MPK3-mediated phosphorylation inactivates MYB4 to promote FIT-dependent iron acquisition.

Hui Song, Guangna Chen, Jiena Xu, Jing Zhang, Shuangyao Li, Shuxun Xu, Yanjun Wu, Li Jiang, Xi Wu, Shuqing Cao

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In one paragraph

Article in EMBO reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed

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1 · What the graph read from it

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5 · Who and what money

Authors and funding

10 authors.

Hui Song *School of Food and Biological Engineering, Hefei University of Technology, Hefei, China.

Guangna Chen *School of Food and Biological Engineering, Hefei University of Technology, Hefei, China.ORCID http://orcid.org/0009-0002-0415-6208

Jiena Xu *School of Food and Biological Engineering, Hefei University of Technology, Hefei, China.ORCID http://orcid.org/0000-0001-6301-8361

Jing ZhangSchool of Food and Biological Engineering, Hefei University of Technology, Hefei, China.ORCID http://orcid.org/0009-0005-8632-7972

Shuangyao LiSchool of Food and Biological Engineering, Hefei University of Technology, Hefei, China.ORCID http://orcid.org/0009-0003-4937-9664

Shuxun XuSchool of Food and Biological Engineering, Hefei University of Technology, Hefei, China.ORCID http://orcid.org/0009-0003-9977-2130

Yanjun WuSchool of Food and Biological Engineering, Hefei University of Technology, Hefei, China.ORCID http://orcid.org/0009-0008-6008-1259

Li JiangSchool of Food and Biological Engineering, Hefei University of Technology, Hefei, China. lijiang@hfut.edu.cn.ORCID http://orcid.org/0000-0002-8530-4737

Xi WuSchool of Food and Biological Engineering, Hefei University of Technology, Hefei, China. xiwu@hfut.edu.cn.ORCID http://orcid.org/0000-0002-0277-9754

Shuqing CaoSchool of Food and Biological Engineering, Hefei University of Technology, Hefei, China. shuqingcao@hfut.edu.cn.ORCID http://orcid.org/0000-0001-6693-877X

Funding

MOST | National Natural Science Foundation of China (NSFC) 32070276MOST | National Natural Science Foundation of China (NSFC) 32270272MOST | NSFC | National Natural Science Foundation of China-Liaoning Joint Fund ( - ) 32300225the china postdoctoral fellowship program of CPSF GZC20240364the china postdoctoral science fundation 2023M740962The fundamental research funds for the central universities of china JZ2025HGTB0185

6 · The paper itself

Abstract

Iron (Fe) is an essential micronutrient for plant growth, and its homeostasis is critically regulated by the transcription factor FIT in response to deficiency. Here, we identify the R2R3-MYB transcription factor MYB4 as a previously unknown negative regulator of Fe acquisition. MYB4 directly interacts with FIT, competing with bHLH38/39 to prevent the formation of transcriptionally active heterodimers, thereby repressing the expression of the key Fe-uptake genes IRT1 and FRO2. We establish that the mitogen-activated protein kinase MPK3 acts upstream in this pathway. Under Fe-deficient conditions, MPK3 is activated and directly phosphorylates MYB4 at Serine 4, promoting its proteasome-dependent destabilization. This post-translational switch releases FIT to dimerize with bHLH partners, activating Fe uptake. Our work unveils the MPK3-MYB4-FIT signaling module as a previously unrecognized regulatory module that contributes to the dynamic control of Fe homeostasis in Arabidopsis.

Indexed as

ArabidopsisArabidopsis ProteinsBasic Helix-Loop-Helix ProteinsIronMitogen-Activated Protein Kinase KinasesTranscription FactorsGene Expression Regulation, PlantHomeostasisPhosphorylationProteasome Endopeptidase ComplexProtein BindingSignal TransductionArabidopsis ProteinsAtMPK3 protein, ArabidopsisBasic Helix-Loop-Helix ProteinsFIT1 protein, ArabidopsisIronMitogen-Activated Protein Kinase KinasesProteasome Endopeptidase ComplexTranscription Factors

Identifiers

PMID42642656

DOI10.1038/s44319-026-00906-1

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.