Open AccessAuxin-induced SCF TIR1 –Aux/IAA interaction involves stable modification of the SCF TIR1 complex
Author(s) -
Stefan Kepinski,
Ottoline Leyser
Publication year - 2004
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0402868101
Subject(s) - auxin , f box protein , skp1 , ubiquitin ligase , chemistry , ubiquitin , arabidopsis , microbiology and biotechnology , biochemistry , repressor , biology , gene expression , mutant , gene
The plant hormone auxin can regulate gene expression by destabilizing members of the Aux/IAA family of transcriptional repressors. 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). SKP1, Cullin, and an F-box-containing protein (SCF)-mediated degradation is an important component of many eukaryotic signaling pathways. In all known cases to date, the interaction between the targets and their cognate SCFs is regulated by signal-induced modification of the target. The mechanism by which auxin promotes the interaction between SCF(TIR1) and Aux/IAAs is not understood, but current hypotheses propose auxin-induced phosphorylation, hydroxylation, or proline isomerization of the Aux/IAAs. We found no evidence to support these hypotheses or indeed that auxin induces any stable modification of Aux/IAAs to increase their affinity for SCF(TIR1). Instead, we present data suggesting that auxin promotes the SCF(TIR1)-Aux/IAA interaction by affecting the SCF component, TIR1, or proteins tightly associated with it.