1
|
Condeles AL, da Silva GS, Hernandes MBB, Toledo Junior JC. Insights on the endogenous labile iron pool binding properties. Biometals 2024:10.1007/s10534-024-00591-4. [PMID: 38691278 DOI: 10.1007/s10534-024-00591-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/18/2024] [Indexed: 05/03/2024]
Abstract
Under normal physiological conditions, the endogenous Labile Iron Pool (LIP) constitutes a ubiquitous, dynamic, tightly regulated reservoir of cellular ferrous iron. Furthermore, LIP is loaded into new apo-iron proteins, a process akin to the activity of metallochaperones. Despite such importance on iron metabolism, the LIP identity and binding properties have remained elusive. We hypothesized that LIP binds to cell constituents (generically denoted C) and forms an iron complex termed CLIP. Combining this binding model with the established Calcein (CA) methodology for assessing cytosolic LIP, we have formulated an equation featuring two experimentally quantifiable parameters (the concentrations of the cytosolic free CA and CA and LIP complex termed CALIP) and three unknown parameters (the total concentrations of LIP and C and their thermodynamic affinity constant Kd). The fittings of cytosolic CALIP × CA concentrations data encompassing a few cellular models to this equation with floating unknown parameters were successful. The computed adjusted total LIP (LIPT) and C (CT) concentrations fall within the sub-to-low micromolar range while the computed Kd was in the 10-2 µM range for all cell types. Thus, LIP binds and has high affinity to cellular constituents found in low concentrations and has remarkably similar properties across different cell types, shedding fresh light on the properties of endogenous LIP within cells.
Collapse
Affiliation(s)
- André Luís Condeles
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil
| | - Gabriel Simonetti da Silva
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil
| | - Maria Beatriz Braghetto Hernandes
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil
| | - José Carlos Toledo Junior
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, 14040-901, Brazil.
| |
Collapse
|
2
|
Hider RC, Pourzand C, Ma Y, Cilibrizzi A. Optical Imaging Opportunities to Inspect the Nature of Cytosolic Iron Pools. Molecules 2023; 28:6467. [PMID: 37764245 PMCID: PMC10537325 DOI: 10.3390/molecules28186467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
The chemical nature of intracellular labile iron pools (LIPs) is described. By virtue of the kinetic lability of these pools, it is suggested that the isolation of such species by chromatography methods will not be possible, but rather mass spectrometric techniques should be adopted. Iron-sensitive fluorescent probes, which have been developed for the detection and quantification of LIP, are described, including those specifically designed to monitor cytosolic, mitochondrial, and lysosomal LIPs. The potential of near-infrared (NIR) probes for in vivo monitoring of LIP is discussed.
Collapse
Affiliation(s)
- Robert Charles Hider
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, UK
- Department of Life Sciences, University of Bath, Bath BA2 7AY, UK;
| | - Charareh Pourzand
- Department of Life Sciences, University of Bath, Bath BA2 7AY, UK;
- Centre for Therapeutic Innovation, University of Bath, Bath BA2 7AY, UK
- Centre for Bioengineering and Biomedical Technologies, University of Bath, Bath BA2 7AY, UK
| | - Yongmin Ma
- Institute of Advanced Studies, School of Pharmaceutical and Chemical Engineering, Taizhou University, 1139 Shifu Avenue, Taizhou 318000, China;
| | - Agostino Cilibrizzi
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, UK
- Centre for Therapeutic Innovation, University of Bath, Bath BA2 7AY, UK
| |
Collapse
|
3
|
Yu J, Leibiger B, Yang SN, Shears SB, Leibiger IB, Berggren PO, Barker CJ. Multiple Inositol Polyphosphate Phosphatase Compartmentalization Separates Inositol Phosphate Metabolism from Inositol Lipid Signaling. Biomolecules 2023; 13:885. [PMID: 37371464 DOI: 10.3390/biom13060885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 06/29/2023] Open
Abstract
Multiple inositol polyphosphate phosphatase (MINPP1) is an enigmatic enzyme that is responsible for the metabolism of inositol hexakisphosphate (InsP6) and inositol 1,3,4,5,6 pentakisphosphate (Ins(1,3,4,5,6)P5 in mammalian cells, despite being restricted to the confines of the ER. The reason for this compartmentalization is unclear. In our previous studies in the insulin-secreting HIT cell line, we expressed MINPP1 in the cytosol to artificially reduce the concentration of these higher inositol phosphates. Undocumented at the time, we noted cytosolic MINPP1 expression reduced cell growth. We were struck by the similarities in substrate preference between a number of different enzymes that are able to metabolize both inositol phosphates and lipids, notably IPMK and PTEN. MINPP1 was first characterized as a phosphatase that could remove the 3-phosphate from inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4). This molecule shares strong structural homology with the major product of the growth-promoting Phosphatidyl 3-kinase (PI3K), phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) and PTEN can degrade both this lipid and Ins(1,3,4,5)P4. Because of this similar substrate preference, we postulated that the cytosolic version of MINPP1 (cyt-MINPP1) may not only attack inositol polyphosphates but also PtdIns(3,4,5)P3, a key signal in mitogenesis. Our experiments show that expression of cyt-MINPP1 in HIT cells lowers the concentration of PtdIns(3,4,5)P3. We conclude this reflects a direct effect of MINPP1 upon the lipid because cyt-MINPP1 actively dephosphorylates synthetic, di(C4:0)PtdIns(3,4,5)P3 in vitro. These data illustrate the importance of MINPP1's confinement to the ER whereby important aspects of inositol phosphate metabolism and inositol lipid signaling can be separately regulated and give one important clarification for MINPP1's ER seclusion.
Collapse
Affiliation(s)
- Jia Yu
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Barbara Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Shao-Nian Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Stephen B Shears
- Inositol Signaling Section, NIEHS, 111, Alexander Drive, Research Triangle Park, Durham, NC 27709, USA
| | - Ingo B Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Christopher J Barker
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| |
Collapse
|
4
|
Nguyen Trung M, Kieninger S, Fandi Z, Qiu D, Liu G, Mehendale NK, Saiardi A, Jessen H, Keller B, Fiedler D. Stable Isotopomers of myo-Inositol Uncover a Complex MINPP1-Dependent Inositol Phosphate Network. ACS CENTRAL SCIENCE 2022; 8:1683-1694. [PMID: 36589890 PMCID: PMC9801504 DOI: 10.1021/acscentsci.2c01032] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Indexed: 05/04/2023]
Abstract
The water-soluble inositol phosphates (InsPs) represent a functionally diverse group of small-molecule messengers involved in a myriad of cellular processes. Despite their centrality, our understanding of human InsP metabolism is incomplete because the available analytical toolset to characterize and quantify InsPs in complex samples is limited. Here, we have synthesized and applied symmetrically and unsymmetrically 13C-labeled myo-inositol and inositol phosphates. These probes were utilized in combination with nuclear magnetic resonance spectroscopy (NMR) and capillary electrophoresis mass spectrometry (CE-MS) to investigate InsP metabolism in human cells. The labeling strategy provided detailed structural information via NMR-down to individual enantiomers-which overcomes a crucial blind spot in the analysis of InsPs. We uncovered a novel branch of InsP dephosphorylation in human cells which is dependent on MINPP1, a phytase-like enzyme contributing to cellular homeostasis. Detailed characterization of MINPP1 activity in vitro and in cells showcased the unique reactivity of this phosphatase. Our results demonstrate that metabolic labeling with stable isotopomers in conjunction with NMR spectroscopy and CE-MS constitutes a powerful tool to annotate InsP networks in a variety of biological contexts.
Collapse
Affiliation(s)
- Minh Nguyen Trung
- Leibniz-Forschungsinstitut
für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
- Institut
für Chemie, Humboldt-Universität
zu Berlin, Brook-Taylor-Strasse
2, 12489 Berlin, Germany
| | - Stefanie Kieninger
- Institut
für Chemie und Biochemie, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Zeinab Fandi
- Leibniz-Forschungsinstitut
für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Danye Qiu
- Institut
für Organische Chemie, Albert-Ludwigs-Universität
Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Guizhen Liu
- Institut
für Organische Chemie, Albert-Ludwigs-Universität
Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Neelay K. Mehendale
- Leibniz-Forschungsinstitut
für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Adolfo Saiardi
- MRC
Laboratory for Molecular Cell Biology, University
College London, WC1E 6BT London, United Kingdom
| | - Henning Jessen
- Institut
für Organische Chemie, Albert-Ludwigs-Universität
Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Bettina Keller
- Institut
für Chemie und Biochemie, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Dorothea Fiedler
- Leibniz-Forschungsinstitut
für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
- Institut
für Chemie, Humboldt-Universität
zu Berlin, Brook-Taylor-Strasse
2, 12489 Berlin, Germany
| |
Collapse
|
5
|
Pedersen CM, Su H. Ring-System-Based Conformational Switches and their Applications in Sensing and Liposomal Drug Delivery. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/s-0040-1720045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
AbstractIn the past decades, a great number of stimuli-responsive systems have been developed to be used as drug-delivery systems with high sensitivity and selectivity in targeted therapy. Despite promising results, the current stimuli-responsive systems suffer from the complexity of preparation, as most novel stimuli-responsive systems are based on polymers. Small molecules have often been neglected as candidates for application for stimuli-responsive systems. Recently, structures based on six-membered ring molecules or bicyclic molecules have been developed into conformational switches working through conformational interconversion. These single conformational switches have significantly reduced the complexity of material preparation compared to polymers or copolymers. In this review, we focus on ring-system-based conformational switches that are involved in sensors and smart drug-delivery systems. We hope that this review will shed light on ring-system-based single conformational switches for use in the development of stimuli-responsive systems.1 Introduction2 Conformation Switches Based On Bispidine Derivatives3 Conformation Switches Based On Cycloalkanes4 Conformation Switches Based On Carbohydrates5 Conclusion
Collapse
Affiliation(s)
| | - Hang Su
- Department of Chemistry, University of Copenhagen
- Practice Innovations Center, Changchun University of Chinese Medicine
| |
Collapse
|
6
|
Quiñone D, Veiga N, Savastano M, Torres J, Bianchi A, Kremer C, Bazzicalupi C. Supramolecular interaction of inositol phosphates with Cu(II): comparative study InsP6-InsP3. CrystEngComm 2022. [DOI: 10.1039/d1ce01733k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
myo-inositol phosphates are an important group of biomolecules that are present in all eukaryotic cells. The most abundant member of this family in nature is InsP6 (H12L1), which interacts strongly...
Collapse
|
7
|
Hider R, Aviles MV, Chen YL, Latunde-Dada GO. The Role of GSH in Intracellular Iron Trafficking. Int J Mol Sci 2021; 22:ijms22031278. [PMID: 33525417 PMCID: PMC7865746 DOI: 10.3390/ijms22031278] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/18/2021] [Indexed: 12/15/2022] Open
Abstract
Evidence is reviewed for the role of glutathione in providing a ligand for the cytosolic iron pool. The possibility of histidine and carnosine forming ternary complexes with iron(II)glutathione is discussed and the physiological significance of these interactions considered. The role of carnosine in muscle, brain, and kidney physiology is far from established and evidence is presented that the iron(II)-binding capability of carnosine relates to this role.
Collapse
|
8
|
Zhang YY, Stockmann R, Ng K, Ajlouni S. Revisiting phytate-element interactions: implications for iron, zinc and calcium bioavailability, with emphasis on legumes. Crit Rev Food Sci Nutr 2020; 62:1696-1712. [PMID: 33190514 DOI: 10.1080/10408398.2020.1846014] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Myo-Inositol hexakisphosphate or phytic acid concentration is a prominent factor known to impede divalent element bioavailability in vegetal foods including legumes. Both in vivo and in vitro studies have suggested that phytic acid and other plant-based constituents may synergistically form insoluble complexes affecting bioavailability of essential elements. This review provides an overview of existing investigations on the role of phytic acid in the binding, solubility and bioavailability of iron, zinc and calcium with a focus on legumes. Given the presence of various interference factors within legume matrices, current findings suggest that the commonly adapted approach of using phytic acid-element molar ratios as a bioavailability predictor may only be valid in limited circumstances. In particular, differences between protein properties and molar concentrations of other interacting ions are likely responsible for the observed poor correlations. The role of phytate degradation in element bioavailability has been previously examined, and in this review we re-emphasize its importance as a tool to enhance mineral bioavailability of mineral fortified legume crops. Food processing strategies to achieve phytate reduction were identified as promising tools to increase mineral bioavailability and included germination and fermentation, particularly when other bioavailability promoters (e.g. NaCl) are simultaneously added.
Collapse
Affiliation(s)
- Yianna Y Zhang
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.,CSIRO Agriculture & Food, Werribee, Victoria, Australia
| | | | - Ken Ng
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Said Ajlouni
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
9
|
Farkaš R, Beňová-Liszeková D, Mentelová L, Beňo M, Babišová K, Trusinová-Pečeňová L, Raška O, Chase BA, Raška I. Endosomal vacuoles of the prepupal salivary glands of Drosophila play an essential role in the metabolic reallocation of iron. Dev Growth Differ 2018; 60:411-430. [PMID: 30123964 DOI: 10.1111/dgd.12562] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 06/30/2018] [Accepted: 07/02/2018] [Indexed: 12/17/2022]
Abstract
In the recent past, we demonstrated that a great deal is going on in the salivary glands of Drosophila in the interval after they release their glycoprotein-rich secretory glue during pupariation. The early-to-mid prepupal salivary glands undergo extensive endocytosis with widespread vacuolation of the cytoplasm followed by massive apocrine secretion. Here, we describe additional novel properties of these endosomes. The use of vital pH-sensitive probes provided confirmatory evidence that these endosomes have acidic contents and that there are two types of endocytosis seen in the prepupal glands. The salivary glands simultaneously generate mildly acidic, small, basally-derived endosomes and strongly acidic, large and apical endosomes. Staining of the large vacuoles with vital acidic probes is possible only after there is ambipolar fusion of both basal and apical endosomes, since only basally-derived endosomes can bring fluorescent probes into the vesicular system. We obtained multiple lines of evidence that the small basally-derived endosomes are chiefly involved in the uptake of dietary Fe3+ iron. The fusion of basal endosomes with the larger and strongly acidic apical endosomes appears to facilitate optimal conditions for ferrireductase activity inside the vacuoles to release metabolic Fe2+ iron. While iron was not detectable directly due to limited staining sensitivity, we found increasing fluorescence of the glutathione-sensitive probe CellTracker Blue CMAC in large vacuoles, which appeared to depend on the amount of iron released by ferrireductase. Moreover, heterologous fluorescently-labeled mammalian iron-bound transferrin is actively taken up, providing direct evidence for active iron uptake by basal endocytosis. In addition, we serendipitously found that small (basal) endosomes were uniquely recognized by PNA lectin, whereas large (apical) vacuoles bound DBA lectin.
Collapse
Affiliation(s)
- Robert Farkaš
- Laboratory of Developmental Genetics, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Denisa Beňová-Liszeková
- Laboratory of Developmental Genetics, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lucia Mentelová
- Laboratory of Developmental Genetics, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.,Department of Genetics, Comenius University, Bratislava, Slovakia
| | - Milan Beňo
- Laboratory of Developmental Genetics, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Klaudia Babišová
- Laboratory of Developmental Genetics, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.,Department of Genetics, Comenius University, Bratislava, Slovakia
| | - Ludmila Trusinová-Pečeňová
- Laboratory of Developmental Genetics, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Otakar Raška
- Institute of Biology and Medical Genetics, 1st Faculty of Medicine, Charles University, Prague, Czech Republic.,Department of Normal, Pathological and Clinical Physiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Bruce A Chase
- Department of Biology, University of Nebraska, Omaha, Nebraska
| | - Ivan Raška
- Institute of Biology and Medical Genetics, 1st Faculty of Medicine, Charles University, Prague, Czech Republic
| |
Collapse
|
10
|
Has Inositol Played Any Role in the Origin of Life? Life (Basel) 2017; 7:life7020024. [PMID: 28587245 PMCID: PMC5492146 DOI: 10.3390/life7020024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/26/2017] [Accepted: 06/02/2017] [Indexed: 12/11/2022] Open
Abstract
Phosphorus, as phosphate, plays a paramount role in biology. Since phosphate transfer reactions are an integral part of contemporary life, phosphate may have been incorporated into the initial molecules at the very beginning. To facilitate the studies into early phosphate utilization, we should look retrospectively to phosphate-rich molecules present in today’s cells. Overlooked by origin of life studies until now, inositol and the inositol phosphates, of which some species possess more phosphate groups that carbon atoms, represent ideal molecules to consider in this context. The current sophisticated association of inositol with phosphate, and the roles that some inositol phosphates play in regulating cellular phosphate homeostasis, intriguingly suggest that inositol might have played some role in the prebiotic process of phosphate exploitation. Inositol can be synthesized abiotically and, unlike glucose or ribose, is chemically stable. This stability makes inositol the ideal candidate for the earliest organophosphate molecules, as primitive inositol phosphates. I also present arguments suggesting roles for some inositol phosphates in early chemical evolution events. Finally, the possible prebiotic synthesis of inositol pyrophosphates could have generated high-energy molecules to be utilized in primitive trans-phosphorylating processes.
Collapse
|
11
|
Veiga N, Torres J, Macho I, Gómez K, González G, Kremer C. Coordination, microprotonation equilibria and conformational changes of myo-inositol hexakisphosphate with pertinence to its biological function. Dalton Trans 2015; 43:16238-51. [PMID: 25058574 DOI: 10.1039/c4dt01350f] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Within all the eukaryotic cells there is an important group of biomolecules that has been potentially related to signalling functions: the myo-inositol phosphates (InsPs). In nature, the most abundant member of this family is the so called InsP6 (phytate, L(12-)), for which our group has strived in the past to elucidate its intricate chemical behaviour. In this work we expand on our earlier findings, shedding light on the inframolecular details of its protonation and complexation processes. We evaluate systematically the chemical performance of InsP6 in the presence and absence of alkali and alkaline earth metal ions, through (31)P NMR measurements, in a non-interacting medium and over a wide pH range. The analysis of the titration curves by means of a model based on the cluster expansion method allows us to describe in detail the distribution of the different protonated microspecies of the ligand. With the aid of molecular modelling tools, we assess the energetic and geometrical characteristics of the protonation sequence and the conformational transition suffered by InsP6 as the pH changes. By completely characterizing the protonation pattern, conformation and geometry of the metal complexes, we unveil the chemical and structural basis behind the influence that the physiologically relevant cations, Na(+), K(+), Mg(2+) and Ca(2+) have over the phytate chemical reactivity. This information is essential in the process of gaining reliable structural knowledge about the most important InsP6 species in the in vitro and in vivo experiments, and how these features modulate their probable biological functions.
Collapse
Affiliation(s)
- Nicolás Veiga
- Cátedra de Química Inorgánica, Departamento Estrella Campos, Facultad de Química, Universidad de la República, CC 1157, Montevideo, Uruguay.
| | | | | | | | | | | |
Collapse
|
12
|
Torres J, Giorgi C, Veiga N, Kremer C, Bianchi A. Interaction of myo-inositol hexakisphosphate with biogenic and synthetic polyamines. Org Biomol Chem 2015; 13:7500-12. [DOI: 10.1039/c5ob00900f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
myo-Inositol hexakisphosphate (phytate) forms very stable adducts with biogenic and synthetic polyamines in aqueous solution.
Collapse
Affiliation(s)
- Julia Torres
- Cátedra de Química Inorgánica
- Departamento Estrella Campos
- Facultad de Química
- Universidad de la República
- Montevideo
| | - Claudia Giorgi
- Department of Chemistry “Ugo Schiff”
- University of Florence
- Sesto Fiorentino
- Italy
| | - Nicolás Veiga
- Cátedra de Química Inorgánica
- Departamento Estrella Campos
- Facultad de Química
- Universidad de la República
- Montevideo
| | - Carlos Kremer
- Cátedra de Química Inorgánica
- Departamento Estrella Campos
- Facultad de Química
- Universidad de la República
- Montevideo
| | - Antonio Bianchi
- Department of Chemistry “Ugo Schiff”
- University of Florence
- Sesto Fiorentino
- Italy
| |
Collapse
|
13
|
Ma Y, Abbate V, Hider RC. Iron-sensitive fluorescent probes: monitoring intracellular iron pools. Metallomics 2015; 7:212-22. [DOI: 10.1039/c4mt00214h] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
14
|
Philpott CC, Ryu MS. Special delivery: distributing iron in the cytosol of mammalian cells. Front Pharmacol 2014; 5:173. [PMID: 25101000 PMCID: PMC4106451 DOI: 10.3389/fphar.2014.00173] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 07/04/2014] [Indexed: 01/19/2023] Open
Abstract
Eukaryotic cells contain hundreds of proteins that require iron cofactors for activity. These iron enzymes are located in essentially every subcellular compartment; thus, iron cofactors must travel to every compartment in the cell. Iron cofactors exist in three basic forms: Heme, iron–sulfur clusters, and simple iron ions (also called non-heme iron). Iron ions taken up by the cell initially enter a kinetically labile, exchangeable pool that is referred to as the labile iron pool. The majority of the iron in this pool is delivered to mitochondria, where it is incorporated into heme and iron–sulfur clusters, as well as non-heme iron enzymes. These cofactors must then be distributed to nascent proteins in the mitochondria, cytosol, and membrane-bound organelles. Emerging evidence suggests that specific systems exist for the distribution of iron cofactors within the cell. These systems include membrane transporters, protein chaperones, specialized carriers, and small molecules. This review focuses on the distribution of iron ions in the cytosol and will highlight differences between the iron distribution systems of simple eukaryotes and mammalian cells.
Collapse
Affiliation(s)
- Caroline C Philpott
- Genetics and Metabolism Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Bethesda, MD, USA
| | - Moon-Suhn Ryu
- Genetics and Metabolism Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Bethesda, MD, USA
| |
Collapse
|
15
|
Veiga N, Torres J, Macho I, Gómez K, Godage HY, Riley AM, Potter BVL, González G, Kremer C. Inframolecular acid-base and coordination properties towards Na(+) and Mg(2+) of myo-inositol 1,3,4,5,6-pentakisphosphate: a structural approach to biologically relevant species. Dalton Trans 2013. [PMID: 23183928 PMCID: PMC4011121 DOI: 10.1039/c2dt31807e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The myo-inositol phosphates (InsPs) are specific signalling metabolites ubiquitous in eukaryotic cells. Although Ins(1,3,4,5,6)P(5) is the second most abundant member of the InsPs family, its certain biological roles are far from being elucidated, in part due to the large number of species formed by Ins(1,3,4,5,6)P(5) in the presence of metal ions. In light of this, we have strived in the past to make a complete and at the same time "biological-user-friendly" description of the Ins(1,3,4,5,6)P(5) chemistry with mono and multivalent cations. In this work we expand these studies focusing on the inframolecular aspects of its protonation equilibria and the microscopic details of its coordination behaviour towards biologically relevant metal ions. We present here a systematic study of the Ins(1,3,4,5,6)P(5) intrinsic acid-base processes, in a non-interacting medium, and over a wide pH range, analyzing the (31)P NMR curves by means of a model based on the Cluster Expansion Method. In addition, we have used a computational approach to analyse the energetic and structural features of the protonation and conformational changes of Ins(1,3,4,5,6)P(5), and how they are influenced by the presence of two physiologically relevant cations, Na(+) and Mg(2+).
Collapse
Affiliation(s)
- Nicolás Veiga
- Cátedra de Química Inorgánica, Departamento Estrella Campos, Facultad de Química, Universidad de la República, CC 1157, Montevideo, Uruguay.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
McCormick SP, Chakrabarti M, Cockrell AL, Park J, Lindahl LS, Lindahl PA. Low-molecular-mass metal complexes in the mouse brain. Metallomics 2013; 5:232-41. [PMID: 23443205 DOI: 10.1039/c3mt00009e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The presence of labile low-molecular-mass (LMM, defined as <10 kDa) metal complexes in cells and super-cellular structures such as the brain has been inferred from chelation studies, but direct evidence is lacking. To evaluate the presence of LMM metal complexes in the brain, supernatant fractions of fresh mouse brain homogenates were passed through a 10 kDa cutoff membrane and subjected to size-exclusion liquid chromatography under anaerobic refrigerated conditions. Fractions were monitored for Mn, Fe, Co, Cu, Zn, Mo, S and P using an on-line ICP-MS. At least 30 different LMM metal complexes were detected along with numerous P- and S- containing species. Reproducibility was assessed by performing the experiment 13 times, using different buffers, and by examining whether complexes changed with time. Eleven Co, 2 Cu, 5 Mn, 4 Mo, 3 Fe and 2 Zn complexes with molecular masses <4 kDa were detected. One LMM Mo complex comigrated with the molybdopterin cofactor. Most Cu and Zn complexes appeared to be protein-bound with masses ranging from 4-20 kDa. Co was the only metal for which the "free" or aqueous complex was reproducibly observed. Aqueous Co may be sufficiently stable in this environment due to its relatively slow water-exchange kinetics. Attempts were made to assign some of these complexes, but further efforts will be required to identify them unambiguously and to determine their functions. This is among the first studies to detect low-molecular-mass transition metal complexes in the mouse brain using LC-ICP-MS.
Collapse
Affiliation(s)
- Sean P McCormick
- Texas A&M University, Department of Chemistry, College Station, TX 77843, USA
| | | | | | | | | | | |
Collapse
|
17
|
Potential of phytase-mediated iron release from cereal-based foods: a quantitative view. Nutrients 2013; 5:3074-98. [PMID: 23917170 PMCID: PMC3775243 DOI: 10.3390/nu5083074] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/01/2013] [Accepted: 07/17/2013] [Indexed: 12/23/2022] Open
Abstract
The major part of iron present in plant foods such as cereals is largely unavailable for direct absorption in humans due to complexation with the negatively charged phosphate groups of phytate (myo-inositol (1,2,3,4,5,6)-hexakisphosphate). Human biology has not evolved an efficient mechanism to naturally release iron from iron phytate complexes. This narrative review will evaluate the quantitative significance of phytase-catalysed iron release from cereal foods. In vivo studies have shown how addition of microbially derived phytases to cereal-based foods has produced increased iron absorption via enzyme-catalysed dephosphorylation of phytate, indicating the potential of this strategy for preventing and treating iron deficiency anaemia. Despite the immense promise of this strategy and the prevalence of iron deficiency worldwide, the number of human studies elucidating the significance of phytase-mediated improvements in iron absorption and ultimately in iron status in particularly vulnerable groups is still low. A more detailed understanding of (1) the uptake mechanism for iron released from partially dephosphorylated phytate chelates, (2) the affinity of microbially derived phytases towards insoluble iron phytate complexes, and (3) the extent of phytate dephosphorylation required for iron release from inositol phosphates is warranted. Phytase-mediated iron release can improve iron absorption from plant foods. There is a need for development of innovative strategies to obtain better effects.
Collapse
|
18
|
Abstract
The nature of the cytosolic iron pool remains largely uncharacterized, although a range of candidate ligands and chaperones have been proposed. Herein an overview is presented of cytosolic non heme and non iron-sulphur cluster protein iron binding sites and the influence of ligands on the redox activity of iron. This analysis leads to the concept of iron(II) glutathione functioning as the labile cytosolic iron pool and offers a means for the selection of iron over manganese in subsequent incorporation into a wide range of iron-dependent enzymes and electron transfer proteins. Glutathione and glutathione-binding glutaredoxins play a critical role in iron sulfur cluster synthesis and Fe(II)GS (iron(II) coordinated by the thiol function of glutathione) is a suitable iron donor for this biosynthetic route. Significantly, both glutathione and glutaredoxins are universally distributed and thus a controlling influence of glutathione on intracellular iron trafficking is likely to be a common feature of the majority of living organisms.
Collapse
Affiliation(s)
- Robert C Hider
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, Stamford Street, London SE1 9NH, UK.
| | | |
Collapse
|
19
|
Barker CJ, Berggren PO. New Horizons in Cellular Regulation by Inositol Polyphosphates: Insights from the Pancreaticβ-Cell. Pharmacol Rev 2013; 65:641-69. [DOI: 10.1124/pr.112.006775] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
|
20
|
Sanz-Penella JM, Frontela C, Ros G, Martinez C, Monedero V, Haros M. Application of bifidobacterial phytases in infant cereals: effect on phytate contents and mineral dialyzability. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:11787-11792. [PMID: 23151205 DOI: 10.1021/jf3034013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Phytase activity was recently described in probiotic bifidobacterial strains, opening the possibilities for their use in foods, due to the generally regarded as safe/qualified presumption of safety status of these bacteria. Two raw materials for infant cereals (multicereal and gluten-free) were examined by measuring the myo-inositol phosphates content and the in vitro Ca, Fe, and Zn availability after a dephytinization process with purified phytases from Bifidobacterium longum spp. infantis and Bifidobacterium pseudocatenulatum. Treatment with both enzymes reduced the contents of phytate as compared to control samples (untreated or treated with fungal phytase) and led to increased levels of myo-inositol triphosphate. Dephytinization followed by an in vitro model of intestinal digestion increased the solubility of Zn. However, phytase treatment did not increase significantly the mineral dialyzability as compared to untreated samples. This is the first example of the application of purified bifidobacterial phytases in food processing and shows the potential of these enzymes to be used in products for human consumption.
Collapse
Affiliation(s)
- Juan Mario Sanz-Penella
- Instituto de Agroquímica y Tecnología de Alimentos, Av. Agustín Escardino 7, 46980 Paterna-Valencia, Spain
| | | | | | | | | | | |
Collapse
|
21
|
Hider RC, Kong XL. Glutathione: a key component of the cytoplasmic labile iron pool. Biometals 2011; 24:1179-87. [PMID: 21769609 DOI: 10.1007/s10534-011-9476-8] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 06/23/2011] [Indexed: 01/16/2023]
Abstract
The cytoplasmic labile iron pool supplies iron to the mitochondrion for heme and iron sulfur cluster synthesis and to many cytoplasmic enzymes, thereby controlling numerous metabolic reactions. Surprisingly the chemical nature of this pool has never been convincingly characterised. Here we provide evidence for iron(II)glutathione being the dominant component of this pool. We report for the first time the affinity constant for the glutathione-iron(II) interaction and use this value to study the cytoplasmic speciation of iron(II). The formation of this complex is a major determinant of the electrode potential of the cytoplasmic ferrous iron pool, a means of selecting between iron(II) and manganese(II) and it provides a substrate for glutaredoxin/iron clusters at the dimer interface of glutaredoxins involved in the synthesis of Fe-S cluster proteins.
Collapse
Affiliation(s)
- Robert C Hider
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, UK.
| | | |
Collapse
|
22
|
Redox and structural aspects on iron inositol 1,2,3-trisphosphate interaction: An experimental and computational approach. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.03.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
23
|
Potentiometric and 31P NMR studies on inositol phosphates and their interaction with iron(III) ions. Carbohydr Res 2011; 346:488-94. [DOI: 10.1016/j.carres.2010.12.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 12/27/2010] [Accepted: 12/28/2010] [Indexed: 11/21/2022]
|
24
|
Veiga N, Torres J, González G, Gómez K, Mansell D, Freeman S, Domínguez S, Kremer C. Insight into the protonation and K(I)-interaction of the inositol 1,2,3-trisphosphate as provided by 31P NMR and theoretical calculations. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2010.11.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
25
|
Mansell D, Veiga N, Torres J, Etchells LL, Bryce RA, Kremer C, Freeman S. Conformational study of the natural iron chelator myo-inositol 1,2,3-trisphosphate using restrained/flexible analogues and computational analysis. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.09.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
26
|
Mansell D, Rattray N, Etchells LL, Schwalbe CH, Blake AJ, Torres J, Kremer C, Bichenkova EV, Barker CJ, Freeman S. Conformational analysis of the natural iron chelator myo-inositol 1,2,3-trisphosphate using a pyrene-based fluorescent mimic. Org Biomol Chem 2010; 8:2850-8. [DOI: 10.1039/c001078b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
27
|
Affiliation(s)
- Aaron Atkinson
- Departments of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah 84132
| | - Dennis R. Winge
- Departments of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah 84132
| |
Collapse
|
28
|
The behaviour of inositol 1,3,4,5,6-pentakisphosphate in the presence of the major biological metal cations. J Biol Inorg Chem 2009; 14:1001-13. [PMID: 19415348 PMCID: PMC2745655 DOI: 10.1007/s00775-009-0510-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 04/20/2009] [Indexed: 01/07/2023]
Abstract
The inositol phosphates are ubiquitous metabolites in eukaryotes, of which the most abundant are inositol hexakisphosphate (InsP 6) and inositol 1,3,4,5,6-pentakisphosphate [Ins(1,3,4,5,6)P5)]. These two compounds, poorly understood functionally, have complicated complexation and solid formation behaviours with multivalent cations. For InsP 6, we have previously described this chemistry and its biological implications (Veiga et al. in J Inorg Biochem 100:1800, 2006; Torres et al. in J Inorg Biochem 99:828, 2005). We now cover similar ground for Ins(1,3,4,5,6)P5, describing its interactions in solution with Na+, K+, Mg2+, Ca2+, Cu2+, Fe2+ and Fe3+, and its solid-formation equilibria with Ca2+ and Mg2+. Ins(1,3,4,5,6)P5 forms soluble complexes of 1:1 stoichiometry with all multivalent cations studied. The affinity for Fe3+ is similar to that of InsP6 and inositol 1,2,3-trisphosphate, indicating that the 1,2,3-trisphosphate motif, which Ins(1,3,4,5,6)P5 lacks, is not absolutely necessary for high-affinity Fe3+ complexation by inositol phosphates, even if it is necessary for their prevention of the Fenton reaction. With excess Ca2+ and Mg2+, Ins(1,3,4,5,6)P5 also forms the polymetallic complexes [M4(H2L)] [where L is fully deprotonated Ins(1,3,4,5,6)P5]. However, unlike InsP6, Ins(1,3,4,5,6)P5 is predicted not to be fully associated with Mg2+ under simulated cytosolic/nuclear conditions. The neutral Mg2+ and Ca2+ complexes have significant windows of solubility, but they precipitate as [Mg4(H2L)] x 23H2O or [Ca4(H2L)] x 16H2O whenever they exceed 135 and 56 microM in concentration, respectively. Nonetheless, the low stability of the [M4(H2L)] complexes means that the 1:1 species contribute to the overall solubility of Ins(1,3,4,5,6)P 5 even under significant Mg2+ or Ca2+ excesses. We summarize the solubility behaviour of Ins(1,3,4,5,6)P5 in straightforward plots.
Collapse
|
29
|
Mansell D, Rattray N, Etchells LL, Schwalbe CH, Blake AJ, Bichenkova EV, Bryce RA, Barker CJ, Díaz A, Kremer C, Freeman S. Fluorescent probe: complexation of Fe3+with the myo-inositol 1,2,3-trisphosphate motif. Chem Commun (Camb) 2008:5161-3. [DOI: 10.1039/b809238a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|