Linked Life Data

19309453

Source:http://linkedlifedata.com/resource/pubmed/id/19309453

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2009-7-2
pubmed:abstractText
The plant hormone auxin (indole-3-acetic acid or IAA) regulates plant development by inducing rapid cellular responses and changes in gene expression. Auxin promotes the degradation of Aux/IAA transcriptional repressors, thereby allowing auxin response factors (ARFs) to activate the transcription of auxin-responsive genes. 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). Binding of Aux/IAA proteins leads to degradation via the 26S proteasome, but evidence for SCF(TIR1)-mediated poly-ubiquitination of Aux/IAA proteins is lacking. Here we used an Arabidopsis cell suspension-based protoplast system to find evidence for SCF(TIR1)-mediated ubiquitination of the Aux/IAA proteins SHY2/IAA3 and BDL/IAA12. Each of these proteins showed a distinct abundance and repressor activity when expressed in this cell system. Moreover, the amount of endogenous TIR1 protein appeared to be rate-limiting for a proper auxin response measured by the co-transfected DR5::GUS reporter construct. Co-transfection with 35S::TIR1 led to auxin-dependent degradation, and excess of 35S::TIR1 even led to degradation of Aux/IAAs in the absence of auxin treatment. Expression of the mutant tir1-1 protein or the related F-box protein COI1, which is involved in jasmonate signaling, had no effect on Aux/IAA degradation. Our results show that SHY2/IAA3 and BDL/IAA12 are poly-ubiquitinated and degraded in response to increased auxin or TIR1 levels. In conclusion, our data provide experimental support for the model that SCF(TIR1)-dependent poly-ubiquitination of Aux/IAA proteins marks these proteins for degradation by the 26S proteasome, leading to activation of auxin-responsive gene expression.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Arabidopsis Proteins, http://linkedlifedata.com/resource/pubmed/chemical/COI1 protein, Arabidopsis, http://linkedlifedata.com/resource/pubmed/chemical/F-Box Proteins, http://linkedlifedata.com/resource/pubmed/chemical/IAA12 protein, Arabidopsis, http://linkedlifedata.com/resource/pubmed/chemical/Indoleacetic Acids, http://linkedlifedata.com/resource/pubmed/chemical/Nuclear Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Plant Growth Regulators, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cell Surface, http://linkedlifedata.com/resource/pubmed/chemical/Repressor Proteins, http://linkedlifedata.com/resource/pubmed/chemical/SHY2 protein, Arabidopsis, http://linkedlifedata.com/resource/pubmed/chemical/TIR1 protein, Arabidopsis
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1365-313X
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
59
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
100-9
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Auxin-induced, SCF(TIR1)-mediated poly-ubiquitination marks AUX/IAA proteins for degradation.
pubmed:affiliation
Institute of Biology, Leiden University, Clusius Laboratorium, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't