1
|
Calise SJ, O’Neill AG, Burrell AL, Dickinson MS, Molfino J, Clarke C, Quispe J, Sokolov D, Buey RM, Kollman JM. Light-sensitive phosphorylation regulates retinal IMPDH1 activity and filament assembly. J Cell Biol 2024; 223:e202310139. [PMID: 38323936 PMCID: PMC10849882 DOI: 10.1083/jcb.202310139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/11/2024] [Accepted: 01/23/2024] [Indexed: 02/08/2024] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) is the rate-limiting enzyme in guanosine triphosphate (GTP) synthesis and assembles into filaments in cells, which desensitizes the enzyme to feedback inhibition and boosts nucleotide production. The vertebrate retina expresses two splice variants IMPDH1(546) and IMPDH1(595). In bovine retinas, residue S477 is preferentially phosphorylated in the dark, but the effects on IMPDH1 activity and regulation are unclear. Here, we generated phosphomimetic mutants to investigate structural and functional consequences of S477 phosphorylation. The S477D mutation resensitized both variants to GTP inhibition but only blocked assembly of IMPDH1(595) filaments. Cryo-EM structures of both variants showed that S477D specifically blocks assembly of a high-activity assembly interface, still allowing assembly of low-activity IMPDH1(546) filaments. Finally, we discovered that S477D exerts a dominant-negative effect in cells, preventing endogenous IMPDH filament assembly. By modulating the structure and higher-order assembly of IMPDH, S477 phosphorylation acts as a mechanism for downregulating retinal GTP synthesis in the dark when nucleotide turnover is decreased.
Collapse
Affiliation(s)
- S. John Calise
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Audrey G. O’Neill
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Anika L. Burrell
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | | | - Josephine Molfino
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Charlie Clarke
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Joel Quispe
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - David Sokolov
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Rubén M. Buey
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Justin M. Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| |
Collapse
|
2
|
Li CMY, Briggs MT, Lee YR, Tin T, Young C, Pierides J, Kaur G, Drew P, Maddern GJ, Hoffmann P, Klingler-Hoffmann M, Fenix K. Use of tryptic peptide MALDI mass spectrometry imaging to identify the spatial proteomic landscape of colorectal cancer liver metastases. Clin Exp Med 2024; 24:53. [PMID: 38492056 PMCID: PMC10944452 DOI: 10.1007/s10238-024-01311-5] [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] [Received: 01/29/2024] [Accepted: 02/22/2024] [Indexed: 03/18/2024]
Abstract
Colorectal cancer (CRC) is the second leading cause of cancer-related deaths worldwide. CRC liver metastases (CRLM) are often resistant to conventional treatments, with high rates of recurrence. Therefore, it is crucial to identify biomarkers for CRLM patients that predict cancer progression. This study utilised matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to spatially map the CRLM tumour proteome. CRLM tissue microarrays (TMAs) of 84 patients were analysed using tryptic peptide MALDI-MSI to spatially monitor peptide abundances across CRLM tissues. Abundance of peptides was compared between tumour vs stroma, male vs female and across three groups of patients based on overall survival (0-3 years, 4-6 years, and 7+ years). Peptides were then characterised and matched using LC-MS/MS. A total of 471 potential peptides were identified by MALDI-MSI. Our results show that two unidentified m/z values (1589.876 and 1092.727) had significantly higher intensities in tumours compared to stroma. Ten m/z values were identified to have correlation with biological sex. Survival analysis identified three peptides (Histone H4, Haemoglobin subunit alpha, and Inosine-5'-monophosphate dehydrogenase 2) and two unidentified m/z values (1305.840 and 1661.060) that were significantly higher in patients with shorter survival (0-3 years relative to 4-6 years and 7+ years). This is the first study using MALDI-MSI, combined with LC-MS/MS, on a large cohort of CRLM patients to identify the spatial proteome in this malignancy. Further, we identify several protein candidates that may be suitable for drug targeting or for future prognostic biomarker development.
Collapse
Affiliation(s)
- Celine Man Ying Li
- Discipline of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA, 5011, Australia
| | - Matthew T Briggs
- Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Yea-Rin Lee
- Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Teresa Tin
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA, 5011, Australia
| | - Clifford Young
- Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - John Pierides
- SA Pathology, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia
| | - Gurjeet Kaur
- Institute for Research in Molecular Medicine, University Sains Malaysia, 11800, Pulau Pinang, Malaysia
| | - Paul Drew
- Discipline of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA, 5011, Australia
| | - Guy J Maddern
- Discipline of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA, 5011, Australia
| | - Peter Hoffmann
- Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | | | - Kevin Fenix
- Discipline of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA, 5011, Australia.
| |
Collapse
|
3
|
Flores-Mendez M, Ohl L, Roule T, Zhou Y, Tintos-Hernández JA, Walsh K, Ortiz-González XR, Akizu N. IMPDH2 filaments protect from neurodegeneration in AMPD2 deficiency. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576443. [PMID: 38328116 PMCID: PMC10849482 DOI: 10.1101/2024.01.20.576443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Metabolic dysregulation is one of the most common causes of pediatric neurodegenerative disorders. However, how the disruption of ubiquitous and essential metabolic pathways predominantly affect neural tissue remains unclear. Here we use mouse models of AMPD2 deficiency to study cellular and molecular mechanisms that lead to selective neuronal vulnerability to purine metabolism imbalance. We show that AMPD deficiency in mice primarily leads to hippocampal dentate gyrus degeneration despite causing a generalized reduction of brain GTP levels. Remarkably, we found that neurodegeneration resistant regions accumulate micron sized filaments of IMPDH2, the rate limiting enzyme in GTP synthesis. In contrast, IMPDH2 filaments are barely detectable in the hippocampal dentate gyrus, which shows a progressive neuroinflammation and neurodegeneration. Furthermore, using a human AMPD2 deficient neural cell culture model, we show that blocking IMPDH2 polymerization with a dominant negative IMPDH2 variant, impairs AMPD2 deficient neural progenitor growth. Together, our findings suggest that IMPDH2 polymerization prevents detrimental GTP deprivation in neurons with available GTP precursor molecules, providing resistance to neurodegeneration. Our findings open the possibility of exploring the involvement of IMPDH2 assembly as a therapeutic intervention for neurodegeneration.
Collapse
Affiliation(s)
- Marco Flores-Mendez
- Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Laura Ohl
- Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas Roule
- Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yijing Zhou
- Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jesus A Tintos-Hernández
- Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104
| | - Kelsey Walsh
- Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xilma R Ortiz-González
- Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Naiara Akizu
- Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
4
|
Romero-Romero ML, Garcia-Seisdedos H. Agglomeration: when folded proteins clump together. Biophys Rev 2023; 15:1987-2003. [PMID: 38192350 PMCID: PMC10771401 DOI: 10.1007/s12551-023-01172-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 11/25/2023] [Indexed: 01/10/2024] Open
Abstract
Protein self-association is a widespread phenomenon that results in the formation of multimeric protein structures with critical roles in cellular processes. Protein self-association can lead to finite protein complexes or open-ended, and potentially, infinite structures. This review explores the concept of protein agglomeration, a process that results from the infinite self-assembly of folded proteins. We highlight its differences from other better-described processes with similar macroscopic features, such as aggregation and liquid-liquid phase separation. We review the sequence, structural, and biophysical factors influencing protein agglomeration. Lastly, we briefly discuss the implications of agglomeration in evolution, disease, and aging. Overall, this review highlights the need to study protein agglomeration for a better understanding of cellular processes.
Collapse
Affiliation(s)
- M. L. Romero-Romero
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology, Dresden, Germany
| | - H. Garcia-Seisdedos
- Department of Structural and Molecular Biology, Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Barcelona, Spain
| |
Collapse
|
5
|
Mane RR, Kale PP. The roles of HDAC with IMPDH and mTOR with JAK as future targets in the treatment of rheumatoid arthritis with combination therapy. JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2023; 20:689-706. [PMID: 36409592 DOI: 10.1515/jcim-2022-0114] [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: 03/12/2022] [Accepted: 07/19/2022] [Indexed: 06/16/2023]
Abstract
Various studies have shown that cytokines are important regulators in rheumatoid arthritis (RA). In synovial inflammation alteration of the enzyme HDAC, IMPDH enzyme, mTOR pathway, and JAK pathway increase cytokine level. These increased cytokine levels are responsible for the inflammation in RA. Inflammation is a physiological and normal reaction of the immune system against dangerous stimuli such as injury and infection. The cytokine-based approach improves the treatment of RA. To reach this goal, various researchers and scientists are working more aggressively by using a combination approach. The present review of combination therapy provides essential evidence about the possible synergistic effect of combinatorial agents. We have focused on the effects of HDAC inhibitor with IMPDH inhibitor and mTOR inhibitor with JAK inhibitor in combination for the treatment of RA. Combining various targeted strategies can be helpful for the treatment of RA.
Collapse
Affiliation(s)
- Reshma Rajendra Mane
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India
| | - Pravin Popatrao Kale
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India
| |
Collapse
|
6
|
Calise SJ, O’Neill AG, Burrell AL, Dickinson MS, Molfino J, Clarke C, Quispe J, Sokolov D, Buey RM, Kollman JM. Light-sensitive phosphorylation regulates enzyme activity and filament assembly of human IMPDH1 retinal splice variants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.21.558867. [PMID: 37790411 PMCID: PMC10542554 DOI: 10.1101/2023.09.21.558867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Inosine monophosphate dehydrogenase (IMPDH) is the rate-limiting enzyme in de novo guanosine triphosphate (GTP) synthesis and is controlled by feedback inhibition and allosteric regulation. IMPDH assembles into micron-scale filaments in cells, which desensitizes the enzyme to feedback inhibition by GTP and boosts nucleotide production. The vertebrate retina expresses two tissue-specific splice variants IMPDH1(546) and IMPDH1(595). IMPDH1(546) filaments adopt high and low activity conformations, while IMPDH1(595) filaments maintain high activity. In bovine retinas, residue S477 is preferentially phosphorylated in the dark, but the effects on IMPDH1 activity and regulation are unclear. Here, we generated phosphomimetic mutants to investigate structural and functional consequences of phosphorylation in IMPDH1 variants. The S477D mutation re-sensitized both variants to GTP inhibition, but only blocked assembly of IMPDH1(595) filaments and not IMPDH1(546) filaments. Cryo-EM structures of both variants showed that S477D specifically blocks assembly of the high activity assembly interface, still allowing assembly of low activity IMPDH1(546) filaments. Finally, we discovered that S477D exerts a dominant-negative effect in cells, preventing endogenous IMPDH filament assembly. By modulating the structure and higher-order assembly of IMPDH, phosphorylation at S477 acts as a mechanism for downregulating retinal GTP synthesis in the dark, when nucleotide turnover is decreased. Like IMPDH1, many other metabolic enzymes dynamically assemble filamentous polymers that allosterically regulate activity. Our work suggests that posttranslational modifications may be yet another layer of regulatory control to finely tune activity by modulating filament assembly in response to changing metabolic demands.
Collapse
Affiliation(s)
- S. John Calise
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Audrey G. O’Neill
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Anika L. Burrell
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | | | - Josephine Molfino
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Charlie Clarke
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Joel Quispe
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - David Sokolov
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Rubén M. Buey
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Justin M. Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| |
Collapse
|
7
|
Keppeke GD, Chang CC, Zhang Z, Liu JL. Effect on cell survival and cytoophidium assembly of the adRP-10-related IMPDH1 missense mutation Asp226Asn. Front Cell Dev Biol 2023; 11:1234592. [PMID: 37731818 PMCID: PMC10507268 DOI: 10.3389/fcell.2023.1234592] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 08/17/2023] [Indexed: 09/22/2023] Open
Abstract
Introduction: Inosine monophosphate dehydrogenase 1 (IMPDH1) is a critical enzyme in the retina, essential for the correct functioning of photoreceptor cells. Mutations in IMPDH1 have been linked to autosomal dominant retinitis pigmentosa subtype 10 (adRP-10), a genetic eye disorder. Some of these mutations such as the Asp226Asn (D226N) lead to the assembly of large filamentous structures termed cytoophidia. D226N also gives IMPDH1 resistance to feedback inhibition by GDP/GTP. This study aims to emulate the adRP-10 condition with a long-term expression of IMPDH1-D226N in vitro and explore cytoophidium assembly and cell survival. We also assessed whether the introduction of an additional mutation (Y12C) to disrupt the cytoophidium has an attenuating effect on the toxicity caused by the D226N mutation. Results: Expression of IMPDH1-D226N in HEp-2 cells resulted in cytoophidium assembly in ∼70% of the cells, but the presence of the Y12C mutation disrupted the filaments. Long-term cell survival was significantly affected by the presence of the D226N mutation, with a decrease of ∼40% in the cells expressing IMPDH1-D226N when compared to IMPDH1-WT; however, survival was significantly recovered in IMPDH1-Y12C/D226N, with only a ∼10% decrease when compared to IMPDH1-WT. On the other hand, the IMPDH1 expression level in the D226N-positive cells was <30% of that of the IMPDH1-WT-positive cells and only slightly higher in the Y12C/D226N, suggesting that although cell survival in Y12C/D226N was recovered, higher expression levels of the mutated IMPDH1 were not tolerated by the cells in the long term. Conclusion: The IMPDH1-D226N effect on photoreceptor cell survival may be the result of a sum of problems: nucleotide unbalance plus a toxic long-life cytoophidium, supported by the observation that by introducing Y12C in IMPDH1 the cytoophidium was disrupted and cell survival significantly recovered, but not the sensibility to GDP/GTP regulation since higher expression levels of IMPDH1-D226N were not tolerated.
Collapse
Affiliation(s)
- Gerson Dierley Keppeke
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
- Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Sao Paulo, Brazil
| | - Chia-Chun Chang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Ziheng Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
8
|
O'Neill AG, Burrell AL, Zech M, Elpeleg O, Harel T, Edvardson S, Mor-Shaked H, Rippert AL, Nomakuchi T, Izumi K, Kollman JM. Neurodevelopmental disorder mutations in the purine biosynthetic enzyme IMPDH2 disrupt its allosteric regulation. J Biol Chem 2023; 299:105012. [PMID: 37414152 PMCID: PMC10407431 DOI: 10.1016/j.jbc.2023.105012] [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] [Received: 05/09/2023] [Revised: 06/23/2023] [Accepted: 06/28/2023] [Indexed: 07/08/2023] Open
Abstract
Inosine 5' monophosphate dehydrogenase (IMPDH) is a critical regulatory enzyme in purine nucleotide biosynthesis that is inhibited by the downstream product GTP. Multiple point mutations in the human isoform IMPDH2 have recently been associated with dystonia and other neurodevelopmental disorders, but the effect of the mutations on enzyme function has not been described. Here, we report the identification of two additional missense variants in IMPDH2 from affected individuals and show that all of the disease-associated mutations disrupt GTP regulation. Cryo-EM structures of one IMPDH2 mutant suggest this regulatory defect arises from a shift in the conformational equilibrium toward a more active state. This structural and functional analysis provides insight into IMPDH2-associated disease mechanisms that point to potential therapeutic approaches and raises new questions about fundamental aspects of IMPDH regulation.
Collapse
Affiliation(s)
- Audrey G O'Neill
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Anika L Burrell
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Simon Edvardson
- Alyn Hospital, Hebrew University School of Medicine, Jerusalem, Israel
| | - Hagar Mor-Shaked
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alyssa L Rippert
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Tomoki Nomakuchi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kosuke Izumi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, Washington, USA.
| |
Collapse
|
9
|
Alhamad S, Elmasry Y, Uwagboe I, Chekmeneva E, Sands C, Cooper BW, Camuzeaux S, Salam A, Parsons M. B7-H3 Associates with IMPDH2 and Regulates Cancer Cell Survival. Cancers (Basel) 2023; 15:3530. [PMID: 37444640 DOI: 10.3390/cancers15133530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Lung cancer is one of the most common cancers worldwide, and despite improvements in treatment regimens, patient prognosis remains poor. Lung adenocarcinomas develop from the lung epithelia and understanding how specific genetic and environmental factors lead to oncogenic transformation in these cells is of great importance to define the pathways that contribute to tumorigenesis. The recent rise in the use of immunotherapy to treat different cancers has prompted the exploration of immune modulators in tumour cells that may provide new targets to manipulate this process. Of these, the B7 family of cell surface receptors, which includes PD-1, is of particular interest due to its role in modulating immune cell responses within the tumour microenvironment. B7-H3 (CD276) is one family member that is upregulated in many cancer types and suggested to contribute to tumour-immune interactions. However, the function and ligand(s) for this receptor in normal lung epithelia and the mechanisms through which the overexpression of B7-H3 regulate cancer progression in the absence of immune cell interactions remain unclear. Here, we present evidence that B7-H3 is associated with one of the key rate-limiting metabolic enzymes IMPDH2, and the localisation of this complex is altered in human lung cancer cells that express high levels of B7-H3. Mechanistically, the IMPDH2:B7-H3 complex provides a protective role in cancer cells to escape oxidative stress triggered by chemotherapy, thus leading to cell survival. We further demonstrate that the loss of B7-H3 in cancer cells has no effect on growth or migration in 2D but promotes the expansion of 3D spheroids in an IMPDH2-dependent manner. These findings provide new insights into the B7-H3 function in the metabolic homeostasis of normal and transformed lung cancer cells, and whilst this molecule remains an interesting target for immunotherapy, these findings caution against the use of anti-B7-H3 therapies in certain clinical settings.
Collapse
Affiliation(s)
- Salwa Alhamad
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guys Campus, New Hunts House, London SE1 1UL, UK
- Department of Biology, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
| | - Yassmin Elmasry
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guys Campus, New Hunts House, London SE1 1UL, UK
| | - Isabel Uwagboe
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guys Campus, New Hunts House, London SE1 1UL, UK
| | - Elena Chekmeneva
- National Phenome Centre, Section of Bioanalytical Chemistry, Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Hospital Campus, IRDB Building, 5th Floor, Du Cane Road, London W12 0NN, UK
| | - Caroline Sands
- National Phenome Centre, Section of Bioanalytical Chemistry, Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Hospital Campus, IRDB Building, 5th Floor, Du Cane Road, London W12 0NN, UK
| | - Benjamin W Cooper
- National Phenome Centre, Section of Bioanalytical Chemistry, Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Hospital Campus, IRDB Building, 5th Floor, Du Cane Road, London W12 0NN, UK
| | - Stephane Camuzeaux
- National Phenome Centre, Section of Bioanalytical Chemistry, Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Hospital Campus, IRDB Building, 5th Floor, Du Cane Road, London W12 0NN, UK
| | - Ash Salam
- National Phenome Centre, Section of Bioanalytical Chemistry, Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Hospital Campus, IRDB Building, 5th Floor, Du Cane Road, London W12 0NN, UK
| | - Maddy Parsons
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guys Campus, New Hunts House, London SE1 1UL, UK
| |
Collapse
|
10
|
O'Neill AG, Burrell AL, Zech M, Elpeleg O, Harel T, Edvardson S, Shaked HM, Rippert AL, Nomakuchi T, Izumi K, Kollman JM. Point mutations in IMPDH2 which cause early-onset neurodevelopmental disorders disrupt enzyme regulation and filament structure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532669. [PMID: 36993700 PMCID: PMC10055058 DOI: 10.1101/2023.03.15.532669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Inosine 5' monophosphate dehydrogenase (IMPDH) is a critical regulatory enzyme in purine nucleotide biosynthesis that is inhibited by the downstream product GTP. Multiple point mutations in the human isoform IMPDH2 have recently been associated with dystonia and other neurodevelopmental disorders, but the effect of the mutations on enzyme function has not been described. Here, we report identification of two additional affected individuals with missense variants in IMPDH2 and show that all of the disease-associated mutations disrupt GTP regulation. Cryo-EM structures of one IMPDH2 mutant suggest this regulatory defect arises from a shift in the conformational equilibrium toward a more active state. This structural and functional analysis provides insight into IMPDH2-associated disease mechanisms that point to potential therapeutic approaches and raises new questions about fundamental aspects of IMPDH regulation.
Collapse
Affiliation(s)
- Audrey G O'Neill
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Anika L Burrell
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Simon Edvardson
- Alyn Hospital, Hebrew University School of Medicine, Jerusalem, Israel
| | - Hagar Mor Shaked
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alyssa L Rippert
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Tomoki Nomakuchi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Kosuke Izumi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| |
Collapse
|
11
|
Kim-Holzapfel DM, Dey R, Richardson BC, Arachchige D, Reddy K, De Vitto H, Bhandari J, French JB. Human uridine 5'-monophosphate synthase stores metabolic potential in inactive biomolecular condensates. J Biol Chem 2023; 299:102949. [PMID: 36708921 PMCID: PMC9978035 DOI: 10.1016/j.jbc.2023.102949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/02/2023] [Accepted: 01/06/2023] [Indexed: 01/27/2023] Open
Abstract
Human uridine 5'-monophosphate synthase (HsUMPS) is a bifunctional enzyme that catalyzes the final two steps in de novo pyrimidine biosynthesis. The individual orotate phosphoribosyl transferase and orotidine monophosphate domains have been well characterized, but little is known about the overall structure of the protein and how the organization of domains impacts function. Using a combination of chromatography, electron microscopy, and complementary biophysical methods, we report herein that HsUMPS can be observed in two structurally distinct states, an enzymatically active dimeric form and a nonactive multimeric form. These two states readily interconvert to reach an equilibrium that is sensitive to perturbations of the active site and the presence of substrate. We determined that the smaller molecular weight form of HsUMPS is an S-shaped dimer that can self-assemble into relatively well-ordered globular condensates. Our analysis suggests that the transition between dimer and multimer is driven primarily by oligomerization of the orotate phosphoribosyl transferase domain. While the cellular distribution of HsUMPS is unaffected, quantification by mass spectrometry revealed that de novo pyrimidine biosynthesis is dysregulated when this protein is unable to assemble into inactive condensates. Taken together, our data suggest that HsUMPS self-assembles into biomolecular condensates as a means to store metabolic potential for the regulation of metabolic rates.
Collapse
Affiliation(s)
- Deborah M Kim-Holzapfel
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA; Molecular and Cellular Biology PhD Program, Stony Brook University, Stony Brook, New York, USA
| | - Raja Dey
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | | | | | - Kanamata Reddy
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Humberto De Vitto
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Janarjan Bhandari
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Jarrod B French
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA.
| |
Collapse
|
12
|
Buey RM, Fernández‐Justel D, Jiménez A, Revuelta JL. The gateway to guanine nucleotides: Allosteric regulation of IMP dehydrogenases. Protein Sci 2022; 31:e4399. [PMID: 36040265 PMCID: PMC9375230 DOI: 10.1002/pro.4399] [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: 06/03/2022] [Revised: 07/07/2022] [Accepted: 07/19/2022] [Indexed: 11/12/2022]
Abstract
Inosine 5′‐monophosphate dehydrogenase (IMPDH) is an evolutionarily conserved enzyme that mediates the first committed step in de novo guanine nucleotide biosynthetic pathway. It is an essential enzyme in purine nucleotide biosynthesis that modulates the metabolic flux at the branch point between adenine and guanine nucleotides. IMPDH plays key roles in cell homeostasis, proliferation, and the immune response, and is the cellular target of several drugs that are widely used for antiviral and immunosuppressive chemotherapy. IMPDH enzyme is tightly regulated at multiple levels, from transcriptional control to allosteric modulation, enzyme filamentation, and posttranslational modifications. Herein, we review recent developments in our understanding of the mechanisms of IMPDH regulation, including all layers of allosteric control that fine‐tune the enzyme activity.
Collapse
Affiliation(s)
- Rubén M. Buey
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
| | - David Fernández‐Justel
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
| | - Alberto Jiménez
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
| | - José L. Revuelta
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
| |
Collapse
|
13
|
Chang CC, Peng M, Zhong J, Zhang Z, Keppeke GD, Sung LY, Liu JL. Molecular crowding facilitates bundling of IMPDH polymers and cytoophidium formation. Cell Mol Life Sci 2022; 79:420. [PMID: 35833994 PMCID: PMC11072341 DOI: 10.1007/s00018-022-04448-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/14/2022] [Accepted: 06/21/2022] [Indexed: 11/29/2022]
Abstract
The cytoophidium is a unique type of membraneless compartment comprising of filamentous protein polymers. Inosine monophosphate dehydrogenase (IMPDH) catalyzes the rate-limiting step of de novo GTP biosynthesis and plays critical roles in active cell metabolism. However, the molecular regulation of cytoophidium formation is poorly understood. Here we show that human IMPDH2 polymers bundle up to form cytoophidium-like aggregates in vitro when macromolecular crowders are present. The self-association of IMPDH polymers is suggested to rely on electrostatic interactions. In cells, the increase of molecular crowding with hyperosmotic medium induces cytoophidia, while the decrease of that by the inhibition of RNA synthesis perturbs cytoophidium assembly. In addition to IMPDH, CTPS and PRPS cytoophidium could be also induced by hyperosmolality, suggesting a universal phenomenon of cytoophidium-forming proteins. Finally, our results indicate that the cytoophidium can prolong the half-life of IMPDH, which is proposed to be one of conserved functions of this subcellular compartment.
Collapse
Affiliation(s)
- Chia-Chun Chang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan
| | - Min Peng
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan
| | - Jiale Zhong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Ziheng Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Gerson Dierley Keppeke
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Sao Paulo, SP, 04023-062, Brazil
| | - Li-Ying Sung
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK.
| |
Collapse
|
14
|
IMPDH dysregulation in disease: a mini review. Biochem Soc Trans 2022; 50:71-82. [PMID: 35191957 PMCID: PMC9022972 DOI: 10.1042/bst20210446] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 12/20/2022]
Abstract
Inosine-5′-monophosphate dehydrogenase (IMPDH) is a highly conserved enzyme in purine metabolism that is tightly regulated on multiple levels. IMPDH has a critical role in purine biosynthesis, where it regulates flux at the branch point between adenine and guanine nucleotide synthesis, but it also has a role in transcription regulation and other moonlighting functions have been described. Vertebrates have two isoforms, IMPDH1 and IMPDH2, and point mutations in each are linked to human disease. Mutations in IMPDH2 in humans are associated with neurodevelopmental disease, but the effects of mutations at the enzyme level have not yet been characterized. Mutations in IMPDH1 lead to retinal degeneration in humans, and recent studies have characterized how they cause functional defects in regulation. IMPDH1 is expressed as two unique splice variants in the retina, a tissue with very high and specific demands for purine nucleotides. Recent studies have revealed functional differences among splice variants, demonstrating that retinal variants up-regulate guanine nucleotide synthesis by reducing sensitivity to feedback inhibition by downstream products. A better understanding of the role of IMPDH1 in the retina and the characterization of an animal disease model will be critical for determining the molecular mechanism of IMPDH1-associated blindness.
Collapse
|
15
|
Burrell AL, Nie C, Said M, Simonet JC, Fernández-Justel D, Johnson MC, Quispe J, Buey RM, Peterson JR, Kollman JM. IMPDH1 retinal variants control filament architecture to tune allosteric regulation. Nat Struct Mol Biol 2022; 29:47-58. [PMID: 35013599 PMCID: PMC9044917 DOI: 10.1038/s41594-021-00706-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/23/2021] [Indexed: 01/06/2023]
Abstract
Inosine-5'-monophosphate dehydrogenase (IMPDH), a key regulatory enzyme in purine nucleotide biosynthesis, dynamically assembles filaments in response to changes in metabolic demand. Humans have two isoforms: IMPDH2 filaments reduce sensitivity to feedback inhibition, while IMPDH1 assembly remains uncharacterized. IMPDH1 plays a unique role in retinal metabolism, and point mutants cause blindness. Here, in a series of cryogenic-electron microscopy structures we show that human IMPDH1 assembles polymorphic filaments with different assembly interfaces in extended and compressed states. Retina-specific splice variants introduce structural elements that reduce sensitivity to GTP inhibition, including stabilization of the extended filament form. Finally, we show that IMPDH1 disease mutations fall into two classes: one disrupts GTP regulation and the other has no effect on GTP regulation or filament assembly. These findings provide a foundation for understanding the role of IMPDH1 in retinal function and disease and demonstrate the diverse mechanisms by which metabolic enzyme filaments are allosterically regulated.
Collapse
Affiliation(s)
- Anika L Burrell
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Chuankai Nie
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Meerit Said
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Jacqueline C Simonet
- Cancer Epigenetics and Signaling Program, Fox Chase Cancer Center, Philadelphia, PA, USA
- Department of Biology, Arcadia University, Glenside, PA, USA
| | - David Fernández-Justel
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Matthew C Johnson
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Department of Structural Biology, Genentech, South San Francisco, CA, USA
| | - Joel Quispe
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Rubén M Buey
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Jeffrey R Peterson
- Cancer Epigenetics and Signaling Program, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
| |
Collapse
|
16
|
Liu X, Huuskonen S, Laitinen T, Redchuk T, Bogacheva M, Salokas K, Pöhner I, Öhman T, Tonduru AK, Hassinen A, Gawriyski L, Keskitalo S, Vartiainen MK, Pietiäinen V, Poso A, Varjosalo M. SARS-CoV-2-host proteome interactions for antiviral drug discovery. Mol Syst Biol 2021; 17:e10396. [PMID: 34709727 PMCID: PMC8552907 DOI: 10.15252/msb.202110396] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 12/20/2022] Open
Abstract
Treatment options for COVID-19, caused by SARS-CoV-2, remain limited. Understanding viral pathogenesis at the molecular level is critical to develop effective therapy. Some recent studies have explored SARS-CoV-2-host interactomes and provided great resources for understanding viral replication. However, host proteins that functionally associate with SARS-CoV-2 are localized in the corresponding subnetwork within the comprehensive human interactome. Therefore, constructing a downstream network including all potential viral receptors, host cell proteases, and cofactors is necessary and should be used as an additional criterion for the validation of critical host machineries used for viral processing. This study applied both affinity purification mass spectrometry (AP-MS) and the complementary proximity-based labeling MS method (BioID-MS) on 29 viral ORFs and 18 host proteins with potential roles in viral replication to map the interactions relevant to viral processing. The analysis yields a list of 693 hub proteins sharing interactions with both viral baits and host baits and revealed their biological significance for SARS-CoV-2. Those hub proteins then served as a rational resource for drug repurposing via a virtual screening approach. The overall process resulted in the suggested repurposing of 59 compounds for 15 protein targets. Furthermore, antiviral effects of some candidate drugs were observed in vitro validation using image-based drug screen with infectious SARS-CoV-2. In addition, our results suggest that the antiviral activity of methotrexate could be associated with its inhibitory effect on specific protein-protein interactions.
Collapse
Affiliation(s)
- Xiaonan Liu
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Sini Huuskonen
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Tuomo Laitinen
- School of PharmacyUniversity of Eastern FinlandKuopioFinland
| | - Taras Redchuk
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Mariia Bogacheva
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Molecular Medicine FinlandUniversity of HelsinkiHelsinkiFinland
- Department of VirologyUniversity of HelsinkiHelsinkiFinland
| | - Kari Salokas
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Ina Pöhner
- School of PharmacyUniversity of Eastern FinlandKuopioFinland
| | - Tiina Öhman
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | | | - Antti Hassinen
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Molecular Medicine FinlandUniversity of HelsinkiHelsinkiFinland
| | - Lisa Gawriyski
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Salla Keskitalo
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Maria K Vartiainen
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Vilja Pietiäinen
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Molecular Medicine FinlandUniversity of HelsinkiHelsinkiFinland
| | - Antti Poso
- School of PharmacyUniversity of Eastern FinlandKuopioFinland
- Department of Internal Medicine VIIIUniversity Hospital TübingenTübingenGermany
| | - Markku Varjosalo
- Institute of BiotechnologyUniversity of HelsinkiHelsinkiFinland
- Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| |
Collapse
|
17
|
Ni S, Zhang T, Zhou C, Long M, Hou X, You L, Li H, Shi L, Su YQ. Coordinated Formation of IMPDH2 Cytoophidium in Mouse Oocytes and Granulosa Cells. Front Cell Dev Biol 2021; 9:690536. [PMID: 34124077 PMCID: PMC8194064 DOI: 10.3389/fcell.2021.690536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 05/07/2021] [Indexed: 11/13/2022] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme catalyzing de novo biosynthesis of guanine nucleotides, aggregates under certain circumstances into a type of non-membranous filamentous macrostructure termed “cytoophidium” or “rod and ring” in several types of cells. However, the biological significance and underlying mechanism of IMPDH assembling into cytoophidium remain elusive. In mouse ovaries, IMPDH is reported to be crucial for the maintenance of oocyte–follicle developmental synchrony by providing GTP substrate for granulosa cell natriuretic peptide C/natriuretic peptide receptor 2 (NPPC/NPR2) system to produce cGMP for sustaining oocyte meiotic arrest. Oocytes and the associated somatic cells in the ovary hence render an exciting model system for exploring the functional significance of formation of IMPDH cytoophidium within the cell. We report here that IMPDH2 cytoophidium forms in vivo in the growing oocytes naturally and in vitro in the cumulus-enclosed oocytes treated with IMPDH inhibitor mycophenolic acid (MPA). Inhibition of IMPDH activity in oocytes and preimplantation embryos compromises oocyte meiotic and developmental competences and the development of embryos beyond the 4-cell stage, respectively. IMPDH cytoopidium also forms in vivo in the granulosa cells of the preovulatory follicles after the surge of luteinizing hormone (LH), which coincides with the resumption of oocyte meiosis and the reduction of IMPDH2 protein expression. In cultured COCs, MPA-treatment causes the simultaneous formation of IMPDH cytoopidium in cumulus cells and the resumption of meiosis in oocytes, which is mediated by the MTOR pathway and is prevented by guanosine supplementation. Therefore, our results indicate that cytoophidia do form in the oocytes and granulosa cells at particular stages of development, which may contribute to the oocyte acquisition of meiotic and developmental competences and the induction of meiosis re-initiation by the LH surge, respectively.
Collapse
Affiliation(s)
- Shiwen Ni
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.,Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Teng Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Chenmin Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.,Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Min Long
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.,Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xuan Hou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Liji You
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.,Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Hui Li
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.,Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Lanying Shi
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.,Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - You-Qiang Su
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.,Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.,Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Hospital, Nanjing Medical University, Nanjing, China.,Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai, China
| |
Collapse
|
18
|
Kofuji S, Sasaki AT. GTP metabolic reprogramming by IMPDH2: unlocking cancer cells' fuelling mechanism. J Biochem 2021; 168:319-328. [PMID: 32702086 DOI: 10.1093/jb/mvaa085] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/16/2020] [Indexed: 12/15/2022] Open
Abstract
Growing cells increase multiple biosynthetic processes in response to the high metabolic demands needed to sustain proliferation. The even higher metabolic requirements in the setting of cancer provoke proportionately greater biosynthesis. Underappreciated key aspects of this increased metabolic demand are guanine nucleotides and adaptive mechanisms to regulate their concentration. Using the malignant brain tumour, glioblastoma, as a model, we have demonstrated that one of the rate-limiting enzymes for guanosine triphosphate (GTP) synthesis, inosine monophosphate dehydrogenase-2 (IMPDH2), is increased and IMPDH2 expression is necessary for the activation of de novo GTP biosynthesis. Moreover, increased IMPDH2 enhances RNA polymerase I and III transcription directly linking GTP metabolism to both anabolic capacity as well as nucleolar enlargement historically observed as associated with cancer. In this review, we will review in detail the basis of these new discoveries and, more generally, summarize the current knowledge on the role of GTP metabolism in cancer.
Collapse
Affiliation(s)
- Satoshi Kofuji
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, 3125 Eden Ave., Cincinnati, OH 45267-0508, USA.,Department of Cancer Biology, University of Cincinnati College of Medicine, 3125 Eden Ave., OH 45267-0508, USA.,Department of Neurosurgery, Brain Tumor Center at UC Gardner Neuroscience Institute, 3113 Bellevue Ave, Cincinnati, OH 45267-0508, USA.,Institute for Advanced Biosciences, Keio University, Kakuganji 246-2, Mizukami, Tsuruoka City, Yamagata 997-0052, Japan
| |
Collapse
|
19
|
Calise SJ, Chan EKL. Anti-rods/rings autoantibody and IMPDH filaments: an update after fifteen years of discovery. Autoimmun Rev 2020; 19:102643. [PMID: 32805424 DOI: 10.1016/j.autrev.2020.102643] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 03/27/2020] [Indexed: 02/07/2023]
Abstract
Autoantibodies to unknown subcellular rod and ring-shaped structures were first discovered in sera from hepatitis C patients in 2005. Early studies showed a strong association between these anti-rods/rings antibodies (anti-RR) and the standard of care interferon-α plus ribavirin combination therapy (IFN/RBV), suggesting that anti-RR are drug-induced autoantibodies. In the context of hepatitis C, anti-RR have been linked with relapse from or lack of response to IFN/RBV in some patient cohorts. However, examples of anti-RR in other diseases and healthy individuals have also been reported over the years, although anti-RR remains a rare autoantibody response in general. The advent of new direct-acting antiviral drugs for chronic hepatitis C and studies of anti-RR from different parts of the world are also beginning to change the perception of anti-RR. The nucleotide biosynthetic enzyme inosine monophosphate dehydrogenase (IMPDH) has been identified as the major autoantigen recognized by anti-RR. Coincidentally, the assembly of IMPDH into micron-scale rod and ring-shaped structures was discovered around the same time as anti-RR. Knowledge of the fundamental biological properties and cellular functions of these structures, referred to as "IMPDH filaments" by cell biologists, has advanced in parallel to anti-RR antibodies. Recent studies have revealed that IMPDH filament assembly is a mechanism to prevent feedback inhibition of IMPDH and is therefore important for the increased nucleotide production required in hyperproliferating cells, like activated T cells. Fifteen years later, we review the history and current knowledge in both the anti-RR autoantibody and IMPDH filament fields. TAKE-HOME MESSAGE: Anti-rods/rings are recognized as an example of a drug-induced autoantibody in hepatitis C patients treated with interferon and ribavirin, although new studies suggest anti-rods/rings may be detected in other contexts and may depend on unknown environmental or genetic factors in different populations. Recent data suggest that the assembly of IMPDH into rod and ring structures, the targets of anti-rods/rings autoantibody, is a mechanism for hyperproliferating cells, like activated T cells, to maintain increased guanine nucleotide levels to support rapid cell division.
Collapse
Affiliation(s)
- S John Calise
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA.
| | - Edward K L Chan
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA.
| |
Collapse
|
20
|
Chong YC, Toh TB, Chan Z, Lin QXX, Thng DKH, Hooi L, Ding Z, Shuen T, Toh HC, Dan YY, Bonney GK, Zhou L, Chow P, Wang Y, Benoukraf T, Chow EKH, Han W. Targeted Inhibition of Purine Metabolism Is Effective in Suppressing Hepatocellular Carcinoma Progression. Hepatol Commun 2020; 4:1362-1381. [PMID: 32923839 PMCID: PMC7471427 DOI: 10.1002/hep4.1559] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/27/2020] [Accepted: 06/10/2020] [Indexed: 12/15/2022] Open
Abstract
Tumor‐specific metabolic rewiring, acquired to confer a proliferative and survival advantage over nontransformed cells, represents a renewed focus in cancer therapy development. Hepatocellular carcinoma (HCC), a malignancy that has hitherto been resistant to compounds targeting oncogenic signaling pathways, represents a candidate cancer to investigate the efficacy of selectively antagonizing such adaptive metabolic reprogramming. To this end, we sought to characterize metabolic changes in HCC necessary for tumorigenesis. We analyzed gene expression profiles in three independent large‐scale patient cohorts who had HCC. We identified a commonly deregulated purine metabolic signature in tumors with the extent of purine biosynthetic enzyme up‐regulation correlated with tumor grade and a predictor of clinical outcome. The functional significance of enhanced purine metabolism as a hallmark in human HCC was then validated using a combination of HCC cell lines, patient‐derived xenograft (PDX) organoids, and mouse models. Targeted ablation of purine biosynthesis by knockdown of the rate‐limiting enzyme inosine‐5′‐monophosphate dehydrogenase (IMPDH) or using the drug mycophenolate mofetil (MMF) reduced HCC proliferation in vitro and decreased the tumor burden in vivo. In comparing the sensitivities of PDX tumor organoids to MMF therapy, we found that HCC tumors defined by high levels of IMPDH and guanosine nucleosides were most susceptible to treatment. Mechanistically, a phosphoinositide 3‐kinase (PI3K)–E2F transcription factor 1 (E2F1) axis coordinated purine biosynthetic enzyme expression, deregulation of which altered the activity of mitogen‐activated protein kinase/RAS signaling. Simultaneously abolishing PI3K signaling and IMPDH activity with clinically approved inhibitors resulted in greatest efficacy in reducing tumor growth in a PDX mouse model. Conclusion: Enhanced purine metabolic activity regulated by PI3K pathway‐dependent activation of E2F1 promotes HCC carcinogenesis, suggesting the potential for targeting purine metabolic reprogramming as a precision therapeutic strategy for patients with HCC.
Collapse
Affiliation(s)
- Yong Chun Chong
- Singapore Bioimaging Consortium, Agency for Science, Technology, and Research Singapore Singapore
| | - Tan Boon Toh
- The N.1 Institute for Health National University of Singapore Singapore Singapore.,Cancer Science Institute of Singapore National University of Singapore Singapore Singapore
| | - Zhiling Chan
- Singapore Bioimaging Consortium, Agency for Science, Technology, and Research Singapore Singapore
| | - Quy Xiao Xuan Lin
- Cancer Science Institute of Singapore National University of Singapore Singapore Singapore
| | - Dexter Kai Hao Thng
- Cancer Science Institute of Singapore National University of Singapore Singapore Singapore
| | - Lissa Hooi
- Cancer Science Institute of Singapore National University of Singapore Singapore Singapore
| | - Zhaobing Ding
- Singapore Bioimaging Consortium, Agency for Science, Technology, and Research Singapore Singapore
| | - Timothy Shuen
- Division of Medical Oncology National Cancer Center Singapore Singapore Singapore
| | - Han Chong Toh
- Division of Medical Oncology National Cancer Center Singapore Singapore Singapore
| | - Yock Young Dan
- Division of Gastroenterology and Hepatology National University Health System Singapore Singapore
| | - Glenn Kunnath Bonney
- Division of Hepatobiliary and Liver Transplantation Surgery National University Health System Singapore Singapore
| | - Lei Zhou
- Department of Medicine National University of Singapore Singapore Singapore
| | - Pierce Chow
- Department of Hepatopancreatobiliary and Transplant Surgery Singapore General Hospital Singapore Singapore
| | - Yulan Wang
- Singapore Phenome Center Lee Kong Chian School of Medicine Nanyang Technological University Singapore Singapore
| | - Touati Benoukraf
- Cancer Science Institute of Singapore National University of Singapore Singapore Singapore.,Discipline of Genetics Faculty of Medicine Memorial University of Newfoundland St. John's Canada
| | - Edward Kai-Hua Chow
- Cancer Science Institute of Singapore National University of Singapore Singapore Singapore
| | - Weiping Han
- Singapore Bioimaging Consortium, Agency for Science, Technology, and Research Singapore Singapore
| |
Collapse
|
21
|
Plana-Bonamaisó A, López-Begines S, Fernández-Justel D, Junza A, Soler-Tapia A, Andilla J, Loza-Alvarez P, Rosa JL, Miralles E, Casals I, Yanes O, de la Villa P, Buey RM, Méndez A. Post-translational regulation of retinal IMPDH1 in vivo to adjust GTP synthesis to illumination conditions. eLife 2020; 9:56418. [PMID: 32254022 PMCID: PMC7176436 DOI: 10.7554/elife.56418] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023] Open
Abstract
We report the in vivo regulation of Inosine-5´-monophosphate dehydrogenase 1 (IMPDH1) in the retina. IMPDH1 catalyzes the rate-limiting step in the de novo synthesis of guanine nucleotides, impacting the cellular pools of GMP, GDP and GTP. Guanine nucleotide homeostasis is central to photoreceptor cells, where cGMP is the signal transducing molecule in the light response. Mutations in IMPDH1 lead to inherited blindness. We unveil a light-dependent phosphorylation of retinal IMPDH1 at Thr159/Ser160 in the Bateman domain that desensitizes the enzyme to allosteric inhibition by GDP/GTP. When exposed to bright light, living mice increase the rate of GTP and ATP synthesis in their retinas; concomitant with IMPDH1 aggregate formation at the outer segment layer. Inhibiting IMPDH activity in living mice delays rod mass recovery. We unveil a novel mechanism of regulation of IMPDH1 in vivo, important for understanding GTP homeostasis in the retina and the pathogenesis of adRP10 IMPDH1 mutations.
Collapse
Affiliation(s)
- Anna Plana-Bonamaisó
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut de Neurociències, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - Santiago López-Begines
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - David Fernández-Justel
- Metabolic Engineering Group, Department of Microbiology and Genetics. University of Salamanca, Salamanca, Spain
| | - Alexandra Junza
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain.,Metabolomics Platform, IISPV, Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
| | - Ariadna Soler-Tapia
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - Jordi Andilla
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | - Pablo Loza-Alvarez
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | - Jose Luis Rosa
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - Esther Miralles
- Centres Cientifics i Tecnològics (CCiTUB), University of Barcelona, Parc Científic de Barcelona, Barcelona, Spain
| | - Isidre Casals
- Centres Cientifics i Tecnològics (CCiTUB), University of Barcelona, Parc Científic de Barcelona, Barcelona, Spain
| | - Oscar Yanes
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain.,Metabolomics Platform, IISPV, Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
| | - Pedro de la Villa
- Physiology Unit, Dept of Systems Biology, School of Medicine, University of Alcalá, Madrid, Spain.,Visual Neurophysiology Group-IRYCIS, Madrid, Spain
| | - Ruben M Buey
- Metabolic Engineering Group, Department of Microbiology and Genetics. University of Salamanca, Salamanca, Spain
| | - Ana Méndez
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut de Neurociències, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| |
Collapse
|
22
|
Begovich K, Yelon D, Wilhelm JE. PRPS polymerization influences lens fiber organization in zebrafish. Dev Dyn 2020; 249:1018-1031. [PMID: 32243675 DOI: 10.1002/dvdy.173] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 02/28/2020] [Accepted: 03/05/2020] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND The self-assembly of metabolic enzymes into filaments or foci highlights an intriguing mechanism for the regulation of metabolic activity. Recently, we identified the conserved polymerization of phosphoribosyl pyrophosphate synthetase (PRPS), which catalyzes the first step in purine nucleotide synthesis, in yeast and cultured mammalian cells. While previous work has revealed that loss of PRPS activity regulates retinal development in zebrafish, the extent to which PRPS filament formation affects tissue development remains unknown. RESULTS By generating novel alleles in the zebrafish PRPS paralogs, prps1a and prps1b, we gained new insight into the role of PRPS filaments during eye development. We found that mutations in prps1a alone are sufficient to generate abnormally small eyes along with defects in head size, pigmentation, and swim bladder inflation. Furthermore, a loss-of-function mutation that truncates the Prps1a protein resulted in the failure of PRPS filament assembly. Lastly, in mutants that fail to assemble PRPS filaments, we observed disorganization of the actin network in the lens fibers. CONCLUSIONS The truncation of Prps1a blocked PRPS filament formation and resulted in a disorganized lens fiber actin network. Altogether, these findings highlight a potential role for PRPS filaments during lens fiber organization in zebrafish.
Collapse
Affiliation(s)
- Kyle Begovich
- Howard Hughes Medical Institute (HHMI) Summer Institute, Marine Biological Laboratory, Woods Hole, Massachusetts, USA.,Division of Biological Sciences, University of California, San Diego, California, USA
| | - Deborah Yelon
- Division of Biological Sciences, University of California, San Diego, California, USA
| | - James E Wilhelm
- Howard Hughes Medical Institute (HHMI) Summer Institute, Marine Biological Laboratory, Woods Hole, Massachusetts, USA.,Division of Biological Sciences, University of California, San Diego, California, USA
| |
Collapse
|
23
|
Ruan H, Song Z, Cao Q, Ni D, Xu T, Wang K, Bao L, Tong J, Xiao H, Xiao W, Cheng G, Xiong Z, Liang H, Liu D, Wang L, Olivier T, Jane BH, Yang H, Zhang X, Chen K. IMPDH1/YB-1 Positive Feedback Loop Assembles Cytoophidia and Represents a Therapeutic Target in Metastatic Tumors. Mol Ther 2020; 28:1299-1313. [PMID: 32209435 DOI: 10.1016/j.ymthe.2020.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/20/2020] [Accepted: 03/05/2020] [Indexed: 01/28/2023] Open
Abstract
Recently, cytoophidium, a nonmembrane-bound intracellular polymeric structure, has been shown to exist in various organisms, including tumor tissues, but its function and mechanism have not yet been examined. Examination of cytoophidia-assembled gene inosine monophosphate dehydrogenase (IMPDH) and cytidine triphosphate synthetase (CTPS) mRNA levels showed that only IMPDH1 levels were significantly higher in the clear cell renal cell carcinoma (ccRCC). IMPDH1 was positively correlated with the metastasis-related gene Y-box binding protein 1 (YB-1) and served as an independent prognostic factor in ccRCC. Kaplan-Meier analysis indicated that patients with tumors that expressed high IMPDH1 levels had a shorter overall survival (OS) and disease-free survival (DFS). Furthermore, detection of cytoophidia by immunofluorescence staining in ccRCC tissues showed that IMPDH1-assembled cytoophidia are positively associated with tumor metastasis. Mechanistically, IMPDH1 and YB-1 formed an autoregulatory positive feedback loop: IMPDH1 maintained YB-1 protein stabilization; YB-1 induced IMPDH1 expression by binding to the IMPDH1 promoter motif. Functionally, IMPDH1-assembled cytoophidia physically interacted with YB-1 and translocated YB-1 into the cell nucleus, thus correlating with ccRCC metastasis. Our findings provide the first solid theoretical rationale for targeting the IMPDH1/YB-1 axis to improve metastatic renal cancer treatment.
Collapse
Affiliation(s)
- Hailong Ruan
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zhengshuai Song
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qi Cao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Dong Ni
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Tianbo Xu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Keshan Wang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Lin Bao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Junwei Tong
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Haibing Xiao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Wen Xiao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Gong Cheng
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zhiyong Xiong
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Huageng Liang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Di Liu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Liang Wang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Tredan Olivier
- Department of Oncology, Centre Leon Berard, 28 Prom. Léa et Napoléon Bullukian, 69008 Lyon, France
| | - Boyle Helen Jane
- Department of Oncology, Centre Leon Berard, 28 Prom. Léa et Napoléon Bullukian, 69008 Lyon, France
| | - Hongmei Yang
- Department of Pathogenic Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoping Zhang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Ke Chen
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| |
Collapse
|
24
|
Johnson MC, Kollman JM. Cryo-EM structures demonstrate human IMPDH2 filament assembly tunes allosteric regulation. eLife 2020; 9:e53243. [PMID: 31999252 PMCID: PMC7018514 DOI: 10.7554/elife.53243] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/29/2020] [Indexed: 02/06/2023] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) mediates the first committed step in guanine nucleotide biosynthesis and plays important roles in cellular proliferation and the immune response. IMPDH reversibly polymerizes in cells and tissues in response to changes in metabolic demand. Self-assembly of metabolic enzymes is increasingly recognized as a general mechanism for regulating activity, typically by stabilizing specific conformations of an enzyme, but the regulatory role of IMPDH filaments has remained unclear. Here, we report a series of human IMPDH2 cryo-EM structures in both active and inactive conformations. The structures define the mechanism of filament assembly, and reveal how filament-dependent allosteric regulation of IMPDH2 makes the enzyme less sensitive to feedback inhibition, explaining why assembly occurs under physiological conditions that require expansion of guanine nucleotide pools. Tuning sensitivity to an allosteric inhibitor distinguishes IMPDH from other metabolic filaments, and highlights the diversity of regulatory outcomes that can emerge from self-assembly.
Collapse
Affiliation(s)
- Matthew C Johnson
- Department of BiochemistryUniversity of WashingtonSeattleUnited States
| | - Justin M Kollman
- Department of BiochemistryUniversity of WashingtonSeattleUnited States
| |
Collapse
|
25
|
Park CK, Horton NC. Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation. Biophys Rev 2019; 11:927-994. [PMID: 31734826 PMCID: PMC6874960 DOI: 10.1007/s12551-019-00602-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.
Collapse
Affiliation(s)
- Chad K. Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Nancy C. Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| |
Collapse
|
26
|
Hayward D, Kouznetsova VL, Pierson HE, Hasan NM, Guzman ER, Tsigelny IF, Lutsenko S. ANKRD9 is a metabolically-controlled regulator of IMPDH2 abundance and macro-assembly. J Biol Chem 2019; 294:14454-14466. [PMID: 31337707 DOI: 10.1074/jbc.ra119.008231] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/10/2019] [Indexed: 12/17/2022] Open
Abstract
Members of a large family of Ankyrin Repeat Domain (ANKRD) proteins regulate numerous cellular processes by binding to specific protein targets and modulating their activity, stability, and other properties. The same ANKRD protein may interact with different targets and regulate distinct cellular pathways. The mechanisms responsible for switches in the ANKRDs' behavior are often unknown. We show that cells' metabolic state can markedly alter interactions of an ANKRD protein with its target and the functional outcomes of this interaction. ANKRD9 facilitates degradation of inosine monophosphate dehydrogenase 2 (IMPDH2), the rate-limiting enzyme in GTP biosynthesis. Under basal conditions ANKRD9 is largely segregated from the cytosolic IMPDH2 in vesicle-like structures. Upon nutrient limitation, ANKRD9 loses its vesicular pattern and assembles with IMPDH2 into rodlike filaments, in which IMPDH2 is stable. Inhibition of IMPDH2 activity with ribavirin favors ANKRD9 binding to IMPDH2 rods. The formation of ANKRD9/IMPDH2 rods is reversed by guanosine, which restores ANKRD9 associations with the vesicle-like structures. The conserved Cys109Cys110 motif in ANKRD9 is required for the vesicle-to-rods transition as well as binding and regulation of IMPDH2. Oppositely to overexpression, ANKRD9 knockdown increases IMPDH2 levels and prevents formation of IMPDH2 rods upon nutrient limitation. Taken together, the results suggest that a guanosine-dependent metabolic switch determines the mode of ANKRD9 action toward IMPDH2.
Collapse
Affiliation(s)
- Dawn Hayward
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Valentina L Kouznetsova
- The Moores Cancer Center, University of California San Diego, La Jolla, California 92093.,San Diego Supercomputer Center University of California San Diego, La Jolla, California 92093
| | - Hannah E Pierson
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Nesrin M Hasan
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Estefany R Guzman
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Igor F Tsigelny
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.,San Diego Supercomputer Center University of California San Diego, La Jolla, California 92093.,Department of Neurosciences, University of California San Diego, La Jolla, California 92093
| | - Svetlana Lutsenko
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| |
Collapse
|
27
|
Wolfe K, Kofuji S, Yoshino H, Sasaki M, Okumura K, Sasaki AT. Dynamic compartmentalization of purine nucleotide metabolic enzymes at leading edge in highly motile renal cell carcinoma. Biochem Biophys Res Commun 2019; 516:50-56. [PMID: 31196624 DOI: 10.1016/j.bbrc.2019.05.190] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/31/2019] [Indexed: 12/30/2022]
Abstract
Compartmentalization is vital for biological systems at multiple levels, including biochemical reactions in metabolism. Organelle-based compartments such as mitochondria and peroxisomes sequester the responsible enzymes and increase the efficiency of metabolism while simultaneously protecting the cell from dangerous intermediates, such as radical oxygen species. Recent studies show intracellular nucleotides, such as ATP and GTP, are heterogeneously distributed in cells with high concentrations at the lamellipodial and filopodial projections, or leading edge. However, the intracellular distribution of purine nucleotide enzymes remains unclear. Here, we report the enhanced localization of GTP-biosynthetic enzymes, including inosine monophosphate dehydrogenase (IMPDH isotype 1 and 2), GMP synthase (GMPS), guanylate kinase (GUK1) and nucleoside diphosphate kinase-A (NDPK-A) at the leading edge in renal cell carcinoma cells. They show significant co-localization at the membrane subdomain, and their co-localization pattern at the membrane is distinct from that of the cell body. While other purine nucleotide biosynthetic enzymes also show significant localization at the leading edge, their co-localization pattern with IMPDH is divergent. In contrast, a key glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), predominantly localized in the cytoplasm. Mechanistically, we found that plasma membrane localization of IMPDH isozymes requires active actin polymerization. Our results demonstrate the formation of a discrete metabolic compartment for localized purine biosynthesis at the leading edge, which may promote localized nucleotide metabolism for cell migration and metastasis in cancers.
Collapse
Affiliation(s)
- Kara Wolfe
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Cancer Biology, University of Cincinnati College of Medicine, OH, 45267, USA
| | - Satoshi Kofuji
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, 734-8553, Japan
| | - Hirofumi Yoshino
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Urology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, 890-8520, Japan
| | - Mika Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Koichi Okumura
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Physiology, University of Arizona, Tucson, AZ, 85724, USA; University of Arizona Cancer Center, Tucson, AZ, 85724, USA
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Cancer Biology, University of Cincinnati College of Medicine, OH, 45267, USA; Department of Neurosurgery, Brain Tumor Center at UC Gardner Neuroscience Institute, Cincinnati, OH, 45267, USA; Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan.
| |
Collapse
|
28
|
Fernández-Justel D, Núñez R, Martín-Benito J, Jimeno D, González-López A, Soriano EM, Revuelta JL, Buey RM. A Nucleotide-Dependent Conformational Switch Controls the Polymerization of Human IMP Dehydrogenases to Modulate their Catalytic Activity. J Mol Biol 2019; 431:956-969. [PMID: 30664871 DOI: 10.1016/j.jmb.2019.01.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 12/29/2022]
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes the rate-limiting step in the de novo GTP biosynthetic pathway and plays essential roles in cell proliferation. As a clinical target, IMPDH has been studied for decades, but it has only been within the last years that we are starting to understand the complexity of the mechanisms of its physiological regulation. Here, we report structural and functional insights into how adenine and guanine nucleotides control a conformational switch that modulates the assembly of the two human IMPDH enzymes into cytoophidia and allosterically regulates their catalytic activity. In vitro reconstituted micron-length cytoophidia-like structures show catalytic activity comparable to unassembled IMPDH but, in turn, are more resistant to GTP/GDP allosteric inhibition. Therefore, IMPDH cytoophidia formation facilitates the accumulation of high levels of guanine nucleotides when the cell requires it. Finally, we demonstrate that most of the IMPDH retinopathy-associated mutations abrogate GTP/GDP-induced allosteric inhibition and alter cytoophidia dynamics.
Collapse
Affiliation(s)
- David Fernández-Justel
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - Rafael Núñez
- Centro de Investigaciones Biológicas (CIB), Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Jaime Martín-Benito
- Centro Nacional de Biotecnología (CNB), Spanish National Research Council (CSIC), Darwin 3, 28039 Madrid, Spain
| | - David Jimeno
- Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca), Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Adrián González-López
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - Eva María Soriano
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - José Luis Revuelta
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007, Salamanca, Spain.
| | - Rubén M Buey
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007, Salamanca, Spain.
| |
Collapse
|
29
|
Calise SJ, Abboud G, Kasahara H, Morel L, Chan EKL. Immune Response-Dependent Assembly of IMP Dehydrogenase Filaments. Front Immunol 2018; 9:2789. [PMID: 30555474 PMCID: PMC6283036 DOI: 10.3389/fimmu.2018.02789] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/12/2018] [Indexed: 12/14/2022] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) catalyzes the conversion of IMP to xanthosine monophosphate, the rate-limiting step in de novo guanosine monophosphate (GMP) synthesis. In cultured cells, IMPDH polymerizes into micron-scale filamentous structures when GMP synthesis is inhibited by depletion of purine precursors or by various drugs, including mycophenolic acid, ribavirin, and methotrexate. IMPDH filaments also spontaneously form in undifferentiated mouse embryonic stem cells and induced pluripotent stem cells, hinting they might function in various highly proliferative cell types. Therefore, we investigated IMPDH filament formation in human and murine T cells, which rely heavily on de novo guanine nucleotide synthesis to rapidly proliferate in response to antigenic challenge. We discovered extensive in vivo IMPDH filament formation in mature T cells, B cells, and other proliferating splenocytes of normal, adult B6 mice. Both cortical and medullary thymocytes in young and old mice also showed considerable assembly of IMPDH filaments. We then stimulated primary human peripheral blood mononuclear cells ex vivo with T cell mitogens phytohemagglutinin (PHA), concanavalin A (ConA), or antibodies to CD3 and CD28 for 72 h. We detected IMPDH filaments in 40–60% of T cells after activation compared to 0–10% of unstimulated T cells. Staining of activated T cells for the proliferation marker Ki-67 also showed an association between IMPDH filament formation and proliferation. Additionally, we transferred ovalbumin-specific CD4+ T cells from B6.OT-II mice into B6.Ly5a recipient mice, challenged these mice with ovalbumin, and harvested spleens 6 days later. In these spleens, we identified abundant IMPDH filaments in transferred T cells by immunofluorescence, indicating that IMPDH also polymerizes during in vivo antigen-specific T cell activation. Overall, our data indicate that IMPDH filament formation is a novel aspect of T cell activation and proliferation, and that filaments might be useful morphological markers for T cell activation. The data also suggest that in vivo IMPDH filament formation could be occurring in a variety of proliferating cell types throughout the body. We propose that T cell activation will be a valuable model for future experiments probing the molecular mechanisms that drive IMPDH polymerization, as well as how IMPDH filament formation affects cell function.
Collapse
Affiliation(s)
- S John Calise
- Department of Oral Biology, University of Florida, Gainesville, FL, United States
| | - Georges Abboud
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL, United States
| | - Hideko Kasahara
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, United States
| | - Laurence Morel
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL, United States
| | - Edward K L Chan
- Department of Oral Biology, University of Florida, Gainesville, FL, United States
| |
Collapse
|
30
|
Chang CC, Keppeke GD, Sung LY, Liu JL. Interfilament interaction between IMPDH and CTPS cytoophidia. FEBS J 2018; 285:3753-3768. [PMID: 30085408 PMCID: PMC6220823 DOI: 10.1111/febs.14624] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 07/03/2018] [Accepted: 08/03/2018] [Indexed: 11/30/2022]
Abstract
Inosine monophosphate dehydrogenase (IMPDH) and cytidine triphosphate synthase (CTPS) are two metabolic enzymes that perform rate‐limiting steps in the de novo synthesis of purine and pyrimidine nucleotides, respectively. It has been shown that IMPDH and CTPS can comprise a filamentous macrostructure termed the cytoophidium, which may play a role in regulation of their catalytic activity. Although these two proteins may colocalise in the same cytoophidium, how they associate with one another is still elusive. As reported herein, we established a model HeLa cell line coexpressing OFP‐tagged IMPDH2 and GFP‐tagged CTPS1 and recorded the assembly, disassembly and movement of the cytoophidium in live cells. Moreover, by using super‐resolution confocal imaging, we demonstrate how IMPDH‐ and CTPS‐based filaments are aligned or intertwined in the mixed cytoophidium. Collectively, our findings provide a panorama of cytoophidium dynamics and suggest that IMPDH and CTPS cytoophidia may coordinate by interfilament interaction.
Collapse
Affiliation(s)
- Chia-Chun Chang
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK.,Institute of Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Gerson D Keppeke
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - Li-Ying Sung
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.,Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Ji-Long Liu
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK.,School of Life Science and Technology, ShanghaiTech University, China
| |
Collapse
|
31
|
Schiavon CR, Griffin ME, Pirozzi M, Parashuraman R, Zhou W, Jinnah HA, Reines D, Kahn RA. Compositional complexity of rods and rings. Mol Biol Cell 2018; 29:2303-2316. [PMID: 30024290 PMCID: PMC6249804 DOI: 10.1091/mbc.e18-05-0274] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Rods and rings (RRs) are large linear- or circular-shaped structures typically described as polymers of IMPDH (inosine monophosphate dehydrogenase). They have been observed across a wide variety of cell types and species and can be induced to form by inhibitors of IMPDH. RRs are thought to play a role in the regulation of de novo guanine nucleotide synthesis; however, the function and regulation of RRs is poorly understood. Here we show that the regulatory GTPase, ARL2, a subset of its binding partners, and several resident proteins at the endoplasmic reticulum (ER) also localize to RRs. We also have identified two new inducers of RR formation: AICAR and glucose deprivation. We demonstrate that RRs can be disassembled if guanine nucleotides can be generated by salvage synthesis regardless of the inducer. Finally, we show that there is an ordered addition of components as RRs mature, with IMPDH first forming aggregates, followed by ARL2, and only later calnexin, a marker of the ER. These findings suggest that RRs are considerably more complex than previously thought and that the function(s) of RRs may include involvement of a regulatory GTPase, its effectors, and potentially contacts with intracellular membranes.
Collapse
Affiliation(s)
- Cara R Schiavon
- Cancer Biology Graduate Program, Graduate Division of Biomedical and Biological Sciences, Laney Graduate School, Atlanta, GA 30307
| | - Maxwell E Griffin
- Cancer Biology Graduate Program, Graduate Division of Biomedical and Biological Sciences, Laney Graduate School, Atlanta, GA 30307
| | - Marinella Pirozzi
- EuroBioImaging Facility, Institute of Protein Biochemistry, 80131 Naples, Italy
| | - Raman Parashuraman
- EuroBioImaging Facility, Institute of Protein Biochemistry, 80131 Naples, Italy
| | - Wei Zhou
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322
| | - H A Jinnah
- Department of Neurology and Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Daniel Reines
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Richard A Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| |
Collapse
|
32
|
Keppeke GD, Chang CC, Peng M, Chen LY, Lin WC, Pai LM, Andrade LEC, Sung LY, Liu JL. IMP/GTP balance modulates cytoophidium assembly and IMPDH activity. Cell Div 2018; 13:5. [PMID: 29946345 PMCID: PMC6004095 DOI: 10.1186/s13008-018-0038-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/06/2018] [Indexed: 02/07/2023] Open
Abstract
Background Inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme in de novo GTP biosynthesis, plays an important role in cell metabolism and proliferation. It has been demonstrated that IMPDH can aggregate into a macrostructure, termed the cytoophidium, in mammalian cells under a variety of conditions. However, the regulation and function of the cytoophidium are still elusive. Results In this study, we report that spontaneous filamentation of IMPDH is correlated with rapid cell proliferation. Intracellular IMP accumulation promoted cytoophidium assembly, whereas elevated GTP level triggered disassociation of aggregates. By using IMPDH2 CBS domain mutant cell models, which are unable to form the cytoophidium, we have determined that the cytoophidium is of the utmost importance for maintaining the GTP pool and normal cell proliferation in the condition that higher IMPDH activity is required. Conclusions Together, our results suggest a novel mechanism whereby cytoophidium assembly upregulates IMPDH activity and mediates guanine nucleotide homeostasis. Electronic supplementary material The online version of this article (10.1186/s13008-018-0038-0) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Gerson Dierley Keppeke
- 1Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT UK
| | - Chia Chun Chang
- 1Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT UK.,2Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan, ROC
| | - Min Peng
- 2Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan, ROC
| | - Li-Yu Chen
- 1Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT UK
| | - Wei-Cheng Lin
- 3Molecular Medicine Research Center, College of Medicine, Chang Gung University, Tao-Yuan, 333 Taiwan, ROC
| | - Li-Mei Pai
- 3Molecular Medicine Research Center, College of Medicine, Chang Gung University, Tao-Yuan, 333 Taiwan, ROC.,4Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Tao-Yuan, 333 Taiwan, ROC.,5Department of Biochemistry, College of Medicine, Chang Gung University, Tao-Yuan, 333 Taiwan, ROC
| | - Luis Eduardo Coelho Andrade
- 6Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Sao Paulo, SP 04023-062 Brazil
| | - Li-Ying Sung
- 2Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan, ROC.,7Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115 Taiwan, ROC
| | - Ji-Long Liu
- 1Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT UK.,8School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China
| |
Collapse
|
33
|
Narvaez-Ortiz HY, Lopez AJ, Gupta N, Zimmermann BH. A CTP Synthase Undergoing Stage-Specific Spatial Expression Is Essential for the Survival of the Intracellular Parasite Toxoplasma gondii. Front Cell Infect Microbiol 2018; 8:83. [PMID: 29623259 PMCID: PMC5874296 DOI: 10.3389/fcimb.2018.00083] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/28/2018] [Indexed: 01/17/2023] Open
Abstract
Cytidine triphosphate synthase catalyzes the synthesis of cytidine 5′-triphosphate (CTP) from uridine 5′-triphosphate (UTP), the final step in the production of cytidine nucleotides. CTP synthases also form filamentous structures of different morphologies known as cytoophidia, whose functions in most organisms are unknown. Here, we identified and characterized a novel CTP synthase (TgCTPS) from Toxoplasma gondii. We show that TgCTPS is capable of substituting for its counterparts in the otherwise lethal double mutant (ura7Δ ura8Δ) of Saccharomyces cerevisiae. Equally, recombinant TgCTPS purified from Escherichia coli encodes for a functional protein in enzyme assays. The epitope-tagged TgCTPS under the control of its endogenous promoter displays a punctate cytosolic distribution, which undergoes spatial reorganization to form foci or filament-like structures when the parasite switches from a nutrient-replete (intracellular) to a nutrient-scarce (extracellular) condition. An analogous phenotype is observed upon nutrient stress or after treatment with a glutamine analog, 6-diazo-5-oxo-L-norleucine (DON). The exposure of parasites to DON disrupts the lytic cycle, and the TgCTPS is refractory to a genetic deletion, suggesting an essential requirement of this enzyme for T. gondii. Not least, this study, together with previous studies, supports that CTP synthase can serve as a potent drug target, because the parasite, unlike human host cells, cannot compensate for the lack of CTP synthase activity.
Collapse
Affiliation(s)
| | - Andrea J Lopez
- Departamento de Ciencias Biologicas, Universidad de los Andes, Bogota, Colombia
| | - Nishith Gupta
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany
| | | |
Collapse
|
34
|
Pua KH, Stiles DT, Sowa ME, Verdine GL. IMPDH2 Is an Intracellular Target of the Cyclophilin A and Sanglifehrin A Complex. Cell Rep 2017; 18:432-442. [PMID: 28076787 DOI: 10.1016/j.celrep.2016.12.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/21/2016] [Accepted: 12/10/2016] [Indexed: 11/16/2022] Open
Abstract
Natural products have demonstrated utility in the clinic and can also act as probes to understand complex cellular pathways. Sanglifehrin A (SFA) is a mixed polyketide and non-ribosomal peptide synthase natural product with sub-nano-molar affinity for its receptor cyclophilin A (PPIA). It has been shown to behave in vitro as an immune suppressant. Here, we identify inosine-5'-monophosphate dehydrogenase 2 (IMPDH2) as an intracellular target of the PPIA-SFA binary complex. The formation of this ternary complex does not inhibit the enzymatic activity of IMPDH2. Rather, ternary complex formation modulates cell growth through interaction with the cystathionine-β-synthase (CBS) domain of IMPDH2. We further demonstrate that the SFA complex is highly isoform selective for IMPDH2 (versus IMPDH1). This work reveals a role for the CBS domains of IMPDH2 in cellular proliferation, suggesting a more complex role than previously suspected for IMPDH2 in T cell activation and proliferation.
Collapse
Affiliation(s)
- Khian Hong Pua
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Warp Drive Bio, Cambridge, MA 02139, USA
| | - Dylan T Stiles
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Warp Drive Bio, Cambridge, MA 02139, USA
| | - Mathew E Sowa
- Warp Drive Bio, Cambridge, MA 02139, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Gregory L Verdine
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Warp Drive Bio, Cambridge, MA 02139, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
| |
Collapse
|
35
|
Anthony SA, Burrell AL, Johnson MC, Duong-Ly KC, Kuo YM, Simonet JC, Michener P, Andrews A, Kollman JM, Peterson JR. Reconstituted IMPDH polymers accommodate both catalytically active and inactive conformations. Mol Biol Cell 2017; 28:mbc.E17-04-0263. [PMID: 28794265 PMCID: PMC5620369 DOI: 10.1091/mbc.e17-04-0263] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/02/2017] [Accepted: 08/04/2017] [Indexed: 01/01/2023] Open
Abstract
Several metabolic enzymes undergo reversible polymerization into macromolecular assemblies. The function of these assemblies is often unclear but in some cases they regulate enzyme activity and metabolic homeostasis. The guanine nucleotide biosynthetic enzyme inosine monophosphate dehydrogenase (IMPDH) forms octamers that polymerize into helical chains. In mammalian cells, IMPDH filaments can associate into micron-length assemblies. Polymerization and enzyme activity are regulated in part by binding of purine nucleotides to an allosteric regulatory domain. ATP promotes octamer polymerization, whereas GTP promotes a compact, inactive conformation whose ability to polymerize is unknown. Also unclear is whether polymerization directly alters IMPDH catalytic activity. To address this, we identified point mutants of human IMPDH2 that either prevent or promote polymerization. Unexpectedly, we found that polymerized and non-assembled forms of recombinant IMPDH have comparable catalytic activity, substrate affinity, and GTP sensitivity and validated this finding in cells. Electron microscopy revealed that substrates and allosteric nucleotides shift the equilibrium between active and inactive conformations in both the octamer and the filament. Unlike other metabolic filaments, which selectively stabilize active or inactive conformations, recombinant IMPDH filaments accommodate multiple states. These conformational states are finely tuned by substrate availability and purine balance, while polymerization may allow cooperative transitions between states.
Collapse
Affiliation(s)
- Sajitha A Anthony
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
| | - Anika L Burrell
- Department of Biochemistry, University of Washington, 1959 NE Pacific Street, Box 357350, Seattle, WA 98195
| | - Matthew C Johnson
- Department of Biochemistry, University of Washington, 1959 NE Pacific Street, Box 357350, Seattle, WA 98195
| | - Krisna C Duong-Ly
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
| | - Yin-Ming Kuo
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
| | - Jacqueline C Simonet
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
| | - Peter Michener
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA 19102
| | - Andrew Andrews
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, 1959 NE Pacific Street, Box 357350, Seattle, WA 98195
| | - Jeffrey R Peterson
- Cancer Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111
| |
Collapse
|
36
|
Highly selective inhibition of IMPDH2 provides the basis of antineuroinflammation therapy. Proc Natl Acad Sci U S A 2017; 114:E5986-E5994. [PMID: 28674004 DOI: 10.1073/pnas.1706778114] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) of human is an attractive target for immunosuppressive agents. Currently, small-molecule inhibitors do not show good selectivity for different IMPDH isoforms (IMPDH1 and IMPDH2), resulting in some adverse effects, which limit their use. Herein, we used a small-molecule probe specifically targeting IMPDH2 and identified Cysteine residue 140 (Cys140) as a selective druggable site. On covalently binding to Cys140, the probe exerts an allosteric regulation to block the catalytic pocket of IMPDH2 and further induces IMPDH2 inactivation, leading to an effective suppression of neuroinflammatory responses. However, the probe does not covalently bind to IMPDH1. Taken together, our study shows Cys140 as a druggable site for selectively inhibiting IMPDH2, which provides great potential for development of therapy agents for autoimmune and neuroinflammatory diseases with less unfavorable tolerability profile.
Collapse
|
37
|
A nucleotide-controlled conformational switch modulates the activity of eukaryotic IMP dehydrogenases. Sci Rep 2017; 7:2648. [PMID: 28572600 PMCID: PMC5454003 DOI: 10.1038/s41598-017-02805-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/19/2017] [Indexed: 12/31/2022] Open
Abstract
Inosine-5′-monophosphate dehydrogenase (IMPDH) is an essential enzyme for nucleotide metabolism and cell proliferation. Despite IMPDH is the target of drugs with antiviral, immunosuppressive and antitumor activities, its physiological mechanisms of regulation remain largely unknown. Using the enzyme from the industrial fungus Ashbya gossypii, we demonstrate that the binding of adenine and guanine nucleotides to the canonical nucleotide binding sites of the regulatory Bateman domain induces different enzyme conformations with significantly distinct catalytic activities. Thereby, the comparison of their high-resolution structures defines the mechanistic and structural details of a nucleotide-controlled conformational switch that allosterically modulates the catalytic activity of eukaryotic IMPDHs. Remarkably, retinopathy-associated mutations lie within the mechanical hinges of the conformational change, highlighting its physiological relevance. Our results expand the mechanistic repertoire of Bateman domains and pave the road to new approaches targeting IMPDHs.
Collapse
|
38
|
Hu J, Ma L, Wang H, Yan H, Zhang D, Li Z, Jiang J, Li Y. A novel benzo-heterocyclic amine derivative N30 inhibits influenza virus replication by depression of Inosine-5'-Monophospate Dehydrogenase activity. Virol J 2017; 14:55. [PMID: 28298229 PMCID: PMC5353780 DOI: 10.1186/s12985-017-0724-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 03/07/2017] [Indexed: 01/02/2023] Open
Abstract
BACKGROUD Influenza virus is still a huge threat to the world-wide public health. Host inosine-5'- monophosphate dehydrogenase (IMPDH) involved in the synthesis of guanine nucleotides, is known to be a potential target to inhibit the replication of viruses. Herein, we evaluated antiviral activity of a benzo-heterocyclic amine derivative N30, which was designed to inhibit IMPDH. RESULTS The results demonstrated that N30 inhibited the replication of H1N1, H3N2, influenza B viruses, including oseltamivir and amantadine resistant strains in vitro. Mechanistically, neuraminidase inhibition assay and hemagglutination inhibition assay suggested that N30 did not directly target the two envelope glycoproteins required for viral adsorption or release. Instead, the compound could depress the activity of IMPDH type II. Based on these findings, we further confirmed that N30 provided a strong inhibition on the replication of respiratory syncytial virus, coronavirus, enterovirus 71 and a diverse strains of coxsackie B virus. CONCLUSIONS We identified the small molecule N30, as an inhibitor of IMPDH, might be a potential candidate to inhibit the replication of various viruses.
Collapse
Affiliation(s)
- Jin Hu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Linlin Ma
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Huiqiang Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Haiyan Yan
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Dajun Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zhuorong Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiandong Jiang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuhuan Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
| |
Collapse
|
39
|
Chitrakar I, Kim-Holzapfel DM, Zhou W, French JB. Higher order structures in purine and pyrimidine metabolism. J Struct Biol 2017; 197:354-364. [PMID: 28115257 DOI: 10.1016/j.jsb.2017.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/14/2017] [Accepted: 01/18/2017] [Indexed: 10/20/2022]
Abstract
The recent discovery of several forms of higher order protein structures in cells has shifted the paradigm of how we think about protein organization and metabolic regulation. These dynamic and controllable protein assemblies, which are composed of dozens or hundreds of copies of an enzyme or related enzymes, have emerged as important players in myriad cellular processes. We are only beginning to appreciate the breadth of function of these types of macromolecular assemblies. These higher order structures, which can be assembled in response to varied cellular stimuli including changing metabolite concentrations or signaling cascades, give the cell the capacity to modulate levels of biomolecules both temporally and spatially. This provides an added level of control with distinct kinetics and unique features that can be harnessed as a subtle, yet powerful regulatory mechanism. Due, in large part, to advances in structural methods, such as crystallography and cryo-electron microscopy, and the advent of super-resolution microscopy techniques, a rapidly increasing number of these higher order structures are being identified and characterized. In this review, we detail what is known about the structure, function and control mechanisms of these mesoscale protein assemblies, with a particular focus on those involved in purine and pyrimidine metabolism. These structures have important implications both for our understanding of fundamental cellular processes and as fertile ground for new targets for drug discovery and development.
Collapse
Affiliation(s)
- Iva Chitrakar
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States
| | - Deborah M Kim-Holzapfel
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States
| | - Weijie Zhou
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, United States
| | - Jarrod B French
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States; Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, United States.
| |
Collapse
|
40
|
Anti-rods/rings autoantibody seropositivity does not affect response to telaprevir treatment for chronic hepatitis C infection. AUTOIMMUNITY HIGHLIGHTS 2016; 7:15. [PMID: 27844412 PMCID: PMC5108729 DOI: 10.1007/s13317-016-0087-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/19/2016] [Indexed: 12/20/2022]
Abstract
PURPOSE Autoantibodies to intracellular 'rods and rings' structures (anti-rods/rings or anti-RR) are strongly associated with hepatitis C (HCV) patients treated with interferon-α/ribavirin (IFN/RBV) and are linked with non-responsiveness to IFN/RBV or relapse, especially in Italian patients. This is the first study to determine whether there is any correlation of anti-RR with non-responsiveness to IFN/RBV treatment in patients also treated with telaprevir (TPV), one of several new therapies for chronic HCV recently implemented. METHODS From 2013 to 2014, 52 HCV-infected patients were treated with IFN/RBV and TPV at five Italian clinics. Patient sera were collected and analyzed by indirect immunofluorescence for the presence of anti-RR antibodies. Patients were classified as anti-RR positive or anti-RR negative, and then various biological and clinical variables were analyzed to compare the two groups, including gender, age, HCV genotype, previous IFN/RBV treatment, and IFN/RBV/TPV treatment outcome. RESULTS Of these 52 HCV patients treated with IFN/RBV/TPV, 10/32 (31%) who previously received IFN/RBV were anti-RR positive, compared to 0 of 20 treatment-naïve patients. Anti-RR-positive patients relapsed more than anti-RR-negative patients (3/10, 30% vs. 2/42, 5%; p < 0.05). However, zero anti-RR-positive patients were non-responsive, and frequencies of sustained virological response were similar (anti-RR positive: 7/10, 70% vs. anti-RR negative: 33/42, 79%). CONCLUSIONS Overall, the data suggest that anti-RR seropositivity is not associated with resistance to TPV treatment in this patient cohort, but monitoring anti-RR-positive patients for relapse within the first 6 months after treatment may be useful.
Collapse
|
41
|
Noble JW, Hunter DV, Roskelley CD, Chan EKL, Mills J. Loukoumasomes Are Distinct Subcellular Structures from Rods and Rings and Are Structurally Associated with MAP2 and the Nuclear Envelope in Retinal Cells. PLoS One 2016; 11:e0165162. [PMID: 27798680 PMCID: PMC5087950 DOI: 10.1371/journal.pone.0165162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 10/07/2016] [Indexed: 12/19/2022] Open
Abstract
“Rods and rings” (RR) and loukoumasomes are similarly shaped, subcellular macromolecular structures with as yet unknown function. RR, so named because of their shape, are formed in response to inhibition in the GTP or CTP synthetic pathways and are highly enriched in the two key enzymes of the nucleotide synthetic pathway. Loukoumasomes also occur as linear and toroidal bodies and were initially inferred to be the same as RR, largely due to their shared shape and size and the fact that it was unclear if they shared the same subcomponents. In human retinoblastoma tissue and cells we have observed toroidal, perinuclear, macromolecular structures of similar size and antigenicity to those previously reported in neurons (neuronal-loukoumasomes). To further characterize the subcomponents of the retinal-loukoumasomes, confocal analysis following immunocytochemical staining for alpha-tubulin, beta-III tubulin and detyrosinated tubulin was performed. These studies indicate that retinal-loukoumasomes are enriched for beta-III tubulin and other tubulins associated with microtubules. Immunofluorescence together with the in situ proximity ligation assay (PLA), confirmed that beta-III tubulin colocalized with detyrosinated tubulin within loukoumasomes. Our results indicate that these tissues contain only loukoumasomes because these macromolecular structures are immunoreactive with an anti-tubulin antibody but are not recognized by the prototype anti-RR/inosine monophosphate dehydrogenase (IMPDH) antibody (It2006). To further compare the RR and retinal-loukoumasomes, retinoblastoma cells were exposed to the IMPDH-inhibitor ribavirin, a drug known to induce the formation of RR. In contrast to RR, the production of retinal-loukoumasomes was unaffected. Coimmunostaining of Y79 cells for beta-III tubulin and IMPDH indicate that these cells, when treated with ribavirin, can contain both retinal-loukoumasomes and RR and that these structures are antigenically distinct. Subcellular fractionation studies indicate that ribavirin increased the RR subcomponent, IMPDH, in the nuclear fraction of Y79 cells from 21.3 ± 5.8% (0 mM ribavirin) to 122.8 ± 7.9% (1 mM ribavirin) while the subcellular localization of the retinal-loukoumasome subcomponent tubulin went unaltered. Further characterization of retinal-loukoumasomes in retinoblastoma cells reveals that they are intimately associated with lamin folds within the nuclear envelope. Using immunofluorescence and the in situ PLA in this cell type, we have observed colocalization of beta-III tubulin with MAP2. As MAP2 is a microtubule-associated protein implicated in microtubule crosslinking, this supports a role for microtubule crosslinkers in the formation of retinal-loukoumasomes. Together, these results suggest that loukoumasomes and RR are distinct subcellular macromolecular structures, formed by different cellular processes and that there are other loukoumasome-like structures within retinal tissues and cells.
Collapse
Affiliation(s)
- Jake W. Noble
- Department of Biology, Trinity Western University, Langley, British Columbia, Canada
| | - Diana V. Hunter
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Calvin D. Roskelley
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Edward K. L. Chan
- Department of Oral Biology, University of Florida, Gainesville, Florida, United States of America
| | - Julia Mills
- Department of Biology, Trinity Western University, Langley, British Columbia, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail:
| |
Collapse
|
42
|
Keppeke GD, Prado MS, Nunes E, Perazzio SF, Rodrigues SH, Ferraz MLG, Chan EKL, Andrade LEC. Differential capacity of therapeutic drugs to induce Rods/Rings structures in vitro and in vivo and generation of anti-Rods/Rings autoantibodies. Clin Immunol 2016; 173:149-156. [PMID: 27746381 DOI: 10.1016/j.clim.2016.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/26/2016] [Accepted: 10/09/2016] [Indexed: 12/27/2022]
Abstract
Some HCV patients using ribavirin and interferon alpha (IFN-α) develop anti-rods and rings (RR) autoantibodies, the main target of which is inosine monophosphate dehydrogenase (IMPDH), the rate-determining enzyme in de novo GTP biosynthesis. In vitro inhibition of IMPDH by ribavirin induces RR formation. Here we investigate whether other commonly used drugs that interfere with GTP biosynthesis can induce RR structures in vitro and vivo and elicit generation of autoantibodies. HEp-2 cells treated for 24h with ribavirin, mycophenolic acid (MPA), azathioprine, methotrexate or acyclovir were positive for RR structures. However, adefovir, entecavir, tenofovir and lamivudine did not induce RR structures in these cells. Structures induced by ribavirin in HEp-2 cells are stable after 24h drug-washout, while structures induced by other drugs are relatively labile, disappearing within 2h. Looking at patients treated with these drugs, HCV patients treated with ribavirin (n=17) showed higher average percentage of RR-positive peripheral mononuclear cells than autoimmune patients treated with RR-inducing immunosuppressant drugs (n=21). Serum from 173 autoimmune patients who had been treated with MPA, azathioprine or methotrexate was tested for presence of anti-RR autoantibodies, and only one sample was found to be positive. Conversely, of 48 anti-RR autoantibody positive samples identified at Fleury Laboratories over 30months, 94% were from HCV patients treated with ribavirin plus IFN-α. These data indicate that RR structures can be induced by a variety of drugs in vitro and in vivo, but anti-RR autoantibody production is mostly restricted to HCV patients under ribavirin+IFN-α treatment.
Collapse
Affiliation(s)
- Gerson Dierley Keppeke
- Rheumatology Division, Federal University of Sao Paulo, Sao Paulo, SP 04023-062, Brazil.
| | - Monica Simon Prado
- Rheumatology Division, Federal University of Sao Paulo, Sao Paulo, SP 04023-062, Brazil
| | - Eunice Nunes
- Gastroenterology Division, Federal University of Sao Paulo, Sao Paulo, SP 04023-062, Brazil
| | - Sandro Felix Perazzio
- Rheumatology Division, Federal University of Sao Paulo, Sao Paulo, SP 04023-062, Brazil; Immunology Division, Fleury Medicine and Health Laboratories, Sao Paulo SP 04102-050, Brazil
| | | | | | - Edward K L Chan
- Department of Oral Biology, University of Florida, Gainesville, FL 32610-0424, USA
| | - Luis Eduardo Coelho Andrade
- Rheumatology Division, Federal University of Sao Paulo, Sao Paulo, SP 04023-062, Brazil; Immunology Division, Fleury Medicine and Health Laboratories, Sao Paulo SP 04102-050, Brazil.
| |
Collapse
|
43
|
Liu JL. The Cytoophidium and Its Kind: Filamentation and Compartmentation of Metabolic Enzymes. Annu Rev Cell Dev Biol 2016; 32:349-372. [DOI: 10.1146/annurev-cellbio-111315-124907] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ji-Long Liu
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom;
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China;
| |
Collapse
|
44
|
Calise SJ, Purich DL, Nguyen T, Saleem DA, Krueger C, Yin JD, Chan EKL. 'Rod and ring' formation from IMP dehydrogenase is regulated through the one-carbon metabolic pathway. J Cell Sci 2016; 129:3042-52. [PMID: 27343244 DOI: 10.1242/jcs.183400] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 06/21/2016] [Indexed: 12/29/2022] Open
Abstract
'Rods and rings' (RRs) are conserved, non-membrane-bound intracellular polymeric structures composed, in part, of inosine monophosphate dehydrogenase (IMPDH), a key enzyme leading to GMP and GTP biosynthesis. RR formation is induced by IMPDH inhibitors as well as glutamine deprivation. They also form upon treatment of cells with glutamine synthetase inhibitors. We now report that depriving cells of serine and glycine promotes RR formation, and we have traced these effects to dihydrofolate reductase (DHFR) and serine hydroxymethyltransferase-2 (SHMT2), pivotal enzymes in one-carbon metabolism and nucleotide biosynthesis. RR assembly is likewise induced upon DHFR inhibition by methotrexate or aminopterin as well as siRNA-mediated knockdown of DHFR or SHMT2. Because RR assembly occurs when guanine nucleotide biosynthesis is inhibited, and because RRs rapidly disassemble after the addition of guanine nucleotide precursors, RR formation might be an adaptive homeostatic mechanism, allowing IMPDH to sense changes in the one-carbon folate pathway.
Collapse
Affiliation(s)
- S John Calise
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Daniel L Purich
- Department of Biochemistry and Molecular Biology, University of Florida, 1200 Newell Drive, Gainesville, FL 32610-0245, USA
| | - Thuy Nguyen
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Dania A Saleem
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Claire Krueger
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Joyce D Yin
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Edward K L Chan
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| |
Collapse
|
45
|
Smith S, Boitz J, Chidambaram ES, Chatterjee A, Ait-Tihyaty M, Ullman B, Jardim A. The cystathionine-β-synthase domains on the guanosine 5''-monophosphate reductase and inosine 5'-monophosphate dehydrogenase enzymes from Leishmania regulate enzymatic activity in response to guanylate and adenylate nucleotide levels. Mol Microbiol 2016; 100:824-40. [PMID: 26853689 DOI: 10.1111/mmi.13352] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2016] [Indexed: 01/24/2023]
Abstract
The Leishmania guanosine 5'-monophosphate reductase (GMPR) and inosine 5'-monophosphate dehydrogenase (IMPDH) are purine metabolic enzymes that function maintaining the cellular adenylate and guanylate nucleotide. Interestingly, both enzymes contain a cystathionine-β-synthase domain (CBS). To investigate this metabolic regulation, the Leishmania GMPR was cloned and shown to be sufficient to complement the guaC (GMPR), but not the guaB (IMPDH), mutation in Escherichia coli. Kinetic studies confirmed that the Leishmania GMPR catalyzed a strict NADPH-dependent reductive deamination of GMP to produce IMP. Addition of GTP or high levels of GMP induced a marked increase in activity without altering the Km values for the substrates. In contrast, the binding of ATP decreased the GMPR activity and increased the GMP Km value 10-fold. These kinetic changes were correlated with changes in the GMPR quaternary structure, induced by the binding of GMP, GTP, or ATP to the GMPR CBS domain. The capacity of these CBS domains to mediate the catalytic activity of the IMPDH and GMPR provides a regulatory mechanism for balancing the intracellular adenylate and guanylate pools.
Collapse
Affiliation(s)
- Sabrina Smith
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Jan Boitz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Ehzilan Subramanian Chidambaram
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Abhishek Chatterjee
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Maria Ait-Tihyaty
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Buddy Ullman
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Armando Jardim
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| |
Collapse
|
46
|
Bessho T, Okada T, Kimura C, Shinohara T, Tomiyama A, Imamura A, Kuwamura M, Nishimura K, Fujimori K, Shuto S, Ishibashi O, Kubata BK, Inui T. Novel Characteristics of Trypanosoma brucei Guanosine 5'-monophosphate Reductase Distinct from Host Animals. PLoS Negl Trop Dis 2016; 10:e0004339. [PMID: 26731263 PMCID: PMC4701174 DOI: 10.1371/journal.pntd.0004339] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 12/08/2015] [Indexed: 12/02/2022] Open
Abstract
The metabolic pathway of purine nucleotides in parasitic protozoa is a potent drug target for treatment of parasitemia. Guanosine 5’-monophosphate reductase (GMPR), which catalyzes the deamination of guanosine 5’-monophosphate (GMP) to inosine 5’-monophosphate (IMP), plays an important role in the interconversion of purine nucleotides to maintain the intracellular balance of their concentration. However, only a few studies on protozoan GMPR have been reported at present. Herein, we identified the GMPR in Trypanosoma brucei, a causative protozoan parasite of African trypanosomiasis, and found that the GMPR proteins were consistently localized to glycosomes in T. brucei bloodstream forms. We characterized its recombinant protein to investigate the enzymatic differences between GMPRs of T. brucei and its host animals. T. brucei GMPR was distinct in having an insertion of a tandem repeat of the cystathionine β-synthase (CBS) domain, which was absent in mammalian and bacterial GMPRs. The recombinant protein of T. brucei GMPR catalyzed the conversion of GMP to IMP in the presence of NADPH, and showed apparent affinities for both GMP and NADPH different from those of its mammalian counterparts. Interestingly, the addition of monovalent cations such as K+ and NH4+ to the enzymatic reaction increased the GMPR activity of T. brucei, whereas none of the mammalian GMPR’s was affected by these cations. The monophosphate form of the purine nucleoside analog ribavirin inhibited T. brucei GMPR activity, though mammalian GMPRs showed no or only a little inhibition by it. These results suggest that the mechanism of the GMPR reaction in T. brucei is distinct from that in the host organisms. Finally, we demonstrated the inhibitory effect of ribavirin on the proliferation of trypanosomes in a dose-dependent manner, suggesting the availability of ribavirin to develop a new therapeutic agent against African trypanosomiasis. Only a limited number of therapeutics for human African trypanosomiasis also known as African sleeping sickness is available today, and it narrows the choice of the drugs to escape from the side effects and the emergence of drug-resistant pathogens. The parasitic protozoa Trypanosoma brucei is the causative reagent of African trypanosomiasis, and is infective to various mammalian species. T. brucei and its mammalian hosts share almost the same metabolic machinery, and therefore it is important to understand the differences in biochemical properties of the metabolic enzymes between T. brucei and its hosts. Here we report that guanosine 5’-monophosphate reductase (GMPR) of T. brucei showed apparent differences in its primary structure and biochemical properties from those of its host counterparts, and was more sensitive to purine nucleotide analogs such as monophosphate forms of ribavirin and mizoribine than were the host GMPRs. Furthermore, ribavirin prevented the proliferation of trypanosomes in vitro. Our present findings may imply the availability of ribavirin and/or its derivatives in a treatment of African trypanosomiasis.
Collapse
Affiliation(s)
- Tomoaki Bessho
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Tetsuya Okada
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Chihiro Kimura
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Takahiro Shinohara
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Ai Tomiyama
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Akira Imamura
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
| | - Mitsuru Kuwamura
- Laboratory of Veterinary Pathology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka, Japan
| | - Kazuhiko Nishimura
- Laboratory of Toxicology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka, Japan
| | - Ko Fujimori
- Laboratory of Biodefense and Regulation, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, Japan
| | - Satoshi Shuto
- Laboratory of Organic Chemistry for Drug Development, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Osamu Ishibashi
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
| | | | - Takashi Inui
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan
- * E-mail:
| |
Collapse
|
47
|
Guanine nucleotide binding to the Bateman domain mediates the allosteric inhibition of eukaryotic IMP dehydrogenases. Nat Commun 2015; 6:8923. [PMID: 26558346 PMCID: PMC4660370 DOI: 10.1038/ncomms9923] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 10/16/2015] [Indexed: 12/26/2022] Open
Abstract
Inosine-5′-monophosphate dehydrogenase (IMPDH) plays key roles in purine nucleotide metabolism and cell proliferation. Although IMPDH is a widely studied therapeutic target, there is limited information about its physiological regulation. Using Ashbya gossypii as a model, we describe the molecular mechanism and the structural basis for the allosteric regulation of IMPDH by guanine nucleotides. We report that GTP and GDP bind to the regulatory Bateman domain, inducing octamers with compromised catalytic activity. Our data suggest that eukaryotic and prokaryotic IMPDHs might have developed different regulatory mechanisms, with GTP/GDP inhibiting only eukaryotic IMPDHs. Interestingly, mutations associated with human retinopathies map into the guanine nucleotide-binding sites including a previously undescribed non-canonical site and disrupt allosteric inhibition. Together, our results shed light on the mechanisms of the allosteric regulation of enzymes mediated by Bateman domains and provide a molecular basis for certain retinopathies, opening the door to new therapeutic approaches. IMP dehydrogenase (IMPDH) plays essential roles in purine metabolism and cell proliferation. Here Buey et al. describe a guanine nucleotides regulated molecular mechanism for allosteric communication between the regulatory and catalytic domains of IMPDH.
Collapse
|
48
|
Chen K, Cao W, Li J, Sprengers D, Hernanda PY, Kong X, van der Laan LJW, Man K, Kwekkeboom J, Metselaar HJ, Peppelenbosch MP, Pan Q. Differential Sensitivities of Fast- and Slow-Cycling Cancer Cells to Inosine Monophosphate Dehydrogenase 2 Inhibition by Mycophenolic Acid. Mol Med 2015; 21:792-802. [PMID: 26467706 DOI: 10.2119/molmed.2015.00126] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 10/12/2015] [Indexed: 01/03/2023] Open
Abstract
As uncontrolled cell proliferation requires nucleotide biosynthesis, inhibiting enzymes that mediate nucleotide biosynthesis constitutes a rational approach to the management of oncological diseases. In practice, however, results of this strategy are mixed and thus elucidation of the mechanisms by which cancer cells evade the effect of nucleotide biosynthesis restriction is urgently needed. Here we explored the notion that intrinsic differences in cancer cell cycle velocity are important in the resistance toward inhibition of inosine monophosphate dehydrogenase (IMPDH) by mycophenolic acid (MPA). In short-term experiments, MPA treatment of fast-growing cancer cells effectively elicited G0/G1 arrest and provoked apoptosis, thus inhibiting cell proliferation and colony formation. Forced expression of a mutated IMPDH2, lacking a binding site for MPA but retaining enzymatic activity, resulted in complete resistance of cancer cells to MPA. In nude mice subcutaneously engrafted with HeLa cells, MPA moderately delayed tumor formation by inhibiting cell proliferation and inducing apoptosis. Importantly, we developed a lentiviral vector-based Tet-on label-retaining system that enables to identify, isolate and functionally characterize slow-cycling or so-called label-retaining cells (LRCs) in vitro and in vivo. We surprisingly found the presence of LRCs in fast-growing tumors. LRCs were superior in colony formation, tumor initiation and resistance to MPA as compared with fast-cycling cells. Thus, the slow-cycling compartment of cancer seems predominantly responsible for resistance to MPA.
Collapse
Affiliation(s)
- Kan Chen
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands.,Bio-X Center, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, China
| | - Wanlu Cao
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Juan Li
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Dave Sprengers
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Pratika Y Hernanda
- Laboratory of Medical Genetics, Biomolecular Research Center, Wijaya Kusuma University, Surabaya, Indonesia
| | - Xiangdong Kong
- Bio-X Center, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, China
| | - Luc J W van der Laan
- Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Kwan Man
- Department of Surgery, Hong Kong University, Hong Kong, China
| | - Jaap Kwekkeboom
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Herold J Metselaar
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Maikel P Peppelenbosch
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Qiuwei Pan
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| |
Collapse
|
49
|
Labesse G, Alexandre T, Gelin M, Haouz A, Munier-Lehmann H. Crystallographic studies of two variants ofPseudomonas aeruginosaIMPDH with impaired allosteric regulation. ACTA ACUST UNITED AC 2015; 71:1890-9. [DOI: 10.1107/s1399004715013115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/07/2015] [Indexed: 11/10/2022]
Abstract
Inosine-5′-monophosphate dehydrogenases (IMPDHs), which are the rate-limiting enzymes in guanosine-nucleotide biosynthesis, are important therapeutic targets. Despite in-depth functional and structural characterizations of various IMPDHs, the role of the Bateman domain containing two CBS motifs remains controversial. Their involvement in the allosteric regulation ofPseudomonas aeruginosaIMPDH by Mg-ATP has recently been reported. To better understand the function of IMPDH and the importance of the CBS motifs, the structure of a variant devoid of these modules (ΔCBS) was solved at high resolution in the apo form and in complex with IMP. In addition, a single amino-acid substitution variant, D199N, was also structurally characterized: the mutation corresponds to the autosomal dominant mutant D226N of human IMPDH1, which is responsible for the onset of the retinopathy adRP10. These new structures shed light onto the possible mechanism of regulation of the IMPDH enzymatic activity. In particular, three conserved loops seem to be key players in this regulation as they connect the tetramer–tetramer interface with the active site and show significant modification upon substrate binding.
Collapse
|
50
|
Chang CC, Lin WC, Pai LM, Lee HS, Wu SC, Ding ST, Liu JL, Sung LY. Cytoophidium assembly reflects upregulation of IMPDH activity. J Cell Sci 2015; 128:3550-5. [PMID: 26303200 PMCID: PMC4610212 DOI: 10.1242/jcs.175265] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/13/2015] [Indexed: 01/18/2023] Open
Abstract
Cytidine triphosphate synthase (CTPS) and inosine monophosphate dehydrogenase (IMPDH) (both of which have two isoforms) can form fiber-like subcellular structures termed 'cytoophidia' under certain circumstances in mammalian cells. Although it has been shown that filamentation of CTPS downregulates its activity by disturbing conformational changes, the activity of IMPDH within cytoophidia is still unclear. Most previous IMPDH cytoophidium studies were performed under conditions involving inhibitors that impair GTP synthesis. Here, we show that IMPDH forms cytoophidia without inhibition of GTP synthesis. First, we find that an elevated intracellular CTP concentration or treatment with 3'-deazauridine, a CTPS inhibitor, promotes IMPDH cytoophidium formation and increases the intracellular GTP pool size. Moreover, restriction of cell growth triggers the disassembly of IMPDH cytoophidia, implying that their presence is correlated with active cell metabolism. Finally, we show that the presence of IMPDH cytoophidia in mouse pancreatic islet cells might correlate with nutrient uptake in the animal. Collectively, our findings reveal that formation of IMPDH cytoophidia reflects upregulation of purine nucleotide synthesis, suggesting that the IMPDH cytoophidium plays a role distinct from that of the CTPS cytoophidium in controlling intracellular nucleotide homeostasis.
Collapse
Affiliation(s)
- Chia-Chun Chang
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Wei-Cheng Lin
- Molecular Medicine Research Center, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan, Republic of China
| | - Li-Mei Pai
- Molecular Medicine Research Center, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan, Republic of China Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan, Republic of China Department of Biochemistry, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan, Republic of China
| | - Hsuan-Shu Lee
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan, Republic of China Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei 10051, Taiwan, Republic of China
| | - Shinn-Chih Wu
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan, Republic of China Department of Animal Science and Technology, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Shih-Torng Ding
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan, Republic of China Department of Animal Science and Technology, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | - Ji-Long Liu
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Li-Ying Sung
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan, Republic of China Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan, Republic of China
| |
Collapse
|