Variation in auxin sensing guides AUX/IAA transcriptional repressor ubiquitylation and destruction.

ABSTRACT: Auxin is a small molecule morphogen that bridges SCF^TIR1/AFB-AUX/IAA co-receptor interactions leading to ubiquitylation and proteasome-dependent degradation of AUX/IAA transcriptional repressors. Here, we systematically dissect auxin sensing by SCF^TIR1-IAA6 and SCF^TIR1-IAA19 co-receptor complexes, and assess IAA6/IAA19 ubiquitylation in vitro and IAA6/IAA19 degradation in vivo. We show that TIR1-IAA19 and TIR1-IAA6 have distinct auxin affinities that correlate with ubiquitylation and turnover dynamics of the AUX/IAA. We establish a system to track AUX/IAA ubiquitylation in IAA6 and IAA19 in vitro and show that it occurs in flexible hotspots in degron-flanking regions adorned with specific Lys residues. We propose that this signature is exploited during auxi

SUBMITTER: Winkler M 

PROVIDER: S-EPMC5467235 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature