Arabidopsis BRUTUS-LIKE E3 ligases negatively regulate iron uptake by targeting transcription factor FIT for recycling

• DOI: 10.1073/pnas.1907971116
• Publication Date: 2019-08-14T23:44:10Z
• Authors: Jorge Rodríguez-C...; James M. Connorton; Inga Kruse; Robert T. Green; Marina Franceschetti; Yi-Tze Chen; Yan Cui; Hong-Qing Ling; Kuo-Chen Yeh; Janneke Balk
• Keywords: Regulon; Transcription

Organisms need to balance sufficient uptake of iron (Fe) with possible toxicity. In plant roots, a regulon genes is transcriptionally activated under Fe deficiency, but it unknown how this response inactivated when becomes available. Here we describe the function 2 partially redundant E3 ubiquitin ligases, BRUTUS-LIKE1 (BTSL1) and BTSL2, in Arabidopsis thaliana provide evidence that they target transcription factor FIT, key regulator uptake, for degradation. The btsl double mutant failed effectively down-regulate controlled by accumulated toxic levels roots leaves. C-terminal domains BTSL1 BTSL2 exhibited ligase activity, interacted FIT not its dimeric partner bHLH39. BTSL proteins were able poly-ubiquitinate vitro promote degradation vivo. Thus, posttranslational control critical prevent excess uptake.