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Sarıgül İ, Žukova A, Alparslan E, Remm S, Pihlak M, Kaldalu N, Tenson T, Maiväli Ü. Involvement of Escherichia coli YbeX/CorC in ribosomal metabolism. Mol Microbiol 2024; 121:984-1001. [PMID: 38494741 DOI: 10.1111/mmi.15248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/19/2024]
Abstract
YbeX of Escherichia coli, a member of the CorC protein family, is encoded in the same operon with ribosome-associated proteins YbeY and YbeZ. Here, we report the involvement of YbeX in ribosomal metabolism. The ΔybeX cells accumulate distinct 16S rRNA degradation intermediates in the 30S particles and the 70S ribosomes. E. coli lacking ybeX has a lengthened lag phase upon outgrowth from the stationary phase. This growth phenotype is heterogeneous at the individual cell level and especially prominent under low extracellular magnesium levels. The ΔybeX strain is sensitive to elevated growth temperatures and to several ribosome-targeting antibiotics that have in common the ability to induce the cold shock response in E. coli. Although generally milder, the phenotypes of the ΔybeX mutant overlap with those caused by ybeY deletion. A genetic screen revealed partial compensation of the ΔybeX growth phenotype by the overexpression of YbeY. These findings indicate an interconnectedness among the ybeZYX operon genes, highlighting their roles in ribosomal assembly and/or degradation.
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Affiliation(s)
- İsmail Sarıgül
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Amata Žukova
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Emel Alparslan
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Sille Remm
- Institute of Technology, University of Tartu, Tartu, Estonia
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
| | - Margus Pihlak
- Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Niilo Kaldalu
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Tanel Tenson
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Ülo Maiväli
- Institute of Technology, University of Tartu, Tartu, Estonia
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2
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Chen YS, Gehring K. New insights into the structure and function of CNNM proteins. FEBS J 2023; 290:5475-5495. [PMID: 37222397 DOI: 10.1111/febs.16872] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/17/2023] [Accepted: 05/23/2023] [Indexed: 05/25/2023]
Abstract
Magnesium (Mg2+ ) is the most abundant divalent cation in cells and plays key roles in almost all biological processes. CBS-pair domain divalent metal cation transport mediators (CNNMs) are a newly characterized class of Mg2+ transporters present throughout biology. Originally discovered in bacteria, there are four CNNM proteins in humans, which are involved in divalent cation transport, genetic diseases, and cancer. Eukaryotic CNNMs are composed of four domains: an extracellular domain, a transmembrane domain, a cystathionine-β-synthase (CBS)-pair domain, and a cyclic nucleotide-binding homology domain. The transmembrane and CBS-pair core are the defining features of CNNM proteins with over 20 000 protein sequences known from over 8000 species. Here, we review the structural and functional studies of eukaryotic and prokaryotic CNNMs that underlie our understanding of their regulation and mechanism of ion transport. Recent structures of prokaryotic CNNMs confirm the transmembrane domain mediates ion transport with the CBS-pair domain likely playing a regulatory role through binding divalent cations. Studies of mammalian CNNMs have identified new binding partners. These advances are driving progress in understanding this deeply conserved and widespread family of ion transporters.
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Affiliation(s)
- Yu Seby Chen
- Department of Biochemistry & Molecular Biology, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Kalle Gehring
- Department of Biochemistry & Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
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3
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Elston R, Mulligan C, Thomas GH. Flipping the switch: dynamic modulation of membrane transporter activity in bacteria. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 37948297 DOI: 10.1099/mic.0.001412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The controlled entry and expulsion of small molecules across the bacterial cytoplasmic membrane is essential for efficient cell growth and cellular homeostasis. While much is known about the transcriptional regulation of genes encoding transporters, less is understood about how transporter activity is modulated once the protein is functional in the membrane, a potentially more rapid and dynamic level of control. In this review, we bring together literature from the bacterial transport community exemplifying the extensive and diverse mechanisms that have evolved to rapidly modulate transporter function, predominantly by switching activity off. This includes small molecule feedback, inhibition by interaction with small peptides, regulation through binding larger signal transduction proteins and, finally, the emerging area of controlled proteolysis. Many of these examples have been discovered in the context of metal transport, which has to finely balance active accumulation of elements that are essential for growth but can also quickly become toxic if intracellular homeostasis is not tightly controlled. Consistent with this, these transporters appear to be regulated at multiple levels. Finally, we find common regulatory themes, most often through the fusion of additional regulatory domains to transporters, which suggest the potential for even more widespread regulation of transporter activity in biology.
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Affiliation(s)
- Rory Elston
- Department of Biology, University of York, York, UK
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4
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Inoue S, Hayashi M, Huang S, Yokosho K, Gotoh E, Ikematsu S, Okumura M, Suzuki T, Kamura T, Kinoshita T, Ma JF. A tonoplast-localized magnesium transporter is crucial for stomatal opening in Arabidopsis under high Mg 2+ conditions. THE NEW PHYTOLOGIST 2022; 236:864-877. [PMID: 35976788 PMCID: PMC9804957 DOI: 10.1111/nph.18410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Plant stomata play an important role in CO2 uptake for photosynthesis and transpiration, but the mechanisms underlying stomatal opening and closing under changing environmental conditions are still not completely understood. Through large-scale genetic screening, we isolated an Arabidopsis mutant (closed stomata2 (cst2)) that is defective in stomatal opening. We cloned the causal gene (MGR1/CST2) and functionally characterized this gene. The mutant phenotype was caused by a mutation in a gene encoding an unknown protein with similarities to the human magnesium (Mg2+ ) efflux transporter ACDP/CNNM. MGR1/CST2 was localized to the tonoplast and showed transport activity for Mg2+ . This protein was constitutively and highly expressed in guard cells. Knockout of this gene resulted in stomatal closing, decreased photosynthesis and growth retardation, especially under high Mg2+ conditions, while overexpression of this gene increased stomatal opening and tolerance to high Mg2+ concentrations. Furthermore, guard cell-specific expression of MGR1/CST2 in the mutant partially restored its stomatal opening. Our results indicate that MGR1/CST2 expression in the leaf guard cells plays an important role in maintaining cytosolic Mg2+ concentrations through sequestering Mg2+ into vacuoles, which is required for stomatal opening, especially under high Mg2+ conditions.
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Affiliation(s)
- Shin‐ichiro Inoue
- Division of Biological Science, Graduate School of ScienceNagoya UniversityFuro‐cho, Chikusa‐kuNagoyaAichi464‐8602Japan
| | - Maki Hayashi
- Division of Biological Science, Graduate School of ScienceNagoya UniversityFuro‐cho, Chikusa‐kuNagoyaAichi464‐8602Japan
| | - Sheng Huang
- Institute of Plant Science and ResourcesOkayama UniversityChuo 2‐20‐1Kurashiki710‐0046Japan
| | - Kengo Yokosho
- Institute of Plant Science and ResourcesOkayama UniversityChuo 2‐20‐1Kurashiki710‐0046Japan
| | - Eiji Gotoh
- Department of Forest Environmental Sciences, Faculty of AgricultureKyushu University744 MotookaFukuoka819‐0395Japan
| | - Shuka Ikematsu
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityFuro‐cho, ChikusaNagoya464‐8602Japan
| | - Masaki Okumura
- Division of Biological Science, Graduate School of ScienceNagoya UniversityFuro‐cho, Chikusa‐kuNagoyaAichi464‐8602Japan
| | - Takamasa Suzuki
- Department of Biological Chemistry, College of Bioscience and BiotechnologyChubu UniversityKasugai‐shiAichi487‐8501Japan
| | - Takumi Kamura
- Division of Biological Science, Graduate School of ScienceNagoya UniversityFuro‐cho, Chikusa‐kuNagoyaAichi464‐8602Japan
| | - Toshinori Kinoshita
- Division of Biological Science, Graduate School of ScienceNagoya UniversityFuro‐cho, Chikusa‐kuNagoyaAichi464‐8602Japan
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityFuro‐cho, ChikusaNagoya464‐8602Japan
| | - Jian Feng Ma
- Institute of Plant Science and ResourcesOkayama UniversityChuo 2‐20‐1Kurashiki710‐0046Japan
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Jin F, Huang Y, Hattori M. Recent Advances in the Structural Biology of Mg 2+ Channels and Transporters. J Mol Biol 2022; 434:167729. [PMID: 35841930 DOI: 10.1016/j.jmb.2022.167729] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 10/17/2022]
Abstract
Magnesium ions (Mg2+) are the most abundant divalent cations in living organisms and are essential for various physiological processes, including ATP utilization and the catalytic activity of numerous enzymes. Therefore, the homeostatic mechanisms associated with cellular Mg2+ are crucial for both eukaryotic and prokaryotic organisms and are thus strictly controlled by Mg2+ channels and transporters. Technological advances in structural biology, such as the expression screening of membrane proteins, in meso phase crystallization, and recent cryo-EM techniques, have enabled the structure determination of numerous Mg2+ channels and transporters. In this review article, we provide an overview of the families of Mg2+ channels and transporters (MgtE/SLC41, TRPM6/7, CorA/Mrs2, CorC/CNNM), and discuss the structural biology prospects based on the known structures of MgtE, TRPM7, CorA and CorC.
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Affiliation(s)
- Fei Jin
- State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Bioactive Small Molecules, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yichen Huang
- State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Bioactive Small Molecules, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Bioactive Small Molecules, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai 200438, China.
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Franken GAC, Huynen MA, Martínez-Cruz LA, Bindels RJM, de Baaij JHF. Structural and functional comparison of magnesium transporters throughout evolution. Cell Mol Life Sci 2022; 79:418. [PMID: 35819535 PMCID: PMC9276622 DOI: 10.1007/s00018-022-04442-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/22/2022] [Accepted: 06/21/2022] [Indexed: 12/16/2022]
Abstract
Magnesium (Mg2+) is the most prevalent divalent intracellular cation. As co-factor in many enzymatic reactions, Mg2+ is essential for protein synthesis, energy production, and DNA stability. Disturbances in intracellular Mg2+ concentrations, therefore, unequivocally result in delayed cell growth and metabolic defects. To maintain physiological Mg2+ levels, all organisms rely on balanced Mg2+ influx and efflux via Mg2+ channels and transporters. This review compares the structure and the function of prokaryotic Mg2+ transporters and their eukaryotic counterparts. In prokaryotes, cellular Mg2+ homeostasis is orchestrated via the CorA, MgtA/B, MgtE, and CorB/C Mg2+ transporters. For CorA, MgtE, and CorB/C, the motifs that form the selectivity pore are conserved during evolution. These findings suggest that CNNM proteins, the vertebrate orthologues of CorB/C, also have Mg2+ transport capacity. Whereas CorA and CorB/C proteins share the gross quaternary structure and functional properties with their respective orthologues, the MgtE channel only shares the selectivity pore with SLC41 Na+/Mg2+ transporters. In eukaryotes, TRPM6 and TRPM7 Mg2+ channels provide an additional Mg2+ transport mechanism, consisting of a fusion of channel with a kinase. The unique features these TRP channels allow the integration of hormonal, cellular, and transcriptional regulatory pathways that determine their Mg2+ transport capacity. Our review demonstrates that understanding the structure and function of prokaryotic magnesiotropic proteins aids in our basic understanding of Mg2+ transport.
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Affiliation(s)
- G A C Franken
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - M A Huynen
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - L A Martínez-Cruz
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park, Derio, 48160, Bizkaia, Spain
| | - R J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - J H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Meng SF, Zhang B, Tang RJ, Zheng XJ, Chen R, Liu CG, Jing YP, Ge HM, Zhang C, Chu YL, Fu AG, Zhao FG, Luan S, Lan WZ. Four plasma membrane-localized MGR transporters mediate xylem Mg 2+ loading for root-to-shoot Mg 2+ translocation in Arabidopsis. MOLECULAR PLANT 2022; 15:805-819. [PMID: 35063662 DOI: 10.1016/j.molp.2022.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 11/14/2021] [Accepted: 01/16/2022] [Indexed: 06/14/2023]
Abstract
Magnesium (Mg2+), an essential structural component of chlorophyll, is absorbed from the soil by roots and transported to shoots to support photosynthesis in plants. However, the molecular mechanisms underlying root-to-shoot Mg2+ translocation remain largely unknown. We describe here the identification of four plasma membrane (PM)-localized transporters, named Mg2+ release transporters (MGRs), that are critical for root-to-shoot Mg transport in Arabidopsis. Functional complementation assays in a Mg2+-uptake-deficient bacterial strain confirmed that these MGRs conduct Mg2+ transport. PM-localized MGRs (MGR4, MGR5, MGR6, and MGR7) were expressed primarily in root stellar cells and participated in the xylem loading step of the long-distance Mg2+ transport process. In particular, MGR4 and MGR6 played a major role in shoot Mg homeostasis, as their loss-of-function mutants were hypersensitive to low Mg2+ but tolerant to high Mg2+ conditions. Reciprocal grafting analysis further demonstrated that MGR4 functions in the root to determine shoot Mg2+ accumulation and physiological phenotypes caused by both low- and high-Mg2+ stress. Taken together, our study has identified the long-sought transporters responsible for root-to-shoot Mg2+ translocation in plants.
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Affiliation(s)
- Su-Fang Meng
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Bin Zhang
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China; Institute of Future Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, China; The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Ren-Jie Tang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Xiao-Jiang Zheng
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China; Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Rui Chen
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Cong-Ge Liu
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Yan-Ping Jing
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China; The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Hai-Man Ge
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Chi Zhang
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China; The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Yan-Li Chu
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Ai-Gen Fu
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Fu-Geng Zhao
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
| | - Wen-Zhi Lan
- State Key Laboratory for Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, Jiangsu, China.
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Lizárraga WC, Mormontoy CG, Calla H, Castañeda M, Taira M, Garcia R, Marín C, Abanto M, Ramirez P. Complete genome sequence of Shewanella algae strain 2NE11, a decolorizing bacterium isolated from industrial effluent in Peru. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2022; 33:e00704. [PMID: 35145887 PMCID: PMC8816663 DOI: 10.1016/j.btre.2022.e00704] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/28/2021] [Accepted: 01/19/2022] [Indexed: 12/14/2022]
Abstract
Shewanella is a microbial group with high potential to be applied in textile effluents bioremediation due to its ability to use a wide variety of substrates as a final electron acceptor in respiration. The present research aimed to describe a new strain, Shewanella algae 2NE11, a decolorizing bacterium isolated from industrial effluent in Peru. S. algae 2NE11 showed an optimal growth under pH 6-9, temperature between 30-40 °C, and 0-4 % NaCl. It can tolerate high concentrations of NaCl until 10% and low temperatures as 4 °C. It decolorizes azo and anthraquinone dyes with a decolorization rate of 89-97%. We performed next-generation sequencing (Pacific Bioscience®) and achieved its complete genome sequence with a length of 5,030,813bp and a GC content of 52.98%. Genomic characterization revealed the presence of protein-coding genes related to decolorization like azoreductase, dyp-peroxidase, oxidoreductases, and the complete Mtr respiratory pathway. Likewise, we identified other properties such as the presence of metal resistant genes, and genes related to lactate and N-acetylglucosamine metabolism. These results highlight its potential to be applied in the bioremediation of textile effluents and guide future research on decolorization metabolic pathways.
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Affiliation(s)
- Wendy C Lizárraga
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Carlo G Mormontoy
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Hedersson Calla
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Maria Castañeda
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Mario Taira
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Ruth Garcia
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Claudia Marín
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
| | - Michel Abanto
- Núcleo Científico y Tecnológico en Biorecursos - BIOREN, Universidad de La Frontera, Temuco, Chile
| | - Pablo Ramirez
- Laboratory of Molecular Microbiology and Biotechnology, Faculty of Biological Sciences, Universidad Nacional Mayor de San Marcos, Lima, Perú
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Tang RJ, Meng SF, Zheng XJ, Zhang B, Yang Y, Wang C, Fu AG, Zhao FG, Lan WZ, Luan S. Conserved mechanism for vacuolar magnesium sequestration in yeast and plant cells. NATURE PLANTS 2022; 8:181-190. [PMID: 35087208 DOI: 10.1038/s41477-021-01087-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Magnesium (Mg2+) is an essential nutrient for all life forms. In fungal and plant cells, the majority of Mg2+ is stored in the vacuole but mechanisms for Mg2+ transport into the vacuolar store are not fully understood. Here we demonstrate that members of ancient conserved domain proteins (ACDPs) from Saccharomyces cerevisiae and Arabidopsis thaliana function in vacuolar Mg2+ sequestration that enables plant and yeast cells to cope with high levels of external Mg2+. We show that the yeast genome (as well as other fungal genomes) harbour a single ACDP homologue, referred to as MAM3, that functions specifically in vacuolar Mg2+ accumulation and is essential for tolerance to high Mg. In parallel, vacuolar ACDP homologues were identified from Arabidopsis and shown to complement the yeast mutant mam3Δ. An Arabidopsis mutant lacking one of the vacuolar ACDP homologues displayed hypersensitivity to high-Mg conditions and accumulated less Mg in the vacuole compared with the wild type. Taken together, our results suggest that conserved transporters mediate vacuolar Mg2+ sequestration in fungal and plant cells to maintain cellular Mg2+ homeostasis in response to fluctuating Mg2+ levels in the environment.
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Affiliation(s)
- Ren-Jie Tang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Su-Fang Meng
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing, China
| | - Xiao-Jiang Zheng
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- College of Life Sciences, Northwest University, Xi'an, China
| | - Bin Zhang
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing, China
- College of Life Sciences, Northwest University, Xi'an, China
| | - Yang Yang
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing, China
| | - Chao Wang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- College of Life Sciences, Northwest University, Xi'an, China
| | - Ai-Gen Fu
- College of Life Sciences, Northwest University, Xi'an, China
| | - Fu-Geng Zhao
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing, China
| | - Wen-Zhi Lan
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing, China.
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
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10
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Cavazza C, Collin-Faure V, Pérard J, Diemer H, Cianférani S, Rabilloud T, Darrouzet E. Proteomic analysis of Rhodospirillum rubrum after carbon monoxide exposure reveals an important effect on metallic cofactor biosynthesis. J Proteomics 2022; 250:104389. [PMID: 34601154 DOI: 10.1016/j.jprot.2021.104389] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 12/14/2022]
Abstract
Some carboxydotrophs like Rhodospirillum rubrum are able to grow with CO as their sole source of energy using a Carbone monoxide dehydrogenase (CODH) and an Energy conserving hydrogenase (ECH) to perform anaerobically the so called water-gas shift reaction (WGSR) (CO + H2O → CO2 + H2). Several studies have focused at the biochemical and biophysical level on this enzymatic system and a few OMICS studies on CO metabolism. Knowing that CO is toxic in particular due to its binding to heme iron atoms, and is even considered as a potential antibacterial agent, we decided to use a proteomic approach in order to analyze R. rubrum adaptation in term of metabolism and management of the toxic effect. In particular, this study allowed highlighting a set of proteins likely implicated in ECH maturation, and important perturbations in term of cofactor biosynthesis, especially metallic cofactors. This shows that even this CO tolerant microorganism cannot avoid completely CO toxic effects associated with its interaction with metallic ions. SIGNIFICANCE: This proteomic study highlights the fact that even in a microorganism able to handle carbon monoxide and in some way detoxifying it via the intrinsic action of the carbon monoxide dehydrogenase (CODH), CO has important effects on metal homeostasis, metal cofactors and metalloproteins. These effects are direct or indirect via transcription regulation, and amplified by the high interdependency of cofactors biosynthesis.
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Affiliation(s)
- Christine Cavazza
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, CBM, F-38000 Grenoble, France.
| | | | - Julien Pérard
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, CBM, F-38000 Grenoble, France.
| | - Hélène Diemer
- Laboratoire de Spectrométrie de Masse BioOrganique (LSMBO), Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France; Infrastructure Nationale de Protéomique ProFI - FR2048 (CNRS-CEA), 67087 Strasbourg, France.
| | - Sarah Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique (LSMBO), Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France; Infrastructure Nationale de Protéomique ProFI - FR2048 (CNRS-CEA), 67087 Strasbourg, France.
| | - Thierry Rabilloud
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, CBM, F-38000 Grenoble, France.
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Ge H, Wang Y, Chen J, Zhang B, Chen R, Lan W, Luan S, Yang L. An Arabidopsis vasculature distributed metal tolerance protein facilitates xylem magnesium diffusion to shoots under high-magnesium environments. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:166-182. [PMID: 34761874 DOI: 10.1111/jipb.13187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
Magnesium (Mg2+ ) is an essential metal for plant growth; however, its over-accumulation in cells can be cytotoxic. The metal tolerance protein family (MTP) belongs to an ubiquitous family of cation diffusion facilitator (CDF) proteins that export divalent metal cations for metal homeostasis and tolerance in all organisms. We describe here the identification of MTP10 to be critical for xylem Mg homeostasis in Arabidopsis under high Mg2+ conditions. The Arabidopsis plant contains 12 MTP genes, and only knockout of MTP10 decreased the tolerance of high-Mg stress. The functional complementation assays in a Mg2+ -uptake-deficient bacterial strain MM281 confirmed that MTP10 conducted Mg2+ transport. MTP10 is localized to the plasma membrane of parenchyma cells around the xylem. Reciprocal grafting analysis further demonstrated that MTP10 functions in the shoot to determine the shoot growth phenotypes under high Mg2+ conditions. Moreover, compared to the wild type, the mtp10 mutant accumulated more Mg2+ in xylem sap under high-Mg stress. This study reveals that MTP10 facilitates Mg2+ diffusion from the xylem to shoots and thus determines Mg homeostasis in shoot vascular tissues during high-Mg stress.
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Affiliation(s)
- Haiman Ge
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Yuan Wang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai, 201602, China
| | - Jinlin Chen
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Bin Zhang
- Chinese Education Ministry's Key Laboratory of Western Resources and Modern Biotechnology, Key Laboratory of Biotechnology Shaanxi Province, College of Life Sciences, Northwest University, Xi'an, 710069, China
| | - Rui Chen
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Wenzhi Lan
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, California, 94702, USA
| | - Lei Yang
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
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12
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Abstract
CNNM/CorB proteins are a broadly conserved family of integral membrane proteins with close to 90,000 protein sequences known. They are associated with Mg2+ transport but it is not known if they mediate transport themselves or regulate other transporters. Here, we determine the crystal structure of an archaeal CorB protein in two conformations (apo and Mg2+-ATP bound). The transmembrane DUF21 domain exists in an inward-facing conformation with a Mg2+ ion coordinated by a conserved π-helix. In the absence of Mg2+-ATP, the CBS-pair domain adopts an elongated dimeric configuration with previously unobserved domain-domain contacts. Hydrogen-deuterium exchange mass spectrometry, analytical ultracentrifugation, and molecular dynamics experiments support a role of the structural rearrangements in mediating Mg2+-ATP sensing. Lastly, we use an in vitro, liposome-based assay to demonstrate direct Mg2+ transport by CorB proteins. These structural and functional insights provide a framework for understanding function of CNNMs in Mg2+ transport and associated diseases.
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13
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Magnesium Hydroxide Nanoparticles Kill Exponentially Growing and Persister Escherichia coli Cells by Causing Physical Damage. NANOMATERIALS 2021; 11:nano11061584. [PMID: 34208716 PMCID: PMC8234494 DOI: 10.3390/nano11061584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 11/24/2022]
Abstract
Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we studied the effects of three different sizes of magnesium hydroxide nanoparticles on antibacterial activity: NM80, NM300, and NM700. NM80 (D50 = 75.2 nm) showed a higher bactericidal effect against Escherichia coli than larger nanoparticles (D50 = 328 nm (NM300) or 726 nm (NM700)). Moreover, NM80 showed a high bactericidal effect against not only exponential cells but also persister cells, which are difficult to eliminate owing to their high tolerance to antibiotics. NM80 eliminated strains in which magnesium-transport genes were knocked out and exhibited a bactericidal effect similar to that observed in the wild-type strain. The bactericidal action involved physical cell damage, as confirmed using scanning electron microscopy, which showed that E. coli cells treated with NM80 were directly injured.
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14
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Akanuma G. Diverse relationships between metal ions and the ribosome. Biosci Biotechnol Biochem 2021; 85:1582-1593. [PMID: 33877305 DOI: 10.1093/bbb/zbab070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/30/2021] [Indexed: 11/12/2022]
Abstract
The ribosome requires metal ions for structural stability and translational activity. These metal ions are important for stabilizing the secondary structure of ribosomal RNA, binding of ribosomal proteins to the ribosome, and for interaction of ribosomal subunits. In this review, various relationships between ribosomes and metal ions, especially Mg2+ and Zn2+, are presented. Mg2+ regulates gene expression by modulating the translational stability and synthesis of ribosomes, which in turn contribute to the cellular homeostasis of Mg2+. In addition, Mg2+ can partly complement the function of ribosomal proteins. Conversely, a reduction in the cellular concentration of Zn2+ induces replacement of ribosomal proteins, which mobilizes free-Zn2+ in the cell and represses translation activity. Evolutional relationships between these metal ions and the ribosome are also discussed.
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Affiliation(s)
- Genki Akanuma
- Department of Life Science, Graduate School of Science, Gakushuin University, Toshima-ku, Tokyo, Japan.,Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan
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15
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Cunrath O, Palmer JD. An overview of Salmonella enterica metal homeostasis pathways during infection. ACTA ACUST UNITED AC 2021; 2:uqab001. [PMID: 34250489 PMCID: PMC8264917 DOI: 10.1093/femsml/uqab001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/19/2021] [Indexed: 12/14/2022]
Abstract
Nutritional immunity is a powerful strategy at the core of the battlefield between host survival and pathogen proliferation. A host can prevent pathogens from accessing biological metals such as Mg, Fe, Zn, Mn, Cu, Co or Ni, or actively intoxicate them with metal overload. While the importance of metal homeostasis for the enteric pathogen Salmonella enterica Typhimurium was demonstrated many decades ago, inconsistent results across various mouse models, diverse Salmonella genotypes, and differing infection routes challenge aspects of our understanding of this phenomenon. With expanding access to CRISPR-Cas9 for host genome manipulation, it is now pertinent to re-visit past results in the context of specific mouse models, identify gaps and incongruities in current knowledge landscape of Salmonella homeostasis, and recommend a straight path forward towards a more universal understanding of this historic host-microbe relationship.
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Affiliation(s)
- Olivier Cunrath
- Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Rd, Oxford, UK OX1 3SZ
| | - Jacob D Palmer
- Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Rd, Oxford, UK OX1 3SZ
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16
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A Multifunctional Protein PolDIP2 in DNA Translesion Synthesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1241:35-45. [PMID: 32383114 DOI: 10.1007/978-3-030-41283-8_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Polymerase δ-interacting protein 2 (PolDIP2) is involved in the multiple protein-protein interactions and plays roles in many cellular processes including regulation of the nuclear redox environment, organization of the mitotic spindle and chromosome segregation, pre-mRNA processing, mitochondrial morphology and functions, cell migration and cellular adhesion. PolDIP2 is also a binding partner of high-fidelity DNA polymerase delta, PCNA and a number of translesion and repair DNA polymerases. The growing evidence suggests that PolDIP2 is a general regulatory protein in DNA damage response. However PolDIP2 functions in DNA translesion synthesis and repair are not fully understood. In this review, we address the functional interaction of PolDIP2 with human DNA polymerases and discuss the possible functions in DNA damage response.
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17
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Role of yoaE Gene Regulated by CpxR in the Survival of Salmonella enterica Serovar Enteritidis in Antibacterial Egg White. mSphere 2020; 5:5/1/e00638-19. [PMID: 31915212 PMCID: PMC6952189 DOI: 10.1128/msphere.00638-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Salmonella enterica serovar Enteritidis is the predominant Salmonella serotype that causes human salmonellosis mainly through contaminated chicken eggs or egg products and has been a global public health threat. The spread and frequent outbreaks of this serotype through eggs correlate significantly with its exceptional survival in eggs, despite the antibacterial properties of egg white. Research on the survival mechanisms of S. Enteritidis in egg white will help develop effective strategies to control the contamination of eggs by this Salmonella serotype and help further elucidate the complex antibacterial mechanisms of egg white. This study revealed the importance of yoaE, a gene with unknown function, on the survival of S. Enteritidis in egg white, as well as its transcriptional regulation by CpxR. Our work provides the basis to reveal the mechanisms of survival of S. Enteritidis in egg white and the specific function of the yoaE gene. The survival ability of Salmonella enterica serovar Enteritidis in antibacterial egg white is an important factor leading to Salmonella outbreaks through eggs and egg products. In this study, the role of the gene yoaE, encoding an inner membrane protein, in the survival of Salmonella Enteritidis in egg white, and its transcriptional regulation by CpxR were investigated. Quantitative reverse transcription-PCR (RT-qPCR) results showed that the yoaE gene expression was upregulated 35-fold after exposure to egg white for 4 h compared to that in M9FeS medium, and the deletion of yoaE (ΔyoaE) dramatically decreased the survival rate of bacteria in egg white to less than 1% of the wild type (WT) and the complementary strain at both 37 and 20°C, indicating that yoaE was essential for bacteria to survive in egg white. Furthermore, the ΔyoaE strain was sensitive to a 3-kDa ultrafiltration matrix of egg white because of its high pH and antimicrobial peptide components. Putative conserved binding sites for the envelope stress response regulator CpxR were found in the yoaE promoter region. In vivo, the RT-qPCR assay results showed that the upregulation of yoaE in a ΔcpxR strain in egg white was 1/5 that of the WT. In vitro, results from DNase I footprinting and electrophoretic mobility shift assays further demonstrated that CpxR could directly bind to the yoaE promoter region, and a specific CpxR binding sequence was identified. In conclusion, it was shown for the first time that CpxR positively regulated the transcription of yoaE, which was indispensable for survival of Salmonella Enteritidis in egg white. IMPORTANCESalmonella enterica serovar Enteritidis is the predominant Salmonella serotype that causes human salmonellosis mainly through contaminated chicken eggs or egg products and has been a global public health threat. The spread and frequent outbreaks of this serotype through eggs correlate significantly with its exceptional survival in eggs, despite the antibacterial properties of egg white. Research on the survival mechanisms of S. Enteritidis in egg white will help develop effective strategies to control the contamination of eggs by this Salmonella serotype and help further elucidate the complex antibacterial mechanisms of egg white. This study revealed the importance of yoaE, a gene with unknown function, on the survival of S. Enteritidis in egg white, as well as its transcriptional regulation by CpxR. Our work provides the basis to reveal the mechanisms of survival of S. Enteritidis in egg white and the specific function of the yoaE gene.
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18
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Giménez-Mascarell P, Oyenarte I, González-Recio I, Fernández-Rodríguez C, Corral-Rodríguez MÁ, Campos-Zarraga I, Simón J, Kostantin E, Hardy S, Díaz Quintana A, Zubillaga Lizeaga M, Merino N, Diercks T, Blanco FJ, Díaz Moreno I, Martínez-Chantar ML, Tremblay ML, Müller D, Siliqi D, Martínez-Cruz LA. Structural Insights into the Intracellular Region of the Human Magnesium Transport Mediator CNNM4. Int J Mol Sci 2019; 20:E6279. [PMID: 31842432 PMCID: PMC6940986 DOI: 10.3390/ijms20246279] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 12/17/2022] Open
Abstract
The four member family of "Cyclin and Cystathionine β-synthase (CBS) domain divalent metal cation transport mediators", CNNMs, are the least-studied mammalian magnesium transport mediators. CNNM4 is abundant in the brain and the intestinal tract, and its abnormal activity causes Jalili Syndrome. Recent findings show that suppression of CNNM4 in mice promotes malignant progression of intestinal polyps and is linked to infertility. The association of CNNM4 with phosphatases of the regenerating liver, PRLs, abrogates its Mg2+-efflux capacity, thus resulting in an increased intracellular Mg2+ concentration that favors tumor growth. Here we present the crystal structures of the two independent intracellular domains of human CNNM4, i.e., the Bateman module and the cyclic nucleotide binding-like domain (cNMP). We also derive a model structure for the full intracellular region in the absence and presence of MgATP and the oncogenic interacting partner, PRL-1. We find that only the Bateman module interacts with ATP and Mg2+, at non-overlapping sites facilitating their positive cooperativity. Furthermore, both domains dimerize autonomously, where the cNMP domain dimer forms a rigid cleft to restrict the Mg2+ induced sliding of the inserting CBS1 motives of the Bateman module, from a twisted to a flat disk shaped dimer.
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Grants
- ETORTEK IE05-147 Departamento de Industria, Innovación, Comercio y Turismo del Gobierno Vasco
- IE07-202 Departamento de Industria, Innovación, Comercio y Turismo del Gobierno Vasco
- 7/13/08/2006/11 Diputación Foral de Bizkaia
- 7/13/08/2005/14 Diputación Foral de Bizkaia
- BFU2010-17857 Ministerio de Ciencia e Innovación
- BFU2013-47531-R Ministerio de Economía, Industria y Competitividad, Gobierno de España
- BES-2014-068464 Ministerio de Economía, Industria y Competitividad, Gobierno de España
- BFU2016-77408-R Ministerio de Economía, Industria y Competitividad, Gobierno de España
- BES-2017-080435 Ministerio de Economía, Industria y Competitividad, Gobierno de España
- CSD2008-00005 MICINN CONSOLIDER-INGENIO 2010 Program
- BAG MX20113 Diamond Light source
- 2013111114 Gobierno Vasco-Departamento de Salud
- SAF2017-87301-R Ministerio de Economía, Industria y Competitividad, Gobierno de España
- BIO15/CA/014 EITB Maratoia
- SEV-2016-0644 Ministerio de Economía, Industria y Competitividad, Gobierno de España
- 12.01.134/2bT4 Berlin Institute of Health
- #343439 Canadian Institute for Health Research
- MX15832-9 Diamond Light Source
- MX15832-10 Diamond Light Source
- PGC2018-096049-B100 Ministerio de Economía, Industria y Competitividad, Gobierno de España
- CTQ2017-83810-R Ministerio de Economía, Industria y Competitividad, Gobierno de España
- PI2010-17 Departamento de Educación, Universidades e Investigación del Gobierno Vasco
- BAG 2019073624 ALBA Synchrotron
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Affiliation(s)
- Paula Giménez-Mascarell
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
| | - Iker Oyenarte
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
| | - Irene González-Recio
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
| | - Carmen Fernández-Rodríguez
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
| | - María Ángeles Corral-Rodríguez
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
| | - Igone Campos-Zarraga
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
| | - Jorge Simón
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
| | - Elie Kostantin
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; (E.K.); (S.H.); (M.L.T.)
| | - Serge Hardy
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; (E.K.); (S.H.); (M.L.T.)
| | - Antonio Díaz Quintana
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla—CSIC. Avda. Americo Vespucio 49, 41092 Sevilla, Spain; (A.D.Q.); (I.D.M.)
| | - Mara Zubillaga Lizeaga
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 800, 48160 Derio, Spain; (M.Z.L.); (N.M.); (T.D.); (F.J.B.)
| | - Nekane Merino
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 800, 48160 Derio, Spain; (M.Z.L.); (N.M.); (T.D.); (F.J.B.)
| | - Tammo Diercks
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 800, 48160 Derio, Spain; (M.Z.L.); (N.M.); (T.D.); (F.J.B.)
| | - Francisco J. Blanco
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 800, 48160 Derio, Spain; (M.Z.L.); (N.M.); (T.D.); (F.J.B.)
- IKERBASQUE, Basque Foundation for Science, María Díaz de Haro 3, 48013 Bilbao, Spain
| | - Irene Díaz Moreno
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla—CSIC. Avda. Americo Vespucio 49, 41092 Sevilla, Spain; (A.D.Q.); (I.D.M.)
| | - María Luz Martínez-Chantar
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), 48160 Derio, Spain
| | - Michel L. Tremblay
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; (E.K.); (S.H.); (M.L.T.)
| | - Dominik Müller
- Department of Pediatric Gastroenterology, Nephrology and Metabolic Disorders, Charité Universitäts medizin, 13353 Berlin, Germany;
| | - Dritan Siliqi
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche (CNR), Via G. Amendola 122/O, 70126 Bari, Italy;
| | - Luis Alfonso Martínez-Cruz
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Bizkaia Science and Technology Park Bld 801A, 48160 Derio, Spain; (P.G.-M.); (I.O.); (I.G.-R.); (C.F.-R.); (M.Á.C.-R.); (I.C.-Z.); (J.S.); (M.L.M.-C.)
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19
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Nau GJ, Horzempa J, O’Dee D, Brown MJ, Russo BC, Hernandez A, Dillon ST, Cheng J, Kane LP, Sanker S, Hukriede NA. A predicted Francisella tularensis DXD-motif glycosyltransferase blocks immune activation. Virulence 2019; 10:643-656. [PMID: 31314675 PMCID: PMC6650193 DOI: 10.1080/21505594.2019.1631662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/07/2019] [Indexed: 02/04/2023] Open
Abstract
Pathogens enhance their survival during infections by manipulating host defenses. Francisella tularensis evades innate immune responses, which we have found to be dependent on an understudied gene ybeX (FTL_0883/FTT_0615c). To understand the function of YbeX, we sought protein interactors in F. tularensis subsp. holarctica live vaccine strain (LVS). An unstudied Francisella protein co-immunoprecipitated with recombinant YbeX, which is a predicted glycosyltransferase with a DXD-motif. There are up to four genomic copies of this gene with identical sequence in strains of F. tularensis pathogenic to humans, despite ongoing genome decay. Disruption mutations were generated by intron insertion into all three copies of this glycosyltransferase domain containing gene in LVS, gdcA1-3. The resulting strains stimulated more cytokines from macrophages in vitro than wild-type LVS and were attenuated in two in vivo infection models. GdcA was released from LVS during culture and was sufficient to block NF-κB activation when expressed in eukaryotic cells. When co-expressed in zebrafish, GdcA and YbeX were synergistically lethal to embryo development. Glycosyltransferases with DXD-motifs are found in a variety of pathogens including NleB, an Escherichia coli type-III secretion system effector that inhibits NF-κB by antagonizing death receptor signaling. To our knowledge, GdcA is the first DXD-motif glycosyltransferase that inhibits NF-κB in immune cells. Together, these findings suggest DXD-motif glycosyltransferases may be a conserved virulence mechanism used by pathogenic bacteria to remodel host defenses.
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Affiliation(s)
- Gerard J. Nau
- Division of Infectious Diseases, Alpert Medical School of Brown University, Providence, RI, USA
| | - Joseph Horzempa
- Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, WV, USA
| | - Dawn O’Dee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Matthew J. Brown
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Brian C. Russo
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ana Hernandez
- Division of Infectious Diseases, Alpert Medical School of Brown University, Providence, RI, USA
| | - Simon T. Dillon
- Beth Israel Deaconess Medical Center Genomics, Proteomics, and Systems Biology Center, Harvard Medical School, Boston, MA, USA
| | - Jing Cheng
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Lawrence P. Kane
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Subramaniam Sanker
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Neil A. Hukriede
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Center for Critical Care Nephrology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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20
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Harris KA, Odzer NB, Breaker RR. Disruption of the OLE ribonucleoprotein complex causes magnesium toxicity in Bacillus halodurans. Mol Microbiol 2019; 112:1552-1563. [PMID: 31461569 DOI: 10.1111/mmi.14379] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2019] [Indexed: 12/26/2022]
Abstract
OLE RNAs represent an unusual class of bacterial noncoding RNAs common in Gram-positive anaerobes. The OLE RNA of the alkaliphile Bacillus halodurans is highly expressed and naturally interacts with at least two RNA-binding proteins called OapA and OapB. The phenotypes of the corresponding knockouts include growth inhibition when exposed to ethanol or other short-chain alcohols or when incubated at modestly reduced temperatures (e.g. 20°C). Intriguingly, the OapA 'PM1' mutant, which carries two amino acid changes to a highly conserved region, yields a dominant-negative phenotype that causes more severe growth defects under these same stress conditions. Herein, we report that the PM1 strain also exhibits extreme sensitivity to elevated Mg2+ concentrations, beginning as low as 2 mM. Suppressor mutants predominantly map to genes for aconitate hydratase and isocitrate dehydrogenase, which are expected to alter cellular citrate concentrations. Citrate reduces the severity of the Mg2+ toxicity phenotype, but neither the genomic mutations nor the addition of citrate to the medium overcomes ethanol toxicity or temperature sensitivity. These findings reveal that OLE RNA and its protein partners are involved in biochemical responses under several stress conditions, wherein the unusual sensitivity to Mg2+ can be independently suppressed by specific genomic mutations.
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Affiliation(s)
- Kimberly A Harris
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA.,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Nicole B Odzer
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Ronald R Breaker
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA.,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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21
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Trachsel E, Redder P, Linder P, Armitano J. Genetic screens reveal novel major and minor players in magnesium homeostasis of Staphylococcus aureus. PLoS Genet 2019; 15:e1008336. [PMID: 31415562 PMCID: PMC6711546 DOI: 10.1371/journal.pgen.1008336] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/27/2019] [Accepted: 07/29/2019] [Indexed: 12/19/2022] Open
Abstract
Magnesium is one of the most abundant metal ions in living cells. Very specific and devoted transporters have evolved for transporting Mg2+ ions across the membrane and maintain magnesium homeostasis. Using genetic screens, we were able to identify the main players in magnesium homeostasis in the opportunistic pathogen Staphylococcus aureus. Here, we show that import of magnesium relies on the redundant activity of either CorA2 or MgtE since in absence of these two importers, bacteria require increased amounts of magnesium in the medium. A third CorA-like importer seems to play a minor role, at least under laboratory conditions. For export of magnesium, we identified two proteins, MpfA and MpfB. MpfA, is the main actor since it is essential for growth in high magnesium concentrations. We show that gain of function mutations or overexpression of the minor factor, MpfB, which is part of a sigmaB controlled stress response regulon, can compensate for the absence of MpfA.
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Affiliation(s)
- Emilie Trachsel
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Peter Redder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- LMGM UMR5100, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Joshua Armitano
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- * E-mail:
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22
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Heeney DD, Yarov-Yarovoy V, Marco ML. Sensitivity to the two peptide bacteriocin plantaricin EF is dependent on CorC, a membrane-bound, magnesium/cobalt efflux protein. Microbiologyopen 2019; 8:e827. [PMID: 30891921 PMCID: PMC6854853 DOI: 10.1002/mbo3.827] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 01/31/2019] [Accepted: 02/04/2019] [Indexed: 12/12/2022] Open
Abstract
Lactic acid bacteria produce a variety of antimicrobial peptides known as bacteriocins. Most bacteriocins are understood to kill sensitive bacteria through receptor‐mediated disruptions. Here, we report on the identification of the Lactobacillus plantarum plantaricin EF (PlnEF) receptor. Spontaneous PlnEF‐resistant mutants of the PlnEF‐indicator strain L. plantarum NCIMB 700965 (LP965) were isolated and confirmed to maintain cellular ATP levels in the presence of PlnEF. Genome comparisons resulted in the identification of a single mutated gene annotated as the membrane‐bound, magnesium/cobalt efflux protein CorC. All isolates contained a valine (V) at position 334 instead of a glycine (G) in a cysteine‐β‐synthase domain at the C‐terminal region of CorC. In silico template‐based modeling of this domain indicated that the mutation resides in a loop between two β‐strands. The relationship between PlnEF, CorC, and metal homeostasis was supported by the finding that PlnEF‐resistance was lost when PlnEF was applied together with high concentrations of Mg2+, Co2+, Zn2+, or Cu2+. Lastly, PlnEF sensitivity was increased upon heterologous expression of LP965 corC but not the G334V CorC mutant in the PlnEF‐resistant strain Lactobacillus casei BL23. These results show that PlnEF kills sensitive bacteria by targeting CorC.
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Affiliation(s)
- Dustin D Heeney
- Department of Food Science & Technology, University of California-Davis, Davis, California
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California
| | - Maria L Marco
- Department of Food Science & Technology, University of California-Davis, Davis, California
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23
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Molecular function and biological importance of CNNM family Mg2+ transporters. J Biochem 2018; 165:219-225. [DOI: 10.1093/jb/mvy095] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 11/19/2018] [Indexed: 12/15/2022] Open
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24
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Kowatz T, Maguire ME. Loss of cytosolic Mg 2+ binding sites in the Thermotoga maritima CorA Mg 2+ channel is not sufficient for channel opening. Biochim Biophys Acta Gen Subj 2018; 1863:25-30. [PMID: 30293964 DOI: 10.1016/j.bbagen.2018.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 08/29/2018] [Accepted: 09/03/2018] [Indexed: 10/28/2022]
Abstract
The CorA Mg2+ channel is a homopentamer with five-fold symmetry. Each monomer consists of a large cytoplasmic domain and two transmembrane helices connected via a short periplasmic loop. In the Thermotoga maritima CorA crystal structure, a Mg2+ is bound between D89 of one monomer and D253 of the adjacent monomer (M1 binding site). Release of Mg2+ from these sites has been hypothesized to cause opening of the channel. We generated mutants to disrupt Mg2+ interaction with the M1 site. Crystal structures of the D89K/D253K and D89R/D253R mutants, determined to 3.05 and 3.3 Å, respectively, showed no significant structural differences with the wild type structure despite absence of Mg2+ at the M1 sites. Both mutants still appear to be in the closed state. All three mutant CorA proteins exhibited transport of 63Ni2+, indicating functionality. Thus, absence of Mg2+ from the M1 sites neither causes channel opening nor prevents function. We also provide evidence that the T. maritima CorA is a Mg2+ channel and not a Co2+ channel.
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Affiliation(s)
- Thomas Kowatz
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4965, USA
| | - Michael E Maguire
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4965, USA.
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25
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Wu YH, Fang C, Zhou P, Wang CS, Xu XW. Complete genome sequence of a heavy metal resistant bacterium Maribacter cobaltidurans B1T, isolated from the deep-sea sediment of the South Atlantic Ocean. Mar Genomics 2018. [DOI: 10.1016/j.margen.2017.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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26
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Li H, Liu C, Zhou L, Zhao Z, Li Y, Qu M, Huang K, Zhang L, Lu Y, Cao M, Gao S, Zhang S. Molecular and functional characterization of the magnesium transporter gene ZmMGT12 in maize. Gene 2018; 665:167-173. [PMID: 29702186 DOI: 10.1016/j.gene.2018.04.068] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 04/04/2018] [Accepted: 04/23/2018] [Indexed: 11/30/2022]
Abstract
Magnesium (Mg) is an essential mineral element for normal plant growth and development, and the CorA/MRS2/MGT-type Mg transporters play a significant role in maintaining Mg homeostasis in plants. In total, 12 maize CorA-like Mg2+ transporters have been identified, but none of them had been functionally characterized. Accordingly, we cloned and functionally characterized ZmMGT12 from the maize CorA-like gene family. ZmMGT12 exhibited the structure typical of Mg2+ transporters, i.e., two conserved TM domains and a GMN tripeptide motif. ZmMGT12, Arabidopsis AtMGT6, and rice OsMRS2-6 shared high protein sequence identity and thus clustered in the same phylogenetic branch, suggesting that they could be homologs. A functional complementation assay in the Salmonella typhimurium MM281 mutant indicated that ZmMGT12 possessed Mg2+ transport ability. ZmMGT12 was expressed in roots, stems, and leaves, with the highest expression in leaves. Moreover, ZmMGT12 expression was induced by light and exhibited a circadian expression pattern. In addition, the expression level of ZmMGT12 in leaf tissue was related to chlorophyll synthesis. Overexpression of ZmMGT12 in Arabidopsis caused no phenotypic change in transgenic plants, including in fresh shoot weight, chlorophyll content, shoot Mg2+ content, and chloroplast Mg2+ content. Together, these results suggest that ZmMGT12 is a Mg2+ transporter and may play a role in Mg transport into chloroplasts.
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Affiliation(s)
- Hongyou Li
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China; Research Center of Buckwheat Industry Technology, Guizhou Normal University, Guiyang 550001, China
| | - Chan Liu
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Lina Zhou
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhuo Zhao
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Yihong Li
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Min Qu
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Kaifeng Huang
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Lu Zhang
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Yanli Lu
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Moju Cao
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Shibin Gao
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Suzhi Zhang
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
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27
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Zeinert R, Martinez E, Schmitz J, Senn K, Usman B, Anantharaman V, Aravind L, Waters LS. Structure-function analysis of manganese exporter proteins across bacteria. J Biol Chem 2018; 293:5715-5730. [PMID: 29440394 DOI: 10.1074/jbc.m117.790717] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 01/26/2018] [Indexed: 01/01/2023] Open
Abstract
Manganese (Mn) is an essential trace nutrient for organisms because of its role in cofactoring enzymes and providing protection against reactive oxygen species (ROS). Many bacteria require manganese to form pathogenic or symbiotic interactions with eukaryotic host cells. However, excess manganese is toxic, requiring cells to have manganese export mechanisms. Bacteria are currently known to possess two widely distributed classes of manganese export proteins, MntP and MntE, but other types of transporters likely exist. Moreover, the structure and function of MntP is not well understood. Here, we characterized the role of three structurally related proteins known or predicted to be involved in manganese transport in bacteria from the MntP, UPF0016, and TerC families. These studies used computational analysis to analyze phylogeny and structure, physiological assays to test sensitivity to high levels of manganese and ROS, and inductively coupled plasma-mass spectrometry (ICP-MS) to measure metal levels. We found that MntP alters cellular resistance to ROS. Moreover, we used extensive computational analyses and phenotypic assays to identify amino acids required for MntP activity. These negatively charged residues likely serve to directly bind manganese and transport it from the cytoplasm through the membrane. We further characterized two other potential manganese transporters associated with a Mn-sensing riboswitch and found that the UPF0016 family of proteins has manganese export activity. We provide here the first phenotypic and biochemical evidence for the role of Alx, a member of the TerC family, in manganese homeostasis. It does not appear to export manganese, but rather it intriguingly facilitates an increase in intracellular manganese concentration. These findings expand the available knowledge about the identity and mechanisms of manganese homeostasis proteins across bacteria and show that proximity to a Mn-responsive riboswitch can be used to identify new components of the manganese homeostasis machinery.
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Affiliation(s)
- Rilee Zeinert
- From the Department of Chemistry, University of Wisconsin, Oshkosh, Wisconsin 54901 and
| | - Eli Martinez
- From the Department of Chemistry, University of Wisconsin, Oshkosh, Wisconsin 54901 and
| | - Jennifer Schmitz
- From the Department of Chemistry, University of Wisconsin, Oshkosh, Wisconsin 54901 and
| | - Katherine Senn
- From the Department of Chemistry, University of Wisconsin, Oshkosh, Wisconsin 54901 and
| | - Bakhtawar Usman
- From the Department of Chemistry, University of Wisconsin, Oshkosh, Wisconsin 54901 and
| | - Vivek Anantharaman
- the National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894
| | - L Aravind
- the National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894
| | - Lauren S Waters
- From the Department of Chemistry, University of Wisconsin, Oshkosh, Wisconsin 54901 and
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28
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Arjona FJ, de Baaij JHF. CrossTalk opposing view: CNNM proteins are not Na + /Mg 2+ exchangers but Mg 2+ transport regulators playing a central role in transepithelial Mg 2+ (re)absorption. J Physiol 2018; 596:747-750. [PMID: 29383729 PMCID: PMC5830416 DOI: 10.1113/jp275249] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Francisco J Arjona
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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29
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Magnesium Extravaganza: A Critical Compendium of Current Research into Cellular Mg 2+ Transporters Other than TRPM6/7. Rev Physiol Biochem Pharmacol 2018; 176:65-105. [PMID: 30406297 DOI: 10.1007/112_2018_15] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Magnesium research has boomed within the last 20 years. The real breakthrough came at the start of the new millennium with the discovery of a plethora of possible Mg homeostatic factors that, in particular, included putative Mg2+ transporters. Until that point, Mg research was limited to biochemical and physiological work, as no target molecular entities were known that could be used to explore the molecular biology of Mg homeostasis at the level of the cell, tissue, organ, or organism and to translate such knowledge into the field of clinical medicine and pharmacology. Because of the aforementioned, Mg2+ and Mg homeostasis, both of which had been heavily marginalized within the biomedical field in the twentieth century, have become overnight a focal point of many studies ranging from primary biomedical research to translational medicine.The amount of literature concerning cellular Mg2+ transport and cellular Mg homeostasis is increasing, together with a certain amount of confusion, especially about the function(s) of the newly discovered and, in the majority of instances, still only putative Mg2+ transporters/Mg2+ homeostatic factors. Newcomers to the field of Mg research will thus find it particularly difficult to orient themselves.Here, we briefly but critically summarize the status quo of the current understanding of the molecular entities behind cellular Mg2+ homeostasis in mammalian/human cells other than TRPM6/7 chanzymes, which have been universally accepted as being unspecific cation channel kinases allowing the flux of Mg2+ while constituting the major gateway for Mg2+ to enter the cell.
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30
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The structural basis of proton driven zinc transport by ZntB. Nat Commun 2017; 8:1313. [PMID: 29101379 PMCID: PMC5670123 DOI: 10.1038/s41467-017-01483-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 09/18/2017] [Indexed: 01/09/2023] Open
Abstract
Zinc is an essential microelement to sustain all forms of life. However, excess of zinc is toxic, therefore dedicated import, export and storage proteins for tight regulation of the zinc concentration have evolved. In Enterobacteriaceae, several membrane transporters are involved in zinc homeostasis and linked to virulence. ZntB has been proposed to play a role in the export of zinc, but the transport mechanism of ZntB is poorly understood and based only on experimental characterization of its distant homologue CorA magnesium channel. Here, we report the cryo-electron microscopy structure of full-length ZntB from Escherichia coli together with the results of isothermal titration calorimetry, and radio-ligand uptake and fluorescent transport assays on ZntB reconstituted into liposomes. Our results show that ZntB mediates Zn2+ uptake, stimulated by a pH gradient across the membrane, using a transport mechanism that does not resemble the one proposed for homologous CorA channels. The bacterial zinc transporter ZntB is important for maintaining zinc homeostasis and is mechanistically not well understood. Here, the authors present the cryo-EM structure of ZntB at 4.2 Å resolution, perform transport assays and propose a model for its Zn2+ transport mechanism.
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31
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Armitano J, Redder P, Guimarães VA, Linder P. An Essential Factor for High Mg 2+ Tolerance of Staphylococcus aureus. Front Microbiol 2016; 7:1888. [PMID: 27933050 PMCID: PMC5122736 DOI: 10.3389/fmicb.2016.01888] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/09/2016] [Indexed: 01/14/2023] Open
Abstract
Internal bacterial concentration of Mg2+, the most abundant divalent cation in living cells, is estimated to be in the single millimolar range. However, many bacteria will thrive in media with only micromolars of Mg2+, by using a range of intensely studied and highly efficient import mechanisms, as well as in media with very high magnesium concentration, presumably mediated by currently unknown export mechanisms. Staphylococcus aureus has a particularly high Mg2+ tolerance for a pathogen, growing unimpaired in up to 770 mM Mg2+, and we here identify SA0657, a key factor in this tolerance. The predicted domain structure of SA0657 is shared with a large number of proteins in bacteria, archaea and even eukarya, for example CorB from Salmonella and the human CNNM protein family. One of the shared domains, a CBS pair potentially involved in Mg2+ sensing, contains the conserved Glycine326 which we establish to be a key residue for SA0657 function. In light of our findings, we propose the name MpfA, Magnesium Protection Factor A, for SA0657.
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Affiliation(s)
- Joshua Armitano
- Department of Microbiology and Molecular Medicine, CMU Faculty of Medicine, University of Geneva Geneva, Switzerland
| | - Peter Redder
- Department of Microbiology and Molecular Medicine, CMU Faculty of Medicine, University of Geneva Geneva, Switzerland
| | - Vanessa A Guimarães
- Department of Microbiology and Molecular Medicine, CMU Faculty of Medicine, University of Geneva Geneva, Switzerland
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, CMU Faculty of Medicine, University of Geneva Geneva, Switzerland
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32
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Vaccaro BJ, Lancaster WA, Thorgersen MP, Zane GM, Younkin AD, Kazakov AE, Wetmore KM, Deutschbauer A, Arkin AP, Novichkov PS, Wall JD, Adams MWW. Novel Metal Cation Resistance Systems from Mutant Fitness Analysis of Denitrifying Pseudomonas stutzeri. Appl Environ Microbiol 2016; 82:6046-56. [PMID: 27474723 PMCID: PMC5038046 DOI: 10.1128/aem.01845-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 07/27/2016] [Indexed: 02/02/2023] Open
Abstract
UNLABELLED Metal ion transport systems have been studied extensively, but the specificity of a given transporter is often unclear from amino acid sequence data alone. In this study, predicted Cu(2+) and Zn(2+) resistance systems in Pseudomonas stutzeri strain RCH2 are compared with those experimentally implicated in Cu(2+) and Zn(2+) resistance, as determined by using a DNA-barcoded transposon mutant library. Mutant fitness data obtained under denitrifying conditions are combined with regulon predictions to yield a much more comprehensive picture of Cu(2+) and Zn(2+) resistance in strain RCH2. The results not only considerably expand what is known about well-established metal ion exporters (CzcCBA, CzcD, and CusCBA) and their accessory proteins (CzcI and CusF), they also reveal that isolates with mutations in some predicted Cu(2+) resistance systems do not show decreased fitness relative to the wild type when exposed to Cu(2+) In addition, new genes are identified that have no known connection to Zn(2+) (corB, corC, Psest_3226, Psest_3322, and Psest_0618) or Cu(2+) resistance (Mrp antiporter subunit gene, Psest_2850, and Psest_0584) but are crucial for resistance to these metal cations. Growth of individual deletion mutants lacking corB, corC, Psest_3226, or Psest_3322 confirmed the observed Zn-dependent phenotypes. Notably, to our knowledge, this is the first time a bacterial homolog of TMEM165, a human gene responsible for a congenital glycosylation disorder, has been deleted and the resulting strain characterized. Finally, the fitness values indicate Cu(2+)- and Zn(2+)-based inhibition of nitrite reductase and interference with molybdenum cofactor biosynthesis for nitrate reductase. These results extend the current understanding of Cu(2+) and Zn(2+) efflux and resistance and their effects on denitrifying metabolism. IMPORTANCE In this study, genome-wide mutant fitness data in P. stutzeri RCH2 combined with regulon predictions identify several proteins of unknown function that are involved in resisting zinc and copper toxicity. For zinc, these include a member of the UPF0016 protein family that was previously implicated in Ca(2+)/H(+) antiport and a human congenital glycosylation disorder, CorB and CorC, which were previously linked to Mg(2+) transport, and Psest_3322 and Psest_0618, two proteins with no characterized homologs. Experiments using mutants lacking Psest_3226, Psest_3322, corB, corC, or czcI verified their proposed functions, which will enable future studies of these little-characterized zinc resistance determinants. Likewise, Psest_2850, annotated as an ion antiporter subunit, and the conserved hypothetical protein Psest_0584 are implicated in copper resistance. Physiological connections between previous studies and phenotypes presented here are discussed. Functional and mechanistic understanding of transport proteins improves the understanding of systems in which members of the same protein family, including those in humans, can have different functions.
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Affiliation(s)
- Brian J Vaccaro
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - W Andrew Lancaster
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Michael P Thorgersen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Grant M Zane
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Adam D Younkin
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Alexey E Kazakov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Kelly M Wetmore
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam P Arkin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Pavel S Novichkov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Judy D Wall
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
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33
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Krzysiak TC, Chen BB, Lear T, Mallampalli RK, Gronenborn AM. Crystal structure and interaction studies of the human FBxo3 ApaG domain. FEBS J 2016; 283:2091-101. [PMID: 27010866 DOI: 10.1111/febs.13721] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/15/2016] [Accepted: 03/22/2016] [Indexed: 12/17/2022]
Abstract
UNLABELLED Transcriptional activation of proinflammatory cytokines, mediated by tumor necrosis factor receptor-associated factors (TRAFs), is in part triggered by the degradation of the F-box protein, FBxl2, via an E3 ligase that contains another F-box protein, FBxo3. The ApaG domain of FBxo3 is required for the interaction with and degradation of FBxl2 [Mallampalli RK et al., (2013) J Immunol 191, 5247-5255]. Here, we report the X-ray structure of the human FBxo3 ApaG domain, residues 278-407, at 2.0 Å resolution. Like bacterial ApaG proteins, this domain is characterized by a classic Immunoglobin/Fibronectin III-type fold, comprising a seven-stranded β-sheet core, surrounded by four extended loops. Although cation binding had been proposed for bacterial ApaG proteins, no interactions with Mg(2+) or Co(2+) were detected for the human ApaG domain. In addition, dinucleotide polyphosphates, which have been reported to be second messengers in the inflammation response and targets of the bacterial apaG-containing operon, are not bound by the human ApaG domain. In the context of the full-length protein, loop 1, comprising residues 294-303, is critical for the interaction with FBxl2. However, titration of the individual ApaG domain with a 15-mer FBxl2 peptide that was phosphorylated on the crucial T404, as well as the inability of the ApaG domain to interact with full-length FBxl2, assessed by coimmunoprecipitation, indicate that the ApaG domain alone is necessary, but not sufficient for binding and degradation of FBxl2. DATABASE PDB ID (5HDW).
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Affiliation(s)
- Troy C Krzysiak
- Department of Structural Biology, Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, PA, USA
| | - Bill B Chen
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, PA, USA.,Acute Lung Injury Center of Excellence, University of Pittsburgh School of Medicine, PA, USA
| | - Travis Lear
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, PA, USA.,Acute Lung Injury Center of Excellence, University of Pittsburgh School of Medicine, PA, USA.,Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, PA, USA
| | - Rama K Mallampalli
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, PA, USA.,Acute Lung Injury Center of Excellence, University of Pittsburgh School of Medicine, PA, USA.,Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, PA, USA.,Medical Specialty Service Line, Veterans Affairs Pittsburgh Healthcare System, PA, USA
| | - Angela M Gronenborn
- Department of Structural Biology, Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, PA, USA
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34
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Tanner JR, Li L, Faucher SP, Brassinga AKC. The CpxRA two-component system contributes to Legionella pneumophila virulence. Mol Microbiol 2016; 100:1017-38. [PMID: 26934669 DOI: 10.1111/mmi.13365] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2016] [Indexed: 12/11/2022]
Abstract
The bacterium Legionella pneumophila is capable of intracellular replication within freshwater protozoa as well as human macrophages, the latter of which results in the serious pneumonia Legionnaires' disease. A primary factor involved in these host cell interactions is the Dot/Icm Type IV secretion system responsible for translocating effector proteins needed to establish and maintain the bacterial replicative niche. Several regulatory factors have been identified to control the expression of the Dot/Icm system and effectors, one of which is the CpxRA two-component system, suggesting essentiality for virulence. In this study, we generated cpxR, cpxA and cpxRA in-frame null mutant strains to further delineate the role of the CpxRA system in bacterial survival and virulence. We found that cpxR is essential for intracellular replication within Acanthamoeba castellanii, but not in U937-derived macrophages. Transcriptome analysis revealed that CpxRA regulates a large number of virulence-associated proteins including Dot/Icm effectors as well as Type II secreted substrates. Furthermore, the cpxR and cpxRA mutant strains were more sodium resistant than the parental strain Lp02, and cpxRA expression reaches maximal levels during postexponential phase. Taken together, our findings suggest the CpxRA system is a key contributor to L. pneumophila virulence in protozoa via virulence factor regulation.
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Affiliation(s)
- Jennifer R Tanner
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Laam Li
- Faculty of Agricultural and Environmental Sciences, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Sébastien P Faucher
- Faculty of Agricultural and Environmental Sciences, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Ann Karen C Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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Oda K, Kamiya T, Shikanai Y, Shigenobu S, Yamaguchi K, Fujiwara T. The Arabidopsis Mg Transporter, MRS2-4, is Essential for Mg Homeostasis Under Both Low and High Mg Conditions. PLANT & CELL PHYSIOLOGY 2016; 57:754-63. [PMID: 26748081 DOI: 10.1093/pcp/pcv196] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/25/2015] [Indexed: 05/20/2023]
Abstract
Magnesium (Mg) is an essential macronutrient, functioning as both a cofactor of many enzymes and as a component of Chl. Mg is abundant in plants; however, further investigation of the Mg transporters involved in Mg uptake and distribution is needed. Here, we isolated an Arabidopsis thaliana mutant sensitive to high calcium (Ca) conditions without Mg supplementation. The causal gene of the mutant encodes MRS2-4, an Mg transporter.MRS2-4 single mutants exhibited growth defects under low Mg conditions, whereas an MRS2-4 and MRS2-7 double mutant exhibited growth defects even under normal Mg concentrations. Under normal Mg conditions, the Mg concentration of the MRS2-4 mutant was lower than that of the wild type. The transcriptome profiles of mrs2-4-1 mutants under normal conditions were similar to those of wild-type plants grown under low Mg conditions. In addition, both mrs2-4 and mrs2-7 mutants were sensitive to high levels of Mg. These results indicate that both MRS2-4 and MRS2-7 are essential for Mg homeostasis, even under normal and high Mg conditions. MRS2-4-green fluorescent protein (GFP) was mainly detected in the endoplasmic reticulum. These results indicate that these two MRS2 transporter genes are essential for the ability to adapt to a wide range of environmental Mg concentrations.
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Affiliation(s)
- Koshiro Oda
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Takehiro Kamiya
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Yusuke Shikanai
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Shuji Shigenobu
- National Institute for Basic Biology, Okazaki, Aichi, 444-8585 Japan
| | | | - Toru Fujiwara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657 Japan
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Feldheim YS, Zusman T, Speiser Y, Segal G. The Legionella pneumophila CpxRA two-component regulatory system: new insights into CpxR's function as a dual regulator and its connection to the effectors regulatory network. Mol Microbiol 2016; 99:1059-79. [PMID: 26713766 DOI: 10.1111/mmi.13290] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2015] [Indexed: 12/22/2022]
Abstract
Legionella pneumophila utilizes the Icm/Dot type-IV secretion system to translocate approximately 300 effector proteins into host cells, and the CpxRA two-component system (TCS) was previously shown to regulate the expression of several of these effectors. In this study, we expanded the pool of L. pneumophila CpxR-regulated genes to 38, including 27 effector-encoding genes. Our study demonstrates for the first time that the CpxR dual regulator has different requirements for activation and repression of target genes. These differences include the positioning of the CpxR regulatory element relative to the promoter element, and the effect of CpxR phosphate donors on the expression of CpxR target genes. In addition, unlike most response regulators, a mutant form of the L. pneumophila CpxR which cannot be phosphorylated was found to self-interact, and to repress gene expression similarly to wild-type CpxR, even though its ability to activate gene expression was reduced. Moreover, the CpxRA TCS was found to activate the expression of LetE which was found to function as a connector protein between the CpxRA TCS and the LetAS-RsmYZ-CsrA regulatory cascade. Our results show that CpxR plays a major role in L. pneumophila pathogenesis gene expression and functions as part of a regulatory network.
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Affiliation(s)
- Yaron S Feldheim
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Tal Zusman
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Yariv Speiser
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Gil Segal
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel
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Takahashi S, Takayanagi A, Takahashi Y, Oshima T, Nishida H. Comparison of transcriptomes of enlarged spheroplasts of Erythrobacter litoralis and Lelliottia amnigena. AIMS Microbiol 2016. [DOI: 10.3934/microbiol.2016.2.152] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Deciphering Mineral Homeostasis in Barley Seed Transfer Cells at Transcriptional Level. PLoS One 2015; 10:e0141398. [PMID: 26536247 PMCID: PMC4633283 DOI: 10.1371/journal.pone.0141398] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022] Open
Abstract
In addition to the micronutrient inadequacy of staple crops for optimal human nutrition, a global downtrend in crop-quality has emerged from intensive breeding for yield. This trend will be aggravated by elevated levels of the greenhouse gas carbon dioxide. Therefore, crop biofortification is inevitable to ensure a sustainable supply of minerals to the large part of human population who is dietary dependent on staple crops. This requires a thorough understanding of plant-mineral interactions due to the complexity of mineral homeostasis. Employing RNA sequencing, we here communicate transfer cell specific effects of excess iron and zinc during grain filling in our model crop plant barley. Responding to alterations in mineral contents, we found a long range of different genes and transcripts. Among them, it is worth to highlight the auxin and ethylene signaling factors Arfs, Abcbs, Cand1, Hps4, Hac1, Ecr1, and Ctr1, diurnal fluctuation components Sdg2, Imb1, Lip1, and PhyC, retroelements, sulfur homeostasis components Amp1, Hmt3, Eil3, and Vip1, mineral trafficking components Med16, Cnnm4, Aha2, Clpc1, and Pcbps, and vacuole organization factors Ymr155W, RabG3F, Vps4, and Cbl3. Our analysis introduces new interactors and signifies a broad spectrum of regulatory levels from chromatin remodeling to intracellular protein sorting mechanisms active in the plant mineral homeostasis. The results highlight the importance of storage proteins in metal ion toxicity-resistance and chelation. Interestingly, the protein sorting and recycling factors Exoc7, Cdc1, Sec23A, and Rab11A contributed to the response as well as the polar distributors of metal-transporters ensuring the directional flow of minerals. Alternative isoform switching was found important for plant adaptation and occurred among transcripts coding for identical proteins as well as transcripts coding for protein isoforms. We also identified differences in the alternative-isoform preference between the treatments, indicating metal-affinity shifts among isoforms of metal transporters. Most important, we found the zinc treatment to impair both photosynthesis and respiration. A wide range of transcriptional changes including stress-related genes and negative feedback loops emphasize the importance to withhold mineral contents below certain cellular levels which otherwise might lead to agronomical impeding side-effects. By illustrating new mechanisms, genes, and transcripts, this report provides a solid platform towards understanding the complex network of plant mineral homeostasis.
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Abstract
This review reviews the properties and regulation of the Salmonella enterica serovar Typhimurium and Escherichia coli transporters that mediate Mg2+ influx: CorA and the Mgt P-type ATPases. In addition, potential Mg2+ regulation of transcription and translation, largely via the PhoPQ two component system, is discussed. CorA proteins are a unique class of transporters and are widespread in the Bacteria and Archaea, with rather distant but functional homologs in eukaryotes. The Mgt transporters are highly homologous to other P-type ATPases but are more closely related to the eukaryotic H+ and Ca2+ ATPases than to most prokaryotic ATPases. Hundreds of homologs of CorA are currently known from genomic sequencing. In contrast, only when extracellular and possibly intracellular Mg2+ levels fall significantly is the expression of mgtA and mgtB induced. Topology studies using blaM and lacZ fusions initially indicated that the Salmonella serovar Typhimurium CorA contained three transmembrane (TM) segments; however, subsequent data obtained using a variety of approaches showed that the CorA superfamily of proteins have only two TMs at the extreme C terminus. PhoP-PhoQ is a two-component system consisting of PhoQ, the sensor/receptor histidine kinase, and PhoP, the response regulator/transcriptional activator. The expression of both mgtA and mgtCB in either E. coli or Salmonella serovar Typhimurium is markedly induced in a PhoPQ-dependent manner by low concentrations of Mg2+ in the medium. phoP and phoQ form an operon with two promoters in both E. coli and Salmonella serovar Typhimurium.
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Ishijima S, Uda M, Hirata T, Shibata M, Kitagawa N, Sagami I. Magnesium uptake of Arabidopsis transporters, AtMRS2-10 and AtMRS2-11, expressed in Escherichia coli mutants: Complementation and growth inhibition by aluminum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1376-82. [DOI: 10.1016/j.bbamem.2015.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/09/2015] [Accepted: 03/06/2015] [Indexed: 10/23/2022]
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Nucleotide binding triggers a conformational change of the CBS module of the magnesium transporter CNNM2 from a twisted towards a flat structure. Biochem J 2015; 464:23-34. [PMID: 25184538 DOI: 10.1042/bj20140409] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Recent studies suggest CNNM2 (cyclin M2) to be part of the long-sought basolateral Mg2+ extruder at the renal distal convoluted tubule, or its regulator. In the present study, we explore structural features and ligand-binding capacities of the Bateman module of CNNM2 (residues 429-584), an intracellular domain structurally equivalent to the region involved in Mg2+ handling by the bacterial Mg2+ transporter MgtE, and AMP binding by the Mg2+ efflux protein CorC. Additionally, we studied the structural impact of the pathogenic mutation T568I located in this region. Our crystal structures reveal that nucleotides such as AMP, ADP or ATP bind at only one of the two cavities present in CNNM2429-584. Mg2+ favours ATP binding by alleviating the otherwise negative charge repulsion existing between acidic residues and the polyphosphate group of ATP. In crystals CNNM2429-584 forms parallel dimers, commonly referred to as CBS (cystathionine β-synthase) modules. Interestingly, nucleotide binding triggers a conformational change in the CBS module from a twisted towards a flat disc-like structure that mostly affects the structural elements connecting the Bateman module with the transmembrane region. We furthermore show that the T568I mutation, which causes dominant hypomagnesaemia, mimics the structural effect induced by nucleotide binding. The results of the present study suggest that the T568I mutation exerts its pathogenic effect in humans by constraining the conformational equilibrium of the CBS module of CNNM2, which becomes 'locked' in its flat form.
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Hirata Y, Funato Y, Miki H. Basolateral sorting of the Mg²⁺ transporter CNNM4 requires interaction with AP-1A and AP-1B. Biochem Biophys Res Commun 2014; 455:184-9. [PMID: 25449265 DOI: 10.1016/j.bbrc.2014.10.138] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 10/28/2014] [Indexed: 12/14/2022]
Abstract
Ancient conserved domain protein/cyclin M (CNNM) 4 is an evolutionarily conserved Mg(2+) transporter that localizes at the basolateral membrane of the intestinal epithelia. Here, we show the complementary importance of clathrin adaptor protein (AP) complexes AP-1A and AP-1B in basolateral sorting of CNNM4. We first confirmed the basolateral localization of both endogenous and ectopically expressed CNNM4 in Madin-Darby Canine Kidney cells, which form highly polarized epithelia in culture. Single knockdown of μ1B, a cargo-recognition subunit of AP-1B, did not affect basolateral localization, but simultaneous knockdown of the μ1A subunit of AP-1A abrogated localization. Mutational analyses showed the importance of three conserved dileucine motifs in CNNM4 for both basolateral sorting and interaction with μ1A and μ1B. These results imply that CNNM4 is sorted to the basolateral membrane by the complementary function of AP-1A and AP-1B.
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Affiliation(s)
- Yusuke Hirata
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Yosuke Funato
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiroaki Miki
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Gillespie JJ, Kaur SJ, Rahman MS, Rennoll-Bankert K, Sears KT, Beier-Sexton M, Azad AF. Secretome of obligate intracellular Rickettsia. FEMS Microbiol Rev 2014; 39:47-80. [PMID: 25168200 DOI: 10.1111/1574-6976.12084] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The genus Rickettsia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) is comprised of obligate intracellular parasites, with virulent species of interest both as causes of emerging infectious diseases and for their potential deployment as bioterrorism agents. Currently, there are no effective commercially available vaccines, with treatment limited primarily to tetracycline antibiotics, although others (e.g. josamycin, ciprofloxacin, chloramphenicol, and azithromycin) are also effective. Much of the recent research geared toward understanding mechanisms underlying rickettsial pathogenicity has centered on characterization of secreted proteins that directly engage eukaryotic cells. Herein, we review all aspects of the Rickettsia secretome, including six secretion systems, 19 characterized secretory proteins, and potential moonlighting proteins identified on surfaces of multiple Rickettsia species. Employing bioinformatics and phylogenomics, we present novel structural and functional insight on each secretion system. Unexpectedly, our investigation revealed that the majority of characterized secretory proteins have not been assigned to their cognate secretion pathways. Furthermore, for most secretion pathways, the requisite signal sequences mediating translocation are poorly understood. As a blueprint for all known routes of protein translocation into host cells, this resource will assist research aimed at uniting characterized secreted proteins with their apposite secretion pathways. Furthermore, our work will help in the identification of novel secreted proteins involved in rickettsial 'life on the inside'.
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Affiliation(s)
- Joseph J Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Simran J Kaur
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - M Sayeedur Rahman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristen Rennoll-Bankert
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Khandra T Sears
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Magda Beier-Sexton
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Abdu F Azad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
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Abstract
Mg(2+) and K(+) are the prevalent di- and monovalent cations inside the cells in all three domains, playing a dominant role in structure and function of biological macromolecules. Ribosomes bind a substantial fraction of total Mg(2+) and K(+) cations. In this issue of the Journal of Bacteriology, Akanuma and coworkers (G. Akanuma et al., J. Bacteriol. 196:3820-3830, 2014, doi:10.1128/JB.01896-14) report a surprising genetic link between ribosome amounts per cell and the intracellular Mg(2+) concentrations.
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Defect in the formation of 70S ribosomes caused by lack of ribosomal protein L34 can be suppressed by magnesium. J Bacteriol 2014; 196:3820-30. [PMID: 25182490 DOI: 10.1128/jb.01896-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To elucidate the biological functions of the ribosomal protein L34, which is encoded by the rpmH gene, the rpmH deletion mutant of Bacillus subtilis and two suppressor mutants were characterized. Although the ΔrpmH mutant exhibited a severe slow-growth phenotype, additional mutations in the yhdP or mgtE gene restored the growth rate of the ΔrpmH strain. Either the disruption of yhdP, which is thought to be involved in the efflux of Mg(2+), or overexpression of mgtE, which plays a major role in the import of Mg(2+), could suppress defects in both the formation of the 70S ribosome and growth caused by the absence of L34. Interestingly, the Mg(2+) content was lower in the ΔrpmH cells than in the wild type, and the Mg(2+) content in the ΔrpmH cells was restored by either the disruption of yhdP or overexpression of mgtE. In vitro experiments on subunit association demonstrated that 50S subunits that lacked L34 could form 70S ribosomes only at a high concentration of Mg(2+). These results showed that L34 is required for efficient 70S ribosome formation and that L34 function can be restored partially by Mg(2+). In addition, the Mg(2+) content was consistently lower in mutants that contained significantly reduced amounts of the 70S ribosome, such as the ΔrplA (L1) and ΔrplW (L23) strains and mutant strains with a reduced number of copies of the rrn operon. Thus, the results indicated that the cellular Mg(2+) content is influenced by the amount of 70S ribosomes.
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46
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Islam Z, Hayashi N, Inoue H, Umezawa T, Kimura Y, Doi H, Romero MF, Hirose S, Kato A. Identification and lateral membrane localization of cyclin M3, likely to be involved in renal Mg2+ handling in seawater fish. Am J Physiol Regul Integr Comp Physiol 2014; 307:R525-37. [PMID: 24965791 DOI: 10.1152/ajpregu.00032.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The kidney of marine teleosts is the major site of Mg(2+) excretion and produces urine with a high Mg(2+) concentration. However, the transporters involved in Mg(2+) excretion are poorly understood. The cyclin M (Cnnm; also known as ancient conserved domain protein) family comprises membrane proteins homologous to the bacterial Mg(2+) and Co(2+) efflux protein, CorC. To understand the molecular mechanism of Mg(2+) homeostasis in marine teleosts, we analyzed the expression of the Cnnm family genes in the seawater (SW) pufferfish, torafugu (Takifugu rubripes), and the closely related euryhaline species, mefugu (Takifugu obscurus). Database mining and phylogenetic analysis indicated that the Takifugu genome contains six members of the Cnnm family: two orthologs of Cnnm1, one of Cnnm2, one of Cnnm3, and two of Cnnm4. RT-PCR analyses indicated that Cnnm2, Cnnm3, and Cnnm4a are expressed in the kidney, whereas other members are mainly expressed in the brain. Renal expression of Cnnm3 was upregulated in SW mefugu, whereas renal expression of Cnnm2 was upregulated in freshwater (FW) mefugu. No significant difference was observed in renal expression of Cnnm4a between SW and FW mefugu. In situ hybridization and immunohistochemical analyses of the SW mefugu kidney revealed that Cnnm3 is expressed in the proximal tubule, and its product localizes to the lateral membrane. When Cnnm3 was expressed in Xenopus laevis oocytes, whole cellular Mg(2+) content and free intracellular Mg(2+) activity significantly decreased. These results suggest that Cnnm3 is involved in body fluid Mg(2+) homeostasis in marine teleosts.
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Affiliation(s)
- Zinia Islam
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
| | - Naoko Hayashi
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
| | - Hana Inoue
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
| | - Takahiro Umezawa
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
| | - Yuuri Kimura
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroyuki Doi
- Shimonoseki Marine Science Museum, Shimonoseki, Japan
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota; Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, Minnesota; and O'Brien Urology Research Center, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Shigehisa Hirose
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
| | - Akira Kato
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan; Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota;
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Hirata Y, Funato Y, Takano Y, Miki H. Mg2+-dependent interactions of ATP with the cystathionine-β-synthase (CBS) domains of a magnesium transporter. J Biol Chem 2014; 289:14731-9. [PMID: 24706765 DOI: 10.1074/jbc.m114.551176] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Ancient conserved domain protein/cyclin M (CNNM) family proteins are evolutionarily conserved Mg(2+) transporters. However, their biochemical mechanism of action remains unknown. Here, we show the functional importance of the commonly conserved cystathionine-β-synthase (CBS) domains and reveal their unique binding ability to ATP. Deletion mutants of CNNM2 and CNNM4, lacking the CBS domains, are unable to promote Mg(2+) efflux. Furthermore, the substitution of one amino acid residue in the CBS domains of CNNM2, which is associated with human hereditary hypomagnesemia, abrogates Mg(2+) efflux. Binding analyses reveal that the CBS domains of CNNM2 bind directly to ATP and not AMP in a manner dependent on the presence of Mg(2+), which is inhibited in a similar pattern by the disease-associated amino acid substitution. The requirement of Mg(2+) for these interactions is a unique feature among CBS domains, which can be explained by the presence of highly electronegative surface potentials around the ATP binding site on CNNM2. These results demonstrate that the CBS domains play essential roles in Mg(2+) efflux, probably through interactions with ATP. Interactions with ATP, which mostly forms complexes with Mg(2+) in cells, may account for the rapid Mg(2+) transport by CNNM family proteins.
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Affiliation(s)
- Yusuke Hirata
- From the Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan and
| | - Yosuke Funato
- From the Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan and
| | - Yu Takano
- the Laboratory of Protein Informatics, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hiroaki Miki
- From the Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan and
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Basolateral Mg2+ extrusion via CNNM4 mediates transcellular Mg2+ transport across epithelia: a mouse model. PLoS Genet 2013; 9:e1003983. [PMID: 24339795 PMCID: PMC3854942 DOI: 10.1371/journal.pgen.1003983] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 10/15/2013] [Indexed: 12/24/2022] Open
Abstract
Transcellular Mg2+ transport across epithelia, involving both apical entry and basolateral extrusion, is essential for magnesium homeostasis, but molecules involved in basolateral extrusion have not yet been identified. Here, we show that CNNM4 is the basolaterally located Mg2+ extrusion molecule. CNNM4 is strongly expressed in intestinal epithelia and localizes to their basolateral membrane. CNNM4-knockout mice showed hypomagnesemia due to the intestinal malabsorption of magnesium, suggesting its role in Mg2+ extrusion to the inner parts of body. Imaging analyses revealed that CNNM4 can extrude Mg2+ by exchanging intracellular Mg2+ with extracellular Na+. Furthermore, CNNM4 mutations cause Jalili syndrome, characterized by recessive amelogenesis imperfecta with cone-rod dystrophy. CNNM4-knockout mice showed defective amelogenesis, and CNNM4 again localizes to the basolateral membrane of ameloblasts, the enamel-forming epithelial cells. Missense point mutations associated with the disease abolish the Mg2+ extrusion activity. These results demonstrate the crucial importance of Mg2+ extrusion by CNNM4 in organismal and topical regulation of magnesium. Magnesium is an essential element for living organisms. Its absorption occurs at the intestine through the barrier comprised of epithelial cells. In this process, transcellular Mg2+ transport across epithelia, involving both entry from one side and extrusion from the other side, is important. Previous studies have revealed the role of Mg2+-permeable channel protein in Mg2+ entry into the epithelial cells. However, the identity of proteins involved in Mg2+ extrusion to the inner parts of body has remained unknown. Mice genetically engineered not to express CNNM4, which localizes to the epithelial membrane facing to the inner parts of body, show hypomagnesemia due to the defect in magnesium absorption. Functional analyses using culture cells directly reveal that CNNM4 can extrude intracellular Mg2+ to the outside of cells. These results indicate that CNNM4 mediates transcellular Mg2+ transport across the intestinal epithelia. Furthermore, we also show that these CNNM4-lacking mice also have a defect in amelogenesis, which is consistent with the disease symptoms of Jalili syndrome that is known to be caused by mutations in the CNNM4 gene.
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Charles RC, Sultana T, Alam MM, Yu Y, Wu-Freeman Y, Bufano MK, Rollins SM, Tsai L, Harris JB, LaRocque RC, Leung DT, Brooks WA, Nga TVT, Dongol S, Basnyat B, Calderwood SB, Farrar J, Khanam F, Gunn JS, Qadri F, Baker S, Ryan ET. Identification of immunogenic Salmonella enterica serotype Typhi antigens expressed in chronic biliary carriers of S. Typhi in Kathmandu, Nepal. PLoS Negl Trop Dis 2013; 7:e2335. [PMID: 23936575 PMCID: PMC3731212 DOI: 10.1371/journal.pntd.0002335] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/12/2013] [Indexed: 11/21/2022] Open
Abstract
Background Salmonella enterica serotype Typhi can colonize and persist in the biliary tract of infected individuals, resulting in a state of asymptomatic chronic carriage. Chronic carriers may act as persistent reservoirs of infection within a community and may introduce infection to susceptible individuals and new communities. Little is known about the interaction between the host and pathogen in the biliary tract of chronic carriers, and there is currently no reliable diagnostic assay to identify asymptomatic S. Typhi carriage. Methodology/Principal Findings To study host-pathogen interactions in the biliary tract during S. Typhi carriage, we applied an immunoscreening technique called in vivo-induced antigen technology (IVIAT), to identify potential biomarkers unique to carriers. IVIAT identifies humorally immunogenic bacterial antigens expressed uniquely in the in vivo environment, and we hypothesized that S. Typhi surviving in the biliary tract of humans may express a distinct antigenic profile. Thirteen S. Typhi antigens that were immunoreactive in carriers, but not in healthy individuals from a typhoid endemic area, were identified. The identified antigens included a number of putative membrane proteins, lipoproteins, and hemolysin-related proteins. YncE (STY1479), an uncharacterized protein with an ATP-binding motif, gave prominent responses in our screen. The response to YncE in patients whose biliary tract contained S. Typhi was compared to responses in patients whose biliary tract did not contain S. Typhi, patients with acute typhoid fever, and healthy controls residing in a typhoid endemic area. Seven of 10 (70%) chronic carriers, 0 of 8 bile culture-negative controls (0%), 0 of 8 healthy Bangladeshis (0%), and 1 of 8 (12.5%) Bangladeshis with acute typhoid fever had detectable anti-YncE IgG in blood. IgA responses were also present. Conclusions/Significance Further evaluation of YncE and other antigens identified by IVIAT could lead to the development of improved diagnostic assays to identify asymptomatic S. Typhi carriers. Salmonella enterica serotype Typhi is the cause of typhoid fever and infects over 21 million individuals and causes 200,000 deaths each year. With adequate treatment, most patients recover from their acute stage of illness and clear infection. However, a small percentage of S. Typhi infected individuals develop a chronic but asymptomatic infection in the biliary tract that can persist for decades. Since S. Typhi is a human-restricted pathogen, chronic carriers may act as reservoirs of infection. Correctly identifying and treating asymptomatic chronic carriers could be critical for ultimate control of typhoid fever. Using an immunoscreening technique called in vivo-induced antigen technology (IVIAT), we have identified potential biomarkers unique to S. Typhi chronic carriers. Further evaluation of these antigens could lead to the development of improved diagnostic assays to detect asymptomatic S. Typhi carriers in typhoid endemic zones, and to an improved understanding of the pathogenesis of S. Typhi in the chronic carrier state.
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Affiliation(s)
- Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA.
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Islam Z, Hayashi N, Yamamoto Y, Doi H, Romero MF, Hirose S, Kato A. Identification and proximal tubular localization of the Mg²⁺ transporter, Slc41a1, in a seawater fish. Am J Physiol Regul Integr Comp Physiol 2013; 305:R385-96. [PMID: 23761638 DOI: 10.1152/ajpregu.00507.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The second most abundant cation in seawater (SW), Mg²⁺, is present at concentrations of ~53 mM. Marine teleosts maintain plasma Mg²⁺ concentration at 1-2 mM by excreting Mg²⁺ into the urine. Urine Mg²⁺ concentrations of SW teleosts exceed 70 mM, most of which is secreted by the renal tubular epithelial cells. However, molecular mechanisms of the Mg²⁺ secretion have yet to be clarified. To identify transporters involved in Mg²⁺ secretion, we analyzed the expression of fish homologs of the Slc41 Mg²⁺ transporter family in various tissues of SW pufferfish torafugu (Takifugu rubripes) and its closely related euryhaline species mefugu (Takifugu obscurus). Takifugu genome contained five members of Slc41 genes, and only Slc41a1 was highly expressed in the kidney. Renal expression of Slc41a1 was markedly elevated when mefugu were transferred from fresh water (FW) to SW. In situ hybridization analysis and immunohistochemistry at the light and electron microscopic levels revealed that Slc41a1 is localized to vacuoles in the apical cytoplasm of the proximal tubules. These results suggest that pufferfish Slc41a1 is a Mg²⁺ transporter involved in renal tubular transepithelial Mg²⁺ secretion by mediating Mg²⁺ transport from the cytosol to the vacuolar lumen, and support the hypothesis that Mg²⁺ secretion is mediated by exocytosis of Mg²⁺-rich vacuoles to the lumen.
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Affiliation(s)
- Zinia Islam
- Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
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