) are related to the circadian clock. SCF(ORE9) seems to be involved in senescence. SCF(EBF1/EBF2) may regulate ethylene signaling. Plays a role during embryogenesis and early postembryonic development, especially during cell elongation and division. Contributes to the correct chromosome segregation during tetrad formation.[1][2][3][4][5][6] [IAA7_ARATH] Aux/IAA proteins are short-lived transcriptional factors that function as repressors of early auxin response genes at low auxin concentrations. Repression is thought to result from the interaction with auxin response factors (ARFs), proteins that bind to the auxin-responsive promoter element (AuxRE). Formation of heterodimers with ARF proteins may alter their ability to modulate early auxin response genes expression.[7] [TIR1_ARATH] Auxin receptor that mediates Aux/IAA proteins proteasomal degradation and auxin-regulated transcription. The SCF(TIR1) E3 ubiquitin ligase complex is involved in auxin-mediated signaling pathway that regulate root and hypocotyl growth, lateral root formation, cell elongation, and gravitropism. Appears to allow pericycle cells to overcome G2 arrest prior to lateral root development. Plays a role in ethylene signaling in roots. Confers sensitivity to the virulent bacterial pathogen P.syringae.[8][9][10][11][12][13][14][15]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Auxin is a pivotal plant hormone that controls many aspects of plant growth and development. Perceived by a small family of F-box proteins including transport inhibitor response 1 (TIR1), auxin regulates gene expression by promoting SCF ubiquitin-ligase-catalysed degradation of the Aux/IAA transcription repressors, but how the TIR1 F-box protein senses and becomes activated by auxin remains unclear. Here we present the crystal structures of the Arabidopsis TIR1-ASK1 complex, free and in complexes with three different auxin compounds and an Aux/IAA substrate peptide. These structures show that the leucine-rich repeat domain of TIR1 contains an unexpected inositol hexakisphosphate co-factor and recognizes auxin and the Aux/IAA polypeptide substrate through a single surface pocket. Anchored to the base of the TIR1 pocket, auxin binds to a partially promiscuous site, which can also accommodate various auxin analogues. Docked on top of auxin, the Aux/IAA substrate peptide occupies the rest of the TIR1 pocket and completely encloses the hormone-binding site. By filling in a hydrophobic cavity at the protein interface, auxin enhances the TIR1-substrate interactions by acting as a 'molecular glue'. Our results establish the first structural model of a plant hormone receptor.
Mechanism of auxin perception by the TIR1 ubiquitin ligase.,Tan X, Calderon-Villalobos LI, Sharon M, Zheng C, Robinson CV, Estelle M, Zheng N Nature. 2007 Apr 5;446(7136):640-5. PMID:17410169[16]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑Gray WM, del Pozo JC, Walker L, Hobbie L, Risseeuw E, Banks T, Crosby WL, Yang M, Ma H, Estelle M. Identification of an SCF ubiquitin-ligase complex required for auxin response in Arabidopsis thaliana. Genes Dev. 1999 Jul 1;13(13):1678-91. PMID:10398681
↑Yang M, Hu Y, Lodhi M, McCombie WR, Ma H. The Arabidopsis SKP1-LIKE1 gene is essential for male meiosis and may control homologue separation. Proc Natl Acad Sci U S A. 1999 Sep 28;96(20):11416-21. PMID:10500191
↑Zhao D, Yu Q, Chen M, Ma H. The ASK1 gene regulates B function gene expression in cooperation with UFO and LEAFY in Arabidopsis. Development. 2001 Jul;128(14):2735-46. PMID:11526079
↑Zhao D, Ni W, Feng B, Han T, Petrasek MG, Ma H. Members of the Arabidopsis-SKP1-like gene family exhibit a variety of expression patterns and may play diverse roles in Arabidopsis. Plant Physiol. 2003 Sep;133(1):203-17. PMID:12970487
↑Liu F, Ni W, Griffith ME, Huang Z, Chang C, Peng W, Ma H, Xie D. The ASK1 and ASK2 genes are essential for Arabidopsis early development. Plant Cell. 2004 Jan;16(1):5-20. Epub 2003 Dec 19. PMID:14688296 doi:10.1105/tpc.017772
↑Liscum E, Reed JW. Genetics of Aux/IAA and ARF action in plant growth and development. Plant Mol Biol. 2002 Jun-Jul;49(3-4):387-400. PMID:12036262
↑Ruegger M, Dewey E, Gray WM, Hobbie L, Turner J, Estelle M. The TIR1 protein of Arabidopsis functions in auxin response and is related to human SKP2 and yeast grr1p. Genes Dev. 1998 Jan 15;12(2):198-207. PMID:9436980
↑Gray WM, del Pozo JC, Walker L, Hobbie L, Risseeuw E, Banks T, Crosby WL, Yang M, Ma H, Estelle M. Identification of an SCF ubiquitin-ligase complex required for auxin response in Arabidopsis thaliana. Genes Dev. 1999 Jul 1;13(13):1678-91. PMID:10398681
↑Alonso JM, Stepanova AN, Solano R, Wisman E, Ferrari S, Ausubel FM, Ecker JR. Five components of the ethylene-response pathway identified in a screen for weak ethylene-insensitive mutants in Arabidopsis. Proc Natl Acad Sci U S A. 2003 Mar 4;100(5):2992-7. Epub 2003 Feb 26. PMID:12606727 doi:https://dx.doi.org/10.1073/pnas.0438070100
↑Dharmasiri N, Dharmasiri S, Weijers D, Lechner E, Yamada M, Hobbie L, Ehrismann JS, Jurgens G, Estelle M. Plant development is regulated by a family of auxin receptor F box proteins. Dev Cell. 2005 Jul;9(1):109-19. PMID:15992545 doi:https://dx.doi.org/S1534-5807(05)00184-X
↑Dharmasiri N, Dharmasiri S, Estelle M. The F-box protein TIR1 is an auxin receptor. Nature. 2005 May 26;435(7041):441-5. PMID:15917797 doi:https://dx.doi.org/nature03543
↑Navarro L, Dunoyer P, Jay F, Arnold B, Dharmasiri N, Estelle M, Voinnet O, Jones JD. A plant miRNA contributes to antibacterial resistance by repressing auxin signaling. Science. 2006 Apr 21;312(5772):436-9. PMID:16627744 doi:https://dx.doi.org/312/5772/436
↑Hayashi K, Tan X, Zheng N, Hatate T, Kimura Y, Kepinski S, Nozaki H. Small-molecule agonists and antagonists of F-box protein-substrate interactions in auxin perception and signaling. Proc Natl Acad Sci U S A. 2008 Apr 8;105(14):5632-7. Epub 2008 Apr 7. PMID:18391211
↑Tan X, Calderon-Villalobos LI, Sharon M, Zheng C, Robinson CV, Estelle M, Zheng N. Mechanism of auxin perception by the TIR1 ubiquitin ligase. Nature. 2007 Apr 5;446(7136):640-5. PMID:17410169 doi:10.1038/nature05731
