Abstract
Organisms need to balance sufficient uptake of iron (Fe) with possible toxicity. In plant roots, a regulon of uptake genes is transcriptionally activated under Fe deficiency, but it is unknown how this response is inactivated when Fe becomes available. Here we describe the function of 2 partially redundant E3 ubiquitin ligases, BRUTUS-LIKE1 (BTSL1) and BTSL2, in Arabidopsis thaliana and provide evidence that they target the transcription factor FIT, a key regulator of Fe uptake, for degradation. The btsl double mutant failed to effectively down-regulate the transcription of genes controlled by FIT, and accumulated toxic levels of Fe in roots and leaves. The C-terminal domains of BTSL1 and BTSL2 exhibited E3 ligase activity, and interacted with FIT but not its dimeric partner bHLH39. The BTSL proteins were able to poly-ubiquitinate FIT in vitro and promote FIT degradation in vivo. Thus, posttranslational control of FIT is critical to prevent excess Fe uptake.
| Original language | English |
|---|---|
| Pages (from-to) | 17584-17591 |
| Number of pages | 8 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 116 |
| Issue number | 35 |
| Early online date | 14 Aug 2019 |
| DOIs | |
| Publication status | Published - 27 Aug 2019 |
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Keywords
- BHLH transcription factor
- dicotyledon
- iron
- micronutrient
- ubiquitin
Cite this
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Arabidopsis BRUTUS-LIKE E3 ligases negatively regulate iron uptake by targeting transcription factor FIT for recycling. / Rodríguez-Celma, Jorge; Connorton, James M.; Kruse, Inga; Green, Robert T.; Franceschetti, Marina; Chen, Yi-Tze; Cui, Yan; Ling, Hong-Qing; Yeh, Kuo-Chen; Balk, Janneke.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 116, No. 35, 27.08.2019, p. 17584-17591.Research output: Contribution to journal › Article
TY - JOUR
T1 - Arabidopsis BRUTUS-LIKE E3 ligases negatively regulate iron uptake by targeting transcription factor FIT for recycling
AU - Rodríguez-Celma, Jorge
AU - Connorton, James M.
AU - Kruse, Inga
AU - Green, Robert T.
AU - Franceschetti, Marina
AU - Chen, Yi-Tze
AU - Cui, Yan
AU - Ling, Hong-Qing
AU - Yeh, Kuo-Chen
AU - Balk, Janneke
PY - 2019/8/27
Y1 - 2019/8/27
N2 - Organisms need to balance sufficient uptake of iron (Fe) with possible toxicity. In plant roots, a regulon of uptake genes is transcriptionally activated under Fe deficiency, but it is unknown how this response is inactivated when Fe becomes available. Here we describe the function of 2 partially redundant E3 ubiquitin ligases, BRUTUS-LIKE1 (BTSL1) and BTSL2, in Arabidopsis thaliana and provide evidence that they target the transcription factor FIT, a key regulator of Fe uptake, for degradation. The btsl double mutant failed to effectively down-regulate the transcription of genes controlled by FIT, and accumulated toxic levels of Fe in roots and leaves. The C-terminal domains of BTSL1 and BTSL2 exhibited E3 ligase activity, and interacted with FIT but not its dimeric partner bHLH39. The BTSL proteins were able to poly-ubiquitinate FIT in vitro and promote FIT degradation in vivo. Thus, posttranslational control of FIT is critical to prevent excess Fe uptake.
AB - Organisms need to balance sufficient uptake of iron (Fe) with possible toxicity. In plant roots, a regulon of uptake genes is transcriptionally activated under Fe deficiency, but it is unknown how this response is inactivated when Fe becomes available. Here we describe the function of 2 partially redundant E3 ubiquitin ligases, BRUTUS-LIKE1 (BTSL1) and BTSL2, in Arabidopsis thaliana and provide evidence that they target the transcription factor FIT, a key regulator of Fe uptake, for degradation. The btsl double mutant failed to effectively down-regulate the transcription of genes controlled by FIT, and accumulated toxic levels of Fe in roots and leaves. The C-terminal domains of BTSL1 and BTSL2 exhibited E3 ligase activity, and interacted with FIT but not its dimeric partner bHLH39. The BTSL proteins were able to poly-ubiquitinate FIT in vitro and promote FIT degradation in vivo. Thus, posttranslational control of FIT is critical to prevent excess Fe uptake.
KW - BHLH transcription factor
KW - dicotyledon
KW - iron
KW - micronutrient
KW - ubiquitin
UR - http://www.scopus.com/inward/record.url?scp=85071515006&partnerID=8YFLogxK
U2 - 10.1073/pnas.1907971116
DO - 10.1073/pnas.1907971116
M3 - Article
C2 - 31413196
AN - SCOPUS:85071515006
VL - 116
SP - 17584
EP - 17591
JO - Proceedings of the National Academy of Sciences
JF - Proceedings of the National Academy of Sciences
SN - 1091-6490
IS - 35
ER -