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Jiang H, Milanov M, Jüngert G, Angebauer L, Flender C, Smudde E, Gather F, Vogel T, Jessen HJ, Koch HG. Control of a chemical chaperone by a universally conserved ATPase. iScience 2024; 27:110215. [PMID: 38993675 PMCID: PMC11237923 DOI: 10.1016/j.isci.2024.110215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/16/2024] [Accepted: 06/05/2024] [Indexed: 07/13/2024] Open
Abstract
The universally conserved YchF/Ola1 ATPases regulate stress response pathways in prokaryotes and eukaryotes. Deletion of YchF/Ola1 leads to increased resistance against environmental stressors, such as reactive oxygen species, while their upregulation is associated with tumorigenesis in humans. The current study shows that in E. coli, the absence of YchF stimulates the synthesis of the alternative sigma factor RpoS by a transcription-independent mechanism. Elevated levels of RpoS then enhance the transcription of major stress-responsive genes. In addition, the deletion of ychF increases the levels of polyphosphate kinase, which in turn boosts the production of the evolutionary conserved and ancient chemical chaperone polyphosphate. This potentially provides a unifying concept for the increased stress resistance in bacteria and eukaryotes upon YchF/Ola1 deletion. Intriguingly, the simultaneous deletion of ychF and the polyphosphate-degrading enzyme exopolyphosphatase causes synthetic lethality in E. coli, demonstrating that polyphosphate production needs to be fine-tuned to prevent toxicity.
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Affiliation(s)
- Hong Jiang
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs University Freiburg, 79104 Freiburg, Germany
| | - Martin Milanov
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs University Freiburg, 79104 Freiburg, Germany
| | - Gabriela Jüngert
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Larissa Angebauer
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Clara Flender
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Eva Smudde
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Fabian Gather
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Tanja Vogel
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Henning J. Jessen
- Institute for Organic Chemistry, Faculty of Chemistry and Pharmacy, University Freiburg 79104 Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
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2
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Borghi F, Azevedo C, Johnson E, Burden JJ, Saiardi A. A mammalian model reveals inorganic polyphosphate channeling into the nucleolus and induction of a hyper-condensate state. CELL REPORTS METHODS 2024; 4:100814. [PMID: 38981472 PMCID: PMC11294840 DOI: 10.1016/j.crmeth.2024.100814] [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: 04/05/2024] [Revised: 05/23/2024] [Accepted: 06/13/2024] [Indexed: 07/11/2024]
Abstract
Inorganic polyphosphate (polyP) is a ubiquitous polymer that controls fundamental processes. To overcome the absence of a genetically tractable mammalian model, we developed an inducible mammalian cell line expressing Escherichia coli polyphosphate kinase 1 (EcPPK1). Inducing EcPPK1 expression prompted polyP synthesis, enabling validation of polyP analytical methods. Virtually all newly synthesized polyP accumulates within the nucleus, mainly in the nucleolus. The channeled polyP within the nucleolus results in the redistribution of its markers, leading to altered rRNA processing. Ultrastructural analysis reveals electron-dense polyP structures associated with a hyper-condensed nucleolus resulting from an exacerbation of the liquid-liquid phase separation (LLPS) phenomena controlling this membraneless organelle. The selective accumulation of polyP in the nucleoli could be interpreted as an amplification of polyP channeling to where its physiological function takes place. Indeed, quantitative analysis of several mammalian cell lines confirms that endogenous polyP accumulates within the nucleolus.
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Affiliation(s)
- Filipy Borghi
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Cristina Azevedo
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Errin Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Jemima J Burden
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Adolfo Saiardi
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
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3
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Hambardikar V, Akosah YA, Scoma ER, Guitart-Mampel M, Urquiza P, Da Costa RT, Perez MM, Riggs LM, Patel R, Solesio ME. Toolkit for cellular studies of mammalian mitochondrial inorganic polyphosphate. Front Cell Dev Biol 2023; 11:1302585. [PMID: 38161329 PMCID: PMC10755588 DOI: 10.3389/fcell.2023.1302585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024] Open
Abstract
Introduction: Inorganic polyphosphate (polyP) is an ancient polymer which is extremely well-conserved throughout evolution, and found in every studied organism. PolyP is composed of orthophosphates linked together by high-energy bonds, similar to those found in ATP. The metabolism and the functions of polyP in prokaryotes and simple eukaryotes are well understood. However, little is known about its physiological roles in mammalian cells, mostly due to its unknown metabolism and lack of systematic methods and effective models for the study of polyP in these organisms. Methods: Here, we present a comprehensive set of genetically modified cellular models to study mammalian polyP. Specifically, we focus our studies on mitochondrial polyP, as previous studies have shown the potent regulatory role of mammalian polyP in the organelle, including bioenergetics, via mechanisms that are not yet fully understood. Results: Using SH-SY5Y cells, our results show that the enzymatic depletion of mitochondrial polyP affects the expression of genes involved in the maintenance of mitochondrial physiology, as well as the structure of the organelle. Furthermore, this depletion has deleterious effects on mitochondrial respiration, an effect that is dependent on the length of polyP. Our results also show that the depletion of mammalian polyP in other subcellular locations induces significant changes in gene expression and bioenergetics; as well as that SH-SY5Y cells are not viable when the amount and/or the length of polyP are increased in mitochondria. Discussion: Our findings expand on the crucial role of polyP in mammalian mitochondrial physiology and place our cell lines as a valid model to increase our knowledge of both mammalian polyP and mitochondrial physiology.
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Affiliation(s)
- Vedangi Hambardikar
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
| | - Yaw A. Akosah
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York City, NY, United States
| | - Ernest R. Scoma
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
| | - Mariona Guitart-Mampel
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
| | - Pedro Urquiza
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
| | - Renata T. Da Costa
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
| | - Matheus M. Perez
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
| | - Lindsey M. Riggs
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
| | - Rajesh Patel
- Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, United States
| | - Maria E. Solesio
- Department of Biology, and Center for Computational and Integrative Biology (CCIB), Rutgers University, Camden, NJ, United States
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4
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TNP Analogues Inhibit the Virulence Promoting IP3-4 Kinase Arg1 in the Fungal Pathogen Cryptococcus neoformans. Biomolecules 2022; 12:biom12101526. [PMID: 36291735 PMCID: PMC9599641 DOI: 10.3390/biom12101526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 11/29/2022] Open
Abstract
New antifungals with unique modes of action are urgently needed to treat the increasing global burden of invasive fungal infections. The fungal inositol polyphosphate kinase (IPK) pathway, comprised of IPKs that convert IP3 to IP8, provides a promising new target due to its impact on multiple, critical cellular functions and, unlike in mammalian cells, its lack of redundancy. Nearly all IPKs in the fungal pathway are essential for virulence, with IP3-4 kinase (IP3-4K) the most critical. The dibenzylaminopurine compound, N2-(m-trifluorobenzylamino)-N6-(p-nitrobenzylamino)purine (TNP), is a commercially available inhibitor of mammalian IPKs. The ability of TNP to be adapted as an inhibitor of fungal IP3-4K has not been investigated. We purified IP3-4K from the human pathogens, Cryptococcus neoformans and Candida albicans, and optimised enzyme and surface plasmon resonance (SPR) assays to determine the half inhibitory concentration (IC50) and binding affinity (KD), respectively, of TNP and 38 analogues. A novel chemical route was developed to efficiently prepare TNP analogues. TNP and its analogues demonstrated inhibition of recombinant IP3-4K from C. neoformans (CnArg1) at low µM IC50s, but not IP3-4K from C. albicans (CaIpk2) and many analogues exhibited selectivity for CnArg1 over the human equivalent, HsIPMK. Our results provide a foundation for improving potency and selectivity of the TNP series for fungal IP3-4K.
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5
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Analytical Methods for Determination of Phytic Acid and Other Inositol Phosphates: A Review. Molecules 2020; 26:molecules26010174. [PMID: 33396544 PMCID: PMC7795710 DOI: 10.3390/molecules26010174] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/28/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022] Open
Abstract
From the early precipitation-based techniques, introduced more than a century ago, to the latest development of enzymatic bio- and nano-sensor applications, the analysis of phytic acid and/or other inositol phosphates has never been a straightforward analytical task. Due to the biomedical importance, such as antinutritional, antioxidant and anticancer effects, several types of methodologies were investigated over the years to develop a reliable determination of these intriguing analytes in many types of biological samples; from various foodstuffs to living cell organisms. The main aim of the present work was to critically overview the development of the most relevant analytical principles, separation and detection methods that have been applied in order to overcome the difficulties with specific chemical properties of inositol phosphates, their interferences, absence of characteristic signal (e.g., absorbance), and strong binding interactions with (multivalent) metals and other biological molecules present in the sample matrix. A systematical and chronological review of the applied methodology and the detection system is given, ranging from the very beginnings of the classical gravimetric and titrimetric analysis, through the potentiometric titrations, chromatographic and electrophoretic separation techniques, to the use of spectroscopic methods and of the recently reported fluorescence and voltammetric bio- and nano-sensors.
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6
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Sanz-Luque E, Bhaya D, Grossman AR. Polyphosphate: A Multifunctional Metabolite in Cyanobacteria and Algae. FRONTIERS IN PLANT SCIENCE 2020; 11:938. [PMID: 32670331 PMCID: PMC7332688 DOI: 10.3389/fpls.2020.00938] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/09/2020] [Indexed: 05/19/2023]
Abstract
Polyphosphate (polyP), a polymer of orthophosphate (PO4 3-) of varying lengths, has been identified in all kingdoms of life. It can serve as a source of chemical bond energy (phosphoanhydride bond) that may have been used by biological systems prior to the evolution of ATP. Intracellular polyP is mainly stored as granules in specific vacuoles called acidocalcisomes, and its synthesis and accumulation appear to impact a myriad of cellular functions. It serves as a reservoir for inorganic PO4 3- and an energy source for fueling cellular metabolism, participates in maintaining adenylate and metal cation homeostasis, functions as a scaffold for sequestering cations, exhibits chaperone function, covalently binds to proteins to modify their activity, and enables normal acclimation of cells to stress conditions. PolyP also appears to have a role in symbiotic and parasitic associations, and in higher eukaryotes, low polyP levels seem to impact cancerous proliferation, apoptosis, procoagulant and proinflammatory responses and cause defects in TOR signaling. In this review, we discuss the metabolism, storage, and function of polyP in photosynthetic microbes, which mostly includes research on green algae and cyanobacteria. We focus on factors that impact polyP synthesis, specific enzymes required for its synthesis and degradation, sequestration of polyP in acidocalcisomes, its role in cellular energetics, acclimation processes, and metal homeostasis, and then transition to its potential applications for bioremediation and medical purposes.
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Affiliation(s)
- Emanuel Sanz-Luque
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, United States
- Department of Biochemistry and Molecular Biology, University of Cordoba, Cordoba, Spain
| | - Devaki Bhaya
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, United States
| | - Arthur R. Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, United States
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7
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Zhu J, Loubéry S, Broger L, Zhang Y, Lorenzo-Orts L, Utz-Pugin A, Fernie AR, Young-Tae C, Hothorn M. A genetically validated approach for detecting inorganic polyphosphates in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:507-516. [PMID: 31816134 DOI: 10.1111/tpj.14642] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 11/08/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
Inorganic polyphosphates (polyPs) are linear polymers of orthophosphate units linked by phosphoanhydride bonds. Polyphosphates represent important stores of phosphate and energy, and are abundant in many pro- and eukaryotic organisms. In plants, the existence of polyPs has been established using microscopy and biochemical extraction methods that are now known to produce artifacts. Here we use a polyP-specific dye and a polyP-binding domain to detect polyPs in plant and algal cells. To develop the staining protocol, we induced polyP granules in Nicotiana benthamiana and Arabidopsis cells by heterologous expression of Escherichia coli polyphosphate kinase 1 (PPK1). Over-expression of PPK1 but not of a catalytically impaired version of the enzyme leads to severe growth phenotypes, suggesting that ATP-dependent synthesis and accumulation of polyPs in the plant cytosol is toxic. We next crossed stable PPK1-expressing Arabidopsis lines with plants expressing the polyP-binding domain of E. coli exopolyphosphatase (PPX1c), which co-localized with PPK1-generated polyP granules. These granules were stained by the polyP-specific dye JC-D7 and appeared as electron-dense structures in transmission electron microscopy sections. Using the polyP staining protocol derived from these experiments, we screened for polyP stores in different organs and tissues of both mono- and dicotyledonous plants. While we could not detect polyP granules in higher plants, we could visualize the polyP-rich acidocalcisomes in the green alga Chlamydomonas reinhardtii.
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Affiliation(s)
- Jinsheng Zhu
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Sylvain Loubéry
- Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Larissa Broger
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Youjun Zhang
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
- Center of Plant System Biology and Biotechnology, Ruski Blvd. 139, Plovdiv, 4000, Bulgaria
| | - Laura Lorenzo-Orts
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Anne Utz-Pugin
- Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Alisdair R Fernie
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Chang Young-Tae
- Center for Self-assembly and Complexity, IBS and Department of Chemistry, POSTECH, 50, Jigok-ro 127beon-gil, Nam-gu, Pohang-si, Gyeongsangbuk-do, Pohang, 37673, Republic of Korea
| | - Michael Hothorn
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
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8
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Zhu J, Loubéry S, Broger L, Zhang Y, Lorenzo-Orts L, Utz-Pugin A, Fernie AR, Young-Tae C, Hothorn M. A genetically validated approach for detecting inorganic polyphosphates in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:507-516. [PMID: 31816134 DOI: 10.1101/630129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 11/08/2019] [Accepted: 12/03/2019] [Indexed: 05/22/2023]
Abstract
Inorganic polyphosphates (polyPs) are linear polymers of orthophosphate units linked by phosphoanhydride bonds. Polyphosphates represent important stores of phosphate and energy, and are abundant in many pro- and eukaryotic organisms. In plants, the existence of polyPs has been established using microscopy and biochemical extraction methods that are now known to produce artifacts. Here we use a polyP-specific dye and a polyP-binding domain to detect polyPs in plant and algal cells. To develop the staining protocol, we induced polyP granules in Nicotiana benthamiana and Arabidopsis cells by heterologous expression of Escherichia coli polyphosphate kinase 1 (PPK1). Over-expression of PPK1 but not of a catalytically impaired version of the enzyme leads to severe growth phenotypes, suggesting that ATP-dependent synthesis and accumulation of polyPs in the plant cytosol is toxic. We next crossed stable PPK1-expressing Arabidopsis lines with plants expressing the polyP-binding domain of E. coli exopolyphosphatase (PPX1c), which co-localized with PPK1-generated polyP granules. These granules were stained by the polyP-specific dye JC-D7 and appeared as electron-dense structures in transmission electron microscopy sections. Using the polyP staining protocol derived from these experiments, we screened for polyP stores in different organs and tissues of both mono- and dicotyledonous plants. While we could not detect polyP granules in higher plants, we could visualize the polyP-rich acidocalcisomes in the green alga Chlamydomonas reinhardtii.
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Affiliation(s)
- Jinsheng Zhu
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Sylvain Loubéry
- Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Larissa Broger
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Youjun Zhang
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
- Center of Plant System Biology and Biotechnology, Ruski Blvd. 139, Plovdiv, 4000, Bulgaria
| | - Laura Lorenzo-Orts
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Anne Utz-Pugin
- Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
| | - Alisdair R Fernie
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Chang Young-Tae
- Center for Self-assembly and Complexity, IBS and Department of Chemistry, POSTECH, 50, Jigok-ro 127beon-gil, Nam-gu, Pohang-si, Gyeongsangbuk-do, Pohang, 37673, Republic of Korea
| | - Michael Hothorn
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 30 Quai E. Ansermet, Geneva, 1211, Switzerland
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9
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Christ JJ, Willbold S, Blank LM. Methods for the Analysis of Polyphosphate in the Life Sciences. Anal Chem 2020; 92:4167-4176. [PMID: 32039586 DOI: 10.1021/acs.analchem.9b05144] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inorganic polyphosphate (polyP) is the polymer of orthophosphate and can be found in all living organisms. For polyP characterization, one or more of six parameters are of interest: the molecular structure (linear, cyclic, or branched), the concentration, the average chain length, the chain length distribution, the cellular localization, and the cation composition. Here, the merits, limitations, and critical parameters of the state-of-the-art methods for the analysis of the six parameters from the life sciences are discussed. With this contribution, we aim to lower the entry barrier into the analytics of polyP, a molecule with prominent, yet often incompletely understood, contributions to cellular function.
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Affiliation(s)
- Jonas Johannes Christ
- Institute of Applied Microbiology-iAMB, Aachen Biology and Biotechnology-ABBt, Worringer Weg 1, RWTH Aachen University, D-52074 Aachen, Germany
| | - Sabine Willbold
- Central Institute for Engineering, Electronics and Analytics, Analytics (ZEA-3), Wilhelm-Johnen-Straße, D-52428 Jülich, Germany
| | - Lars Mathias Blank
- Institute of Applied Microbiology-iAMB, Aachen Biology and Biotechnology-ABBt, Worringer Weg 1, RWTH Aachen University, D-52074 Aachen, Germany
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10
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Lorenzo‐Orts L, Couto D, Hothorn M. Identity and functions of inorganic and inositol polyphosphates in plants. THE NEW PHYTOLOGIST 2020; 225:637-652. [PMID: 31423587 PMCID: PMC6973038 DOI: 10.1111/nph.16129] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/22/2019] [Indexed: 05/08/2023]
Abstract
Inorganic polyphosphates (polyPs) and inositol pyrophosphates (PP-InsPs) form important stores of inorganic phosphate and can act as energy metabolites and signaling molecules. Here we review our current understanding of polyP and inositol phosphate (InsP) metabolism and physiology in plants. We outline methods for polyP and InsP detection, discuss the known plant enzymes involved in their synthesis and breakdown, and summarize the potential physiological and signaling functions for these enigmatic molecules in plants.
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Affiliation(s)
- Laura Lorenzo‐Orts
- Structural Plant Biology LaboratoryDepartment of Botany and Plant BiologyUniversity of Geneva30 Quai E. AnsermetGeneva1211Switzerland
| | - Daniel Couto
- Structural Plant Biology LaboratoryDepartment of Botany and Plant BiologyUniversity of Geneva30 Quai E. AnsermetGeneva1211Switzerland
| | - Michael Hothorn
- Structural Plant Biology LaboratoryDepartment of Botany and Plant BiologyUniversity of Geneva30 Quai E. AnsermetGeneva1211Switzerland
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11
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Lorenzo-Orts L, Hohmann U, Zhu J, Hothorn M. Molecular characterization of CHAD domains as inorganic polyphosphate-binding modules. Life Sci Alliance 2019; 2:2/3/e201900385. [PMID: 31133615 PMCID: PMC6537752 DOI: 10.26508/lsa.201900385] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/20/2019] [Accepted: 05/20/2019] [Indexed: 12/23/2022] Open
Abstract
A domain of unknown function termed CHAD, present in all kingdoms of life, is characterized as a specific inorganic polyphosphate-binding domain. Inorganic polyphosphates (polyPs) are linear polymers of orthophosphate units linked by phosphoanhydride bonds. Here, we report that bacterial, archaeal, and eukaryotic conserved histidine α-helical (CHAD) domains are specific polyP-binding modules. Crystal structures reveal that CHAD domains are formed by two four-helix bundles, giving rise to a central pore surrounded by conserved basic surface patches. Different CHAD domains bind polyPs with dissociation constants ranging from the nano- to mid-micromolar range, but not nucleic acids. A CHAD—polyP complex structure reveals the phosphate polymer binding across the central pore and along the two basic patches. Mutational analysis of CHAD—polyP interface residues validates the complex structure. The presence of a CHAD domain in the polyPase ygiF enhances its enzymatic activity. The only known CHAD protein from the plant Ricinus communis localizes to the nucleus/nucleolus when expressed in Arabidopsis and tobacco, suggesting that plants may harbor polyPs in these compartments. We propose that CHAD domains may be used to engineer the properties of polyP-metabolizing enzymes and to specifically localize polyP stores in eukaryotic cells and tissues.
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Affiliation(s)
- Laura Lorenzo-Orts
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Ulrich Hohmann
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Jinsheng Zhu
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Michael Hothorn
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
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12
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Gu C, Stashko MA, Puhl-Rubio AC, Chakraborty M, Chakraborty A, Frye SV, Pearce KH, Wang X, Shears SB, Wang H. Inhibition of Inositol Polyphosphate Kinases by Quercetin and Related Flavonoids: A Structure-Activity Analysis. J Med Chem 2019; 62:1443-1454. [PMID: 30624931 DOI: 10.1021/acs.jmedchem.8b01593] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dietary flavonoids inhibit certain protein kinases and phospholipid kinases by competing for their ATP-binding sites. These nucleotide pockets have structural elements that are well-conserved in two human small-molecule kinases, inositol hexakisphosphate kinase (IP6K) and inositol polyphosphate multikinase (IPMK), which synthesize multifunctional inositol phosphate cell signals. Herein, we demonstrate that both kinases are inhibited by quercetin and 16 related flavonoids; IP6K is the preferred target. Relative inhibitory activities were rationalized by X-ray analysis of kinase/flavonoid crystal structures; this detailed structure-activity analysis revealed hydrophobic and polar ligand/protein interactions, the degree of flexibility of key amino acid side chains, and the importance of water molecules. The seven most potent IP6K inhibitors were incubated with intact HCT116 cells at concentrations of 2.5 μM; diosmetin was the most selective and effective IP6K inhibitor (>70% reduction in activity). Our data can instruct on pharmacophore properties to assist the future development of inositol phosphate kinase inhibitors. Finally, we propose that dietary flavonoids may inhibit IP6K activity in cells that line the gastrointestinal tract.
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Affiliation(s)
- Chunfang Gu
- Inositol Signaling Group, Signal Transduction Laboratory , National Institute of Environmental Health Sciences , Research Triangle Park , North Carolina 27709 , United States
| | - Michael A Stashko
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Ana C Puhl-Rubio
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Molee Chakraborty
- Department of Pharmacology and Physiology , Saint Louis University School of Medicine , M370, Schwitalla Hall, 1402 South Grand Boulevard , Saint Louis , Missouri 63104 , United States
| | - Anutosh Chakraborty
- Department of Pharmacology and Physiology , Saint Louis University School of Medicine , M370, Schwitalla Hall, 1402 South Grand Boulevard , Saint Louis , Missouri 63104 , United States
| | - Stephen V Frye
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Kenneth H Pearce
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Xiaodong Wang
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Stephen B Shears
- Inositol Signaling Group, Signal Transduction Laboratory , National Institute of Environmental Health Sciences , Research Triangle Park , North Carolina 27709 , United States
| | - Huanchen Wang
- Inositol Signaling Group, Signal Transduction Laboratory , National Institute of Environmental Health Sciences , Research Triangle Park , North Carolina 27709 , United States
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13
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Pokhrel A, Lingo JC, Wolschendorf F, Gray MJ. Assaying for Inorganic Polyphosphate in Bacteria. J Vis Exp 2019. [PMID: 30735204 DOI: 10.3791/58818] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Inorganic polyphosphate (polyP) is a biological polymer found in cells from all domains of life, and is required for virulence and stress response in many bacteria. There are a variety of methods for quantifying polyP in biological materials, many of which are either labor-intensive or insensitive, limiting their usefulness. We present here a streamlined method for polyP quantification in bacteria, using a silica membrane column extraction optimized for rapid processing of multiple samples, digestion of polyP with the polyP-specific exopolyphosphatase ScPPX, and detection of the resulting free phosphate with a sensitive ascorbic acid-based colorimetric assay. This procedure is straightforward, inexpensive, and allows reliable polyP quantification in diverse bacterial species. We present representative polyP quantification from the Gram-negative bacterium (Escherichia coli), the Gram-positive lactic acid bacterium (Lactobacillus reuteri), and the mycobacterial species (Mycobacterium smegmatis). We also include a simple protocol for nickel affinity purification of mg quantities of ScPPX, which is not currently commercially available.
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Affiliation(s)
- Arya Pokhrel
- Department of Microbiology, University of Alabama at Birmingham
| | - Jordan C Lingo
- Division of Infectious Diseases, University of Alabama at Birmingham
| | | | - Michael J Gray
- Department of Microbiology, University of Alabama at Birmingham;
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14
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Sulfurimonas subgroup GD17 cells accumulate polyphosphate under fluctuating redox conditions in the Baltic Sea: possible implications for their ecology. ISME JOURNAL 2018; 13:482-493. [PMID: 30291329 DOI: 10.1038/s41396-018-0267-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/04/2018] [Accepted: 05/11/2018] [Indexed: 12/16/2022]
Abstract
The central Baltic Sea is characterized by a pelagic redox zone exhibiting high dark CO2 fixation rates below the chemocline. These rates are mainly driven by chemolithoautotrophic and denitrifying Sulfurimonas GD17 subgroup cells which are motile and fast-reacting r-strategists. Baltic Sea redox zones are unstable and a measurable overlap of nitrate and reduced sulfur, essential for chemosynthesis, is often only available on small scales and short times due to local mixing events. This raises the question of how GD17 cells gain access to electron donors or acceptors over longer term periods and under substrate deficiency. One possible answer is that GD17 cells store high-energy-containing polyphosphate during favorable nutrient conditions to survive periods of nutrient starvation. We used scanning electron microscopy with energy-dispersive X-ray spectroscopy to investigate potential substrate enrichments in single GD17 cells collected from Baltic Sea redox zones. More specific substrate enrichment features were identified in experiments using Sulfurimonas gotlandica GD1T, a GD17 representative. Sulfurimonas cells accumulated polyphosphate both in situ and in vitro. Combined genome and culture-dependent analyses suggest that polyphosphate serves as an energy reservoir to maintain cellular integrity at unfavorable substrate conditions. This redox-independent energy supply would be a precondition for sustaining the r-strategy lifestyle of GD17 and may represent a newly identified survival strategy for chemolithoautotrophic prokaryotes occupying eutrophic redox zones.
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15
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Abstract
Inositol phosphates (IPs) comprise a family of ubiquitous eukaryotic signaling molecules. They have been linked to the regulation of a pleiotropy of important cellular activities, but low abundance and detection difficulties have hampered our understanding. Here we present a method to purify and enrich IPs or other phosphate-rich metabolites from mammalian cells or other sample types. Acid-extracted IPs from cells bind selectively via their phosphate groups to titanium dioxide beads. After washing, the IPs are easily eluted from the beads by increasing the pH. This technique, in combination with downstream analytical methods such as PAGE or SAX-HPLC, opens unprecedented investigative possibilities, allowing appropriate analysis of IPs from virtually any biological or non-biological source.
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Affiliation(s)
- Miranda Sc Wilson
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
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16
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Saiardi A, Azevedo C, Desfougères Y, Portela-Torres P, Wilson MSC. Microbial inositol polyphosphate metabolic pathway as drug development target. Adv Biol Regul 2017; 67:74-83. [PMID: 28964726 DOI: 10.1016/j.jbior.2017.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 12/27/2022]
Abstract
Inositol polyphosphates are a diverse and multifaceted class of intracellular messengers omnipresent in eukaryotic cells. These water-soluble molecules regulate many aspects of fundamental cell physiology. Removing this metabolic pathway is deleterious: inositol phosphate kinase null mutations can result in lethality or substantial growth phenotypes. Inositol polyphosphate synthesis occurs through the actions of a set of kinases that phosphorylate phospholipase-generated IP3 to higher phosphorylated forms, such as the fully phosphorylated IP6 and the inositol pyrophosphates IP7 and IP8. Unicellular organisms have a reduced array of the kinases for synthesis of higher phosphorylated inositol polyphosphates, while human cells possess two metabolic routes to IP6. The enzymes responsible for inositol polyphosphate synthesis have been identified in all eukaryote genomes, although their amino acid sequence homology is often barely detectable by common search algorithms. Homology between human and microbial inositol phosphate kinases is restricted to a few catalytically important residues. Recent studies of the inositol phosphate metabolic pathways in pathogenic fungi (Cryptococcus neoformans) and protozoa (Trypanosome brucei) have revealed the importance of the highly phosphorylated inositol polyphosphates to the fitness and thus virulence of these pathogens. Given this, identification of inositol kinase inhibitors specifically targeting the kinases of pathogenic microorganisms is desirable and achievable.
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Affiliation(s)
- Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK.
| | - Cristina Azevedo
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Yann Desfougères
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Paloma Portela-Torres
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Miranda S C Wilson
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
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17
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Kostanjšek R, Vittori M, Srot V, van Aken PA, Štrus J. Polyphosphate-accumulating bacterial community colonizing the calcium bodies of terrestrial isopod crustaceans Titanethes albus and Hyloniscus riparius. FEMS Microbiol Ecol 2017; 93:3753549. [PMID: 28449118 DOI: 10.1093/femsec/fix053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 04/17/2017] [Indexed: 11/13/2022] Open
Abstract
Terrestrial isopods from the group Trichoniscidae accumulate calcium in specialized organs, known as the calcium bodies. These consist of two pairs of epithelial sacs located alongside the digestive system. These organs contain various forms of calcium and constantly present bacteria. To elucidate their origin and role, we analyzed the bacteria of the calcium bodies in the cave-dwelling isopod Titanethes albus and the epigean species Hyloniscus riparius, by microscopy, histochemistry, energy dispersive X-ray spectrometry, 16S rRNA analysis and in situ hybridization. The calcium bodies of both species comprise numerous and diverse bacterial communities consisting of known soil bacteria. Despite their diversity, these bacteria share the polyphosphate-accumulation ability. We present the model of phosphorous dynamics in the calcium bodies during the molting cycle and potentially beneficial utilization of the symbiotic phosphate by the host in cyclic regeneration of the cuticle. Although not fully understood, this unique symbiosis represents the first evidence of polyphosphate-accumulating bacterial symbionts in the tissue of a terrestrial animal.
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Affiliation(s)
- Rok Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Miloš Vittori
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Vesna Srot
- Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Peter A van Aken
- Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Jasna Štrus
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
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18
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Azevedo C, Saiardi A. Eukaryotic Phosphate Homeostasis: The Inositol Pyrophosphate Perspective. Trends Biochem Sci 2017; 42:219-231. [DOI: 10.1016/j.tibs.2016.10.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 12/24/2022]
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19
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Bru S, Jiménez J, Canadell D, Ariño J, Clotet J. Improvement of biochemical methods of polyP quantification. MICROBIAL CELL 2016; 4:6-15. [PMID: 28357384 PMCID: PMC5354550 DOI: 10.15698/mic2017.01.551] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polyphosphate (polyP) is an abundant and physiologically important biomolecule
for virtually any living cell. Therefore, determination of changes in cellular
content of polyP is crucial for its functional characterization. Determination
of cellular polyP has been performed by many different methods, and the lack of
a standardized procedure is possibly responsible for the large dispersion of
results found in the relevant literature. For a relatively simple organism, such
as the yeast Saccharomyces cerevisiae, this variation can be up
to 12-fold. polyP extraction and determination of free phosphate released by
enzymatic degradation of the polymer is a method quite common and relatively
straightforward for polyP determination. By using the yeast S.
cerevisiae as model, we have experimentally evaluated the different
steps in this procedure in order to identify critical issues that might explain
the disparate reported results. As the main output of this evaluation we propose
a straightforward and robust procedure that can be used as gold standard
protocol for cellular polyP purification and determination from unicellular
organisms, thus providing consistency to measurements and facilitating
inter-laboratory comparisons and biological interpretation of the results.
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Affiliation(s)
- Samuel Bru
- Department of Basic Sciences, Faculty of Medicine and Health Sciences. Universitat Internacional de Catalunya. Barcelona, Spain
| | - Javier Jiménez
- Department of Basic Sciences, Faculty of Medicine and Health Sciences. Universitat Internacional de Catalunya. Barcelona, Spain
| | - David Canadell
- Departament de Bioquímica i Biologia Molecular and Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona. Cerdanyola del Vallès, Spain
| | - Joaquín Ariño
- Departament de Bioquímica i Biologia Molecular and Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona. Cerdanyola del Vallès, Spain
| | - Josep Clotet
- Department of Basic Sciences, Faculty of Medicine and Health Sciences. Universitat Internacional de Catalunya. Barcelona, Spain
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20
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Abstract
The fluorescent dye DAPI is useful for its association with and consequent amplification of an ∼460 nm emission maximum upon binding to dsDNA. Labelling with higher DAPI concentrations is a technique used to reveal Pi polymers [polyphosphate (polyP)], with a red-shift to ∼520-550 nm fluorescence emission. DAPI-polyP emissions of ∼580 nm are also generated upon 415 nm excitation. Red-shifted DAPI emission has been associated with polyP and RNA and has more recently been reported with polyadenylic acid (polyA), specific inositol phosphates (IPs) and heparin. We find that amorphous calcium phosphate (ACP) also demonstrates red-shifted DAPI emission at high DAPI concentrations. This DAPI spectral shift has been attributed to DAPI-DAPI electrostatic interactions enabled by molecules with high negative charge density that increase the local DAPI concentration and favour DAPI molecular proximity, as observed by increasing the dye/phosphate ratio. Excitation of dry DAPI (∼360 nm) confirmed a red-shifted DAPI emission. Whereas enzymatic approaches to modify substrates can help define the nature of DAPI fluorescence signals, multiple approaches beyond red-shifted DAPI excitation/emission are advised before conclusions are drawn about DAPI substrate identification.
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21
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Suess PM, Gomer RH. Extracellular Polyphosphate Inhibits Proliferation in an Autocrine Negative Feedback Loop in Dictyostelium discoideum. J Biol Chem 2016; 291:20260-9. [PMID: 27519410 DOI: 10.1074/jbc.m116.737825] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Indexed: 11/06/2022] Open
Abstract
Polyphosphate is a polymer of phosphate residues linked by high energy phosphoanhydride bonds. Despite being highly conserved throughout nature, its function is poorly understood. Here we show that Dictyostelium cells accumulate extracellular polyphosphate, and this acts to inhibit proliferation at high cell densities. In shaking culture, extracellular polyphosphate concentrations increase as cell density increases, and if the concentration of polyphosphate observed at the stationary phase is added to cells at mid-log, proliferation is halted. Adding an exopolyphosphatase to cell cultures or stationary phase conditioned medium decreases polyphosphate levels and abrogates the anti-proliferative effect. The cells show saturable binding of polyphosphate, suggesting the presence of a cell surface polyphosphate receptor. Extracellular polyphosphate accumulation is potentiated by decreased nutrient levels, potentially as a means to anticipate starvation. Loss of the Dictyostelium polyphosphate kinase DdPpk1 causes intracellular polyphosphate levels to become undetectable and negatively affects fitness, cytokinesis, and germination. However, cells lacking DdPpk1 accumulate ∼50% normal levels of extracellular polyphosphate, suggesting an additional means of synthesis. We found that cells lacking inositol hexakisphosphate kinase, which is responsible for the synthesis of the inositol pyrophosphates IP7 and IP8, reach abnormally high cell densities and show decreased extracellular polyphosphate levels. Two different enzymes thus appear to mediate the synthesis of Dictyostelium extracellular polyphosphate, which is used as a signal in an autocrine negative feedback loop to regulate cell proliferation.
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Affiliation(s)
- Patrick M Suess
- From the Department of Biology, Texas A&M University, College Station, Texas 77843-3474
| | - Richard H Gomer
- From the Department of Biology, Texas A&M University, College Station, Texas 77843-3474
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22
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Schlagenhauf A, Pohl S, Haidl H, Leschnik B, Gallistl S, Muntean W. Non-enzymatic quantification of polyphosphate levels in platelet lysates and releasates. J Pharm Biomed Anal 2016; 131:1-5. [PMID: 27521983 DOI: 10.1016/j.jpba.2016.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/01/2016] [Accepted: 08/03/2016] [Indexed: 12/28/2022]
Abstract
Inorganic polyphosphate has been shown to be shed upon platelet activation inducing prothrombotic stimuli on the coagulation system. Several methods have been published to detect and quantify polyphosphate in various cells and tissues, but evaluation of platelet content has only been achieved by indirect detection of orthophosphate after enzymatic digestion, thus, relying heavily on specificity of an exopolyphosphatase that is not commercially available. We present a non-enzymatic method for quantification of platelet-derived polyphosphate featuring optimized extraction on silica spin-columns, followed by specific fluorescence detection using DAPI. This allowed us to quantify polyphosphate in platelet lysates, but also in releasates of TRAP-activated platelets for the first time. Extraction of exogenous polyphosphate from buffer and sample matrices resulted in quantitative yields while removing matrix effects observed with direct fluorescence detection. Treatment of eluted fractions with phosphatase completely abrogated polyphosphate-specific fluorescence arguing for no additional compounds influencing the fluorescence detection. This was confirmed by no change in fluorescence intensity in samples previously treated with DNase and RNase. Taken together, we developed a robust and easily standardizable method to quantify polyphosphate in platelet lysates and releasates that will facilitate polyphosphate related investigations of platelet physiology and coagulation.
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Affiliation(s)
- Axel Schlagenhauf
- Department of General Pediatrics and Adolescent Medicine, Medical University of Graz, Austria.
| | - Sina Pohl
- Department of General Pediatrics and Adolescent Medicine, Medical University of Graz, Austria
| | - Harald Haidl
- Department of General Pediatrics and Adolescent Medicine, Medical University of Graz, Austria
| | - Bettina Leschnik
- Department of General Pediatrics and Adolescent Medicine, Medical University of Graz, Austria
| | - Siegfried Gallistl
- Department of General Pediatrics and Adolescent Medicine, Medical University of Graz, Austria
| | - Wolfgang Muntean
- Department of General Pediatrics and Adolescent Medicine, Medical University of Graz, Austria
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23
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Developmental accumulation of inorganic polyphosphate affects germination and energetic metabolism in Dictyostelium discoideum. Proc Natl Acad Sci U S A 2016; 113:996-1001. [PMID: 26755590 DOI: 10.1073/pnas.1519440113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Inorganic polyphosphate (polyP) is composed of linear chains of phosphate groups linked by high-energy phosphoanhydride bonds. However, this simple, ubiquitous molecule remains poorly understood. The use of nonstandardized analytical methods has contributed to this lack of clarity. By using improved polyacrylamide gel electrophoresis we were able to visualize polyP extracted from Dictyostelium discoideum. We established that polyP is undetectable in cells lacking the polyphosphate kinase (DdPpk1). Generation of this ppk1 null strain revealed that polyP is important for the general fitness of the amoebae with the mutant strain displaying a substantial growth defect. We discovered an unprecedented accumulation of polyP during the developmental program, with polyP increasing more than 100-fold. The failure of ppk1 spores to accumulate polyP results in a germination defect. These phenotypes are underpinned by the ability of polyP to regulate basic energetic metabolism, demonstrated by a 2.5-fold decrease in the level of ATP in vegetative ppk1. Finally, the lack of polyP during the development of ppk1 mutant cells is partially offset by an increase of both ATP and inositol pyrophosphates, evidence for a model in which there is a functional interplay between inositol pyrophosphates, ATP, and polyP.
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24
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Kolozsvari B, Firth S, Saiardi A. Raman spectroscopy detection of phytic acid in plant seeds reveals the absence of inorganic polyphosphate. MOLECULAR PLANT 2015; 8:826-828. [PMID: 25620771 DOI: 10.1016/j.molp.2015.01.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/15/2015] [Accepted: 01/15/2015] [Indexed: 06/04/2023]
Affiliation(s)
- Bernadett Kolozsvari
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Steven Firth
- Department of Chemistry, University College London, London WC1H 0AJ, UK
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
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25
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Shears SB. Inositol pyrophosphates: why so many phosphates? Adv Biol Regul 2014; 57:203-16. [PMID: 25453220 DOI: 10.1016/j.jbior.2014.09.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 09/23/2014] [Accepted: 09/25/2014] [Indexed: 10/24/2022]
Abstract
The inositol pyrophosphates (PP-InsPs) are a specialized group of "energetic" signaling molecules found in yeasts, plants and animals. PP-InsPs boast the most crowded three dimensional phosphate arrays found in Nature; multiple phosphates and diphosphates are crammed around the six-carbon, inositol ring. Yet, phosphate esters are also a major energy currency in cells. So the synthesis of PP-InsPs, and the maintenance of their levels in the face of a high rate of ongoing turnover, all requires significant bioenergetic input. What are the particular properties of PP-InsPs that repay this investment of cellular energy? Potential answers to that question are discussed here, against the backdrop of a recent hypothesis that signaling by PP-InsPs is evolutionarily ancient. The latter idea is extended herein, with the proposal that the primordial origins of PP-InsPs is reflected in the apparent lack of isomeric specificity of certain of their actions. Nevertheless, there are other aspects of signaling by these polyphosphates that are more selective for a particular PP-InsP isomer. Consideration of the nature of both specific and non-specific effects of PP-InsPs can help rationalize why such molecules possess so many phosphates.
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Affiliation(s)
- Stephen B Shears
- Inositol Signaling Group, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, NIH, DHHS, PO Box 12233, Research Triangle Park, NC 27709, USA.
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