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Pittman JK, Hirschi KD. CAX control: multiple roles of vacuolar cation/H + exchangers in metal tolerance, mineral nutrition and environmental signalling. PLANT BIOLOGY (STUTTGART, GERMANY) 2024. [PMID: 39030923 DOI: 10.1111/plb.13698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Accepted: 06/16/2024] [Indexed: 07/22/2024]
Abstract
Plant vacuolar transporters, particularly CAX (Cation/H+ Exchangers) responsible for Ca2+/H+ exchange on the vacuole tonoplast, play a central role in governing cellular pH, ion balance, nutrient storage, metal accumulation, and stress responses. Furthermore, CAX variants have been employed to enhance the calcium content of crops, contributing to biofortification efforts. Recent research has uncovered the broader significance of these transporters in plant signal transduction and element partitioning. The use of genetically encoded Ca2+ sensors has begun to highlight the crucial role of CAX isoforms in generating cytosolic Ca2+ signals, underscoring their function as pivotal hubs in diverse environmental and developmental signalling networks. Interestingly, it has been observed that the loss of CAX function can be advantageous in specific stress conditions, both for biotic and abiotic stressors. Determining the optimal timing and approach for modulating the expression of CAX is a critical concern. In the future, strategically manipulating the temporal loss of CAX function in agriculturally important crops holds promise to bolster plant immunity, enhance cold tolerance, and fortify resilience against one of agriculture's most significant challenges, namely flooding.
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Affiliation(s)
- J K Pittman
- Department of Earth and Environmental Sciences, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - K D Hirschi
- Children's Nutrition Research, Baylor College of Medicine, Houston, TX, USA
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2
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Guan Q, David L, Moran R, Grela I, Ortega A, Scott P, Warnock L, Chen S. Role of NPR1 in Systemic Acquired Stomatal Immunity. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12112137. [PMID: 37299116 DOI: 10.3390/plants12112137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/21/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023]
Abstract
Stomatal immunity is the primary gate of the plant pathogen defense system. Non-expressor of Pathogenesis Related 1 (NPR1) is the salicylic acid (SA) receptor, which is critical for stomatal defense. SA induces stomatal closure, but the specific role of NPR1 in guard cells and its contribution to systemic acquired resistance (SAR) remain largely unknown. In this study, we compared the response to pathogen attack in wild-type Arabidopsis and the npr1-1 knockout mutant in terms of stomatal movement and proteomic changes. We found that NPR1 does not regulate stomatal density, but the npr1-1 mutant failed to close stomata when under pathogen attack, resulting in more pathogens entering the leaves. Moreover, the ROS levels in the npr1-1 mutant were higher than in the wild type, and several proteins involved in carbon fixation, oxidative phosphorylation, glycolysis, and glutathione metabolism were differentially changed in abundance. Our findings suggest that mobile SAR signals alter stomatal immune response possibly by initiating ROS burst, and the npr1-1 mutant has an alternative priming effect through translational regulation.
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Affiliation(s)
- Qijie Guan
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA
| | - Lisa David
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Riley Moran
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Ivan Grela
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Angelica Ortega
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Peter Scott
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Lindsey Warnock
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Sixue Chen
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
- University of Florida Genetics Institue (UFGI), University of Florida, Gainesville, FL 32610, USA
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32610, USA
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3
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Identification and validation of candidate genes for high calcium content in finger millet [Eleusine coracana (L.) Gaertn.] through genome-wide association study. J Cereal Sci 2022. [DOI: 10.1016/j.jcs.2022.103517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Hao P, Lv X, Fu M, Xu Z, Tian J, Wang Y, Zhang X, Xu X, Wu T, Han Z. Long-distance mobile mRNA CAX3 modulates iron uptake and zinc compartmentalization. EMBO Rep 2022; 23:e53698. [PMID: 35254714 PMCID: PMC9066076 DOI: 10.15252/embr.202153698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 01/25/2022] [Accepted: 02/24/2022] [Indexed: 12/15/2022] Open
Abstract
Iron deficiency in plants can lead to excessive absorption of zinc; however, important details of this mechanism have yet to be elucidated. Here, we report that MdCAX3 mRNA is transported from the leaf to the root, and that MdCAX3 is then activated by MdCXIP1. Suppression of MdCAX3 expression leads to an increase in the root apoplastic pH, which is associated with the iron deficiency response. Notably, overexpression of MdCAX3 does not affect the apoplastic pH in a MdCXIP1 loss-of-function Malus baccata (Mb) mutant that has a deletion in the MdCXIP1 promoter. This deletion in Mb weakens MdCXIP1 expression. Co-expression of MdCAX3 and MdCXIP1 in Mb causes a decrease in the root apoplastic pH. Furthermore, suppressing MdCAX3 in Malus significantly reduces zinc vacuole compartmentalization. We also show that MdCAX3 activated by MdCXIP1 is not only involved in iron uptake, but also in regulating zinc detoxification by compartmentalizing zinc in vacuoles to avoid iron starvation-induced zinc toxicity. Thus, mobile MdCAX3 mRNA is involved in the regulation of iron and zinc homeostasis in response to iron starvation.
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Affiliation(s)
- Pengbo Hao
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Xinmin Lv
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Mengmeng Fu
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Zhen Xu
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Ji Tian
- Plant Science and Technology College, Beijing University of Agriculture, Beijing, China
| | - Yi Wang
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Xinzhong Zhang
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Xuefeng Xu
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Ting Wu
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
| | - Zhenhai Han
- State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, China
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Song X, Yang X, Ying Z, Zhang H, Liu J, Liu Q. Identification and Function of Apicoplast Glutaredoxins in Neospora caninum. Int J Mol Sci 2021; 22:ijms222111946. [PMID: 34769376 PMCID: PMC8584781 DOI: 10.3390/ijms222111946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/28/2021] [Accepted: 11/02/2021] [Indexed: 01/09/2023] Open
Abstract
Glutaredoxins (GRXs), important components of the intracellular thiol redox system, are involved in multiple cellular processes. In a previous study, we identified five GRXs in the apicomplexan parasite, Neospora caninum. In the present study, we confirmed that the GRXs S14 and C5 are located in the apicoplast, which suggests unique functions for these proteins. Although single-gene deficiency did not affect the growth of parasites, a double knockout (Δgrx S14Δgrx C5) significantly reduced their reproductive capacity. However, there were no significant changes in redox indices (GSH/GSSG ratio, reactive oxygen species and hydroxyl radical levels) in double-knockout parasites, indicating that grx S14 and grx C5 are not essential for maintaining the redox balance in parasite cells. Key amino acid mutations confirmed that the Cys203 of grx S14 and Cys253/256 of grx C5 are important for parasite growth. Based on comparative proteomics, 79 proteins were significantly downregulated in double-knockout parasites, including proteins mainly involved in the electron transport chain, the tricarboxylic acid cycle and protein translation. Collectively, GRX S14 and GRX C5 coordinate the growth of parasites. However, considering their special localization, the unique functions of GRX S14 and GRX C5 need to be further studied.
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Affiliation(s)
- Xingju Song
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China; (X.S.); (X.Y.); (Z.Y.); (H.Z.); (J.L.)
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Xu Yang
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China; (X.S.); (X.Y.); (Z.Y.); (H.Z.); (J.L.)
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Zhu Ying
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China; (X.S.); (X.Y.); (Z.Y.); (H.Z.); (J.L.)
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Heng Zhang
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China; (X.S.); (X.Y.); (Z.Y.); (H.Z.); (J.L.)
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Jing Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China; (X.S.); (X.Y.); (Z.Y.); (H.Z.); (J.L.)
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Qun Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China; (X.S.); (X.Y.); (Z.Y.); (H.Z.); (J.L.)
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Correspondence:
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Martins V, Gerós H. The grapevine CAX-interacting protein VvCXIP4 is exported from the nucleus to activate the tonoplast Ca 2+/H + exchanger VvCAX3. PLANTA 2020; 252:35. [PMID: 32767128 DOI: 10.1007/s00425-020-03442-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
The nuclear-localized CAX-interacting protein VvCXIP4 is exported to the cytosol after a Ca2+ pulse, to activate the tonoplast-localized Ca2+/H+ exchanger VvCAX3. Vacuolar cation/H+ exchangers (CAXs) have long been recognized as 'housekeeping' components in cellular Ca2+ and trace metal homeostasis, being involved in a range of key cellular and physiological processes. However, the mechanisms that drive functional activation of the transporters are largely unknown. In the present study, we investigated the function of a putative grapevine CAX-interacting protein, VvCXIP4, by testing its ability to activate VvCAX3, previously characterized as a tonoplast-localized Ca2+/H+ exchanger. VvCAX3 contains an autoinhibitory domain that drives inactivation of the transporter and thus, is incapable of suppressing the Ca2+-hypersensitive phenotype of the S. cerevisiae mutant K667. In this study, the co-expression of VvCXIP4 and VvCAX3 in this strain efficiently rescued its growth defect at high Ca2+ levels. Flow cytometry experiments showed that yeast harboring both proteins effectively accumulated higher Ca2+ levels than cells expressing each of the proteins separately. Bimolecular fluorescence complementation (BiFC) assays allowed visualization of the direct interaction between the proteins in tobacco plants and in yeast, and also showed the self-interaction of VvCAX3 but not of VvCXIP4. Subcellular localization studies showed that, despite being primarily localized to the nucleus, VvCXIP4 is able to move to other cell compartments upon a Ca2+ stimulus, becoming prone to interaction with the tonoplast-localized VvCAX3. qPCR analysis showed that both genes are more expressed in grapevine stems and leaves, followed by the roots, and that the steady-state transcript levels were higher in the pulp than in the skin of grape berries. Also, both VvCXIP4 and VvCAX3 were upregulated by Ca2+ and Na+, indicating they share common regulatory mechanisms. However, VvCXIP4 was also upregulated by Li+, Cu2+ and Mn2+, and its expression increased steadily throughout grape berry development, contrary to VvCAX3, suggesting additional physiological roles for VvCXIP4, including the regulation of VvCAXs not yet functionally characterized. The main novelty of the present study was the demonstration of physical interaction between CXIP and CAX proteins from a woody plant model by BiFC assays, demonstrating the intracellular mobilization of CXIPs in response to Ca2+.
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Affiliation(s)
- Viviana Martins
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-Os-Montes and Alto Douro, 5001-801, Vila Real, Portugal.
| | - Hernâni Gerós
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-Os-Montes and Alto Douro, 5001-801, Vila Real, Portugal
- Centre of Biological Engineering (CEB), Department of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
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Valassakis C, Dervisi I, Agalou A, Papandreou N, Kapetsis G, Podia V, Haralampidis K, Iconomidou VA, Spaink HP, Roussis A. Novel interactions of Selenium Binding Protein family with the PICOT containing proteins AtGRXS14 and AtGRXS16 in Arabidopsis thaliana. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 281:102-112. [PMID: 30824043 DOI: 10.1016/j.plantsci.2019.01.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
During abiotic stress the primary symptom of phytotoxicity can be ROS production which is strictly regulated by ROS scavenging pathways involving enzymatic and non-enzymatic antioxidants. Furthermore, ROS are well-described secondary messengers of cellular processes, while during the course of evolution, plants have accomplished high degree of control over ROS and used them as signalling molecules. Glutaredoxins (GRXs) are small and ubiquitous glutathione (GSH) -or thioredoxin reductase (TR)-dependent oxidoreductases belonging to the thioredoxin (TRX) superfamily which are conserved in most eukaryotes and prokaryotes. In Arabidopsis thaliana GRXs are subdivided into four classes playing a central role in oxidative stress responses and physiological functions. In this work, we describe a novel interaction of AtGRXS14 with the Selenium Binding Protein 1 (AtSBP1), a protein proposed to be integrated in a regulatory network that senses alterations in cellular redox state and acts towards its restoration. We further show that SBP protein family interacts with AtGRXS16 that also contains a PICOT domain, like AtGRXS14.
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Affiliation(s)
- Chrysanthi Valassakis
- Department of Botany, Faculty of Biology, National & Kapodistrian University of Athens, 15784, Athens, Greece
| | - Irene Dervisi
- Department of Botany, Faculty of Biology, National & Kapodistrian University of Athens, 15784, Athens, Greece
| | - Adamantia Agalou
- Institute of Biology, Leiden University, Leiden, the Netherlands
| | - Nikolaos Papandreou
- Department of Cell Biology and Biophysics, Faculty of Biology, National & Kapodistrian University, 15784, Athens, Greece
| | - Georgios Kapetsis
- Department of Botany, Faculty of Biology, National & Kapodistrian University of Athens, 15784, Athens, Greece
| | - Varvara Podia
- Department of Botany, Faculty of Biology, National & Kapodistrian University of Athens, 15784, Athens, Greece
| | - Kosmas Haralampidis
- Department of Botany, Faculty of Biology, National & Kapodistrian University of Athens, 15784, Athens, Greece
| | - Vassiliki A Iconomidou
- Department of Cell Biology and Biophysics, Faculty of Biology, National & Kapodistrian University, 15784, Athens, Greece
| | - Herman P Spaink
- Institute of Biology, Leiden University, Leiden, the Netherlands
| | - Andreas Roussis
- Department of Botany, Faculty of Biology, National & Kapodistrian University of Athens, 15784, Athens, Greece.
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Chen S, Liu Y, Deng Y, Liu Y, Dong M, Tian Y, Sun H, Li Y. Cloning and functional analysis of the VcCXIP4 and VcYSL6 genes as Cd-regulating genes in blueberry. Gene 2019; 686:104-117. [PMID: 30391441 DOI: 10.1016/j.gene.2018.10.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 10/11/2018] [Accepted: 10/27/2018] [Indexed: 11/26/2022]
Abstract
Blueberries (Vaccinium ssp.) show relatively high resistance to pollution and have been reported to successfully colonize acid and heavy metal-contaminated soils. Blueberries were subjected to cadmium stress using a simulated pot-culture method. The intact CDS regions of VcCXIP4 and VcYSL6 were obtained, VcCXIP4 was located in the nucleus, while VcYSL6 was located in the chloroplast. Both genes were constructed into a modified plant expression vector pCambia1301 for tobacco transformation with agrobacterium infection methods. Results showed that VcCXIP4 did not function alone in regulating cadmium (Cd) transport. Cd content of Cd in the leaves of VcYSL6 transgenic tobacco by 15.57% under high Cd concentration. Both, VcCXIP4 and VcYSL6 genes were up-regulated under Cd stress. Blueberry primarily accumulated excess Cd in the root, but Cd content in the fruit was almost independent of Cd content in the soil. Further, the effect of soil Cd content on fruit Cd content was not significant. VcCXIP4 is likely to interact with other proteins to regulate excess Cd in blueberry, while VcYSL6 is a Cd transporter required for excess Cd detoxification in blueberry.
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Affiliation(s)
- Shaopeng Chen
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China; College of Agriculture, Jilin Agricultural Science and Technology University, Jilin 132101, PR China
| | - Yushan Liu
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Yu Deng
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Yue Liu
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Mei Dong
- College of Horticulture, Jilin Agricultural University, Changchun 130118, PR China
| | - Youwen Tian
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Haiyue Sun
- College of Horticulture, Jilin Agricultural University, Changchun 130118, PR China.
| | - Yadong Li
- College of Horticulture, Jilin Agricultural University, Changchun 130118, PR China.
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Jin W, Long Y, Fu C, Zhang L, Xiang J, Wang B, Li M. Ca 2+ imaging and gene expression profiling of Lonicera Confusa in response to calcium-rich environment. Sci Rep 2018; 8:7068. [PMID: 29728644 PMCID: PMC5935734 DOI: 10.1038/s41598-018-25611-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/26/2018] [Indexed: 12/30/2022] Open
Abstract
As a medicinal plant widely planted in southwest karst of China, the study of adaptation mechanisms of Lonicera confusa, especially to karst calcium-rich environment, can provide important theoretical basis for repairing desertification by genetic engineering. In this study, the Ca2+ imaging in the leaves of L. confusa was explored by LSCM (Laser Scanning Confocal Microscopy) and TEM (Transmission Electron Microscopy), which revealed that the calcium could be transported to gland, epidermal hair and stoma in the leaves of L. confusa in high-Ca2+ environment. In addition, we simulated the growth environment of L. confusa and identified DEGs (Differentially Expressed Genes) under different Ca2+ concentrations by RNA sequencing. Further analysis showed that these DEGs were assigned with some important biological processes. Furthermore, a complex protein-protein interaction network among DEGs in L. Confusa was constructed and some important regulatory genes and transcription factors were identified. Taken together, this study displayed the Ca2+ transport and the accumulation of Ca2+ channels and pools in L. Confusa with high-Ca2+ treatment. Moreover, RNA sequencing provided a global picture of differential gene expression patterns in L. Confusa with high-Ca2+ treatment, which will help to reveal the molecular mechanism of the adaptation of L. confusa to high-Ca2+ environment in the future.
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Affiliation(s)
- Wenwen Jin
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.,Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, Hubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie Mountains, Huanggang Normal University, Huanggang, 438000, China
| | - Yan Long
- Institute of Biotechnology, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Chunhua Fu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Libin Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Jun Xiang
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, Hubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie Mountains, Huanggang Normal University, Huanggang, 438000, China.
| | - Baoshan Wang
- College of Life Science, Shandong Normal University, Jinan, 250000, China
| | - Maoteng Li
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.,Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, Hubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie Mountains, Huanggang Normal University, Huanggang, 438000, China
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10
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Lu Y. Assembly and Transfer of Iron-Sulfur Clusters in the Plastid. FRONTIERS IN PLANT SCIENCE 2018; 9:336. [PMID: 29662496 PMCID: PMC5890173 DOI: 10.3389/fpls.2018.00336] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/28/2018] [Indexed: 05/09/2023]
Abstract
Iron-Sulfur (Fe-S) clusters and proteins are essential to many growth and developmental processes. In plants, they exist in the plastids, mitochondria, cytosol, and nucleus. Six types of Fe-S clusters are found in the plastid: classic 2Fe-2S, NEET-type 2Fe-2S, Rieske-type 2Fe-2S, 3Fe-4S, 4Fe-4S, and siroheme 4Fe-4S. Classic, NEET-type, and Rieske-type 2Fe-2S clusters have the same 2Fe-2S core; similarly, common and siroheme 4Fe-4S clusters have the same 4Fe-4S core. Plastidial Fe-S clusters are assembled by the sulfur mobilization (SUF) pathway, which contains cysteine desulfurase (EC 2.8.1.7), sulfur transferase (EC 2.8.1.3), Fe-S scaffold complex, and Fe-S carrier proteins. The plastidial cysteine desulfurase-sulfur transferase-Fe-S-scaffold complex system is responsible for de novo assembly of all plastidial Fe-S clusters. However, different types of Fe-S clusters are transferred to recipient proteins via respective Fe-S carrier proteins. This review focuses on recent discoveries on the molecular functions of different assembly and transfer factors involved in the plastidial SUF pathway. It also discusses potential points for regulation of the SUF pathway, relationships among the plastidial, mitochondrial, and cytosolic Fe-S assembly and transfer pathways, as well as several open questions about the carrier proteins for Rieske-type 2Fe-2S, NEET-type 2Fe-2S, and 3F-4S clusters.
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Pham K, Dong J, Jiang X, Qu Y, Yu H, Yang Y, Olea W, Marini JC, Chan L, Wang J, Wehrens XHT, Cui X, Li Y, Hadsell DL, Cheng N. Loss of glutaredoxin 3 impedes mammary lobuloalveolar development during pregnancy and lactation. Am J Physiol Endocrinol Metab 2017; 312:E136-E149. [PMID: 27894063 PMCID: PMC5374299 DOI: 10.1152/ajpendo.00150.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 10/26/2016] [Accepted: 11/14/2016] [Indexed: 12/20/2022]
Abstract
Mammalian glutaredoxin 3 (Grx3) has been shown to be important for regulating cellular redox homeostasis in the cell. Our previous studies indicate that Grx3 is significantly overexpressed in various human cancers including breast cancer and demonstrate that Grx3 controls cancer cell growth and invasion by regulating reactive oxygen species (ROS) and NF-κB signaling pathways. However, it remains to be determined whether Grx3 is required for normal mammary gland development and how it contributes to epithelial cell proliferation and differentiation in vivo. In the present study, we examined Grx3 expression in different cell types within the developing mouse mammary gland (MG) and found enhanced expression of Grx3 at pregnancy and lactation stages. To assess the physiological role of Grx3 in MG, we generated the mutant mice in which Grx3 was deleted specifically in mammary epithelial cells (MECs). Although the reduction of Grx3 expression had only minimal effects on mammary ductal development in virgin mice, it did reduce alveolar density during pregnancy and lactation. The impairment of lobuloalveolar development was associated with high levels of ROS accumulation and reduced expression of milk protein genes. In addition, proliferative gene expression was significantly suppressed with proliferation defects occurring in knockout MECs during alveolar development compared with wild-type controls. Therefore, our findings suggest that Grx3 is a key regulator of ROS in vivo and is involved in pregnancy-dependent mammary gland development and secretory activation through modulating cellular ROS.
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Affiliation(s)
- Khanh Pham
- USDA/ARS Children Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Jie Dong
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas
| | - Xiqian Jiang
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas
| | - Ying Qu
- Department of Surgery, Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai Medical Center, Los Angeles, California
| | - Han Yu
- USDA/ARS Children Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Yisheng Yang
- Department of Medicine, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio
| | - Walter Olea
- USDA/ARS Children Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Juan C Marini
- Section of Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Lawrence Chan
- Department of Medicine, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Jin Wang
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas
- Center for Drug Discovery, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas; and
| | - Xander H T Wehrens
- USDA/ARS Children Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
- Department of Medicine, Baylor College of Medicine, Houston, Texas
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas; and
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, Texas
| | - Xiaojiang Cui
- Department of Surgery, Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai Medical Center, Los Angeles, California
| | - Yi Li
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Darryl L Hadsell
- USDA/ARS Children Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Ninghui Cheng
- USDA/ARS Children Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas;
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas; and
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12
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Pham K, Pal R, Qu Y, Liu X, Yu H, Shiao SL, Wang X, O'Brian Smith E, Cui X, Rodney GG, Cheng N. Nuclear glutaredoxin 3 is critical for protection against oxidative stress-induced cell death. Free Radic Biol Med 2015; 85:197-206. [PMID: 25975981 PMCID: PMC4902114 DOI: 10.1016/j.freeradbiomed.2015.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 04/17/2015] [Accepted: 05/01/2015] [Indexed: 01/12/2023]
Abstract
Mammalian glutaredoxin 3 (Grx3) has been shown to be critical in maintaining redox homeostasis and regulating cell survival pathways in cancer cells. However, the regulation of Grx3 is not fully understood. In the present study, we investigate the subcellular localization of Grx3 under normal growth and oxidative stress conditions. Both fluorescence imaging of Grx3-RFP fusion and Western blot analysis of cellular fractionation indicate that Grx3 is predominantly localized in the cytoplasm under normal growth conditions, whereas under oxidizing conditions, Grx3 is translocated into and accumulated in the nucleus. Grx3 nuclear accumulation was reversible in a redox-dependent fashion. Further analysis indicates that neither the N-terminal Trx-like domain nor the two catalytic cysteine residues in the active CGFS motif of Grx3 are involved in its nuclear translocation. Decreased levels of Grx3 render cells susceptible to cellular oxidative stress, whereas overexpression of nuclear-targeted Grx3 is sufficient to suppress cells' sensitivity to oxidant treatments and reduce reactive oxygen species production. These findings provide novel insights into the regulation of Grx3, which is crucial for cell survival against environmental insults.
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Affiliation(s)
- Khanh Pham
- USDA/ARS Children׳s Nutrition Research Center, Department of Pediatrics, Houston, TX 77030, USA
| | - Rituraj Pal
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ying Qu
- Department of Surgery and Department of Obstetrics and Gynecology, Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Xi Liu
- Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Han Yu
- USDA/ARS Children׳s Nutrition Research Center, Department of Pediatrics, Houston, TX 77030, USA
| | - Stephen L Shiao
- Radiation Oncology and Biochemical Sciences, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Xinquan Wang
- Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - E O'Brian Smith
- USDA/ARS Children׳s Nutrition Research Center, Department of Pediatrics, Houston, TX 77030, USA
| | - Xiaojiang Cui
- Department of Surgery and Department of Obstetrics and Gynecology, Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA.
| | - George G Rodney
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ninghui Cheng
- USDA/ARS Children׳s Nutrition Research Center, Department of Pediatrics, Houston, TX 77030, USA.
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13
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Wang L, Li Y, Jacquot JP, Rouhier N, Xia B. Characterization of poplar GrxS14 in different structural forms. Protein Cell 2014; 5:329-33. [PMID: 24639280 PMCID: PMC3996159 DOI: 10.1007/s13238-014-0042-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Lei Wang
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, 100871, China
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14
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Structural insights into the N-terminal GIY-YIG endonuclease activity of Arabidopsis glutaredoxin AtGRXS16 in chloroplasts. Proc Natl Acad Sci U S A 2013; 110:9565-70. [PMID: 23690600 DOI: 10.1073/pnas.1306899110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Glutaredoxins (Grxs) have been identified across taxa as important mediators in various physiological functions. A chloroplastic monothiol glutaredoxin, AtGRXS16 from Arabidopsis thaliana, comprises two distinct functional domains, an N-terminal domain (NTD) with GlyIleTyr-TyrIleGly (GIY-YIG) endonuclease motif and a C-terminal Grx module, to coordinate redox regulation and DNA cleavage in chloroplasts. Structural determination of AtGRXS16-NTD showed that it possesses a GIY-YIG endonuclease fold, but the critical residues for the nuclease activity are different from typical GIY-YIG endonucleases. AtGRXS16-NTD was able to cleave λDNA and chloroplast genomic DNA, and the nuclease activity was significantly reduced in AtGRXS16. Functional analysis indicated that AtGRXS16-NTD could inhibit the ability of AtGRXS16 to suppress the sensitivity of yeast grx5 cells to oxidative stress; however, the C-terminal Grx domain itself and AtGRXS16 with a Cys123Ser mutation were active in these cells and able to functionally complement a Grx5 deficiency in yeast. Furthermore, the two functional domains were shown to be negatively regulated through the formation of an intramolecular disulfide bond. These findings unravel a manner of regulation for Grxs and provide insights into the mechanistic link between redox regulation and DNA metabolism in chloroplasts.
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15
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Leal Valentim F, Neven F, Boyen P, van Dijk ADJ. Interactome-wide prediction of protein-protein binding sites reveals effects of protein sequence variation in Arabidopsis thaliana. PLoS One 2012; 7:e47022. [PMID: 23077539 PMCID: PMC3471968 DOI: 10.1371/journal.pone.0047022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 09/07/2012] [Indexed: 11/18/2022] Open
Abstract
The specificity of protein-protein interactions is encoded in those parts of the sequence that compose the binding interface. Therefore, understanding how changes in protein sequence influence interaction specificity, and possibly the phenotype, requires knowing the location of binding sites in those sequences. However, large-scale detection of protein interfaces remains a challenge. Here, we present a sequence- and interactome-based approach to mine interaction motifs from the recently published Arabidopsis thaliana interactome. The resultant proteome-wide predictions are available via www.ab.wur.nl/sliderbio and set the stage for further investigations of protein-protein binding sites. To assess our method, we first show that, by using a priori information calculated from protein sequences, such as evolutionary conservation and residue surface accessibility, we improve the performance of interface prediction compared to using only interactome data. Next, we present evidence for the functional importance of the predicted sites, which are under stronger selective pressure than the rest of protein sequence. We also observe a tendency for compensatory mutations in the binding sites of interacting proteins. Subsequently, we interrogated the interactome data to formulate testable hypotheses for the molecular mechanisms underlying effects of protein sequence mutations. Examples include proteins relevant for various developmental processes. Finally, we observed, by analysing pairs of paralogs, a correlation between functional divergence and sequence divergence in interaction sites. This analysis suggests that large-scale prediction of binding sites can cast light on evolutionary processes that shape protein-protein interaction networks.
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Affiliation(s)
| | - Frank Neven
- Hasselt University and Transnational University of Limburg, Hasselt, Belgium
| | - Peter Boyen
- Hasselt University and Transnational University of Limburg, Hasselt, Belgium
| | - Aalt D. J. van Dijk
- Plant Research International, Bioscience, Wageningen, The Netherlands
- * E-mail:
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16
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Meyer Y, Belin C, Delorme-Hinoux V, Reichheld JP, Riondet C. Thioredoxin and glutaredoxin systems in plants: molecular mechanisms, crosstalks, and functional significance. Antioxid Redox Signal 2012; 17:1124-60. [PMID: 22531002 DOI: 10.1089/ars.2011.4327] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Thioredoxins (Trx) and glutaredoxins (Grx) constitute families of thiol oxidoreductases. Our knowledge of Trx and Grx in plants has dramatically increased during the last decade. The release of the Arabidopsis genome sequence revealed an unexpectedly high number of Trx and Grx genes. The availability of several genomes of vascular and nonvascular plants allowed the establishment of a clear classification of the genes and the chronology of their appearance during plant evolution. Proteomic approaches have been developed that identified the putative Trx and Grx target proteins which are implicated in all aspects of plant growth, including basal metabolism, iron/sulfur cluster formation, development, adaptation to the environment, and stress responses. Analyses of the biochemical characteristics of specific Trx and Grx point to a strong specificity toward some target enzymes, particularly within plastidial Trx and Grx. In apparent contradiction with this specificity, genetic approaches show an absence of phenotype for most available Trx and Grx mutants, suggesting that redundancies also exist between Trx and Grx members. Despite this, the isolation of mutants inactivated in multiple genes and several genetic screens allowed the demonstration of the involvement of Trx and Grx in pathogen response, phytohormone pathways, and at several control points of plant development. Cytosolic Trxs are reduced by NADPH-thioredoxin reductase (NTR), while the reduction of Grx depends on reduced glutathione (GSH). Interestingly, recent development integrating biochemical analysis, proteomic data, and genetics have revealed an extensive crosstalk between the cytosolic NTR/Trx and GSH/Grx systems. This crosstalk, which occurs at multiple levels, reveals the high plasticity of the redox systems in plants.
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Affiliation(s)
- Yves Meyer
- Laboratoire Génome et Développement des Plantes, Université de Perpignan, Perpignan, France
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17
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Wu Q, Lin J, Liu JZ, Wang X, Lim W, Oh M, Park J, Rajashekar CB, Whitham SA, Cheng NH, Hirschi KD, Park S. Ectopic expression of Arabidopsis glutaredoxin AtGRXS17 enhances thermotolerance in tomato. PLANT BIOTECHNOLOGY JOURNAL 2012; 10:945-55. [PMID: 22762155 DOI: 10.1111/j.1467-7652.2012.00723.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
While various signalling networks regulate plant responses to heat stress, the mechanisms regulating and unifying these diverse biological processes are largely unknown. Our previous studies indicate that the Arabidopsis monothiol glutaredoxin, AtGRXS17, is crucial for temperature-dependent postembryonic growth in Arabidopsis. In the present study, we further demonstrate that AtGRXS17 has conserved functions in anti-oxidative stress and thermotolerance in both yeast and plants. In yeast, AtGRXS17 co-localized with yeast ScGrx3 in the nucleus and suppressed the sensitivity of yeast grx3grx4 double-mutant cells to oxidative stress and heat shock. In plants, GFP-AtGRXS17 fusion proteins initially localized in the cytoplasm and the nuclear envelope but migrated to the nucleus during heat stress. Ectopic expression of AtGRXS17 in tomato plants minimized photo-oxidation of chlorophyll and reduced oxidative damage of cell membrane systems under heat stress. This enhanced thermotolerance correlated with increased catalase (CAT) enzyme activity and reduced H₂O₂ accumulation in AtGRXS17-expressing tomatoes. Furthermore, during heat stress, expression of the heat shock transcription factor (HSF) and heat shock protein (HSP) genes was up-regulated in AtGRXS17-expressing transgenic plants compared with wild-type controls. Thus, these findings suggest a specific protective role of a redox protein against temperature stress and provide a genetic engineering strategy to improve crop thermotolerance.
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Affiliation(s)
- Qingyu Wu
- Department of Horticulture, Forestry and Recreation Resources, Kansas State University, Manhattan, KS, USA
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18
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Noctor G, Mhamdi A, Chaouch S, Han Y, Neukermans J, Marquez-Garcia B, Queval G, Foyer CH. Glutathione in plants: an integrated overview. PLANT, CELL & ENVIRONMENT 2012; 35:454-84. [PMID: 21777251 DOI: 10.1111/j.1365-3040.2011.02400.x] [Citation(s) in RCA: 791] [Impact Index Per Article: 65.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants cannot survive without glutathione (γ-glutamylcysteinylglycine) or γ-glutamylcysteine-containing homologues. The reasons why this small molecule is indispensable are not fully understood, but it can be inferred that glutathione has functions in plant development that cannot be performed by other thiols or antioxidants. The known functions of glutathione include roles in biosynthetic pathways, detoxification, antioxidant biochemistry and redox homeostasis. Glutathione can interact in multiple ways with proteins through thiol-disulphide exchange and related processes. Its strategic position between oxidants such as reactive oxygen species and cellular reductants makes the glutathione system perfectly configured for signalling functions. Recent years have witnessed considerable progress in understanding glutathione synthesis, degradation and transport, particularly in relation to cellular redox homeostasis and related signalling under optimal and stress conditions. Here we outline the key recent advances and discuss how alterations in glutathione status, such as those observed during stress, may participate in signal transduction cascades. The discussion highlights some of the issues surrounding the regulation of glutathione contents, the control of glutathione redox potential, and how the functions of glutathione and other thiols are integrated to fine-tune photorespiratory and respiratory metabolism and to modulate phytohormone signalling pathways through appropriate modification of sensitive protein cysteine residues.
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Affiliation(s)
- Graham Noctor
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, Orsay cedex, France.
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19
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Riondet C, Desouris JP, Montoya JG, Chartier Y, Meyer Y, Reichheld JP. A dicotyledon-specific glutaredoxin GRXC1 family with dimer-dependent redox regulation is functionally redundant with GRXC2. PLANT, CELL & ENVIRONMENT 2012; 35:360-73. [PMID: 21767278 DOI: 10.1111/j.1365-3040.2011.02355.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The major known function of glutaredoxins (Grxs) is to reduce disulphide bridges. Recently, some have also been shown to interact with iron-sulphur clusters. These can be classified in two subgroups: class II Grx are found in all living organisms and are implicated in assembly of iron-sulphur clusters, while class I Grx are represented by only two members known to form a holodimer structure containing a cluster in vitro, but with an unknown function different from class II. Here, we report that in eukaryotic plants, GRXC1 (class I) orthologs are exclusively present in dicotyledonous plants, suggesting a specific function. Indeed, in Arabidopsis thaliana, reducing activity of recombinant GRXC1 is regulated by redox-dependent stability of the cluster. In planta, GRXC1 has been found predominantly in a holodimeric form, indicating the presence of the cluster in vivo. This suggests that GRXC1 acts as a redox sensor, reducing downstream pathways under oxidative conditions. GRXC2, the closest homolog of GRXC1, is unable to form a cluster in vitro. Knock-out mutants in grxc1 or grxc2 are aphenotypic, but the double mutant produces a lethal phenotype at an early stage after pollinization, suggesting that GRXC1 and GRXC2 share redundant and vital functions.
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Affiliation(s)
- Christophe Riondet
- Laboratoire Génome et Développement des Plantes, UMR 5096 CNRS-UPVD, 58 Avenue de Villeneuve - Bat T, 66860 Perpignan Cedex, France.
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20
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Differential transcript accumulation in chickpea during early phases of compatible interaction with a necrotrophic fungus Ascochyta rabiei. Mol Biol Rep 2011; 39:4635-46. [PMID: 21956755 DOI: 10.1007/s11033-011-1255-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 09/14/2011] [Indexed: 12/18/2022]
Abstract
The initial phases of the disease establishment are very crucial for the compatible interactions. Pathogens must overcome the responses generated by the host for the onset of disease invasion. The compatible interaction is inadequately represented in plant-pathogen interaction studies. To gain broader insight into the early responses elicited by chickpea blight fungus Ascochyta rabiei during compatible interaction; we isolated early responsive genes of chickpea using PCR based suppression subtractive hybridization (SSH) strategy. We obtained ~250 unique genes after homology search and redundancy elimination. Based on their potential cellular functions, these genes were broadly classified into eleven different categories viz. stress, signaling, gene regulation, cellular metabolism and genes of unknown functions. Present study revealed few unexpected genes which have a possible role in induced immunity and disease progression. We employed macroarray, northern blot, real-time PCR and cluster analysis to develop transcript profiles. Most of the genes analyzed were early induced and were transcriptionally upregulated upon 24 h post inoculation. Our approach has rendered the isolation of early responsive genes involved in signaling and regulation of metabolic changes upon fungal infection. The information obtained will help to dissect the molecular mechanisms during compatible chickpea-Ascochyta interactions.
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21
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Manohar M, Shigaki T, Mei H, Park S, Marshall J, Aguilar J, Hirschi KD. Characterization of Arabidopsis Ca2+/H+ exchanger CAX3. Biochemistry 2011; 50:6189-95. [PMID: 21657244 DOI: 10.1021/bi2003839] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Plant calcium (Ca(2+)) gradients, millimolar levels in the vacuole and micromolar levels in the cytoplasm, are regulated in part by high-capacity vacuolar cation/H(+) exchangers (CAXs). Several CAX transporters, including CAX1, appear to contain an approximately 40-amino acid N-terminal regulatory region (NRR) that modulates transport through N-terminal autoinhibition. Deletion of the NRR from several CAXs (sCAX) enhances function in plant and yeast expression assays; however, to date, there are no functional assays for CAX3 (or sCAX3), which is 77% identical and 91% similar in sequence to CAX1. In this report, we create a series of truncations in the CAX3 NRR and demonstrate activation of CAX3 in both yeast and plants by truncating a large portion (up to 90 amino acids) of the NRR. Experiments with endomembrane-enriched vesicles isolated from yeast expressing activated CAX3 demonstrate that the gene encodes Ca(2+)/H(+) exchange with properties distinct from those of CAX1. The phenotypes produced by activated CAX3-expressing in transgenic tobacco lines are also distinct from those produced by sCAX1-expressing plants. These studies demonstrate shared and unique aspects of CAX1 and CAX3 transport and regulation.
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Affiliation(s)
- Murli Manohar
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates Street, Houston, Texas 77030, United States
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22
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Cheng NH, Zhang W, Chen WQ, Jin J, Cui X, Butte NF, Chan L, Hirschi KD. A mammalian monothiol glutaredoxin, Grx3, is critical for cell cycle progression during embryogenesis. FEBS J 2011; 278:2525-2539. [PMID: 21575136 DOI: 10.1111/j.1742-4658.2011.08178.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Glutaredoxins (Grxs) have been shown to be critical in maintaining redox homeostasis in living cells. Recently, an emerging subgroup of Grxs with one cysteine residue in the putative active motif (monothiol Grxs) has been identified. However, the biological and physiological functions of this group of proteins have not been well characterized. Here, we characterize a mammalian monothiol Grx (Grx3, also termed TXNL2/PICOT) with high similarity to yeast ScGrx3/ScGrx4. In yeast expression assays, mammalian Grx3s were localized to the nuclei and able to rescue growth defects of grx3grx4 cells. Furthermore, Grx3 inhibited iron accumulation in yeast grx3gxr4 cells and suppressed the sensitivity of mutant cells to exogenous oxidants. In mice, Grx3 mRNA was ubiquitously expressed in developing embryos, adult tissues and organs, and was induced during oxidative stress. Mouse embryos absent of Grx3 grew smaller with morphological defects and eventually died at 12.5 days of gestation. Analysis in mouse embryonic fibroblasts revealed that Grx3(-/-) cells had impaired growth and cell cycle progression at the G(2) /M phase, whereas the DNA replication during the S phase was not affected by Grx3 deletion. Furthermore, Grx3-knockdown HeLa cells displayed a significant delay in mitotic exit and had a higher percentage of binucleated cells. Therefore, our findings suggest that the mammalian Grx3 has conserved functions in protecting cells against oxidative stress and deletion of Grx3 in mice causes early embryonic lethality which could be due to defective cell cycle progression during late mitosis.
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Affiliation(s)
- Ning-Hui Cheng
- United States Department of Agriculture / Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Wei Zhang
- Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Wei-Qin Chen
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Jianping Jin
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Xiaojiang Cui
- Department of Molecular Oncology, John Wayne Cancer Institute, Santa Monica, CA, USA
| | - Nancy F Butte
- United States Department of Agriculture / Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Lawrence Chan
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Kendal D Hirschi
- United States Department of Agriculture / Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
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23
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Noctor G, Queval G, Mhamdi A, Chaouch S, Foyer CH. Glutathione. THE ARABIDOPSIS BOOK 2011; 9:e0142. [PMID: 22303267 PMCID: PMC3267239 DOI: 10.1199/tab.0142] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Glutathione is a simple sulfur compound composed of three amino acids and the major non-protein thiol in many organisms, including plants. The functions of glutathione are manifold but notably include redox-homeostatic buffering. Glutathione status is modulated by oxidants as well as by nutritional and other factors, and can influence protein structure and activity through changes in thiol-disulfide balance. For these reasons, glutathione is a transducer that integrates environmental information into the cellular network. While the mechanistic details of this function remain to be fully elucidated, accumulating evidence points to important roles for glutathione and glutathione-dependent proteins in phytohormone signaling and in defense against biotic stress. Work in Arabidopsis is beginning to identify the processes that govern glutathione status and that link it to signaling pathways. As well as providing an overview of the components that regulate glutathione homeostasis (synthesis, degradation, transport, and redox turnover), the present discussion considers the roles of this metabolite in physiological processes such as light signaling, cell death, and defense against microbial pathogen and herbivores.
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Affiliation(s)
- Graham Noctor
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
| | - Guillaume Queval
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
- Present address: Department of Plant Systems Biology, Flanders Institute for Biotechnology and Department of Plant Biotechnologyand Genetics, Gent University, 9052 Gent, Belgium
| | - Amna Mhamdi
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
| | - Sejir Chaouch
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
| | - Christine H. Foyer
- Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds, LS2 9JT, UK
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24
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Pittman JK. Vacuolar Ca(2+) uptake. Cell Calcium 2011; 50:139-46. [PMID: 21310481 DOI: 10.1016/j.ceca.2011.01.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 12/31/2010] [Accepted: 01/03/2011] [Indexed: 12/22/2022]
Abstract
Calcium transporters that mediate the removal of Ca(2+) from the cytosol and into internal stores provide a critical role in regulating Ca(2+) signals following stimulus induction and in preventing calcium toxicity. The vacuole is a major calcium store in many organisms, particularly plants and fungi. Two main pathways facilitate the accumulation of Ca(2+) into vacuoles, Ca(2+)-ATPases and Ca(2+)/H(+) exchangers. Here I review the biochemical and regulatory features of these transporters that have been characterised in yeast and plants. These Ca(2+) transport mechanisms are compared with those being identified from other vacuolated organisms including algae and protozoa. Studies suggest that Ca(2+) uptake into vacuoles and other related acidic Ca(2+) stores occurs by conserved mechanisms which developed early in evolution.
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Affiliation(s)
- Jon K Pittman
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
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25
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Ca2+ Pumps and Ca2+ Antiporters in Plant Development. SIGNALING AND COMMUNICATION IN PLANTS 2011. [DOI: 10.1007/978-3-642-14369-4_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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26
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Dayod M, Tyerman SD, Leigh RA, Gilliham M. Calcium storage in plants and the implications for calcium biofortification. PROTOPLASMA 2010; 247:215-31. [PMID: 20658253 DOI: 10.1007/s00709-010-0182-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 07/06/2010] [Indexed: 05/20/2023]
Abstract
Calcium (Ca) is an essential nutrient for plants and animals, with key structural and signalling roles, and its deficiency in plants can result in poor biotic and abiotic stress tolerance, reduced crop quality and yield. Likewise, low Ca intake in humans has been linked to various diseases (e.g. rickets, osteoporosis, hypertension and colorectal cancer) which can threaten quality of life and have major economic costs. Biofortification of various food crops with Ca has been suggested as a good method to enhance human intake of Ca and is advocated as an economically and environmentally advantageous strategy. Efforts to enhance Ca content of crops via transgenic means have had promising results. Overall Ca content of transgenic plants has been increased but in some cases adverse affects on plant function have been observed. This suggests that a better understanding of how Ca ions (Ca(2+)) are stored and transported through plants is required to maximise the effectiveness of future approaches.
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Affiliation(s)
- Maclin Dayod
- Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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27
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Garg R, Jhanwar S, Tyagi AK, Jain M. Genome-wide survey and expression analysis suggest diverse roles of glutaredoxin gene family members during development and response to various stimuli in rice. DNA Res 2010; 17:353-67. [PMID: 21044985 PMCID: PMC2993539 DOI: 10.1093/dnares/dsq023] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Glutaredoxins (GRXs) are glutathione-dependent oxidoreductase enzymes involved in a variety of cellular processes. In this study, our analysis revealed the presence of 48 genes encoding GRX proteins in the rice genome. GRX proteins could be classified into four classes, namely CC-, CGFS-, CPYC- and GRL-type, based on phylogenetic analysis. The classification was supported with organization of predicted conserved putative motifs in GRX proteins. We found that expansion of this gene family has occurred largely via whole genome duplication events in a species-specific manner. We explored rice oligonucleotide array data to gain insights into the function of GRX gene family members during various stages of development and in response to environmental stimuli. The comprehensive expression analysis suggested diverse roles of GRX genes during growth and development in rice. Some of the GRX genes were expressed in specific organs/developmental stages only. The expression of many of rice GRX genes was influenced by various phytohormones, abiotic and biotic stress conditions, suggesting an important role of GRX proteins in response to these stimuli. The identification of GRX genes showing differential expression in specific tissues or in response to environmental stimuli provide a new avenue for in-depth characterization of selected genes of importance.
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Affiliation(s)
- Rohini Garg
- National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110 067, India
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Zhao J, Connorton JM, Guo Y, Li X, Shigaki T, Hirschi KD, Pittman JK. Functional studies of split Arabidopsis Ca2+/H+ exchangers. J Biol Chem 2009; 284:34075-83. [PMID: 19819871 PMCID: PMC2797178 DOI: 10.1074/jbc.m109.070235] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Indexed: 11/06/2022] Open
Abstract
In plants, high capacity tonoplast cation/H(+) antiport is mediated in part by a family of cation exchanger (CAX) transporters. Functional association between CAX1 and CAX3 has previously been shown. In this study we further examine the interactions between CAX protein domains through the use of nonfunctional halves of CAX transporters. We demonstrate that a protein coding for an N-terminal half of an activated variant of CAX1 (sCAX1) can associate with the C-terminal half of either CAX1 or CAX3 to form a functional transporter that may exhibit unique transport properties. Using yeast split ubiquitin, in planta bimolecular fluorescence complementation, and gel shift experiments, we demonstrate a physical interaction among the half proteins. Moreover, the half-proteins both independently localized to the same yeast endomembrane. Co-expressing variants of N- and C-terminal halves of CAX1 and CAX3 in yeast suggested that the N-terminal region mediates Ca(2+) transport, whereas the C-terminal half defines salt tolerance phenotypes. Furthermore, in yeast assays, auto-inhibited CAX1 could be differentially activated by CAX split proteins. The N-terminal half of CAX1 when co-expressed with CAX1 activated Ca(2+) transport, whereas co-expressing C-terminal halves of CAX variants with CAX1 conferred salt tolerance but no apparent Ca(2+) transport. These findings demonstrate plasticity through hetero-CAX complex formation as well as a novel means to engineer CAX transport.
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Affiliation(s)
- Jian Zhao
- From the United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030-2600
| | - James M. Connorton
- the Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom, and
| | - YingQing Guo
- From the United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030-2600
| | - Xiangkai Li
- From the United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030-2600
| | - Toshiro Shigaki
- From the United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030-2600
| | - Kendal D. Hirschi
- From the United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030-2600
- the Vegetable and Fruit Improvement Center, Texas A & M University, College Station, Texas 77845
| | - Jon K. Pittman
- the Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom, and
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Abstract
In numerous plant signal transduction pathways, Ca2+ is a versatile second messenger which controls the activation of many downstream actions in response to various stimuli. There is strong evidence to indicate that information encoded within these stimulus-induced Ca2+ oscillations can provide signalling specificity. Such Ca2+ signals, or 'Ca2+ signatures', are generated in the cytosol, and in noncytosolic locations including the nucleus and chloroplast, through the coordinated action of Ca2+ influx and efflux pathways. An increased understanding of the functions and regulation of these various Ca2+ transporters has improved our appreciation of the role these transporters play in specifically shaping the Ca2+ signatures. Here we review the evidence which indicates that Ca2+ channel, Ca2+-ATPase and Ca2+ exchanger isoforms can indeed modulate specific Ca2+ signatures in response to an individual signal.
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Affiliation(s)
- Martin R McAinsh
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK;Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Jon K Pittman
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK;Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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Morris J, Tian H, Park S, Sreevidya CS, Ward JM, Hirschi KD. AtCCX3 is an Arabidopsis endomembrane H+ -dependent K+ transporter. PLANT PHYSIOLOGY 2008; 148:1474-86. [PMID: 18775974 PMCID: PMC2577254 DOI: 10.1104/pp.108.118810] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 08/30/2008] [Indexed: 05/18/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) cation calcium exchangers (CCXs) were recently identified as a subfamily of cation transporters; however, no plant CCXs have been functionally characterized. Here, we show that Arabidopsis AtCCX3 (At3g14070) and AtCCX4 (At1g54115) can suppress yeast mutants defective in Na(+), K(+), and Mn(2+) transport. We also report high-capacity uptake of (86)Rb(+) in tonoplast-enriched vesicles from yeast expressing AtCCX3. Cation competition studies showed inhibition of (86)Rb(+) uptake in AtCCX3 cells by excess Na(+), K(+), and Mn(2+). Functional epitope-tagged AtCCX3 fusion proteins were localized to endomembranes in plants and yeast. In Arabidopsis, AtCCX3 is primarily expressed in flowers, while AtCCX4 is expressed throughout the plant. Quantitative polymerase chain reaction showed that expression of AtCCX3 increased in plants treated with NaCl, KCl, and MnCl(2). Insertional mutant lines of AtCCX3 and AtCCX4 displayed no apparent growth defects; however, overexpression of AtCCX3 caused increased Na(+) accumulation and increased (86)Rb(+) transport. Uptake of (86)Rb(+) increased in tonoplast-enriched membranes isolated from Arabidopsis lines expressing CCX3 driven by the cauliflower mosaic virus 35S promoter. Overexpression of AtCCX3 in tobacco (Nicotiana tabacum) produced lesions in the leaves, stunted growth, and resulted in the accumulation of higher levels of numerous cations. In summary, these findings suggest that AtCCX3 is an endomembrane-localized H(+)-dependent K(+) transporter with apparent Na(+) and Mn(2+) transport properties distinct from those of previously characterized plant transporters.
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Affiliation(s)
- Jay Morris
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, Texas 77845, USA
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31
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Meyer AJ. The integration of glutathione homeostasis and redox signaling. JOURNAL OF PLANT PHYSIOLOGY 2008; 165:1390-403. [PMID: 18171593 DOI: 10.1016/j.jplph.2007.10.015] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 10/10/2007] [Accepted: 10/11/2007] [Indexed: 05/23/2023]
Abstract
Formation of reactive oxygen species (ROS) is a common feature of abiotic and biotic stress reactions. ROS need to be detoxified to avoid deleterious reactions, but at the same time, the increased formation of ROS can also be exploited for redox signaling. Glutathione, as the most abundant low-molecular weight thiol in the cellular redox system, is used for both detoxification of ROS and transmission of redox signals. Detoxification of H(2)O(2) through the glutathione-ascorbate cycle leads to a transient change in the degree of oxidation of the cellular glutathione pool, and thus a change in the glutathione redox potential. The shift in the glutathione redox potential can be sensed by glutaredoxins (GRXs), small ubiquitous oxidoreductases, which reversibly transfer electrons between the glutathione redox buffer and thiol groups of target proteins. While very little is known about native GRX target proteins and their behavior in vivo, it is shown here that reduction-oxidation-sensitive GFP (roGFP), when expressed in plants, is an artificial target protein of GRXs. The specific interaction of roGFP with GRX results in continuous formation and release of the roGFP disulfide bridge depending on the actual redox potential of the cellular glutathione buffer. Ratiometric analysis of redox-dependent fluorescence allows dynamic imaging of the glutathione redox potential. It was hypothesized that a similar equilibration occurs between the glutathione buffer and native target proteins of GRXs. As a consequence, even minor deviations in the glutathione redox potential due to either depletion of reduced glutathione (GSH) or increasing oxidation can be exploited for fine tuning the activity of target proteins. The integration of the glutathione buffer with redox-active target proteins is a local reaction in specific subcellular compartments. This observation emphasizes the importance of subcellular compartmentalization in understanding the biology of the cellular redox system in plants.
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Affiliation(s)
- Andreas J Meyer
- Heidelberg Institute of Plant Sciences, University of Heidelberg, Heidelberg, Germany
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32
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Tripathi T, Rahlfs S, Becker K, Bhakuni V. Structural and stability characteristics of a monothiol glutaredoxin: Glutaredoxin-like protein 1 from Plasmodium falciparum. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:946-52. [DOI: 10.1016/j.bbapap.2008.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 03/26/2008] [Accepted: 03/28/2008] [Indexed: 01/16/2023]
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Sundaram S, Rathinasabapathi B, Ma LQ, Rosen BP. An arsenate-activated glutaredoxin from the arsenic hyperaccumulator fern Pteris vittata L. regulates intracellular arsenite. J Biol Chem 2007; 283:6095-101. [PMID: 18156657 DOI: 10.1074/jbc.m704149200] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To elucidate the mechanisms of arsenic resistance in the arsenic hyperaccumulator fern Pteris vittata L., a cDNA for a glutaredoxin (Grx) Pv5-6 was isolated from a frond expression cDNA library based on the ability of the cDNA to increase arsenic resistance in Escherichia coli. The deduced amino acid sequence of Pv5-6 showed high homology with an Arabidopsis chloroplastic Grx and contained two CXXS putative catalytic motifs. Purified recombinant Pv5-6 exhibited glutaredoxin activity that was increased 1.6-fold by 10 mm arsenate. Site-specific mutation of Cys(67) to Ala(67) resulted in the loss of both GRX activity and arsenic resistance. PvGrx5 was expressed in E. coli mutants in which the arsenic resistance genes of the ars operon were deleted (strain AW3110), a deletion of the gene for the ArsC arsenate reductase (strain WC3110), and a strain in which the ars operon was deleted and the gene for the GlpF aquaglyceroporin was disrupted (strain OSBR1). Expression of PvGrx5 increased arsenic tolerance in strains AW3110 and WC3110, but not in OSBR1, suggesting that PvGrx5 had a role in cellular arsenic resistance independent of the ars operon genes but dependent on GlpF. AW3110 cells expressing PvGrx5 had significantly lower levels of arsenite when compared with vector controls when cultured in medium containing 2.5 mm arsenate. Our results are consistent with PvGrx5 having a role in regulating intracellular arsenite levels, by either directly or indirectly modulating the aquaglyceroporin. To our knowledge, PvGrx5 is the first plant Grx implicated in arsenic metabolism.
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Affiliation(s)
- Sabarinath Sundaram
- Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, University of Florida, Gainesville, FL 32611-0690, USA
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Cheng NH, Liu JZ, Brock A, Nelson RS, Hirschi KD. AtGRXcp, an Arabidopsis chloroplastic glutaredoxin, is critical for protection against protein oxidative damage. J Biol Chem 2006; 281:26280-8. [PMID: 16829529 DOI: 10.1074/jbc.m601354200] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutaredoxins (Grxs) are ubiquitous small heat-stable disulfide oxidoreductases and members of the thioredoxin (Trx) fold protein family. In bacterial, yeast, and mammalian cells, Grxs appear to be involved in maintaining cellular redox homeostasis. However, in plants, the physiological roles of Grxs have not been fully characterized. Recently, an emerging subgroup of Grxs with one cysteine residue in the putative active motif (monothiol Grxs) has been identified but not well characterized. Here we demonstrate that a plant protein, AtGRXcp, is a chloroplast-localized monothiol Grx with high similarity to yeast Grx5. In yeast expression assays, AtGRXcp localized to the mitochondria and suppressed the sensitivity of yeast grx5 cells to H2O2 and protein oxidation. AtGRXcp expression can also suppress iron accumulation and partially rescue the lysine auxotrophy of yeast grx5 cells. Analysis of the conserved monothiol motif suggests that the cysteine residue affects AtGRXcp expression and stability. In planta, AtGRXcp expression was elevated in young cotyledons, green tissues, and vascular bundles. Analysis of atgrxcp plants demonstrated defects in early seedling growth under oxidative stresses. In addition, atgrxcp lines displayed increased protein carbonylation within chloroplasts. Thus, this work describes the initial functional characterization of a plant monothiol Grx and suggests a conserved biological function in protecting cells against protein oxidative damage.
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Affiliation(s)
- Ning-Hui Cheng
- Plant Physiology Group, United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
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35
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Shigaki T, Hirschi KD. Diverse functions and molecular properties emerging for CAX cation/H+ exchangers in plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2006; 8:419-29. [PMID: 16906482 DOI: 10.1055/s-2006-923950] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Steep concentration gradients of many ions are actively maintained, with lower concentrations typically located in the cytosol, and higher concentrations in organelles and outside the cell. The vacuole is an important storage organelle for many ions. The concentration gradient of cations is established across the plant tonoplast, in part, by high-capacity cation/H+ (CAX) exchange activity. While plants may not be green yeast, analysis of CAX regulation and substrate specificity has been greatly aided by utilizing yeast as an experimental tool. The basic CAX biology in ARABIDOPSIS has immediate relevance toward understanding the functional interplay between diverse transport processes. The long-range applied goals are to identify novel transporters and express them in crop plants in order to "mine" nutrients out of the soil and into plants. In doing so, this could boost the levels of essential nutrients in plants.
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Affiliation(s)
- T Shigaki
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA.
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36
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Schaaf G, Honsbein A, Meda AR, Kirchner S, Wipf D, von Wirén N. AtIREG2 encodes a tonoplast transport protein involved in iron-dependent nickel detoxification in Arabidopsis thaliana roots. J Biol Chem 2006; 281:25532-40. [PMID: 16790430 DOI: 10.1074/jbc.m601062200] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Iron acquisition in Arabidopsis depends mainly on AtIRT1, a Fe2+ transporter in the plasma membrane of root cells. However, substrate specificity of AtIRT1 is low, leading to an excess accumulation of other transition metals in iron-deficient plants. In the present study we describe AtIREG2 as a nickel transporter at the vacuolar membrane that counterbalances the low substrate specificity of AtIRT1 and possibly other iron transport systems in iron-deficient root cells. AtIREG2 is co-regulated with AtIRT1 by the transcription factor FRU/FIT1, encodes a membrane protein, which has 10 putative transmembrane domains and shares homology with vertebrate Fe2+ exporters. Heterologous expression of AtIREG2 in various yeast mutants, however, did not demonstrate an iron transport function. Instead, expression in wild-type and nickel-sensitive cot1 yeast cells conferred enhanced tolerance to elevated concentrations of nickel at acidic pH. A role in vacuolar substrate transport was further supported by localization of AtIREG2-GFP fusion proteins to the tonoplast in Arabidopsis suspension cells and root cells of intact plants. Transgenic plants overexpressing AtIREG2 showed an increased tolerance to elevated concentrations of nickel, whereas T-DNA insertion lines lacking AtIREG2 expression were more sensitive to nickel, particularly under iron deficiency, and accumulated less nickel in roots. We therefore propose a role of AtIREG2 in vacuolar loading of nickel under iron deficiency and thus identify it as a novel component in the iron deficiency stress response.
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Affiliation(s)
- Gabriel Schaaf
- Institut für Pflanzenernährung, Universität Hohenheim, 70593 Stuttgart, Germany
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37
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Noctor G. Metabolic signalling in defence and stress: the central roles of soluble redox couples. PLANT, CELL & ENVIRONMENT 2006; 29:409-25. [PMID: 17080595 DOI: 10.1111/j.1365-3040.2005.01476.x] [Citation(s) in RCA: 241] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Plant growth and development are driven by electron transfer reactions. Modifications of redox components are both monitored and induced by cells, and are integral to responses to environmental change. Key redox compounds in the soluble phase of the cell are NAD, NADP, glutathione and ascorbate--all of which interact strongly with reactive oxygen. This review takes an integrated view of the NAD(P)-glutathione-ascorbate network. These compounds are considered not as one-dimensional 'reductants' or 'antioxidants' but as redox couples that can act together to condition cellular redox tone or that can act independently to transmit specific information that tunes signalling pathways. Emphasis is placed on recent developments highlighting the complexity of redox-dependent defence reactions, and the importance of interactions between the reduction state of soluble redox couples and their concentration in mediating dynamic signalling in response to stress. Signalling roles are assessed within the context of interactions with reactive oxygen, phytohormones and calcium, and the biochemical reactions through which redox couples could be sensed are discussed.
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Affiliation(s)
- Graham Noctor
- Institut de Biotechnologie des Plantes, UMR CNRS 8618, Université de Paris XI, 91405 Orsay cedex, France.
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38
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Kamiya T, Akahori T, Ashikari M, Maeshima M. Expression of the vacuolar Ca2+/H+ exchanger, OsCAX1a, in rice: cell and age specificity of expression, and enhancement by Ca2+. PLANT & CELL PHYSIOLOGY 2006; 47:96-106. [PMID: 16275657 DOI: 10.1093/pcp/pci227] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Calcium is an essential macronutrient for plants and functions in signal transduction. Regulation of the cytosolic calcium concentration is required for normal cell growth. In calcium homeostasis in plant cells, Ca(2+)/H(+) exchangers are involved in Ca(2+) compartmentalization into intracellular compartments. Here, we examine the intracellular localization of a rice Ca(2+)/H(+) exchanger, OsCAX1a, fused to a green fluorescent protein and transiently expressed in onion epidermis and rice protoplasts. Green fluorescence was observed in the vacuolar membrane. After sucrose gradient centrifugation of the homogenate of rice plants, OsCAX1a was detected in the same fraction as the vacuolar membrane aquaporin gamma-TIP. We then quantified the mRNA and protein of OsCAX1a in plants grown with metal ions. OsCAX1a mRNA was induced in roots by high concentrations of Ca(2+). The protein level in shoots was also increased in the presence of high concentrations of Ca(2+). Furthermore, transgenic rice plants transformed with the OsCAX1a promoter fused to beta-glucuronidase showed reporter expression in vascular bundles, stomata, trichomes, steles, flowers, embryos and aleurone layers. In the case of stomata and trichomes, transcription of OsCAX1a was particularly high in aged organs. These results suggest that OsCAX1a transports Ca(2+) into vacuoles and is involved in Ca(2+) homeostasis in cells that suffer from high concentrations of Ca(2+).
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Affiliation(s)
- Takehiro Kamiya
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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39
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Meyer Y, Reichheld JP, Vignols F. Thioredoxins in Arabidopsis and other plants. PHOTOSYNTHESIS RESEARCH 2005; 86:419-33. [PMID: 16307307 DOI: 10.1007/s11120-005-5220-y] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Accepted: 04/08/2005] [Indexed: 05/05/2023]
Abstract
Regulation of disulfide dithiol exchange has become increasingly important in our knowledge of plant life. Initially discovered as regulators of light-dependent malate biosynthesis in the chloroplast, plant thioredoxins are now implicated in a large panel of reactions related to metabolism, defense and development. In this review we describe the numerous thioredoxin types encoded by the Arabidopsis genome, and provide evidence that they are present in all higher plants. Some results suggest cross-talk between thioredoxins and glutaredoxins, the second family of disulfide dithiol reductase. The development of proteomics in plants revealed an unexpectedly large number of putative target proteins for thioredoxins and glutaredoxins. Nevertheless, we are far from a clear understanding of the actual function of each thioredoxin in planta. Although hampered by functional redundancies between genes, genetic approaches are probably unavoidable to define which thioredoxin interacts with which target protein and evaluate the physiological consequences.
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Affiliation(s)
- Yves Meyer
- Laboratoire de Physiologie et Biologie Moléculaire des Plantes, Université UMR CNRS 5096 Genome et Développement des Plantes, 52, Av Paul Alduy , 66860 Perpignan, France.
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40
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Roelfsema MRG, Hedrich R. In the light of stomatal opening: new insights into 'the Watergate'. THE NEW PHYTOLOGIST 2005; 167:665-91. [PMID: 16101906 DOI: 10.1111/j.1469-8137.2005.01460.x] [Citation(s) in RCA: 300] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Stomata can be regarded as hydraulically driven valves in the leaf surface, which open to allow CO2 uptake and close to prevent excessive loss of water. Movement of these 'Watergates' is regulated by environmental conditions, such as light, CO2 and humidity. Guard cells can sense environmental conditions and function as motor cells within the stomatal complex. Stomatal movement results from the transport of K+ salts across the guard cell membranes. In this review, we discuss the biophysical principles and mechanisms of stomatal movement and relate these to ion transport at the plasma membrane and vacuolar membrane. Studies with isolated guard cells, combined with recordings on single guard cells in intact plants, revealed that light stimulates stomatal opening via blue light-specific and photosynthetic-active radiation-dependent pathways. In addition, guard cells sense changes in air humidity and the water status of distant tissues via the stress hormone abscisic acid (ABA). Guard cells thus provide an excellent system to study cross-talk, as multiple signaling pathways induce both short- and long-term responses in these sensory cells.
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Affiliation(s)
- M Rob G Roelfsema
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences, Biocenter, Würzburg University, Julius-von-Sachs-Platz 2, D-97082 Würzburg, Germany
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41
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Cheng NH, Pittman JK, Shigaki T, Lachmansingh J, LeClere S, Lahner B, Salt DE, Hirschi KD. Functional association of Arabidopsis CAX1 and CAX3 is required for normal growth and ion homeostasis. PLANT PHYSIOLOGY 2005; 138:2048-60. [PMID: 16055687 PMCID: PMC1183394 DOI: 10.1104/pp.105.061218] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Cation levels within the cytosol are coordinated by a network of transporters. Here, we examine the functional roles of calcium exchanger 1 (CAX1), a vacuolar H+/Ca2+ transporter, and the closely related transporter CAX3. We demonstrate that like CAX1, CAX3 is also localized to the tonoplast. We show that CAX1 is predominately expressed in leaves, while CAX3 is highly expressed in roots. Previously, using a yeast assay, we demonstrated that an N-terminal truncation of CAX1 functions as an H+/Ca2+ transporter. Here, we use the same yeast assay to show that full-length CAX1 and full-length CAX3 can partially, but not fully, suppress the Ca2+ hypersensitive yeast phenotype and coexpression of full-length CAX1 and CAX3 conferred phenotypes not produced when either transporter was expressed individually. In planta, CAX3 null alleles were modestly sensitive to exogenous Ca2+ and also displayed a 22% reduction in vacuolar H+-ATPase activity. cax1/cax3 double mutants displayed a severe reduction in growth, including leaf tip and flower necrosis and pronounced sensitivity to exogenous Ca2+ and other ions. These growth defects were partially suppressed by addition of exogenous Mg2+. The double mutant displayed a 42% decrease in vacuolar H+/Ca2+ transport, and a 47% decrease in H+-ATPase activity. While the ionome of cax1 and cax3 lines were modestly perturbed, the cax1/cax3 lines displayed increased PO4(3-), Mn2+, and Zn2+ and decreased Ca2+ and Mg2+ in shoot tissue. These findings suggest synergistic function of CAX1 and CAX3 in plant growth and nutrient acquisition.
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Affiliation(s)
- Ning-Hui Cheng
- United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA
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42
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Rouhier N, Villarejo A, Srivastava M, Gelhaye E, Keech O, Droux M, Finkemeier I, Samuelsson G, Dietz KJ, Jacquot JP, Wingsle G. Identification of plant glutaredoxin targets. Antioxid Redox Signal 2005; 7:919-29. [PMID: 15998247 DOI: 10.1089/ars.2005.7.919] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Glutaredoxins (Grxs) are small ubiquitous proteins of the thioredoxin (Trx) family, which catalyze dithiol-disulfide exchange reactions or reduce protein-mixed glutathione disulfides. In plants, several Trx-interacting proteins have been isolated from different compartments, whereas very few Grx-interacting proteins are known. We describe here the determination of Grx target proteins using a mutated poplar Grx, various tissular and subcellular plant extracts, and liquid chromatography coupled to tandem mass spectrometry detection. We have identified 94 putative targets, involved in many processes, including oxidative stress response [peroxiredoxins (Prxs), ascorbate peroxidase, catalase], nitrogen, sulfur, and carbon metabolisms (methionine synthase, alanine aminotransferase, phosphoglycerate kinase), translation (elongation factors E and Tu), or protein folding (heat shock protein 70). Some of these proteins were previously found to interact with Trx or to be glutathiolated in other organisms, but others could be more specific partners of Grx. To substantiate further these data, Grx was shown to support catalysis of the stroma beta-type carbonic anhydrase and Prx IIF of Arabidopsis thaliana, but not of poplar 2-Cys Prx. Overall, these data suggest that the interaction could occur randomly either with exposed cysteinyl disulfide bonds formed within or between target proteins or with mixed disulfides between a protein thiol and glutathione.
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Affiliation(s)
- Nicolas Rouhier
- Unité Mixte de Recherches 1136 INRA UHP (Interaction Arbres Microorganismes), IFR 110 Génomique Ecophysiologie et Ecologie Fonctionnelles, Université Henri Poincaré, Vandoeuvre, France.
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Cheng NH, Liu JZ, Nelson RS, Hirschi KD. Characterization of CXIP4, a novel Arabidopsis protein that activates the H+/Ca2+ antiporter, CAX1. FEBS Lett 2004; 559:99-106. [PMID: 14960315 DOI: 10.1016/s0014-5793(04)00036-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Revised: 01/03/2004] [Accepted: 01/03/2004] [Indexed: 01/13/2023]
Abstract
Precise regulation of calcium transporters is essential for modulating the Ca2+ signaling network that is involved in the growth and adaptation of all organisms. The Arabidopsis H+/Ca2+ antiporter, CAX1, is a high capacity and low affinity Ca2+ transporter and several CAX1-like transporters are found in Arabidopsis. When heterologously expressed in yeast, CAX1 is unable to suppress the Ca2+ hypersensitivity of yeast vacuolar Ca2+ transporter mutants due to an N-terminal autoinhibition mechanism that prevents Ca2+ transport. Using a yeast screen, we have identified CAX nteracting Protein 4 (CXIP4) that activated full-length CAX1, but not full-length CAX2, CAX3 or CAX4. CXIP4 encodes a novel plant protein with no bacterial, fungal, animal, or mammalian homologs. Expression of a GFP-CXIP4 fusion in yeast and plant cells suggests that CXIP4 is targeted predominantly to the nucleus. Using a yeast growth assay, CXIP4 activated a chimeric CAX construct that contained specific portions of the N-terminus of CAX1. Together with other recent studies, these results suggest that CAX1 is regulated by several signaling molecules that converge on the N-terminus of CAX1 to regulate H+/Ca2+ antiport.
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Affiliation(s)
- Ning-Hui Cheng
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates Street, Houston, TX 77030, USA.
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Cheng NH, Pittman JK, Zhu JK, Hirschi KD. The protein kinase SOS2 activates the Arabidopsis H(+)/Ca(2+) antiporter CAX1 to integrate calcium transport and salt tolerance. J Biol Chem 2003; 279:2922-6. [PMID: 14583601 DOI: 10.1074/jbc.m309084200] [Citation(s) in RCA: 202] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The regulation of ions within cells is an indispensable component of growth and adaptation. The plant SOS2 protein kinase and its associated Ca(2+) sensor, SOS3, have been demonstrated to modulate the plasma membrane H(+)/Na(+) antiporter SOS1; however, how these regulators modulate Ca(2+) levels within cells is poorly understood. Here we demonstrate that SOS2 regulates the vacuolar H(+)/Ca(2+) antiporter CAX1. Using a yeast growth assay, co-expression of SOS2 specifically activated CAX1, whereas SOS3 did not. CAX1-like chimeric transporters were activated by SOS2 if the chimeric proteins contained the N terminus of CAX1. Vacuolar membranes from CAX1-expressing cells were made to be H(+)/Ca(2+)-competent by the addition of SOS2 protein in a dose-dependent manner. Using a yeast two-hybrid assay, SOS2 interacted with the N terminus of CAX1. In each of these yeast assays, the activation of CAX1 by SOS2 was SOS3-independent. In planta, the high level of expression of a deregulated version of CAX1 caused salt sensitivity. These findings suggest multiple functions for SOS2 and provide a mechanistic link between Ca(2+) and Na(+) homeostasis in plants.
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Affiliation(s)
- Ning-Hui Cheng
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA
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Waditee R, Hossain GS, Tanaka Y, Nakamura T, Shikata M, Takano J, Takabe T, Takabe T. Isolation and functional characterization of Ca2+/H+ antiporters from cyanobacteria. J Biol Chem 2003; 279:4330-8. [PMID: 14559898 DOI: 10.1074/jbc.m310282200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genome sequences of cyanobacteria, Synechocystis sp. PCC 6803, Anabaena sp. PCC 7120, and Thermosynechococcus elongatus BP-1 revealed the presence of a single Ca2+/H+ antiporter in these organisms. Here, we isolated the putative Ca2+/H+ antiporter gene from Synechocystis sp. PCC 6803 (synCAX) as well as a homologous gene from a halotolerant cyanobacterium Aphanothece halophytica (apCAX). In contrast to plant vacuolar CAXs, the full-length apCAX and synCAX genes complemented the Ca2+-sensitive phenotype of an Escherichia coli mutant. ApCAX and SynCAX proteins catalyzed specifically the Ca2+/H+ exchange reaction at alkaline pH. Immunological analysis suggested their localization in plasma membranes. The Synechocystis sp. PCC 6803 cells disrupted of synCAX exhibited lower Ca2+ efflux activity and a salt-sensitive phenotype. Overexpression of ApCAX and SynCAX enhanced the salt tolerance of Synechococcus sp. PCC 7942 cells. Mutagenesis analyses indicate the importance of two conserved acidic amino acid residues, Glu-74 and Glu-324, in the transmembrane segments for the exchange activity. These results clearly indicate that cyanobacteria contain a Ca2+/H+ antiporter in their plasma membranes, which plays an important role for salt tolerance.
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