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Desmarini D, Liu G, Jessen H, Bowring B, Connolly A, Crossett B, Djordjevic JT. Arg1 from Cryptococcus neoformans lacks PI3 kinase activity and conveys virulence roles via its IP 3-4 kinase activity. mBio 2024:e0060824. [PMID: 38742909 DOI: 10.1128/mbio.00608-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024] Open
Abstract
Inositol tris/tetrakis phosphate kinases (IP3-4K) in the human fungal priority pathogens, Cryptococcus neoformans (CnArg1) and Candida albicans (CaIpk2), convey numerous virulence functions, yet it is not known whether the IP3-4K catalytic activity or a scaffolding role is responsible. We therefore generated a C. neoformans strain with a non-functional kinase, referred to as the dead-kinase (dk) CnArg1 strain (dkArg1). We verified that, although dkARG1 cDNA cloned from this strain produced a protein with the expected molecular weight, dkArg1 was catalytically inactive with no IP3-4K activity. Using recombinant CnArg1 and CaIpk2, we confirmed that, unlike the IP3-4K homologs in humans and Saccharomyces cerevisiae, CnArg1 and CaIpk2 do not phosphorylate the lipid-based substrate, phosphatidylinositol 4,5-bisphosphate, and therefore do not function as class I PI3Ks. Inositol polyphosphate profiling using capillary electrophoresis-electrospray ionization-mass spectrometry revealed that IP3 conversion is blocked in the dkArg1 and ARG1 deletion (Cnarg1Δ) strains and that 1-IP7 and a recently discovered isomer (4/6-IP7) are made by wild-type C. neoformans. Importantly, the dkArg1 and Cnarg1Δ strains had similar virulence defects, including suppressed growth at 37°C, melanization, capsule production, and phosphate starvation response, and were avirulent in an insect model, confirming that virulence is dependent on IP3-4K catalytic activity. Our data also implicate the dkArg1 scaffold in transcriptional regulation of arginine metabolism but via a different mechanism to S. cerevisiae since CnArg1 is dispensable for growth on different nitrogen sources. IP3-4K catalytic activity therefore plays a dominant role in fungal virulence, and IPK pathway function has diverged in fungal pathogens.IMPORTANCEThe World Health Organization has emphasized the urgent need for global action in tackling the high morbidity and mortality rates stemming from invasive fungal infections, which are exacerbated by the limited variety and compromised effectiveness of available drug classes. Fungal IP3-4K is a promising target for new therapy, as it is critical for promoting virulence of the human fungal priority pathogens, Cryptococcus neoformans and Candida albicans, and impacts numerous functions, including cell wall integrity. This contrasts to current therapies, which only target a single function. IP3-4K enzymes exert their effect through their inositol polyphosphate products or via the protein scaffold. Here, we confirm that the IP3-4K catalytic activity of CnArg1 promotes all virulence traits in C. neoformans that are attenuated by ARG1 deletion, reinforcing our ongoing efforts to find inositol polyphosphate effector proteins and to create inhibitors targeting the IP3-4K catalytic site, as a new antifungal drug class.
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Affiliation(s)
- Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, Australia
- Faculty of Medicine and Health, Sydney Institute for Infectious Diseases, University of Sydney, Sydney, Australia
| | - Guizhen Liu
- Institute of Organic Chemistry, University of Freiburg, Freiburg im Breisgau, Germany
- Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Henning Jessen
- Institute of Organic Chemistry, University of Freiburg, Freiburg im Breisgau, Germany
- Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Bethany Bowring
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, Australia
- Faculty of Medicine and Health, Sydney Institute for Infectious Diseases, University of Sydney, Sydney, Australia
| | - Angela Connolly
- Sydney Mass Spectrometry, University of Sydney, Sydney, Australia
| | - Ben Crossett
- Sydney Mass Spectrometry, University of Sydney, Sydney, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, Australia
- Faculty of Medicine and Health, Sydney Institute for Infectious Diseases, University of Sydney, Sydney, Australia
- Westmead Hospital, Western Sydney Local Health District, Sydney, Australia
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2
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Gross AS, Ghillebert R, Schuetter M, Reinartz E, Rowland A, Bishop BC, Stumpe M, Dengjel J, Graef M. A metabolite sensor subunit of the Atg1/ULK complex regulates selective autophagy. Nat Cell Biol 2024; 26:366-377. [PMID: 38316984 PMCID: PMC10940145 DOI: 10.1038/s41556-024-01348-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/03/2024] [Indexed: 02/07/2024]
Abstract
Cells convert complex metabolic information into stress-adapted autophagy responses. Canonically, multilayered protein kinase networks converge on the conserved Atg1/ULK kinase complex (AKC) to induce non-selective and selective forms of autophagy in response to metabolic changes. Here we show that, upon phosphate starvation, the metabolite sensor Pho81 interacts with the adaptor subunit Atg11 at the AKC via an Atg11/FIP200 interaction motif to modulate pexophagy by virtue of its conserved phospho-metabolite sensing SPX domain. Notably, core AKC components Atg13 and Atg17 are dispensable for phosphate starvation-induced autophagy revealing significant compositional and functional plasticity of the AKC. Our data indicate that, instead of functioning as a selective autophagy receptor, Pho81 compensates for partially inactive Atg13 by promoting Atg11 phosphorylation by Atg1 critical for pexophagy during phosphate starvation. Our work shows Atg11/FIP200 adaptor subunits bind not only selective autophagy receptors but also modulator subunits that convey metabolic information directly to the AKC for autophagy regulation.
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Affiliation(s)
- A S Gross
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
- Gregor Mendel Institute of Molecular Plant Biology, Vienna Biocenter, Vienna, Austria
| | - R Ghillebert
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - M Schuetter
- Max Planck Research Metabolomics Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - E Reinartz
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - A Rowland
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - B C Bishop
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - M Stumpe
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - J Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - M Graef
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany.
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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3
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Du J, Dong Y, Zhu H, Deng Y, Sa C, Yu Q, Li M. DNA damage-induced autophagy is regulated by inositol polyphosphate synthetases in Candida albicans. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119622. [PMID: 37913846 DOI: 10.1016/j.bbamcr.2023.119622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 10/16/2023] [Accepted: 10/22/2023] [Indexed: 11/03/2023]
Abstract
DNA damage-induced autophagy is a new type of autophagy that differs from traditional macroautophagy; however, this type of autophagy has not been identified in the pathogenic fungus Candida albicans. Inositol polyphosphates are involved in the regulation of DNA damage repair and macroautophagy; however, whether inositol polyphosphates are involved in the regulation of DNA damage-induced autophagy remains unclear. In this study, we identified DNA damage-induced autophagy in C. albicans and systematically investigated the mechanisms of inositol polyphosphate pathway regulation. We found that the core machinery of macro autophagy is also essential for DNA damage-induced autophagy, and that inositol polyphosphate synthetases Kcs1, Ipk1, and Vip1 play a critical role in autophagy. In this study, we focused on Kcs1 and Vip1, which are responsible for the synthesis of inositol pyrophosphate. The kcs1Δ/Δ and vip1Δ/Δ strains exhibited reduced number of phagophore assembly sites (PAS) and autophagic bodies. The recruitment of autophagy-related gene 1 (Atg1) to PAS was significantly affected in the kcs1Δ/Δ and vip1Δ/Δ strains. Target of rapamycin complex 1 kinase activity was elevated in kcs1Δ/Δ and vip1Δ/Δ strains, which significantly inhibited the initiation of autophagy. Atg18 Localization was altered in these mutants. The absence of Kcs1 or Vip1 caused the downregulation of RAD53, a key gene in the DNA damage response. These data provide further understanding of the mechanism of autophagy regulation in C. albicans.
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Affiliation(s)
- Jiawen Du
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yixuan Dong
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Hangqi Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ying Deng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Chula Sa
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
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4
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Gu C, Li X, Zong G, Wang H, Shears SB. IP8: A quantitatively minor inositol pyrophosphate signaling molecule that punches above its weight. Adv Biol Regul 2024; 91:101002. [PMID: 38064879 DOI: 10.1016/j.jbior.2023.101002] [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: 11/21/2023] [Accepted: 11/27/2023] [Indexed: 02/25/2024]
Abstract
The inositol pyrophosphates (PP-IPs) are specialized members of the wider inositol phosphate signaling family that possess functionally significant diphosphate groups. The PP-IPs exhibit remarkable functionally versatility throughout the eukaryotic kingdoms. However, a quantitatively minor PP-IP - 1,5 bisdiphosphoinositol tetrakisphosphate (1,5-IP8) - has received considerably less attention from the cell signalling community. The main purpose of this review is to summarize recently-published data which have now brought 1,5-IP8 into the spotlight, by expanding insight into the molecular mechanisms by which this polyphosphate regulates many fundamental biological processes.
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Affiliation(s)
- Chunfang Gu
- Inositol signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709 USA
| | - Xingyao Li
- Inositol signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709 USA
| | - Guangning Zong
- Inositol signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709 USA
| | - Huanchen Wang
- Inositol signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709 USA.
| | - Stephen B Shears
- Inositol signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709 USA.
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5
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Chabert V, Kim GD, Qiu D, Liu G, Michaillat Mayer L, Jamsheer K M, Jessen HJ, Mayer A. Inositol pyrophosphate dynamics reveals control of the yeast phosphate starvation program through 1,5-IP 8 and the SPX domain of Pho81. eLife 2023; 12:RP87956. [PMID: 37728314 PMCID: PMC10511240 DOI: 10.7554/elife.87956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023] Open
Abstract
Eukaryotic cells control inorganic phosphate to balance its role as essential macronutrient with its negative bioenergetic impact on reactions liberating phosphate. Phosphate homeostasis depends on the conserved INPHORS signaling pathway that utilizes inositol pyrophosphates and SPX receptor domains. Since cells synthesize various inositol pyrophosphates and SPX domains bind them promiscuously, it is unclear whether a specific inositol pyrophosphate regulates SPX domains in vivo, or whether multiple inositol pyrophosphates act as a pool. In contrast to previous models, which postulated that phosphate starvation is signaled by increased production of the inositol pyrophosphate 1-IP7, we now show that the levels of all detectable inositol pyrophosphates of yeast, 1-IP7, 5-IP7, and 1,5-IP8, strongly decline upon phosphate starvation. Among these, specifically the decline of 1,5-IP8 triggers the transcriptional phosphate starvation response, the PHO pathway. 1,5-IP8 inactivates the cyclin-dependent kinase inhibitor Pho81 through its SPX domain. This stimulates the cyclin-dependent kinase Pho85-Pho80 to phosphorylate the transcription factor Pho4 and repress the PHO pathway. Combining our results with observations from other systems, we propose a unified model where 1,5-IP8 signals cytosolic phosphate abundance to SPX proteins in fungi, plants, and mammals. Its absence triggers starvation responses.
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Affiliation(s)
- Valentin Chabert
- Département d'immunobiologie, Université de LausanneEpalingesSwitzerland
| | - Geun-Don Kim
- Département d'immunobiologie, Université de LausanneEpalingesSwitzerland
| | - Danye Qiu
- Institute of Organic Chemistry, Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
| | - Guizhen Liu
- Institute of Organic Chemistry, Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
| | | | | | - Henning J Jessen
- Institute of Organic Chemistry, Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
| | - Andreas Mayer
- Département d'immunobiologie, Université de LausanneEpalingesSwitzerland
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6
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Pipercevic J, Kohl B, Gerasimaite R, Comte-Miserez V, Hostachy S, Müntener T, Agustoni E, Jessen HJ, Fiedler D, Mayer A, Hiller S. Inositol pyrophosphates activate the vacuolar transport chaperone complex in yeast by disrupting a homotypic SPX domain interaction. Nat Commun 2023; 14:2645. [PMID: 37156835 PMCID: PMC10167327 DOI: 10.1038/s41467-023-38315-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 04/25/2023] [Indexed: 05/10/2023] Open
Abstract
Many proteins involved in eukaryotic phosphate homeostasis are regulated by SPX domains. In yeast, the vacuolar transporter chaperone (VTC) complex contains two such domains, but mechanistic details of its regulation are not well understood. Here, we show at the atomic level how inositol pyrophosphates interact with SPX domains of subunits Vtc2 and Vtc3 to control the activity of the VTC complex. Vtc2 inhibits the catalytically active VTC subunit Vtc4 by homotypic SPX-SPX interactions via the conserved helix α1 and the previously undescribed helix α7. Binding of inositol pyrophosphates to Vtc2 abrogates this interaction, thus activating the VTC complex. Accordingly, VTC activation is also achieved by site-specific point mutations that disrupt the SPX-SPX interface. Structural data suggest that ligand binding induces reorientation of helix α1 and exposes the modifiable helix α7, which might facilitate its post-translational modification in vivo. The variable composition of these regions within the SPX domain family might contribute to the diversified SPX functions in eukaryotic phosphate homeostasis.
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Affiliation(s)
- Joka Pipercevic
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Bastian Kohl
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Ruta Gerasimaite
- Department of Immunobiology, University of Lausanne, Chemin des Boveresses 155, CP51 1066, Epalinges, Switzerland
- Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Véronique Comte-Miserez
- Department of Immunobiology, University of Lausanne, Chemin des Boveresses 155, CP51 1066, Epalinges, Switzerland
| | - Sarah Hostachy
- Department of Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Thomas Müntener
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Elia Agustoni
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Henning Jacob Jessen
- Institute of Organic Chemistry, University of Freiburg, Albertstraße 21, 79104, Freiburg, Germany
| | - Dorothea Fiedler
- Department of Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Andreas Mayer
- Department of Immunobiology, University of Lausanne, Chemin des Boveresses 155, CP51 1066, Epalinges, Switzerland
| | - Sebastian Hiller
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland.
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7
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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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8
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Kuenzel NA, Alcázar-Román AR, Saiardi A, Bartsch SM, Daunaraviciute S, Fiedler D, Fleig U. Inositol Pyrophosphate-Controlled Kinetochore Architecture and Mitotic Entry in S. pombe. J Fungi (Basel) 2022; 8:933. [PMID: 36135658 PMCID: PMC9506091 DOI: 10.3390/jof8090933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Inositol pyrophosphates (IPPs) comprise a specific class of signaling molecules that regulate central biological processes in eukaryotes. The conserved Vip1/PPIP5K family controls intracellular IP8 levels, the highest phosphorylated form of IPPs present in yeasts, as it has both inositol kinase and pyrophosphatase activities. Previous studies have shown that the fission yeast S. pombe Vip1/PPIP5K family member Asp1 impacts chromosome transmission fidelity via the modulation of spindle function. We now demonstrate that an IP8 analogue is targeted by endogenous Asp1 and that cellular IP8 is subject to cell cycle control. Mitotic entry requires Asp1 kinase function and IP8 levels are increased at the G2/M transition. In addition, the kinetochore, the conductor of chromosome segregation that is assembled on chromosomes is modulated by IP8. Members of the yeast CCAN kinetochore-subcomplex such as Mal2/CENP-O localize to the kinetochore depending on the intracellular IP8-level: higher than wild-type IP8 levels reduce Mal2 kinetochore targeting, while a reduction in IP8 has the opposite effect. As our perturbations of the inositol polyphosphate and IPP pathways demonstrate that kinetochore architecture depends solely on IP8 and not on other IPPs, we conclude that chromosome transmission fidelity is controlled by IP8 via an interplay between entry into mitosis, kinetochore architecture, and spindle dynamics.
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Affiliation(s)
- Natascha Andrea Kuenzel
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Abel R. Alcázar-Román
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower St., London WC1E 6BT, UK
| | - Simon M. Bartsch
- 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
| | - Sarune Daunaraviciute
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, 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
| | - Ursula Fleig
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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9
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Nguyen Trung M, Furkert D, Fiedler D. Versatile signaling mechanisms of inositol pyrophosphates. Curr Opin Chem Biol 2022; 70:102177. [PMID: 35780751 DOI: 10.1016/j.cbpa.2022.102177] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 01/03/2023]
Abstract
Inositol pyrophosphates (PP-InsPs) constitute a group of highly charged messengers, which regulate central biological processes in health and disease, such as cellular phosphate and general energy homeostasis. Deciphering the molecular mechanisms underlying PP-InsP-mediated signaling remains a challenge due to the unique properties of these molecules, the different modes of action they can access, and a somewhat limited chemical and analytical toolset. Herein, we summarize the most recent mechanistic insights into PP-InsP signaling, which illustrate our progress in connecting mechanism and function of PP-InsPs.
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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
| | - David Furkert
- 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
| | - 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.
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10
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Blocking Polyphosphate Mobilization Inhibits Pho4 Activation and Virulence in the Pathogen Candida albicans. mBio 2022; 13:e0034222. [PMID: 35575514 PMCID: PMC9239153 DOI: 10.1128/mbio.00342-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ability of pathogenic fungi to obtain essential nutrients from the host is vital for virulence. In Candida albicans, acquisition of the macronutrient phosphate is regulated by the Pho4 transcription factor and is important for both virulence and resistance to host-encountered stresses. All cells store phosphate in the form of polyphosphate (polyP), a ubiquitous polymer comprising tens to hundreds of phosphate residues. Release of phosphate from polyP is one of the first responses evoked in response to phosphate starvation, and here, we sought to explore the importance of polyP mobilization in the pathobiology of C. albicans. We found that two polyphosphatases, Ppn1 and Ppx1, function redundantly to release phosphate from polyP in C. albicans. Strikingly, we reveal that blocking polyP mobilization prevents the activation of the Pho4 transcription factor: following Pi starvation, Pho4 fails to accumulate in the nucleus and induce Pi acquisition genes in ppn1Δ ppx1Δ cells. Consequently, ppn1Δ ppx1Δ cells display impaired resistance to the same range of stresses that require Pho4 for survival. In addition, cells lacking both polyphosphatases are exquisitely sensitive to DNA replication stress, indicating that polyP mobilization is needed to support the phosphate-demanding process of DNA replication. Blocking polyP mobilization also results in significant morphological defects, as ppn1Δ ppx1Δ cells form large pseudohypha-like cells that are resistant to serum-induced hypha formation. Thus, polyP mobilization impacts key processes important for the pathobiology of C. albicans, and consistent with this, we found that blocking this process attenuates the virulence of this important human fungal pathogen.
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11
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Mechanistic insights into the regulation of plant phosphate homeostasis by the rice SPX2 - PHR2 complex. Nat Commun 2022; 13:1581. [PMID: 35332155 PMCID: PMC8948245 DOI: 10.1038/s41467-022-29275-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 03/03/2022] [Indexed: 01/21/2023] Open
Abstract
Phosphate (Pi) starvation response (PHR) transcription factors play key roles in plant Pi homeostasis maintenance. They are negatively regulated by stand-alone SPX proteins, cellular receptors for inositol pyrophosphate (PP-InsP) nutrient messengers. How PP-InsP-bound SPX interacts with PHRs is poorly understood. Here, we report crystal structures of the rice SPX2/InsP6/PHR2 complex and of the PHR2 DNA binding (MYB) domain in complex with target DNA at resolutions of 3.1 Å and 2.7 Å, respectively. In the SPX2/InsP6/PHR2 complex, the signalling-active SPX2 assembles into a domain-swapped dimer conformation and binds two copies of PHR2, targeting both its coiled-coil (CC) oligomerisation domain and MYB domain. Our results reveal that the SPX2 senses PP-InsPs to inactivate PHR2 by establishing severe steric clashes with the PHR2 MYB domain, preventing DNA binding, and by disrupting oligomerisation of the PHR2 CC domain, attenuating promoter binding. Our findings rationalize how PP-InsPs activate SPX receptor proteins to target PHR family transcription factors. SPX receptors regulate plant phosphate response via PHR transcription factors. Here, based on crystal structure analysis of rice PHR2 complexes, the authors propose that SPX2 regulates PHR2 by preventing DNA binding and oligomerisation of the PHR2 CC domain.
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Satheesh V, Tahir A, Li J, Lei M. Plant phosphate nutrition: sensing the stress. STRESS BIOLOGY 2022; 2:16. [PMID: 37676547 PMCID: PMC10441931 DOI: 10.1007/s44154-022-00039-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/31/2022] [Indexed: 09/08/2023]
Abstract
Phosphorus (P) is obtained by plants as phosphate (Pi) from the soil and low Pi levels affects plant growth and development. Adaptation to low Pi condition entails sensing internal and external Pi levels and translating those signals to molecular and morphophysiological changes in the plant. In this review, we present findings related to local and systemin Pi sensing with focus the molecular mechanisms behind root system architectural changes and the impact of hormones and epigenetic mechanisms affecting those changes. We also present some of the recent advances in the Pi sensing and signaling mechanisms focusing on inositol pyrophosphate InsP8 and its interaction with SPX domain proteins to regulate the activity of the central regulator of the Pi starvation response, PHR.
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Affiliation(s)
- Viswanathan Satheesh
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602 China
| | - Ayesha Tahir
- Department of Biosciences, COMSATS University Islamabad, Park Road, Islamabad, Pakistan
| | - Jinkai Li
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Mingguang Lei
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602 China
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13
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Phosphate Starvation by Energy Metabolism Disturbance in Candida albicansvip1Δ/Δ Induces Lipid Droplet Accumulation and Cell Membrane Damage. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030686. [PMID: 35163951 PMCID: PMC8839741 DOI: 10.3390/molecules27030686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/11/2022] [Accepted: 01/15/2022] [Indexed: 11/17/2022]
Abstract
Phosphorus in the form of phosphate (Pi) is an essential element for metabolic processes, including lipid metabolism. In yeast, the inositol polyphosphate kinase vip1 mediated synthesis of inositol heptakisphosphate (IP7) regulates the phosphate-responsive (PHO) signaling pathway, which plays an important role in response to Pi stress. The role of vip1 in Pi stress and lipid metabolism of Candida albicans has not yet been studied. We found that when vip1Δ/Δ was grown in glucose medium, if Pi was supplemented in the medium or mitochondrial Pi transporter was overexpressed in the strain, the lipid droplet (LD) content was reduced and membrane damage was alleviated. However, further studies showed that neither the addition of Pi nor the overexpression of the Pi transporter affected the energy balance of vip1Δ/Δ. In addition, the LD content of vip1Δ/Δ grown in Pi limitation medium PNMC was lower than that grown in SC, and the metabolic activity of vip1Δ/Δ grown in PNMC was also lower than that grown in SC medium. This suggests that the increase in Pi demand by a high energy metabolic rate is the cause of LD accumulation in vip1Δ/Δ. In addition, in the vip1Δ/Δ strains, the core transcription factor PHO4 in the PHO pathway was transported to the vacuole and degraded, which reduced the pathway activity. However, this does not mean that knocking out vip1 completely blocks the activation of the PHO pathway, because the LD content of vip1Δ/Δ grown in the medium with β-glycerol phosphate as the Pi source was significantly reduced. In summary, the increased Pi demand and the decreased PHO pathway activity in vip1Δ/Δ ultimately lead to LD accumulation and cell membrane damage.
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14
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Wang Z, Kuo HF, Chiou TJ. Intracellular phosphate sensing and regulation of phosphate transport systems in plants. PLANT PHYSIOLOGY 2021; 187:2043-2055. [PMID: 35235674 PMCID: PMC8644344 DOI: 10.1093/plphys/kiab343] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/29/2021] [Indexed: 05/04/2023]
Abstract
Recent research on the regulation of cellular phosphate (Pi) homeostasis in eukaryotes has collectively made substantial advances in elucidating inositol pyrophosphates (PP-InsP) as Pi signaling molecules that are perceived by the SPX (Syg1, Pho81, and Xpr1) domains residing in multiple proteins involved in Pi transport and signaling. The PP-InsP-SPX signaling module is evolutionarily conserved across eukaryotes and has been elaborately adopted in plant Pi transport and signaling systems. In this review, we have integrated these advances with prior established knowledge of Pi and PP-InsP metabolism, intracellular Pi sensing, and transcriptional responses according to the dynamics of cellular Pi status in plants. Anticipated challenges and pending questions as well as prospects are also discussed.
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Affiliation(s)
- Zhengrui Wang
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Hui-Fen Kuo
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Tzyy-Jen Chiou
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
- Author for communication:
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Couto D, Richter A, Walter H, Furkert D, Hothorn M, Fiedler D. Using Biotinylated myo-Inositol Hexakisphosphate to Investigate Inositol Pyrophosphate-Protein Interactions with Surface-Based Biosensors. Biochemistry 2021; 60:2739-2748. [PMID: 34499474 DOI: 10.1021/acs.biochem.1c00497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Inositol pyrophosphates (PP-InsPs) are highly phosphorylated molecules that have emerged as central nutrient messengers in eukaryotic organisms. They can bind to structurally diverse target proteins to regulate biological functions, such as protein-protein interactions. PP-InsPs are strongly negatively charged and interact with highly basic surface patches in proteins, making their quantitative biochemical analysis challenging. Here, we present the synthesis of biotinylated myo-inositol hexakisphosphates and their application in surface plasmon resonance and grating-coupled interferometry assays, to enable the rapid identification, validation, and kinetic characterization of InsP- and PP-InsP-protein interactions.
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Affiliation(s)
- Daniel Couto
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Annika Richter
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany.,Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Henriette Walter
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany.,Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - David Furkert
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany.,Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Michael Hothorn
- Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Dorothea Fiedler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany.,Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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Bhalla K, Qu X, Kretschmer M, Kronstad JW. The phosphate language of fungi. Trends Microbiol 2021; 30:338-349. [PMID: 34479774 DOI: 10.1016/j.tim.2021.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 11/20/2022]
Abstract
Phosphate is an essential macronutrient for fungal proliferation as well as a key mediator of antagonistic, beneficial, and pathogenic interactions between fungi and other organisms. In this review, we summarize recent insights into the integration of phosphate metabolism with mechanisms of fungal adaptation that support growth and survival. In particular, we highlight aspects of phosphate sensing important for responses to stress and regulation of cell-surface changes with an impact on fungal pathogenesis, host immune responses, and disease outcomes. Additionally, new studies provide insights into the influence of phosphate availability on cooperative or antagonistic interactions between fungi and other microbes, the associations of mycorrhizal and endophytic fungi with plants, and connections with plant immunity. Overall, phosphate homeostasis is emerging as an integral part of fungal metabolism and communication to support diverse lifestyles.
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Affiliation(s)
- Kabir Bhalla
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Xianya Qu
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Matthias Kretschmer
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - James W Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada.
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Lev S, Bowring B, Desmarini D, Djordjevic JT. Inositol polyphosphate-protein interactions: Implications for microbial pathogenicity. Cell Microbiol 2021; 23:e13325. [PMID: 33721399 PMCID: PMC9286782 DOI: 10.1111/cmi.13325] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/03/2021] [Accepted: 03/07/2021] [Indexed: 11/29/2022]
Abstract
Inositol polyphosphates (IPs) and inositol pyrophosphates (PP-IPs) regulate diverse cellular processes in eukaryotic cells. IPs and PP-IPs are highly negatively charged and exert their biological effects by interacting with specific protein targets. Studies performed predominantly in mammalian cells and model yeasts have shown that IPs and PP-IPs modulate target function through allosteric regulation, by promoting intra- and intermolecular stabilization and, in the case of PP-IPs, by donating a phosphate from their pyrophosphate (PP) group to the target protein. Technological advances in genetics have extended studies of IP function to microbial pathogens and demonstrated that disrupting PP-IP biosynthesis and PP-IP-protein interaction has a profound impact on pathogenicity. This review summarises the complexity of IP-mediated regulation in eukaryotes, including microbial pathogens. It also highlights examples of poor conservation of IP-protein interaction outcome despite the presence of conserved IP-binding domains in eukaryotic proteomes.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Bethany Bowring
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
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