1
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Wang J, Zhu H, Huang R, Xu J, Huang L, Yang J, Chen W. CIP1, a CIPK23-interacting transporter, is implicated in Cd tolerance and phytoremediation. JOURNAL OF HAZARDOUS MATERIALS 2024; 471:134276. [PMID: 38640682 DOI: 10.1016/j.jhazmat.2024.134276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 04/07/2024] [Accepted: 04/09/2024] [Indexed: 04/21/2024]
Abstract
Environmental pollution from cadmium (Cd) presents a serious threat to plant growth and development. Therefore, it's crucial to find out how plants resist this toxic metal to develop strategies for remediating Cd-contaminated soils. In this study, we identified CIP1, a transporter protein, by screening interactors of the protein kinase CIPK23. CIP1 is located in vesicles membranes and can transport Cd2+ when expressed in yeast cells. Cd stress specifically induced the accumulation of CIP1 transcripts and functional proteins, particularly in the epidermal cells of the root tip. CIKP23 could interact directly with the central loop region of CIP1, phosphorylating it, which is essential for the efficient transport of Cd2+. A loss-of-function mutation of CIP1 in wild-type plants led to increased sensitivity to Cd stress. Conversely, tobacco plants overexpressing CIP1 exhibited improved Cd tolerance and increased Cd accumulation capacity. Interestingly, this Cd accumulation was restricted to roots but not shoots, suggesting that manipulating CIP1 does not risk Cd contamination of plants' edible parts. Overall, this study characterizes a novel Cd transporter, CIP1, with potential to enhance plant tolerance to Cd toxicity while effectively eliminating environmental contamination without economic losses.
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Affiliation(s)
- Jiayi Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Huihui Zhu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Vegetable Biology, College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Ru'nan Huang
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China
| | - Jiming Xu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Li Huang
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou 310058, China
| | - Jianli Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Vegetable Biology, College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China.
| | - Weiwei Chen
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China.
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2
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Panchal P, Bhatia C, Chen Y, Sharma M, Bhadouria J, Verma L, Maurya K, Miller AJ, Giri J. A citrate efflux transporter important for manganese distribution and phosphorus uptake in rice. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1748-1765. [PMID: 37715733 DOI: 10.1111/tpj.16463] [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] [Received: 11/29/2022] [Revised: 08/26/2023] [Accepted: 09/01/2023] [Indexed: 09/18/2023]
Abstract
The plant citrate transporters, functional in mineral nutrient uptake and homeostasis, usually belong to the multidrug and toxic compound extrusion transporter family. We identified and functionally characterized a rice (Oryza sativa) citrate transporter, OsCT1, which differs from known plant citrate transporters and is structurally close to rice silicon transporters. Domain analysis depicted that OsCT1 carries a bacterial citrate-metal transporter domain, CitMHS. OsCT1 showed citrate efflux activity when expressed in Xenopus laevis oocytes and is localized to the cell plasma membrane. It is highly expressed in the shoot and reproductive tissues of rice, and its promoter activity was visible in cells surrounding the vasculature. The OsCT1 knockout (KO) lines showed a reduced citrate content in the shoots and the root exudates, whereas overexpression (OE) line showed higher citrate exudation from their roots. Further, the KO and OE lines showed variations in the manganese (Mn) distribution leading to changes in their agronomical traits. Under deficient conditions (Mn-sufficient conditions followed by 8 days of 0 μm MnCl2 · 4H2 O treatment), the supply of manganese towards the newer leaf was found to be obstructed in the KO line. There were no significant differences in phosphorus (P) distribution; however, P uptake was reduced in the KO and increased in OE lines at the vegetative stage. Further, experiments in Xenopus oocytes revealed that OsCT1 could efflux citrate with Mn. In this way, we provide insights into a mechanism of citrate-metal transport in plants and its role in mineral homeostasis, which remains conserved with their bacterial counterparts.
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Affiliation(s)
- Poonam Panchal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Chitra Bhatia
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Yi Chen
- Biochemistry and Metabolism Department, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Meenakshi Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Jyoti Bhadouria
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Lokesh Verma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Kanika Maurya
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Anthony J Miller
- Biochemistry and Metabolism Department, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Jitender Giri
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
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3
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Ramoneda J, Stallard-Olivera E, Hoffert M, Winfrey CC, Stadler M, Niño-García JP, Fierer N. Building a genome-based understanding of bacterial pH preferences. SCIENCE ADVANCES 2023; 9:eadf8998. [PMID: 37115929 PMCID: PMC10146879 DOI: 10.1126/sciadv.adf8998] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The environmental preferences of many microbes remain undetermined. This is the case for bacterial pH preferences, which can be difficult to predict a priori despite the importance of pH as a factor structuring bacterial communities in many systems. We compiled data on bacterial distributions from five datasets spanning pH gradients in soil and freshwater systems (1470 samples), quantified the pH preferences of bacterial taxa across these datasets, and compiled genomic data from representative bacterial taxa. While taxonomic and phylogenetic information were generally poor predictors of bacterial pH preferences, we identified genes consistently associated with pH preference across environments. We then developed and validated a machine learning model to estimate bacterial pH preferences from genomic information alone, a model that could aid in the selection of microbial inoculants, improve species distribution models, or help design effective cultivation strategies. More generally, we demonstrate the value of combining biogeographic and genomic data to infer and predict the environmental preferences of diverse bacterial taxa.
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Affiliation(s)
- Josep Ramoneda
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Corresponding author. (J.R.); (N.F.)
| | - Elias Stallard-Olivera
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Michael Hoffert
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Claire C. Winfrey
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Masumi Stadler
- Département des Sciences Biologiques, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-Ville, Montréal, QC H3C 3P8, Canada
| | - Juan Pablo Niño-García
- Département des Sciences Biologiques, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-Ville, Montréal, QC H3C 3P8, Canada
- Escuela de Microbiología, Universidad de Antioquia, Ciudad Universitaria Calle 67 No 12 53-108, Medellín, Colombia
| | - Noah Fierer
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
- Corresponding author. (J.R.); (N.F.)
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Abstract
Tricarboxylates such as citrate are the preferred carbon sources for Pseudomonas aeruginosa, an opportunistic pathogen that causes chronic human infections. However, the membrane transport process for the tricarboxylic acid cycle intermediates citrate and cis-aconitate is poorly characterized. Transport is thought to be controlled by the TctDE two-component system, which mediates transcription of the putative major transporter OpdH. Here, we search for previously unidentified transporters of citrate and cis-aconitate using both protein homology and RNA sequencing approaches. We uncover new transporters and show that OpdH is not the major citrate importer; instead, citrate transport primarily relies on the tripartite TctCBA system, which is encoded in the opdH operon. Deletion of tctA causes a growth lag on citrate and loss of growth on cis-aconitate. Combinatorial deletion of newly discovered transporters can fully block citrate utilization. We then characterize transcriptional control of the opdH operon in tctDE mutants and show that loss of tctD blocks citrate utilization due to an inability to express opdH-tctCBA. However, tctE and tctDE mutants evolve heritable adaptations that restore growth on citrate as the sole carbon source. IMPORTANCE Pseudomonas aeruginosa is a bacterium that infects hospitalized patients and is often highly resistant to antibiotic treatment. It preferentially uses small organic acids called tricarboxylates rather than sugars as a source of carbon for growth. The transport of many of these molecules from outside the cell to the interior occurs through unknown channels. Here, we examined how the tricarboxylates citrate and cis-aconitate are transported in P. aeruginosa. We then sought to understand how production of proteins that permit citrate and cis-aconitate transport is regulated by a signaling system called TctDE. We identified new transporters for these molecules, clarified the function of a known transport system, and directly tied transporter expression to the presence of an intact TctDE system.
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Li H, Ramia NE, Borges F, Revol-Junelles AM, Vogensen FK, Leisner JJ. Identification of Potential Citrate Metabolism Pathways in Carnobacterium maltaromaticum. Microorganisms 2021; 9:microorganisms9102169. [PMID: 34683489 PMCID: PMC8537297 DOI: 10.3390/microorganisms9102169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 11/16/2022] Open
Abstract
In the present study, we describe the identification of potential citrate metabolism pathways for the lactic acid bacterium (LAB) Carnobacterium maltaromaticum. A phenotypic assay indicated that four of six C. maltaromaticum strains showed weak (Cm 6-1 and ATCC 35586) or even delayed (Cm 3-1 and Cm 5-1) citrate utilization activity. The remaining two strains, Cm 4-1 and Cm 1-2 gave negative results. Additional analysis showed no or very limited utilization of citrate in media containing 1% glucose and 22 or 30 mM citrate and inoculated with Cm 6-1 or ATCC 35586. Two potential pathways of citrate metabolism were identified by bioinformatics analyses in C. maltaromaticum including either oxaloacetate (pathway 1) or tricarboxylic compounds such as isocitrate and α-ketoglutarate (pathway 2) as intermediates. Genes encoding pathway 1 were present in two out of six strains while pathway 2 included genes present in all six strains. The two potential citrate metabolism pathways in C. maltaromaticum may potentially affect the sensory profiles of milk and soft cheeses subjected to growth with this species.
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Affiliation(s)
- Heng Li
- Pasteurien College, Soochow University, Suzhou 215123, China;
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark
| | - Nancy E. Ramia
- Laboratoire d’Ingénierie des Biomolécules (LIBio), Ecole Nationale Supérieure d’Agronomie et des Industries Alimentaires (ENSAIA), Université de Lorraine, LIBio, F-54000 Nancy, France; (N.E.R.); (F.B.); (A.-M.R.-J.)
| | - Frédéric Borges
- Laboratoire d’Ingénierie des Biomolécules (LIBio), Ecole Nationale Supérieure d’Agronomie et des Industries Alimentaires (ENSAIA), Université de Lorraine, LIBio, F-54000 Nancy, France; (N.E.R.); (F.B.); (A.-M.R.-J.)
| | - Anne-Marie Revol-Junelles
- Laboratoire d’Ingénierie des Biomolécules (LIBio), Ecole Nationale Supérieure d’Agronomie et des Industries Alimentaires (ENSAIA), Université de Lorraine, LIBio, F-54000 Nancy, France; (N.E.R.); (F.B.); (A.-M.R.-J.)
| | - Finn Kvist Vogensen
- Department of Food Science, Faculty of Science, University of Copenhagen, DK-1958 Frederiksberg, Denmark;
| | - Jørgen J. Leisner
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark
- Correspondence:
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6
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Consequences of NaCT/SLC13A5/mINDY deficiency: good versus evil, separated only by the blood-brain barrier. Biochem J 2021; 478:463-486. [PMID: 33544126 PMCID: PMC7868109 DOI: 10.1042/bcj20200877] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
NaCT/SLC13A5 is a Na+-coupled transporter for citrate in hepatocytes, neurons, and testes. It is also called mINDY (mammalian ortholog of ‘I'm Not Dead Yet’ in Drosophila). Deletion of Slc13a5 in mice leads to an advantageous phenotype, protecting against diet-induced obesity, and diabetes. In contrast, loss-of-function mutations in SLC13A5 in humans cause a severe disease, EIEE25/DEE25 (early infantile epileptic encephalopathy-25/developmental epileptic encephalopathy-25). The difference between mice and humans in the consequences of the transporter deficiency is intriguing but probably explainable by the species-specific differences in the functional features of the transporter. Mouse Slc13a5 is a low-capacity transporter, whereas human SLC13A5 is a high-capacity transporter, thus leading to quantitative differences in citrate entry into cells via the transporter. These findings raise doubts as to the utility of mouse models to evaluate NaCT biology in humans. NaCT-mediated citrate entry in the liver impacts fatty acid and cholesterol synthesis, fatty acid oxidation, glycolysis, and gluconeogenesis; in neurons, this process is essential for the synthesis of the neurotransmitters glutamate, GABA, and acetylcholine. Thus, SLC13A5 deficiency protects against obesity and diabetes based on what the transporter does in hepatocytes, but leads to severe brain deficits based on what the transporter does in neurons. These beneficial versus detrimental effects of SLC13A5 deficiency are separable only by the blood-brain barrier. Can we harness the beneficial effects of SLC13A5 deficiency without the detrimental effects? In theory, this should be feasible with selective inhibitors of NaCT, which work only in the liver and do not get across the blood-brain barrier.
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7
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Byrd N, Lloyd JR, Small JS, Taylor F, Bagshaw H, Boothman C, Morris K. Microbial Degradation of Citric Acid in Low Level Radioactive Waste Disposal: Impact on Biomineralization Reactions. Front Microbiol 2021; 12:565855. [PMID: 33995289 PMCID: PMC8114274 DOI: 10.3389/fmicb.2021.565855] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/10/2021] [Indexed: 11/18/2022] Open
Abstract
Organic complexants are present in some radioactive wastes and can challenge waste disposal as they may enhance subsurface mobility of radionuclides and contaminant species via chelation. The principal sources of organic complexing agents in low level radioactive wastes (LLW) originate from chemical decontamination activities. Polycarboxylic organic decontaminants such as citric and oxalic acid are of interest as currently there is a paucity of data on their biodegradation at high pH and under disposal conditions. This work explores the biogeochemical fate of citric acid, a model decontaminant, under high pH anaerobic conditions relevant to disposal of LLW in cementitious disposal environments. Anaerobic microcosm experiments were set up, using a high pH adapted microbial inoculum from a well characterized environmental site, to explore biodegradation of citrate under representative repository conditions. Experiments were initiated at three different pH values (10, 11, and 12) and citrate was supplied as the electron donor and carbon source, under fermentative, nitrate-, Fe(III)- and sulfate- reducing conditions. Results showed that citrate was oxidized using nitrate or Fe(III) as the electron acceptor at > pH 11. Citrate was fully degraded and removed from solution in the nitrate reducing system at pH 10 and pH 11. Here, the microcosm pH decreased as protons were generated during citrate oxidation. In the Fe(III)-reducing systems, the citrate removal rate was slower than in the nitrate reducing systems. This was presumably as Fe(III)-reduction consumes fewer moles of citrate than nitrate reduction for the same molar concentrations of electron acceptor. The pH did not change significantly in the Fe(III)-reducing systems. Sulfate reduction only occurred in a single microcosm at pH 10. Here, citrate was fully removed from solution, alongside ingrowth of acetate and formate, likely fermentation products. The acetate and lactate were subsequently used as electron donors during sulfate-reduction and there was an associated decrease in solution pH. Interestingly, in the Fe(III) reducing experiments, Fe(II) ingrowth was observed at pH values recorded up to 11.7. Here, TEM analysis of the resultant solid Fe-phase indicated that nanocrystalline magnetite formed as an end product of Fe(III)-reduction under these extreme conditions. PCR-based high-throughput 16S rRNA gene sequencing revealed that bacteria capable of nitrate Fe(III) and sulfate reduction became enriched in the relevant, biologically active systems. In addition, some fermentative organisms were identified in the Fe(III)- and sulfate-reducing systems. The microbial communities present were consistent with expectations based on the geochemical data. These results are important to improve long-term environmental safety case development for cementitious LLW waste disposal.
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Affiliation(s)
- Natalie Byrd
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
| | - Jonathan R Lloyd
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
| | - Joe S Small
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom.,National Nuclear Laboratory, Warrington, United Kingdom
| | - Frank Taylor
- Low Level Waste Repository Ltd., Seascale, United Kingdom
| | - Heath Bagshaw
- School of Engineering, The University of Liverpool, Liverpool, United Kingdom
| | - Christopher Boothman
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
| | - Katherine Morris
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
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8
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Saxena M, Loza-Rosas SA, Gaur K, Sharma S, Pérez Otero SC, Tinoco AD. Exploring titanium(IV) chemical proximity to iron(III) to elucidate a function for Ti(IV) in the human body. Coord Chem Rev 2018; 363:109-125. [PMID: 30270932 PMCID: PMC6159949 DOI: 10.1016/j.ccr.2018.03.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Despite its natural abundance and widespread use as food, paint additive, and in bone implants, no specific biological function of titanium is known in the human body. High concentrations of Ti(IV) could result in cellular toxicity, however, the absence of Ti toxicity in the blood of patients with titanium bone implants indicates the presence of one or more biological mechanisms to mitigate toxicity. Similar to Fe(III), Ti(IV) in blood binds to the iron transport protein serum transferrin (sTf), which gives credence to the possibility of its cellular uptake mechanism by transferrin-directed endocytosis. However, once inside the cell, how sTf bound Ti(IV) is released into the cytoplasm, utilized, or stored remain largely unknown. To explain the molecular mechanisms involved in Ti use in cells we have drawn parallels with those for Fe(III). Based on its chemical similarities with Fe(III), we compare the biological coordination chemistry of Fe(III) and Ti(IV) and hypothesize that Ti(IV) can bind to similar intracellular biomolecules. The comparable ligand affinity profiles suggest that at high Ti(IV) concentrations, Ti(IV) could compete with Fe(III) to bind to biomolecules and would inhibit Fe bioavailability. At the typical Ti concentrations in the body, Ti might exist as a labile pool of Ti(IV) in cells, similar to Fe. Ti could exhibit different types of properties that would determine its cellular functions. We predict some of these functions to mimic those of Fe in the cell and others to be specific to Ti. Bone and cellular speciation and localization studies hint toward various intracellular targets of Ti like phosphoproteins, DNA, ribonucleotide reductase, and ferritin. However, to decipher the exact mechanisms of how Ti might mediate these roles, development of innovative and more sensitive methods are required to track this difficult to trace metal in vivo.
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Affiliation(s)
- Manoj Saxena
- Department of Chemistry, University of Puerto Rico Río Piedras, San Juan, PR 00931
| | - Sergio A. Loza-Rosas
- Department of Chemistry, University of Puerto Rico Río Piedras, San Juan, PR 00931
| | - Kavita Gaur
- Department of Chemistry, University of Puerto Rico Río Piedras, San Juan, PR 00931
| | - Shweta Sharma
- Department of Environmental Sciences, University of Puerto Rico Río Piedras, San Juan, PR 00931
| | - Sofia C. Pérez Otero
- Department of Chemistry, University of Puerto Rico Río Piedras, San Juan, PR 00931
| | - Arthur D. Tinoco
- Department of Chemistry, University of Puerto Rico Río Piedras, San Juan, PR 00931
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9
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Ogura J, Babu E, Miyauchi S, Ramachandran S, Nemeth E, Bhutia YD, Ganapathy V. Identification of a novel Na +-coupled Fe 3+-citrate transport system, distinct from mammalian INDY, for uptake of citrate in mammalian cells. Sci Rep 2018; 8:2519. [PMID: 29410496 PMCID: PMC5802838 DOI: 10.1038/s41598-018-20620-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/22/2018] [Indexed: 01/05/2023] Open
Abstract
NaCT is a Na+-coupled transporter for citrate expressed in hepatocytes and neurons. It is the mammalian ortholog of INDY (I’m Not Dead Yet), a transporter which modifies lifespan in Drosophila. Here we describe a hitherto unknown transport system for citrate in mammalian cells. When liver and mammary epithelial cells were pretreated with the iron supplement ferric ammonium citrate (FAC), uptake of citrate increased >10-fold. Iron chelators abrogated the stimulation of citrate uptake in FAC-treated cells. The iron exporter ferroportin had no role in this process. The stimulation of citrate uptake also occurred when Fe3+ was added during uptake without pretreatment. Similarly, uptake of Fe3+ was enhanced by citrate. The Fe3+-citrate uptake was coupled to Na+. This transport system was detectable in primary hepatocytes and neuronal cell lines. The functional features of this citrate transport system distinguish it from NaCT. Loss-of-function mutations in NaCT cause early-onset epilepsy and encephalopathy; the newly discovered Na+-coupled Fe3+-citrate transport system might offer a novel treatment strategy for these patients to deliver citrate into affected neurons independent of NaCT. It also has implications to iron-overload conditions where circulating free iron increases, which would stimulate cellular uptake of citrate and consequently affect multiple metabolic pathways.
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Affiliation(s)
- Jiro Ogura
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Ellappan Babu
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Seiji Miyauchi
- Department of Pharmaceutics, Toho University, Funabashi, Chiba, 274-8510, Japan
| | - Sabarish Ramachandran
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Elizebeta Nemeth
- Department of Medicine and Center for Iron Disorders, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Yangzom D Bhutia
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA.
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10
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Loza-Rosas SA, Saxena M, Delgado Y, Gaur K, Pandrala M, Tinoco AD. A ubiquitous metal, difficult to track: towards an understanding of the regulation of titanium(iv) in humans. Metallomics 2017; 9:346-356. [PMID: 28164202 PMCID: PMC5397357 DOI: 10.1039/c6mt00223d] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Despite the ubiquitous nature of titanium(iv) and several examples of its beneficial behavior in different organisms, the metal remains underappreciated in biology. There is little understanding of how the metal might play an important function in the human body. Nonetheless, a new insight is obtained regarding the molecular mechanisms that regulate the blood speciation of the metal to maintain it in a nontoxic and potentially bioavailable form for use in the body. This review surveys the literature on Ti(iv) application in prosthetics and in the development of anticancer therapeutics to gain an insight into soluble Ti(iv) influx in the body and its long-term impact. The limitation in analytical tools makes it difficult to depict the full picture of how Ti(iv) is transported and distributed throughout the body. An improved understanding of Ti function and its interaction with biomolecules will be helpful in developing future technologies for its imaging in the body.
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Affiliation(s)
- Sergio A Loza-Rosas
- Department of Chemistry, University of Puerto Rico, Rio Piedras, San Juan, PR 00969, USA.
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11
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Tinoco AD, Saxena M, Sharma S, Noinaj N, Delgado Y, Quiñones González EP, Conklin SE, Zambrana N, Loza-Rosas SA, Parks TB. Unusual Synergism of Transferrin and Citrate in the Regulation of Ti(IV) Speciation, Transport, and Toxicity. J Am Chem Soc 2016; 138:5659-65. [PMID: 27070073 DOI: 10.1021/jacs.6b01966] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human serum transferrin (sTf) is a protein that mediates the transport of iron from blood to cells. Assisted by the synergistic anion carbonate, sTf transports Fe(III) by binding the metal ion in a closed conformation. Previous studies suggest sTf's role as a potential transporter of other metals such as titanium. Ti is a widely used metal in colorants, foods, and implants. A substantial amount of Ti is leached into blood from these implants. However, the fate of the leached Ti and its transport into the cells is not known. Understanding Ti interaction with sTf assumes a greater significance with our ever increasing exposure to Ti in the form of implants. On the basis of in vitro studies, it was speculated that transferrin can bind Ti(IV) assisted by a synergistic anion. However, the role and identity of the synergistic anion(s) and the conformational state in which sTf binds Ti(IV) are not known. Here we have solved the first X-ray crystal structure of a Ti(IV)-bound sTf. We find that sTf binds Ti(IV) in an open conformation with both carbonate and citrate as synergistic anions at the metal binding sites, an unprecedented role for citrate. Studies with cell lines suggest that Ti(IV)-sTf is transported into cells and that sTf and citrate regulate the metal's blood speciation and attenuate its cytotoxic property. Our results provide the first glimpse into the citrate-transferrin synergism in the regulation of Ti(IV) bioactivity and offers insight into the future design of Ti(IV)-based anticancer drugs.
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Affiliation(s)
| | | | | | - Nicholas Noinaj
- Department of Biological Sciences, Purdue University , 240 S. Martin Jischke Drive, Hockmeyer Hall, West Lafayette, Indiana 47907, United States
| | | | | | | | | | | | - Timothy B Parks
- VA Caribbean Healthcare System, 10 Casia Street, San Juan, Puerto Rico 00921
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Huta B, Lensboeur JJ, Lowe AJ, Zubieta J, Doyle RP. Metal-citrate complex uptake and CitMHS transporters: From coordination chemistry to possible vaccine development. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2012.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chu C, Darling K, Netusil R, Doyle RP, Zubieta J. Synthesis and structure of a lead(II)–citrate: {Na(H2O)3}[Pb5(C6H5O7)3(C6H6O7)(H2O)3]·9.5H2O. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.08.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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