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Tan S, Li S, Zhang XY, Li YM, Zhang P, Yin LP. Monoubiquitinated MxIRT1 acts as an iron receptor to determine MxIRT1 vacuole degradation or plasma membrane recycling via endocytosis. PLANT SIGNALING & BEHAVIOR 2022; 17:2095141. [PMID: 35775587 PMCID: PMC9255258 DOI: 10.1080/15592324.2022.2095141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
IRON-REGULATED TRANSPORTER 1 (IRT1) is critical for iron uptake in roots, and its exocytosis to the plasma membrane (PM) is regulated by the iron status sensed by the histidine-rich domain (HRM). However, studies on the fate of IRT1 after fusion with PM in response to iron conditions are still limited. In this study, we found that K165 and K196 regulate the monoubiquitination of MxIRT1 (mUb-MxIRT1), which acts as a receptor delivering signals from HRM to downstream effectors such as clathrin to determine the fate of MxIRT1. Iron supply led MxIRT1 in the PM to monoubiquitin-dependent endocytosis which could be inhibited by endocytosis inhibitor TyrA23 or in the double site-directed mutant K165/K196R. Subsequently, the endocytosis pathway to the vacuole was inhibited by vacuolar protease inhibitor Leupeptin in excessive iron conditions and the inability of being able to respond to iron change, indicated by the protein accumulating in the PM, contributed to iron toxicity in K165/K196R transgenic Arabidopsis. With iron availability decreasing again, MxIRT1 could dock close to the PM waiting for to be recycled. Another monoubiquitination site, K26, was necessary for MxIRT1 Endoplasmic Reticulum (ER) export as site-directed mutant K26R lost the ability of PM targeting, and co-localized with the COPII subunit of the coat protein OsSec24. Therefore, after K26-directed ER export and iron-induced PM fusion, mUb-MxIRT1 determines subsequent vacuolar degradation or recycling to the PM via endocytosis for maintaining iron homeostasis.
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Affiliation(s)
- Song Tan
- School of Pharmacy, Anhui University of Chinese Medicine, Hefei, Anhui, China
- College of Life Science, Capital Normal University, Beijing, China
- Anhui Province Key Laboratory of Research & Development of Chinese Medicine, Hefei, Anhui, China
| | - Shuang Li
- College of Life Science, Capital Normal University, Beijing, China
| | - Xiu-Yue Zhang
- College of Life Science, Capital Normal University, Beijing, China
| | - Yu-Meng Li
- College of Life Science, Capital Normal University, Beijing, China
| | - Peng Zhang
- College of Life Science, Capital Normal University, Beijing, China
| | - Li-Ping Yin
- College of Life Science, Capital Normal University, Beijing, China
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Tan S, Zhang X, Zhang Q, Li YM, Zhang P, Yin LP. HRM and CRAC in MxIRT1 act as iron sensors to determine MxIRT1 vesicle-PM fusion and metal transport. PLANT SIGNALING & BEHAVIOR 2022; 17:2005881. [PMID: 34809535 PMCID: PMC8928839 DOI: 10.1080/15592324.2021.2005881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/09/2021] [Accepted: 11/09/2021] [Indexed: 06/13/2023]
Abstract
The IRON-REGULATED TRANSPORTER1 (IRT1) is critical for iron uptake in roots, and its exocytosis to the plasma membrane (PM) is regulated by detergent-resistant membranes. However, studies on IRT1 exocytosis and function in response to iron status are limited. Presently, we found that the histidine-rich motif (HRM) of MxIRT1 could bind to iron directly and HRM determined the delivery of MxIRT1 to the PM, after which the cholesterol recognition amino acid consensus (CRAC) motif-regulated MxIRT1 mediated metal transport. IMAC assay revealed that H192 was the vital site for HRM binding to Fe2+, and metal-binding activity was stopped after the deletion of HRM (MxIRT1∆HM) or in H192 site-directed mutants (H192A). MxIRT1∆HM or H192A in transgenic yeast and Arabidopsis failed to localize in the PM and displayed impaired iron absorption. In the PM, Y266 in CRAC was required for metal transport; Y266A transgenic Arabidopsis displayed the same root length, Cd2+ flux, and Fe concentration as Arabidopsis mutant irt1 under iron-deficient conditions. Therefore, H192 in HRM may be an iron sensor to regulate delivery of MxIRT1 vesicles to the PM after binding with iron; Y266 in CRAC acts as an iron sensor for active metal transport under iron-deficient conditions.
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Affiliation(s)
- Song Tan
- School of Pharmacy, Anhui University of Chinese Medicine, Hefei, China
- College of Life Science, Capital Normal University, Beijing, China
| | - Xi Zhang
- College of Life Science, Capital Normal University, Beijing, China
| | - Qi Zhang
- College of Life Science, Capital Normal University, Beijing, China
| | - Yu-Meng Li
- College of Life Science, Capital Normal University, Beijing, China
| | - Peng Zhang
- College of Life Science, Capital Normal University, Beijing, China
| | - Li-Ping Yin
- College of Life Science, Capital Normal University, Beijing, China
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Spielmann J, Vert G. The many facets of protein ubiquitination and degradation in plant root iron-deficiency responses. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:2071-2082. [PMID: 32945865 DOI: 10.1093/jxb/eraa441] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
Organisms need to deal with the absolute requirement for metals and also their possible toxicity. This is achieved through an intricate network of signaling pathways that are integrated to ultimately fine-tune iron uptake and metabolism. The mechanisms by which plants cope with iron limitation and the associated genomic responses are well characterized. On top of this transcriptional cascade is another level of regulation involving the post-translational protein modification and degradation. The ubiquitination and/or degradation of several transcription factors in the iron-deficiency signaling pathways and metal transporters has recently come to light. In this review we discuss the mechanisms and possible roles of protein modification and turnover in the regulation of root iron-deficiency responses. We also highlight the tight coupling between metal sensing by E3 ubiquitin ligases or bifunctional transporters and protein degradation.
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Affiliation(s)
- Julien Spielmann
- Plant Science Research Laboratory (LRSV), UMR5546 CNRS/Université Toulouse 3, 24 chemin de Borde Rouge, Auzeville-Tolosane, France
| | - Grégory Vert
- Plant Science Research Laboratory (LRSV), UMR5546 CNRS/Université Toulouse 3, 24 chemin de Borde Rouge, Auzeville-Tolosane, France
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Ivanov R, Vert G. Endocytosis in plants: Peculiarities and roles in the regulated trafficking of plant metal transporters. Biol Cell 2020; 113:1-13. [PMID: 33044749 DOI: 10.1111/boc.202000118] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/07/2020] [Indexed: 12/14/2022]
Abstract
The removal of transmembrane proteins from the plasma membrane via endocytosis has emerged as powerful strategy in the regulation of receptor signalling and molecule transport. In the last decade, IRON-REGULATED TRANSPORTER1 (IRT1) has been established as one of the key plant model proteins for studying endomembrane trafficking. The use of IRT1 and additional other metal transporters has uncovered novel factors involved in plant endocytosis and facilitated a better understanding of the role of endocytosis in the fine balancing of plant metal homoeostasis. In this review, we outline the specifics of plant endocytosis compared to what is known in yeast and mammals, and based on several examples, we demonstrate how studying metal transport has contributed to extending our knowledge of endocytic trafficking by shedding light on novel regulatory mechanisms and factors.
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Affiliation(s)
- Rumen Ivanov
- Institute of Botany, Heinrich-Heine University, Düsseldorf, D-40225, Germany
| | - Grégory Vert
- Plant Science Research Laboratory (LRSV), UMR5546 CNRS/Université Toulouse 3, Auzeville-Tolosane, 31320, France
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Tan S, Zhang P, Xiao W, Feng B, Chen LY, Li S, Li P, Zhao WZ, Qi XT, Yin LP. TMD1 domain and CRAC motif determine the association and disassociation of MxIRT1 with detergent-resistant membranes. Traffic 2017; 19:122-137. [PMID: 29112302 DOI: 10.1111/tra.12540] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 11/01/2017] [Accepted: 11/01/2017] [Indexed: 12/23/2022]
Abstract
Iron is essential for most living organisms. The iron-regulated transporter1 (IRT1) plays a major role in iron uptake in roots, and its trafficking from endoplasmic reticulum (ER) to plasma membrane (PM) is tightly coordinated with changes in iron environment. However, studies on the IRT1 response are limited. Here, we report that Malus xiaojinesis IRT1 (MxIRT1) associates with detergent-resistant membranes (DRMs, a biochemical counterpart of PM microdomains), whereas the PM microdomains are known platforms for signal transduction in the PM. Depending on the shift of MxIRT1 from microdomains to homogeneous regions in PM, MxIRT1-mediated iron absorption is activated by the cholesterol recognition/interaction amino acid consensus (CRAC) motif of MxIRT1. MxIRT1 initially associates with DRMs in ER via its transmembrane domain 1 (TMD1), and thus begins DRMs-dependent intracellular trafficking. Subsequently, MxIRT1 is sequestered in COPII vesicles via the ER export signal sequence in MxIRT1. These studies suggest that iron homeostasis is influenced by the CRAC motif and TMD1 domain due to their determination of MxIRT1-DRMs association.
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Affiliation(s)
- Song Tan
- College of Life Science, Capital Normal University, Beijing, China
| | - Peng Zhang
- College of Life Science, Capital Normal University, Beijing, China.,State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Xiao
- College of Life Science, Capital Normal University, Beijing, China.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Bing Feng
- College of Life Science, Capital Normal University, Beijing, China
| | - Lan-You Chen
- College of Life Science, Capital Normal University, Beijing, China
| | - Shuang Li
- College of Life Science, Capital Normal University, Beijing, China
| | - Peng Li
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Wei-Zhong Zhao
- School of Mathematical Sciences, Capital Normal University, Beijing, China
| | - Xiao-Ting Qi
- College of Life Science, Capital Normal University, Beijing, China
| | - Li-Ping Yin
- College of Life Science, Capital Normal University, Beijing, China
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Hasan MK, Cheng Y, Kanwar MK, Chu XY, Ahammed GJ, Qi ZY. Responses of Plant Proteins to Heavy Metal Stress-A Review. FRONTIERS IN PLANT SCIENCE 2017; 8:1492. [PMID: 28928754 PMCID: PMC5591867 DOI: 10.3389/fpls.2017.01492] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/11/2017] [Indexed: 05/17/2023]
Abstract
Plants respond to environmental pollutants such as heavy metal(s) by triggering the expression of genes that encode proteins involved in stress response. Toxic metal ions profoundly affect the cellular protein homeostasis by interfering with the folding process and aggregation of nascent or non-native proteins leading to decreased cell viability. However, plants possess a range of ubiquitous cellular surveillance systems that enable them to efficiently detoxify heavy metals toward enhanced tolerance to metal stress. As proteins constitute the major workhorses of living cells, the chelation of metal ions in cytosol with phytochelatins and metallothioneins followed by compartmentalization of metals in the vacuoles as well as the repair of stress-damaged proteins or removal and degradation of proteins that fail to achieve their native conformations are critical for plant tolerance to heavy metal stress. In this review, we provide a broad overview of recent advances in cellular protein research with regards to heavy metal tolerance in plants. We also discuss how plants maintain functional and healthy proteomes for survival under such capricious surroundings.
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Affiliation(s)
- Md. Kamrul Hasan
- Department of Horticulture, Zhejiang UniversityHangzhou, China
- Department of Agricultural Chemistry, Sylhet Agricultural UniversitySylhet, Bangladesh
| | - Yuan Cheng
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Vegetables, Zhejiang Academy of Agricultural SciencesHangzhou, China
| | | | - Xian-Yao Chu
- Zhejiang Institute of Geological Survey, Geological Research Center for Agricultural Applications, China Geological SurveyBeijing, China
| | | | - Zhen-Yu Qi
- Agricultural Experiment Station, Zhejiang UniversityHangzhou, China
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Zhang XY, Zhang X, Zhang Q, Pan XX, Yan LC, Ma XJ, Zhao WZ, Qi XT, Yin LP. Zea mays Fe deficiency-related 4 (ZmFDR4) functions as an iron transporter in the plastids of monocots. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:147-163. [PMID: 28103409 DOI: 10.1111/tpj.13482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 01/02/2017] [Accepted: 01/09/2017] [Indexed: 05/25/2023]
Abstract
Iron (Fe)-homeostasis in the plastids is closely associated with Fe transport proteins that prevent Fe from occurring in its toxic free ionic forms. However, the number of known protein families related to Fe transport in the plastids (about five) and the function of iron in non-green plastids is limited. In the present study, we report the functional characterization of Zea mays Fe deficiency-related 4 (ZmFDR4), which was isolated from a differentially expressed clone of a cDNA library of Fe deficiency-induced maize roots. ZmFDR4 is homologous to the bacterial FliP superfamily, coexisted in both algae and terrestrial plants, and capable of restoring the normal growth of the yeast mutant fet3fet4, which possesses defective Fe uptake systems. ZmFDR4 mRNA is ubiquitous in maize and is inducible by iron deficiency in wheat. Transient expression of the 35S:ZmFDR4-eGFP fusion protein in rice protoplasts indicated that ZmFDR4 maybe localizes to the plastids envelope and thylakoid. In 35S:c-Myc-ZmFDR4 transgenic tobacco, immunohistochemistry and immunoblotting confirmed that ZmFDR4 is targeted to both the chloroplast envelope and thylakoid. Meanwhile, ultrastructure analysis indicates that ZmFDR4 promotes the density of plastids and accumulation of starch grains. Moreover, Bathophenanthroline disulfonate (BPDS) colorimetry and inductively coupled plasma mass spectrometry (ICP-MS) indicate that ZmFDR4 is related to Fe uptake by plastids and increases seed Fe content. Finally, 35S:c-Myc-ZmFDR4 transgenic tobacco show enhanced photosynthetic efficiency. Therefore, the results of the present study demonstrate that ZmFDR4 functions as an iron transporter in monocot plastids and provide insight into the process of Fe uptake by plastids.
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Affiliation(s)
- Xiu-Yue Zhang
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xi Zhang
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Qi Zhang
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xiao-Xi Pan
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Luo-Chen Yan
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xiao-Juan Ma
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Wei-Zhong Zhao
- Institute of Mathematics and Interdisciplinary Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Xiao-Ting Qi
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
| | - Li-Ping Yin
- College of Life Sciences, Capital Normal University, No. 105 Xisanhuan North Street, Haidian District, Beijing, 100048, China
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