IRON MAN interacts with BRUTUS to maintain iron homeostasis in Arabidopsis
| 论文编号: | |||||||||
| 作者: | Li Y; Lu CK; Li CY | ||||||||
| 刊物名称: | Proceedings of the National Academy of Sciences of the United States of America | ||||||||
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| 论文题目英文: | IRON MAN interacts with BRUTUS to maintain iron homeostasis in Arabidopsis | ||||||||
| 年: | Sep 2021 | ||||||||
| 卷: | 118 | ||||||||
| 期: | 39 | ||||||||
| 页: | e2109063118 | ||||||||
| 联系作者: | Liang G | ||||||||
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| 影响因子: | 11.205 | ||||||||
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| 摘要: | IRON MAN (IMA) peptides, a family of small peptides, control iron (Fe) transport in plants, but their roles in Fe signaling remain unclear. BRUTUS (BTS) is a potential Fe sensor that negatively regulates Fe homeostasis by promoting the ubiquitin-mediated degradation of bHLH105 and bHLH115, two positive regulators of the Fe deficiency response. Here, we show that IMA peptides interact with BTS. The C-terminal parts of IMA peptides contain a conserved BTS interaction domain (BID) that is responsible for their interaction with the C terminus of BTS. Arabidopsis thaliana plants constitutively expressing IMA genes phenocopy the bts-2 mutant. Moreover, IMA peptides are ubiquitinated and degraded by BTS. bHLH105 and bHLH115 also share a BID, which accounts for their interaction with BTS. IMA peptides compete with bHLH105/bHLH115 for interaction with BTS, thereby inhibiting the degradation of these transcription factors by BTS. Genetic analyses suggest that bHLH105/bHLH115 and IMA3 have additive roles and function downstream of BTS. Moreover, the transcription of both BTS and IMA3 is activated directly by bHLH105 and bHLH115 under Fe-deficient conditions. Our findings provide a conceptual framework for understanding the regulation of Fe homeostasis: IMA peptides protect bHLH105/bHLH115 from degradation by sequestering BTS, thereby activating the Fe deficiency response. | ||||||||
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