Protein Information

Name ubiquitin
Synonyms HMG20; RPS27A; UBA80; UBCEP 1; UBCEP1; UBA52; UBCEP 2; UBCEP2…

Compound Information

Name IAA
CAS

Reference List

PubMed Abstract RScore(About this table)
19915560 Nishimura K, Fukagawa T, Takisawa H, Kakimoto T, Kanemaki M: An auxin-based degron system for the rapid depletion of proteins in nonplant cells. Nat Methods. 2009 Dec;6(12):917-22. Epub 2009 Nov 15.

Plants have evolved a unique system in which the plant hormone auxin directly induces rapid degradation of the AUX/IAA family of transcription repressors by a specific form of the SCF E3 ubiquitin ligase.
31(0,1,1,1) Details
18391211 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.


TIR1 is the substrate receptor of the ubiquitin-ligase complex SCF (TIR1).
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15208392 Chuang HW, Zhang W, Gray WM: Arabidopsis ETA2, an apparent ortholog of the human cullin-interacting protein CAND1, is required for auxin responses mediated by the SCF (TIR1) ubiquitin ligase. Plant Cell. 2004 Jul;16(7):1883-97. Epub 2004 Jun 18.

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12782725 Gray WM, Muskett PR, Chuang HW, Parker JE: Arabidopsis SGT1b is required for SCF (TIR1)-mediated auxin response. Plant Cell. 2003 Jun;15(6):1310-9.


This complex functions as a ubiquitin protein ligase that targets members of the auxin/indoleacetic acid (Aux/IAA) family of transcriptional regulators for ubiquitin-mediated degradation in response to auxin.
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19114460 Gilkerson J, Hu J, Brown J, Jones A, Sun TP, Callis J: Isolation and characterization of cul1-7, a recessive allele of CULLIN1 that disrupts SCF function at the C terminus of CUL1 in Arabidopsis thaliana. Genetics. 2009 Mar;181(3):945-63. Epub 2008 Dec 29.


Many aspects of plant biology depend on the ubiquitin proteasome system for degradation of regulatory proteins.
2(0,0,0,2) Details
18631113 Mockaitis K, Estelle M: Auxin receptors and plant development: a new signaling paradigm. Annu Rev Cell Dev Biol. 2008;24:55-80.


Auxin binds to TIR1, the F-box subunit of the ubiquitin ligase complex SCF (TIR1), and stabilizes the interaction between TIR1 and Aux/IAA substrates.
2(0,0,0,2) Details
17410169 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.

2(0,0,0,2) Details
17559514 Yang P, Smalle J, Lee S, Yan N, Emborg TJ, Vierstra RD: Ubiquitin C-terminal hydrolases 1 and 2 affect shoot architecture in Arabidopsis. Plant J. 2007 Aug;51(3):441-57. Epub 2007 Jun 8.

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15994909 Tao LZ, Cheung AY, Nibau C, Wu HM: RAC GTPases in tobacco and Arabidopsis mediate auxin-induced formation of proteolytically active nuclear protein bodies that contain AUX/IAA proteins. Plant Cell. 2005 Aug;17(8):2369-83. Epub 2005 Jul 1.


Auxin signaling relies on ubiquitin ligase SCF (TIR1)-mediated 26S proteasome-dependent proteolysis of a large family of short-lived transcription regulators, auxin/indole acetic acid (Aux/IAA), resulting in the derepression of auxin-responsive genes.
2(0,0,0,2) Details
11713520 Gray WM, Kepinski S, Rouse D, Leyser O, Estelle M: Auxin regulates SCF (TIR1)-dependent degradation of AUX/IAA proteins. Nature. 2001 Nov 15;414(6861):271-6.


Previous studies have implicated the ubiquitin-ligase SCF (TIR1) and the AUX/IAA proteins in auxin response.
1(0,0,0,1) Details
12887580 Zenser N, Dreher KA, Edwards SR, Callis J: Acceleration of Aux/IAA proteolysis is specific for auxin and independent of AXR1. Plant J. 2003 Aug;35(3):285-94.


To further examine auxin-mediated increases in proteolysis, the degradation of two other LUC fusion proteins, a non-cleavable ubiquitin LUC fusion (UB1-72::LUC) and SAUR15::LUC was determined in vivo in seedlings.
1(0,0,0,1) Details
17579493 Abel S: Auxin is surfacing. ACS Chem Biol. 2007 Jun 15;2(6):380-4.


This work establishes a novel mechanism of E3 regulation by small molecules and promises a novel strategy for the treatment of human disorders associated with defective ubiquitin-dependent proteolysis.
1(0,0,0,1) Details
18298415 Sato A, Yamamoto KT: Overexpression of the non-canonical Aux/IAA genes causes auxin-related aberrant phenotypes in Arabidopsis. Physiol Plant. 2008 Jun;133(2):397-405. Epub 2008 Feb 21.


Degradation of Aux/IAA proteins which are triggered by the ubiquitin ligase complex containing the auxin F-box receptors (AFBs), is thought to be the primary reaction of auxin signaling.
1(0,0,0,1) Details
16920877 Walsh TA, Neal R, Merlo AO, Honma M, Hicks GR, Wolff K, Matsumura W, Davies JP: Mutations in an auxin receptor homolog AFB5 and in SGT1b confer resistance to synthetic picolinate auxins and not to 2,4-dichlorophenoxyacetic acid or indole-3-acetic acid in Arabidopsis. Plant Physiol. 2006 Oct;142(2):542-52. Epub 2006 Aug 18.


TIR1 is the recognition component of the Skp1-cullin-F-box complex associated with the ubiquitin-proteasome pathway involved in auxin signaling and has recently been shown to be a receptor for IAA and 2,4-D.
1(0,0,0,1) Details
19171357 Hayashi K, Kamio S, Oono Y, Townsend LB, Nozaki H: Toyocamycin specifically inhibits auxin signaling mediated by SCFTIR1 pathway. Phytochemistry. 2009 Jan;70(2):190-7. Epub 2009 Jan 24.


Toyocamycin also blocked auxin-enhanced degradation of the Aux/IAA repressor modulated by the SCF (TIR1) ubiquitin-proteasome pathway without inhibiting proteolytic activity of proteasome.
1(0,0,0,1) Details
12690101 Hayashi K, Jones AM, Ogino K, Yamazoe A, Oono Y, Inoguchi M, Kondo H, Nozaki H: Yokonolide B, a novel inhibitor of auxin action, blocks degradation of AUX/IAA factors. J Biol Chem. 2003 Jun 27;278(26):23797-806. Epub 2003 Apr 9.


Gain of function mutants such as shy2-2, slr1, and axr2-1 encoding AUX/IAA transcriptional repressors and loss of function mutants encoding components of the ubiquitin-proteolytic pathway such as axr1-3 and tir1-1, which display increased AUX/IAAs protein stability, are less sensitive to YkB, although axr1 and tir1 mutants were sensitive to MG132, a general proteasome inhibitor, consistent with a site of action downstream of AXR1 and TIR.
1(0,0,0,1) Details
15295098 Kepinski S, Leyser O: Auxin-induced SCFTIR1-Aux/IAA interaction involves stable modification of the SCFTIR1 complex. Proc Natl Acad Sci U S A. 2004 Aug 17;101(33):12381-6. Epub 2004 Aug 4.


Auxin-induced Aux/IAA degradation requires the protein-ubiquitin ligase SCF (TIR1), with auxin acting to enhance the interaction between the Aux/IAAs and SCF (TIR1).
1(0,0,0,1) Details
19309453 Maraschin Fdos S, Memelink J, Offringa R: Auxin-induced, SCF (TIR1)-mediated poly-ubiquitination marks AUX/IAA proteins for degradation. Plant J. 2009 Jul;59(1):100-9. Epub 2009 Feb 26.


Auxin enhances the binding of Aux/IAA proteins to the receptor TIR1, which is an F-box protein that is part of the E3 ubiquitin ligase complex SCF (TIR1).
1(0,0,0,1) Details
15917798 Kepinski S, Leyser O: The Arabidopsis F-box protein TIR1 is an auxin receptor. . Nature. 2005 May 26;435(7041):446-51.


Central to auxin response are changes in gene expression, brought about by auxin-induced interaction between the Aux/IAA transcriptional repressor proteins and the ubiquitin-ligase complex SCF (TIR1), thus targeting for them proteolysis.
1(0,0,0,1) Details
12226665 Xie Q, Guo HS, Dallman G, Fang S, Weissman AM, Chua NH: SINAT5 promotes ubiquitin-related degradation of NAC1 to attenuate auxin signals. Nature. 2002 Sep 12;419(6903):167-70.

1(0,0,0,1) Details
12036263 Dharmasiri S, Estelle M: The role of regulated protein degradation in auxin response. Plant Mol Biol. 2002 Jun-Jul;49(3-4):401-9.


Recent genetic studies in Arabidopsis indicate that auxin regulates this system by promoting the ubiquitin-mediated degradation of the Aux/IAA proteins, thus permitting ARF function.
1(0,0,0,1) Details
11709180 Rogg LE, Bartel B: Auxin signaling: derepression through regulated proteolysis. Dev Cell. 2001 Nov;1(5):595-604.


Aux/IAA proteins are unstable, and their degradation is triggered by a ubiquitin-protein ligase that is regulated by modification with a ubiquitin-related protein.
1(0,0,0,1) Details
16478940 Laskowski M: Teaching resources. Sci STKE. 2006 Feb 14;2006(322):tr1.


TIR1 is an auxin receptor and also a subunit of an SCF-type ubiquitin ligase.
1(0,0,0,1) Details
16317577 Raghavan C, Ong EK, Dalling MJ, Stevenson TW: Regulation of genes associated with auxin, ethylene and ABA pathways by 2,4-dichlorophenoxyacetic acid in Arabidopsis. Funct Integr Genomics. 2006 Jan;6(1):60-70. Epub 2005 Nov 22.


Results of this study indicated that 2,4-D induced the expression of auxin-response genes (IAA1, IAA13, IAA19) at both auxinic and herbicidal levels of application, whereas the TIR1 and ASK1 genes, which are associated with ubiquitin-mediated auxin signalling, were down-regulated in response to low concentrations of 2,4-D application.
1(0,0,0,1) Details
12036262 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.


Mutations have been identified in a wide variety of auxin-response components, including auxin transporters, protein kinases and phosphatases, components of a ubiquitin-proteosome pathway, and transcriptional regulators.
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17692850 Scherer GF, Zahn M, Callis J, Jones AM: A role for phospholipase A in auxin-regulated gene expression. FEBS Lett. 2007 Sep 4;581(22):4205-11. Epub 2007 Aug 3.


Factors that bind to the auxin response elements of the DR5 promoter and thereby regulate gene expression are regulated by a set of proteins such as Aux/IAA1 whose abundances are, in part, under control of E3 ubiquitin ligase SCF complexes.
1(0,0,0,1) Details