1
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Normantovich M, Amitzur A, Offri S, Pashkovsky E, Shnaider Y, Nizan S, Yogev O, Jacob A, Taylor CG, Desbiez C, Whitham SA, Bar-Ziv A, Perl-Treves R. The melon Fom-1-Prv resistance gene pair: Correlated spatial expression and interaction with a viral protein. Plant Direct 2024; 8:e565. [PMID: 38389929 PMCID: PMC10883720 DOI: 10.1002/pld3.565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 02/24/2024]
Abstract
The head-to-head oriented pair of melon resistance genes, Fom-1 and Prv, control resistance to Fusarium oxysporum races 0 and 2 and papaya ringspot virus (PRSV), respectively. They encode, via several RNA splice variants, TIR-NBS-LRR proteins, and Prv has a C-terminal extra domain with a second NBS homologous sequence. In other systems, paired R-proteins were shown to operate by "labor division," with one protein having an extra integrated domain that directly binds the pathogen's Avr factor, and the second protein executing the defense response. We report that the expression of the two genes in two pairs of near-isogenic lines was higher in the resistant isoline and inducible by F. oxysporum race 2 but not by PRSV. The intergenic DNA region separating the coding sequences of the two genes acted as a bi-directional promoter and drove GUS expression in transgenic melon roots and transgenic tobacco plants. Expression of both genes was strong in melon root tips, around the root vascular cylinder, and the phloem and xylem parenchyma of tobacco stems and petioles. The pattern of GUS expression suggests coordinated expression of the two genes. In agreement with the above model, Prv's extra domain was shown to interact with the cylindrical inclusion protein of PRSV both in yeast cells and in planta.
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Affiliation(s)
- Michael Normantovich
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Arie Amitzur
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Sharon Offri
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Ekaterina Pashkovsky
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Yula Shnaider
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Shahar Nizan
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Ohad Yogev
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Avi Jacob
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | | | | | - Steven A Whitham
- Department of Plant Pathology and Microbiology Iowa State University Ames Iowa USA
| | - Amalia Bar-Ziv
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
| | - Rafael Perl-Treves
- The Mina and Everard Goodman Faculty of Life Sciences Bar Ilan University Ramat Gan Israel
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2
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Davidson O, Yogev O, Poem E, Firstenberg O. Single-Photon Synchronization with a Room-Temperature Atomic Quantum Memory. Phys Rev Lett 2023; 131:033601. [PMID: 37540860 DOI: 10.1103/physrevlett.131.033601] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/31/2023] [Indexed: 08/06/2023]
Abstract
Efficient synchronization of single photons that are compatible with narrow band atomic transitions is an outstanding challenge, which could prove essential for photonic quantum information processing. Here we report on the synchronization of independently generated single photons using a room-temperature atomic quantum memory. The photon source and the memory are interconnected by fibers and employ the same ladder-level atomic scheme. We store and retrieve the heralded single photons with end-to-end efficiency of η_{e2e}=25% and final antibunching of g_{h}^{(2)}=0.023. Our synchronization process results in an over tenfold increase in the photon-pair coincidence rate, reaching a rate of more than 1000 detected synchronized photon pairs per second. The indistinguishability of the synchronized photons is verified by a Hong-Ou-Mandel interference measurement.
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Affiliation(s)
- Omri Davidson
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ohad Yogev
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eilon Poem
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ofer Firstenberg
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
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3
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Oppenheim T, Radzinski M, Braitbard M, Brielle ES, Yogev O, Goldberger E, Yesharim Y, Ravid T, Schneidman-Duhovny D, Reichmann D. The Cdc48 N-terminal domain has a molecular switch that mediates the Npl4-Ufd1-Cdc48 complex formation. Structure 2023; 31:764-779.e8. [PMID: 37311459 DOI: 10.1016/j.str.2023.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 02/28/2023] [Accepted: 05/18/2023] [Indexed: 06/15/2023]
Abstract
Cdc48 (VCP/p97) is a major AAA-ATPase involved in protein quality control, along with its canonical cofactors Ufd1 and Npl4 (UN). Here, we present novel structural insights into the interactions within the Cdc48-Npl4-Ufd1 ternary complex. Using integrative modeling, we combine subunit structures with crosslinking mass spectrometry (XL-MS) to map the interaction between Npl4 and Ufd1, alone and in complex with Cdc48. We describe the stabilization of the UN assembly upon binding with the N-terminal-domain (NTD) of Cdc48 and identify a highly conserved cysteine, C115, at the Cdc48-Npl4-binding interface which is central to the stability of the Cdc48-Npl4-Ufd1 complex. Mutation of Cys115 to serine disrupts the interaction between Cdc48-NTD and Npl4-Ufd1 and leads to a moderate decrease in cellular growth and protein quality control in yeast. Our results provide structural insight into the architecture of the Cdc48-Npl4-Ufd1 complex as well as its in vivo implications.
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Affiliation(s)
- Tal Oppenheim
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Meytal Radzinski
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Merav Braitbard
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Esther S Brielle
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ohad Yogev
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Eliya Goldberger
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yarden Yesharim
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Tommer Ravid
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Dina Schneidman-Duhovny
- School of Computer Science and Engineering, the Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Dana Reichmann
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, the Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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4
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Yogev O, Weissbrod O, Battistoni G, Bressan D, Naamati A, Falciatori I, Berkyurek AC, Rasnic R, Izuagbe R, Hosmillo M, Ilan S, Grossman I, McCormick L, Honeycutt CC, Johnston T, Gagne M, Douek DC, Goodfellow I, Hannon GJ, Erlich Y. From a genome-wide screen of RNAi molecules against SARS-CoV-2 to a validated broad-spectrum and potent prophylaxis. Commun Biol 2023; 6:277. [PMID: 36928598 PMCID: PMC10019795 DOI: 10.1038/s42003-023-04589-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 02/13/2023] [Indexed: 03/18/2023] Open
Abstract
Expanding the arsenal of prophylactic approaches against SARS-CoV-2 is of utmost importance, specifically those strategies that are resistant to antigenic drift in Spike. Here, we conducted a screen of over 16,000 RNAi triggers against the SARS-CoV-2 genome, using a massively parallel assay to identify hyper-potent siRNAs. We selected Ten candidates for in vitro validation and found five siRNAs that exhibited hyper-potent activity (IC50 < 20 pM) and strong blockade of infectivity in live-virus experiments. We further enhanced this activity by combinatorial pairing of the siRNA candidates and identified cocktails that were active against multiple types of variants of concern (VOC). We then examined over 2,000 possible mutations in the siRNA target sites by using saturation mutagenesis and confirmed broad protection of the leading cocktail against future variants. Finally, we demonstrated that intranasal administration of this siRNA cocktail effectively attenuates clinical signs and viral measures of disease in the gold-standard Syrian hamster model. Our results pave the way for the development of an additional layer of antiviral prophylaxis that is orthogonal to vaccines and monoclonal antibodies.
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Affiliation(s)
- Ohad Yogev
- Eleven Therapeutics, Cambridge, United Kingdom.
| | | | - Giorgia Battistoni
- Eleven Therapeutics, Cambridge, United Kingdom
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, United Kingdom
| | - Dario Bressan
- Eleven Therapeutics, Cambridge, United Kingdom
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, United Kingdom
| | - Adi Naamati
- Eleven Therapeutics, Cambridge, United Kingdom
| | | | | | | | - Rhys Izuagbe
- University of Cambridge, Department of Pathology, Division of Virology, Cambridge, United Kingdom
| | - Myra Hosmillo
- University of Cambridge, Department of Pathology, Division of Virology, Cambridge, United Kingdom
| | | | | | - Lauren McCormick
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Christopher Cole Honeycutt
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Timothy Johnston
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Matthew Gagne
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Daniel C Douek
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ian Goodfellow
- University of Cambridge, Department of Pathology, Division of Virology, Cambridge, United Kingdom
| | - Gregory James Hannon
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, United Kingdom
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5
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Yogev O, Weissbrod O, Battistoni G, Bressan D, Naamti A, Falciatori I, Berkyurek AC, Rasnic R, Hosmillo M, Ilan S, Grossman I, McCormick L, Honeycutt CC, Johnston T, Gagne M, Douek DC, Goodfellow I, Hannon GJ, Erlich Y. Genome wide screen of RNAi molecules against SARS-CoV-2 creates a broadly potent prophylaxis. bioRxiv 2022:2022.04.12.488010. [PMID: 35441162 PMCID: PMC9016640 DOI: 10.1101/2022.04.12.488010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Expanding the arsenal of prophylactic approaches against SARS-CoV-2 is of utmost importance, specifically those strategies that are resistant to antigenic drift in Spike. Here, we conducted a screen with over 16,000 RNAi triggers against the SARS-CoV-2 genome using a massively parallel assay to identify hyper-potent siRNAs. We selected 10 candidates for in vitro validation and found five siRNAs that exhibited hyper-potent activity with IC50<20pM and strong neutralisation in live virus experiments. We further enhanced the activity by combinatorial pairing of the siRNA candidates to develop siRNA cocktails and found that these cocktails are active against multiple types of variants of concern (VOC). We examined over 2,000 possible mutations to the siRNA target sites using saturation mutagenesis and identified broad protection against future variants. Finally, we demonstrated that intranasal administration of the siRNA cocktail effectively attenuates clinical signs and viral measures of disease in the Syrian hamster model. Our results pave the way to development of an additional layer of antiviral prophylaxis that is orthogonal to vaccines and monoclonal antibodies.
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Affiliation(s)
- Ohad Yogev
- Eleven Therapeutics, Cambridge, United Kingdom
| | | | - Giorgia Battistoni
- Eleven Therapeutics, Cambridge, United Kingdom
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, United Kingdom
| | - Dario Bressan
- Eleven Therapeutics, Cambridge, United Kingdom
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, United Kingdom
| | - Adi Naamti
- Eleven Therapeutics, Cambridge, United Kingdom
| | | | | | | | - Myra Hosmillo
- University of Cambridge, Department of Pathology, Division of Virology, Cambridge, United Kingdom
| | | | | | - Lauren McCormick
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Christopher C. Honeycutt
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Timothy Johnston
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Matthew Gagne
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Daniel C. Douek
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ian Goodfellow
- University of Cambridge, Department of Pathology, Division of Virology, Cambridge, United Kingdom
| | - Gregory J. Hannon
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, United Kingdom
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6
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Magalhaes I, Yogev O, Mattsson J, Schurich A. The Metabolic Profile of Tumor and Virally Infected Cells Shapes Their Microenvironment Counteracting T Cell Immunity. Front Immunol 2019; 10:2309. [PMID: 31636636 PMCID: PMC6788393 DOI: 10.3389/fimmu.2019.02309] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/12/2019] [Indexed: 12/11/2022] Open
Abstract
Upon activation naïve T cells undergo metabolic changes to support the differentiation into subsets of effector or regulatory cells, and enable subsequent metabolic adaptations to form memory. Interfering with these metabolic alterations leads to abrogation or reprogramming of T cell differentiation, demonstrating the importance of these pathways in T cell development. It has long been appreciated that the conversion of a healthy cell to a cancerous cell is accompanied by metabolic changes, which support uncontrolled proliferation. Especially in solid tumors these metabolic changes significantly influence the tumor microenvironment (TME) and affect tumor infiltrating immune cells. The TME is often hypoxic and nutrient depleted, additionally tumor cells produce co-inhibitory signals, together suppressing the immune response. Interestingly, viruses can stimulate a metabolism akin to that seen in tumor cells in their host cells and even in neighboring cells (e.g., via transfer of virally modified extracellular vesicles). Thus, viruses create their own niche which favors viral persistence and propagation, while again keeping the immune response at bay. In this review we will focus on the mechanisms employed by tumor cells and viruses influencing T cell metabolic regulation and the impact they have on shaping T cell fate.
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Affiliation(s)
- Isabelle Magalhaes
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Ohad Yogev
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Jonas Mattsson
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
- Gloria and Seymour Epstein Chair in Cell Therapy and Transplantation, Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Anna Schurich
- Department of Infectious Diseases, King's College London, London, United Kingdom
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7
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Radzinski M, Fassler R, Yogev O, Breuer W, Shai N, Gutin J, Ilyas S, Geffen Y, Tsytkin-Kirschenzweig S, Nahmias Y, Ravid T, Friedman N, Schuldiner M, Reichmann D. Temporal profiling of redox-dependent heterogeneity in single cells. eLife 2018; 7:37623. [PMID: 29869985 PMCID: PMC6023615 DOI: 10.7554/elife.37623] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/04/2018] [Indexed: 01/22/2023] Open
Abstract
Cellular redox status affects diverse cellular functions, including proliferation, protein homeostasis, and aging. Thus, individual differences in redox status can give rise to distinct sub-populations even among cells with identical genetic backgrounds. Here, we have created a novel methodology to track redox status at single cell resolution using the redox-sensitive probe Grx1-roGFP2. Our method allows identification and sorting of sub-populations with different oxidation levels in either the cytosol, mitochondria or peroxisomes. Using this approach, we defined a redox-dependent heterogeneity of yeast cells and characterized growth, as well as proteomic and transcriptomic profiles of distinctive redox subpopulations. We report that, starting in late logarithmic growth, cells of the same age have a bi-modal distribution of oxidation status. A comparative proteomic analysis between these populations identified three key proteins, Hsp30, Dhh1, and Pnc1, which affect basal oxidation levels and may serve as first line of defense proteins in redox homeostasis.
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Affiliation(s)
- Meytal Radzinski
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rosi Fassler
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ohad Yogev
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - William Breuer
- Proteomics and Mass Spectrometry Unit, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nadav Shai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Jenia Gutin
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel.,School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sidra Ilyas
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yifat Geffen
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sabina Tsytkin-Kirschenzweig
- Grass Center for Bioengineering, Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yaakov Nahmias
- Grass Center for Bioengineering, Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tommer Ravid
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nir Friedman
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel.,School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Dana Reichmann
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
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8
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Rimon O, Suss O, Goldenberg M, Fassler R, Yogev O, Amartely H, Propper G, Friedler A, Reichmann D. A Role of Metastable Regions and Their Connectivity in the Inactivation of a Redox-Regulated Chaperone and Its Inter-Chaperone Crosstalk. Antioxid Redox Signal 2017; 27:1252-1267. [PMID: 28394178 DOI: 10.1089/ars.2016.6900] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS A recently discovered group of conditionally disordered chaperones share a very unique feature; they need to lose structure to become active as chaperones. This activation mechanism makes these chaperones particularly suited to respond to protein-unfolding stress conditions, such as oxidative unfolding. However, the role of this disorder in stress-related activation, chaperone function, and the crosstalk with other chaperone systems is not yet clear. Here, we focus on one of the members of the conditionally disordered chaperones, a thiol-redox switch of the bacterial proteostasis system, Hsp33. RESULTS By modifying the Hsp33's sequence, we reveal that the metastable region has evolved to abolish redox-dependent chaperone activity, rather than enhance binding affinity for client proteins. The intrinsically disordered region of Hsp33 serves as an anchor for the reduced, inactive state of Hsp33, and it dramatically affects the crosstalk with the synergetic chaperone system, DnaK/J. Using mass spectrometry, we describe the role that the metastable region plays in determining client specificity during normal and oxidative stress conditions in the cell. Innovation and Conclusion: We uncover a new role of protein plasticity in Hsp33's inactivation, client specificity, crosstalk with the synergistic chaperone system DnaK/J, and oxidative stress-specific interactions in bacteria. Our results also suggest that Hsp33 might serve as a member of the house-keeping proteostasis machinery, tasked with maintaining a "healthy" proteome during normal conditions, and that this function does not depend on the metastable linker region. Antioxid. Redox Signal. 27, 1252-1267.
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Affiliation(s)
- Oded Rimon
- 1 Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem , Jerusalem, Israel
| | - Ohad Suss
- 1 Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem , Jerusalem, Israel
| | - Mor Goldenberg
- 1 Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem , Jerusalem, Israel
| | - Rosi Fassler
- 1 Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem , Jerusalem, Israel
| | - Ohad Yogev
- 1 Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem , Jerusalem, Israel
| | - Hadar Amartely
- 2 Institute of Chemistry, The Hebrew University of Jerusalem , Safra Campus Givat Ram, Jerusalem, Israel
| | - Guy Propper
- 1 Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem , Jerusalem, Israel
| | - Assaf Friedler
- 2 Institute of Chemistry, The Hebrew University of Jerusalem , Safra Campus Givat Ram, Jerusalem, Israel
| | - Dana Reichmann
- 1 Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem , Jerusalem, Israel
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9
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Yogev O, Henderson S, Hayes MJ, Marelli SS, Ofir-Birin Y, Regev-Rudzki N, Herrero J, Enver T. Herpesviruses shape tumour microenvironment through exosomal transfer of viral microRNAs. PLoS Pathog 2017; 13:e1006524. [PMID: 28837697 PMCID: PMC5570218 DOI: 10.1371/journal.ppat.1006524] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/11/2017] [Indexed: 01/27/2023] Open
Abstract
Metabolic changes within the cell and its niche affect cell fate and are involved in many diseases and disorders including cancer and viral infections. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS). KSHV latently infected cells express only a subset of viral genes, mainly located within the latency-associated region, among them 12 microRNAs. Notably, these miRNAs are responsible for inducing the Warburg effect in infected cells. Here we identify a novel mechanism enabling KSHV to manipulate the metabolic nature of the tumour microenvironment. We demonstrate that KSHV infected cells specifically transfer the virus-encoded microRNAs to surrounding cells via exosomes. This flow of genetic information results in a metabolic shift toward aerobic glycolysis in the surrounding non-infected cells. Importantly, this exosome-mediated metabolic reprogramming of neighbouring cells supports the growth of infected cells, thereby contributing to viral fitness. Finally, our data show that this miRNA transfer-based regulation of cell metabolism is a general mechanism used by other herpesviruses, such as EBV, as well as for the transfer of non-viral onco-miRs. This exosome-based crosstalk provides viruses with a mechanism for non-infectious transfer of genetic material without production of new viral particles, which might expose them to the immune system. We suggest that viruses and cancer cells use this mechanism to shape a specific metabolic niche that will contribute to their fitness.
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Affiliation(s)
- Ohad Yogev
- UCL Cancer Institute, Research Department of Cancer Biology, Paul O’Gorman Building, University College London, London, England, United Kingdom
| | - Stephen Henderson
- UCL Cancer Institute, Bill Lyons Informatics Centre, Paul O’Gorman Building, University College London, London, England, United Kingdom
| | - Matthew John Hayes
- UCL Institute of Ophthalmology, EM-Unit, Bath Street, London, England, United Kingdom
| | - Sara Sofia Marelli
- UCL Cancer Institute, Research Department of Cancer Biology, Paul O’Gorman Building, University College London, London, England, United Kingdom
| | - Yifat Ofir-Birin
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Neta Regev-Rudzki
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Javier Herrero
- UCL Cancer Institute, Bill Lyons Informatics Centre, Paul O’Gorman Building, University College London, London, England, United Kingdom
| | - Tariq Enver
- UCL Cancer Institute, Research Department of Cancer Biology, Paul O’Gorman Building, University College London, London, England, United Kingdom
- * E-mail:
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10
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Yogev O, Lagos D, Enver T, Boshoff C. Kaposi's sarcoma herpesvirus microRNAs induce metabolic transformation of infected cells. PLoS Pathog 2014; 10:e1004400. [PMID: 25255370 PMCID: PMC4177984 DOI: 10.1371/journal.ppat.1004400] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/14/2014] [Indexed: 02/01/2023] Open
Abstract
Altered cell metabolism is inherently connected with pathological conditions including cancer and viral infections. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS). KS tumour cells display features of lymphatic endothelial differentiation and in their vast majority are latently infected with KSHV, while a small number are lytically infected, producing virions. Latently infected cells express only a subset of viral genes, mainly located within the latency-associated region, among them 12 microRNAs. Notably, the metabolic properties of KSHV-infected cells closely resemble the metabolic hallmarks of cancer cells. However, how and why KSHV alters host cell metabolism remains poorly understood. Here, we investigated the effect of KSHV infection on the metabolic profile of primary dermal microvascular lymphatic endothelial cells (LEC) and the functional relevance of this effect. We found that the KSHV microRNAs within the oncogenic cluster collaborate to decrease mitochondria biogenesis and to induce aerobic glycolysis in infected cells. KSHV microRNAs expression decreases oxygen consumption, increase lactate secretion and glucose uptake, stabilize HIF1α and decreases mitochondria copy number. Importantly this metabolic shift is important for latency maintenance and provides a growth advantage. Mechanistically we show that KSHV alters host cell energy metabolism through microRNA-mediated down regulation of EGLN2 and HSPA9. Our data suggest that the KSHV microRNAs induce a metabolic transformation by concurrent regulation of two independent pathways; transcriptional reprograming via HIF1 activation and reduction of mitochondria biogenesis through down regulation of the mitochondrial import machinery. These findings implicate viral microRNAs in the regulation of the cellular metabolism and highlight new potential avenues to inhibit viral latency. Kaposi's sarcoma (KS) is the most common cancer in HIV-infected untreated individuals. Kaposi's sarcoma-associated herpesvirus (KSHV) is the infectious cause of this neoplasm. The discovery of KSHV and its oncogenic enigmas has enlightened many fields of tumor biology and viral oncogenesis. The metabolic properties of KS significantly differ from those of normal cells and resemble cancer cells in general, but the mechanisms employed by KSHV to alter host cell metabolism are poorly understood. Our work demonstrates that KSHV microRNAs can alter cell metabolism through coherent control of independent pathways, a key feature of microRNA-mediated control of cellular functions. This provides a fresh perspective for how microRNA-encoding pathogens shape a cell's metabolism to create an optimal environment for their survival and/or replication. Indeed, we show that, in the case of KSHV, viral microRNA-driven regulation of metabolism is important for viral latency. These findings will evoke new and exciting approaches to prevent KSHV from establishing latency and later on KS.
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MESH Headings
- Aerobiosis
- Blotting, Western
- Bone Neoplasms/metabolism
- Bone Neoplasms/pathology
- Bone Neoplasms/virology
- Cell Proliferation
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Endothelial Cells/virology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Endothelium, Vascular/virology
- Energy Metabolism
- Gene Expression Regulation, Viral
- Glucose/metabolism
- Herpesvirus 8, Human/physiology
- Humans
- Lactic Acid/metabolism
- MicroRNAs/genetics
- Mitochondria/metabolism
- Mitochondria/pathology
- Mitochondria/virology
- Osteosarcoma/metabolism
- Osteosarcoma/pathology
- Osteosarcoma/virology
- Oxygen Consumption
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Sarcoma, Kaposi/metabolism
- Sarcoma, Kaposi/pathology
- Sarcoma, Kaposi/virology
- Tumor Cells, Cultured
- Virion/metabolism
- Virus Latency
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Affiliation(s)
- Ohad Yogev
- UCL Cancer Institute, Research Department of Cancer Biology, University College London, London, United Kingdom
- * E-mail:
| | - Dimitris Lagos
- Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, United Kingdom
| | - Tariq Enver
- UCL Cancer Institute, Research Department of Cancer Biology, University College London, London, United Kingdom
| | - Chris Boshoff
- UCL Cancer Institute, Research Department of Cancer Biology, University College London, London, United Kingdom
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11
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Abstract
In this issue of Cell Host & Microbe, Chang and Ganem (2013) report that Kaposi's sarcoma-associated herpesvirus infection of lymphatic endothelial cells (LECs), but not blood endothelial cells (BECs), activates mTORC1 signaling and sensitizes LECs to rapamycin-induced killing. The differential rapamycin sensitivity is explained by a unique LEC-specific virus latency program.
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Affiliation(s)
- Ohad Yogev
- Cancer Research UK Viral Oncology Group, UCL Cancer Institute, Huntley Street, University College London, London WC1E 6BT, UK
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12
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Abstract
Dual targeting is an important and abundant phenomenon. Indeed, we estimate that more than a third of the yeast mitochondrial proteome is dual localized. The enzyme fumarase is a highly conserved protein in all organisms with respect to its sequence, structure, and enzymatic activity. In eukaryotes, it is dual localized to the cytosol and mitochondria. In Saccharomyces cerevisiae, the dual localization of fumarase is achieved by the reverse translocation mechanism; all fumarase molecules harbor a mitochondrial targeting sequence (MTS), are targeted to mitochondria, begin their translocation, and are processed by mitochondrial processing peptidase in the matrix. A subset of these processed fumarase molecules in transit is then fully imported into the matrix, whereas the majority moves back into the cytosol by reverse translocation. The proposed driving force for fumarase distribution is protein folding during import. Here, we asked how reverse translocation could have evolved on a prokaryotic protein that had already acquired expression from the nuclear genome and a targeting sequence. To address this question, we used, as a model, the Escherichia coli FumC Class II fumarase, which is homologous to eukaryotic fumarases (∼58% identity and ∼74% similarity to the yeast Fum1). Starting with an exclusively mitochondrial targeted FumC (attached to a strong MTS), we show that two randomly acquired mutations within the prokaryotic FumC sequence are sufficient to cause substantial dual targeting by reverse translocation. In fact, the unmutated MTS-FumC also has some ability to be dual targeted but only at low temperatures. Our results suggest that in this case, evolution of dual targeting by reverse translocation is based on naturally occurring and fortuitously conserved features of fumarase folding.
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Affiliation(s)
- Efrat Burak
- Department of Microbiology Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
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13
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Nechushtai R, Conlan AR, Harir Y, Song L, Yogev O, Eisenberg-Domovich Y, Livnah O, Michaeli D, Rosen R, Ma V, Luo Y, Zuris JA, Paddock ML, Cabantchik ZI, Jennings PA, Mittler R. Characterization of Arabidopsis NEET reveals an ancient role for NEET proteins in iron metabolism. Plant Cell 2012; 24:2139-54. [PMID: 22562611 PMCID: PMC3442592 DOI: 10.1105/tpc.112.097634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The NEET family is a newly discovered group of proteins involved in a diverse array of biological processes, including autophagy, apoptosis, aging, diabetes, and reactive oxygen homeostasis. They form a novel structure, the NEET fold, in which two protomers intertwine to form a two-domain motif, a cap, and a unique redox-active labile 2Fe-2S cluster binding domain. To accelerate the functional study of NEET proteins, as well as to examine whether they have an evolutionarily conserved role, we identified and characterized a plant NEET protein. Here, we show that the Arabidopsis thaliana At5g51720 protein (At-NEET) displays biochemical, structural, and biophysical characteristics of a NEET protein. Phenotypic characterization of At-NEET revealed a key role for this protein in plant development, senescence, reactive oxygen homeostasis, and Fe metabolism. A role in Fe metabolism was further supported by biochemical and cell biology studies of At-NEET in plant and mammalian cells, as well as mutational analysis of its cluster binding domain. Our findings support the hypothesis that NEET proteins have an ancient role in cells associated with Fe metabolism.
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Affiliation(s)
- Rachel Nechushtai
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Andrea R. Conlan
- Departments of Chemistry, Biochemistry, and Physics, University of California at San Diego, La Jolla, California 92093
| | - Yael Harir
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Luhua Song
- Department of Biological Sciences, College of Arts and Sciences, University of North Texas, Denton, Texas 76203-5017
| | - Ohad Yogev
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yael Eisenberg-Domovich
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Oded Livnah
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Dorit Michaeli
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Rachel Rosen
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Vincent Ma
- Department of Biological Sciences, College of Arts and Sciences, University of North Texas, Denton, Texas 76203-5017
| | - Yuting Luo
- Department of Biological Sciences, College of Arts and Sciences, University of North Texas, Denton, Texas 76203-5017
| | - John A. Zuris
- Departments of Chemistry, Biochemistry, and Physics, University of California at San Diego, La Jolla, California 92093
| | - Mark L. Paddock
- Departments of Chemistry, Biochemistry, and Physics, University of California at San Diego, La Jolla, California 92093
| | - Zvi Ioav Cabantchik
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Patricia A. Jennings
- Departments of Chemistry, Biochemistry, and Physics, University of California at San Diego, La Jolla, California 92093
| | - Ron Mittler
- The Alexander Silberman Institute of Life Science and the Wolfson Center for Applied Structural Biology, Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Department of Biological Sciences, College of Arts and Sciences, University of North Texas, Denton, Texas 76203-5017
- Address correspondence to
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14
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Abstract
The enzyme fumarase is a conserved protein in all organisms with regard to its sequence, structure and function. This enzyme participates in the tricarboxylic acid cycle in mitochondria which is essential for cellular respiration in eukaryotes. However, a common theme conserved from yeast to humans is the existence of a cytosolic form of fumarase; hence this protein is dual localized. We have coined identical (or nearly identical) proteins situated in different subcellular locations 'echoforms' or 'echoproteins'. Fumarase was the first example of a dual localized protein whose mechanism of distribution was found to be based on a single translation product. Consequently, fumarase has become a paradigm for three unique eukaryotic cellular phenomena related to protein dual localization: (a) distribution between mitochondria and the cytoplasm involves reverse translocation; (b) targeting to mitochondria involves translation coupled import; and (c) there are two echoforms possessing distinct functions in the respective subcellular compartments. Here we describe and discuss these fumarase related phenomena and in addition point out approaches for studying dual function of distributed proteins, in particular compartment-specific depletion. In the case of fumarase, the cytoplasmic function was only recently discovered; the enzyme was found to participate in the cellular response to DNA double strand breaks. Strikingly, upon DNA damage the protein is transported from the cytosol to the nucleus, where by virtue of its enzymatic activity it participates in the DNA damage response.
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Affiliation(s)
- Ohad Yogev
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
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15
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Abstract
The study of miRNAs and other noncoding RNAs has revolutionised our understanding of gene expression regulation during cancer development and progression, creating one of the fastest-growing research fields in cancer with realistic therapeutic potential. The 2011 Non-coding RNAs and Cancer Symposium hosted by the University College London Cancer Institute focused on the function and regulation of noncoding RNAs during oncogenesis.
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Affiliation(s)
- Ohad Yogev
- Cancer Research UK Viral Oncology Group, UCL Cancer Institute, University College London, Paul O'Gorman Building, 72 Huntley Street, London, WC1E 6BT, UK.
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16
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Yogev O, Pines O. Dual targeting of mitochondrial proteins: mechanism, regulation and function. Biochim Biophys Acta 2010; 1808:1012-20. [PMID: 20637721 DOI: 10.1016/j.bbamem.2010.07.004] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2010] [Revised: 07/04/2010] [Accepted: 07/07/2010] [Indexed: 01/25/2023]
Abstract
One solution found in evolution to increase the number of cellular functions, without increasing the number of genes, is distribution of single gene products to more than one cellular compartment. It is well documented that in eukaryotic cells, molecules of one protein can be located in several subcellular locations, a phenomenon termed dual targeting, dual localization, or dual distribution. The differently localized proteins are coined in this review "echoforms" indicating repetitious forms of the same protein (echo in Greek denotes repetition) distinctly placed in the cell. This term replaces the term to "isoproteins" or "isoenzymes" which are reserved for proteins with the same activity but different amino acid sequences. Echoforms are identical or nearly identical, even though, as referred to in this review may, in some cases, surprisingly have a totally different function in the different compartments. With regard to mitochondria, our operational definition of dual targeted proteins refers to situations in which one of the echoforms is translocated through/into a mitochondrial membrane. In this review we ask how, when and why mitochondrial proteins are dual localized in the cell. We describe mechanisms of dual targeting of proteins between mitochondria and other compartments of the eukaryotic cell. In particular, we have paid attention to situations in which dual localization is regulated in time, location or function. In addition, we have attempted to provide a broader view concerning the phenomenon of dual localization of proteins by looking at mechanisms that are beyond our simple definition of dual targeting. This article is part of a Special Issue entitled Protein translocation across or insertion into membranes.
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Affiliation(s)
- Ohad Yogev
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel
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17
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Yogev O, Yogev O, Singer E, Shaulian E, Goldberg M, Fox TD, Pines O. Fumarase: a mitochondrial metabolic enzyme and a cytosolic/nuclear component of the DNA damage response. PLoS Biol 2010; 8:e1000328. [PMID: 20231875 PMCID: PMC2834712 DOI: 10.1371/journal.pbio.1000328] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 02/03/2010] [Indexed: 02/07/2023] Open
Abstract
Upon DNA damage, a cytosolic form of the mitochondrial enzyme fumarase moves into the nucleus where, by virtue of its enzymatic activity, it participates in the cell's response to DNA damage. This potentially explains its known role as a tumor suppressor. In eukaryotes, fumarase (FH in human) is a well-known tricarboxylic-acid-cycle enzyme in the mitochondrial matrix. However, conserved from yeast to humans is a cytosolic isoenzyme of fumarase whose function in this compartment remains obscure. A few years ago, FH was surprisingly shown to underlie a tumor susceptibility syndrome, Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC). A biallelic inactivation of FH has been detected in almost all HLRCC tumors, and therefore FH was suggested to function as a tumor suppressor. Recently it was suggested that FH inhibition leads to elevated intracellular fumarate, which in turn acts as a competitive inhibitor of HPH (HIF prolyl hydroxylase), thereby causing stabilization of HIF (Hypoxia-inducible factor) by preventing proteasomal degradation. The transcription factor HIF increases the expression of angiogenesis regulated genes, such as VEGF, which can lead to high microvessel density and tumorigenesis. Yet this mechanism does not fully explain the large cytosolic population of fumarase molecules. We constructed a yeast strain in which fumarase is localized exclusively to mitochondria. This led to the discovery that the yeast cytosolic fumarase plays a key role in the protection of cells from DNA damage, particularly from DNA double-strand breaks. We show that the cytosolic fumarase is a member of the DNA damage response that is recruited from the cytosol to the nucleus upon DNA damage induction. This function of fumarase depends on its enzymatic activity, and its absence in cells can be complemented by high concentrations of fumaric acid. Our findings suggest that fumarase and fumaric acid are critical elements of the DNA damage response, which underlies the tumor suppressor role of fumarase in human cells and which is most probably HIF independent. This study shows an exciting crosstalk between primary metabolism and the DNA damage response, thereby providing a scenario for metabolic control of tumor propagation. Fumarate hydratase (FH; also known as fumarase) is an enzyme found in both the cytoplasm and mitochondria of all eukaryotes. In mitochondria, FH is involved in generating energy for the cell through a metabolic pathway called the Krebs cycle. Its role in the cytoplasm, however, is unclear. FH can function as a tumor suppressor: its absence is linked to the formation of human kidney tumors in a syndrome termed HLRCC. We show here that the cytoplasmic version of FH has an unexpected role in repairing DNA double-strand breaks in the nucleus. This role involves the movement of FH from the cytoplasm into the nucleus and depends on its enzymatic activity. Strikingly, when FH is absent from cells, its function in DNA repair can be substituted by high concentrations of one of the enzyme's products, fumaric acid. Our findings imply that FH deficiency leads to cancer because there is not enough fumaric acid in the nucleus to stimulate repair of DNA double-strand breaks; the persistence of these breaks is believed to provoke cancer. The study thus makes a surprising connection between primary metabolism and the cell's response to DNA damage.
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Affiliation(s)
- Ohad Yogev
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Orli Yogev
- Department of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Esti Singer
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Eitan Shaulian
- Department of Biochemistry and Molecular Biology, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Michal Goldberg
- Department of Genetics, The Institute of Life Sciences, The Hebrew University, Jerusalem, Israel
| | - Thomas D. Fox
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Ophry Pines
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University, Jerusalem, Israel
- * E-mail:
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18
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Abstract
The growing number of biological functions affected by autophagy ascribes a special significance to identification of factors regulating it. The activator protein-1 (AP-1) transcription factors are involved in most aspects of cellular proliferation, death, or survival, yet no information regarding their involvement in autophagy is available. Here, we show that the AP-1 proteins JunB and c-Jun, but not JunD, c-Fos, or Fra-1, inhibit autophagy. JunB inhibits autophagy induced by starvation, overexpression of a short form of ARF (smARF), a potent inducer of autophagy, or even after rapamycin treatment. In agreement, acute repression of JunB expression, by JunB knockdown, potently induces autophagy. As expected from autophagy-inhibiting proteins, Jun B and c-Jun expression is reduced by starvation. Decrease in JunB mRNA expression and posttranscriptional events downregulate JunB protein expression after starvation. The inhibition of autophagy by JunB is not mediated by mammalian target of rapamycin (mTOR) regulation, as it occurs also in the absence of mTOR activity, and autophagy induced by JunB knockdown is not correlated with changes in mTOR activity. Nevertheless, the transcriptional activities of c-Jun and JunB are required for autophagy inhibition, and JunB incapable of heterodimerizing is a less effective inhibitor of autophagy. Most importantly, inhibition of autophagy in starved HeLa cells by JunB enhances apoptotic cell death. We suggest that JunB and c-Jun are regulators of autophagy whose expression responds to autophagy-inducing signals.
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Affiliation(s)
- Orli Yogev
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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19
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Conlan A, Paddock ML, Yogev O, Harir Y, Mittler R, Jennings P, Nechushtai R. Initial Characterization of a New Class of 2Fe-2S Proteins from the Plant Arabidopsis Thaliana. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.3062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Regev-Rudzki N, Yogev O, Pines O. The mitochondrial targeting sequence tilts the balance between mitochondrial and cytosolic dual localization. J Cell Sci 2008; 121:2423-31. [DOI: 10.1242/jcs.029207] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dual localization of proteins in the cell has appeared in recent years to be a more abundant phenomenon than previously reported. One of the mechanisms by which a single translation product is distributed between two compartments, involves retrograde movement of a subset of processed molecules back through the organelle-membrane. Here, we investigated the specific contribution of the mitochondrial targeting sequence (MTS), as a cis element, in the distribution of two proteins, aconitase and fumarase. Whereas the cytosolic presence of fumarase is obvious, the cytosolic amount of aconitase is minute. Therefore, we created (1) MTS-exchange mutants, exchanging the MTS of aconitase and fumarase with each other as well as with those of other proteins and, (2) a set of single mutations, limited to the MTS of these proteins. Distribution of both proteins is affected by mutations, a fact particularly evident for aconitase, which displays extraordinary amounts of processed protein in the cytosol. Thus, we show for the first time, that the MTS has an additional role beyond targeting: it determines the level of retrograde movement of proteins back into the cytosol. Our results suggest that the translocation rate and folding of proteins during import into mitochondria determines the extent to which molecules are withdrawn back into the cytosol.
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Affiliation(s)
- Neta Regev-Rudzki
- Department of Molecular Biology, Hebrew University Medical School, Jerusalem 91120, Israel
| | - Ohad Yogev
- Department of Molecular Biology, Hebrew University Medical School, Jerusalem 91120, Israel
| | - Ophry Pines
- Department of Molecular Biology, Hebrew University Medical School, Jerusalem 91120, Israel
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21
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Abstract
Fumarase represents proteins that cannot be imported into mitochondria after the termination of translation (post-translationally). Utilizing mitochondrial and cytosolic versions of the tobacco etch virus (TEV) protease, we show that mitochondrially targeted fumarase harboring a TEV protease recognition sequence is efficiently cleaved by the mitochondrial but not by the cytosolic TEV protease. Nonetheless, fumarase was readily cleaved by cytosolic TEV when its import into mitochondria was slowed down by either (i) disrupting the activity of the TOM complex, (ii) lowering the growth temperature, or (iii) reducing the inner membrane electrochemical potential. Accessibility of the fumarase nascent chain to TEV protease under such conditions was prevented by low cycloheximide concentrations, which impede translation. In addition, depletion of the ribosome-associated nascent polypeptide-associated complex (NAC) reduced the fumarase rate of translocation into mitochondria and exposed it to TEV cleavage in the cytosol. These results indicate that cytosolic exposure of the fumarase nascent chain depends on both translocation and translation rates, allowing us to discuss the possibility that import of fumarase into mitochondria occurs while the ribosome is still attached to the nascent chain.
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Affiliation(s)
- Ohad Yogev
- Department of Molecular Biology, Hebrew University Medical School, Jerusalem 91120, Israel
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22
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Abstract
We employed the backward masking paradigm to map the early computation involved in the perception of printed words in Hebrew. By independently manipulating orthographic and phonological overlap between targets and masks, we examined whether orthographic and phonological structure imposes late or early constraints on lexical access. The results demonstrated that the probability of reinstating a masked target depended on both the orthographic and the phonological overlap between the target and the mask. However, whereas phonemic structure seems to constrain lexical access only at short exposure durations, orthographic overlap also exerts its influence at longer durations.
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Affiliation(s)
- R Frost
- Department of Psychology, Hebrew University, Jerusalem, Israel.
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