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Maekawa S, Nishikawa I, Horiguchi G. Impaired inosine monophosphate dehydrogenase leads to plant-specific ribosomal stress responses in Arabidopsis thaliana. JOURNAL OF PLANT RESEARCH 2024:10.1007/s10265-024-01578-5. [PMID: 39235732 DOI: 10.1007/s10265-024-01578-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 08/23/2024] [Indexed: 09/06/2024]
Abstract
Nucleotides are the building blocks of living organisms and their biosynthesis must be tightly regulated. Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in GTP synthesis that is essential for biological activities, such as RNA synthesis. In animals, the suppression of IMPDH function causes ribosomal stress (also known as nucleolar stress), a disorder in ribosome biogenesis that results in cell proliferation defects and apoptosis. Despite its importance, plant IMPDH has not been analyzed in detail. Therefore, we analyzed the phenotypes of mutants of the two IMPDH genes in Arabidopsis thaliana and investigated their relationship with ribosomal stress. Double mutants of IMPDH1 and IMPDH2 were lethal, and only the impdh2 mutants showed growth defects and transient chlorophyll deficiency. These results suggested that IMPDH1 and IMPDH2 are redundant and essential, whereas IMPDH2 has a crucial role. In addition, the impdh2 mutants showed a reduction in nucleolus size and resistance to several translation inhibitors, which is a known response to ribosomal stress. Furthermore, the IMPDH1/impdh1 impdh2 mutants showed more severe growth defects and phenotypes such as reduced plastid rRNA levels and abnormal processing patterns than the impdh2 mutants. Finally, multiple mutations of impdh with as2, which has abnormal leaf polarity, caused the development of needle-like leaves because of the enhancement of the as2 phenotype, which is a typical effect observed in mutants of genes involved in ribosome biogenesis. These results indicated that IMPDH is closely related to ribosome biogenesis, and that mutations in the genes lead to not only known responses to ribosomal stress, but also plant-specific responses.
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Affiliation(s)
- Shugo Maekawa
- Institute of Natural Sciences, Senshu University, Higashimita 2-1-1, Tama, Kawasaki, Kanagawa, 214-8580, Japan.
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo, 171-8501, Japan.
| | - Ikuto Nishikawa
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo, 171-8501, Japan
- Medical Institute of Bioregulation, Kyushu University, Fukuoka City, Fukuoka, 812-8582, Japan
| | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo, 171-8501, Japan
- Research Center for Life Science, College of Science, Rikkyo University, Toshima, Tokyo, 171-8501, Japan
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McCartney ME, Wheeler GM, O’Neill AG, Patel JH, Litt ZR, Calise SJ, Kollman JM, Wills AE. Appendage regeneration requires IMPDH2 and creates a sensitized environment for enzyme filament formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.29.605679. [PMID: 39131357 PMCID: PMC11312571 DOI: 10.1101/2024.07.29.605679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Regeneration of lost tissue requires biosynthesis of metabolites needed for cell proliferation and growth. Among these are the critical purine nucleotides ATP and GTP. The abundance and balance of these purines is regulated by inosine monophosphate dehydrogenase 2 (IMPDH2), which catalyzes the committing step of GTP synthesis. IMPDH2 assembles into filaments that resist allosteric inhibition under conditions of high GTP demand. Here we asked whether IMPDH2 is required in the highly proliferative context of regeneration, and whether its assembly into filaments takes place in regenerating tissue. We find that inhibition of IMPDH2 leads to impaired tail regeneration and reduced cell proliferation in the tadpole Xenopus tropicalis. We find that both endogenous and fluorescent fusions of IMPDH2 robustly assemble into filaments throughout the tadpole tail, and that the regenerating tail creates a sensitized condition for filament formation. These findings clarify the role of purine biosynthesis in regeneration and reveal that IMPDH2 enzyme filament formation is a biologically relevant mechanism of regulation in vertebrate regeneration.
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Affiliation(s)
| | - Gavin M. Wheeler
- Department of Biochemistry. University of Washington, Seattle WA
| | - Audrey G. O’Neill
- Department of Biochemistry. University of Washington, Seattle WA
- Program in Biological Physics, Structure, and Design. University of Washington, Seattle WA
| | - Jeet H. Patel
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia PA
| | - Zoey R. Litt
- Department of Biochemistry. University of Washington, Seattle WA
| | - S. John Calise
- Department of Biochemistry. University of Washington, Seattle WA
| | | | - Andrea E. Wills
- Department of Biochemistry. University of Washington, Seattle WA
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Wang J, Wang Y, Jiang Y, Li S, Jia X, Xiao X, Sun W, Wang P, Zhang Q. Datasets-Based IMPDH1 Revisited: Heterozygous Missense Variants for Dominant Retinitis Pigmentosa While Truncation Variants Are Likely Non-Pathogenic. Curr Eye Res 2024; 49:853-861. [PMID: 38604988 DOI: 10.1080/02713683.2024.2336158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
PURPOSE Heterozygous variants of IMPDH1 are associated with autosomal dominant retinitis pigmentosa (adRP). The current study aims to investigate the characteristics of the adRP-associated variants. METHODS IMPDH1 variants from our exome sequencing dataset were retrieved and systemically evaluated through multiple online prediction tools, comparative genomics (in-house dataset, HGMD, and gnomAD), and phenotypic association. Potential pathogenic variants (PPVs) were further confirmed by Sanger sequencing and segregation analysis. RESULTS In total, seven heterozygous PPVs (six missenses and one inframe) were identified in 10 families with RP, in which six of the seven might be classified as pathogenic or likely pathogenic while one others as variants of uncertain significance. IMPDH1 variants contributed to 0.7% (10/1519) of RP families in our cohort, ranking the top four genes implicated in adRP. These adRP-associated variants were located in exons 8-10, a region within or downstream of the CBS domain. All these variants were predicted to be damaged by at least three of the six online prediction tools. Two truncation variants were considered non-pathogenic. Hitherto, 41 heterozygous variants of IMPDH1 were detected in 110 families in published literature, including 33 missenses, two inframes, and six truncations (including a synonymous variant affecting splicing). Of the 35 missense and inframe variants, most were clustered in exons 8-10 (77.1%, 27/35), including 18 (51.4%, 18/35) in exon 10 accounting for 70.9% (78/110) of the families. However, truncation variants were enriched in the general population with a pLI value of 0 (tolerated), and the reported variants in patients with RP did not cluster in specific region. CONCLUSIONS Our data together with comprehensive analysis of existing datasets suggest that causative variants of IMPDH1 are usually missense and mostly clustered in exons 8-10. Conversely, most missense variants outside this region and truncation variants should be interpreted with great care in clinical gene test.
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Affiliation(s)
- Junwen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Department of Ophthalmology, The Central Hospital of Enshi Tujia and Miao Autonomous Prefecture, Enshi, Hubei, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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4
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Shan Z, Rivero-Gamez A, Lyumkis D, Horton NC. Two-metal ion mechanism of DNA cleavage by activated, filamentous SgrAI. J Biol Chem 2024; 300:107576. [PMID: 39009341 PMCID: PMC11367474 DOI: 10.1016/j.jbc.2024.107576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/21/2024] [Accepted: 07/09/2024] [Indexed: 07/17/2024] Open
Abstract
Enzymes that form filamentous assemblies with modulated enzymatic activities have gained increasing attention in recent years. SgrAI is a sequence specific type II restriction endonuclease that forms polymeric filaments with accelerated DNA cleavage activity and expanded DNA sequence specificity. Prior studies have suggested a mechanistic model linking the structural changes accompanying SgrAI filamentation to its accelerated DNA cleavage activity. In this model, the conformational changes that are specific to filamentous SgrAI maximize contacts between different copies of the enzyme within the filament and create a second divalent cation binding site in each subunit, which in turn facilitates the DNA cleavage reaction. However, our understanding of the atomic mechanism of catalysis is incomplete. Herein, we present two new structures of filamentous SgrAI solved using cryo-EM. The first structure, resolved to 3.3 Å, is of filamentous SgrAI containing an active site mutation that is designed to stall the DNA cleavage reaction, which reveals the enzymatic configuration prior to DNA cleavage. The second structure, resolved to 3.1 Å, is of WT filamentous SgrAI containing cleaved substrate DNA, which reveals the enzymatic configuration at the end of the enzymatic cleavage reaction. Both structures contain the phosphate moiety at the cleavage site and the biologically relevant divalent cation cofactor Mg2+ and define how the Mg2+ cation reconfigures during enzymatic catalysis. The data support a model for the activation mechanism that involves binding of a second Mg2+ in the SgrAI active site as a direct result of filamentation induced conformational changes.
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Affiliation(s)
- Zelin Shan
- The Salk Institute of Biological Sciences, La Jolla, California, USA
| | - Andres Rivero-Gamez
- The Salk Institute of Biological Sciences, La Jolla, California, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego La Jolla, California, USA
| | - Dmitry Lyumkis
- The Salk Institute of Biological Sciences, La Jolla, California, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego La Jolla, California, USA.
| | - Nancy C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA.
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Huang S, Zhang J, He P, Cui X, Hou Y, Su W, Li F. Radiation-induced upregulation of FGL1 promotes esophageal squamous cell carcinoma metastasis via IMPDH1. BMC Cancer 2024; 24:557. [PMID: 38702629 PMCID: PMC11067193 DOI: 10.1186/s12885-024-12313-7] [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: 01/23/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND While radiation therapy remains pivotal in esophageal squamous cell carcinoma (ESCC) treatment, the perplexing phenomenon of post-radiation metastasis presents a formidable clinical challenge. This study investigates the role of fibrinogen-like protein 1 (FGL1) in driving ESCC metastasis following radiation exposure. METHODS FGL1 expression in post-radiation ESCC cells was meticulously examined using qRT-PCR, western blotting, and immunofluorescence. The impact of FGL1 on ESCC cell invasion and migration was assessed through Transwell and wound healing assays. In vivo, the metastatic potential of ESCC in response to FGL1 was scrutinized using nude mice models. Comprehensive RNA sequencing and functional experiments elucidated the intricate mechanism associated with FGL1. RESULTS Radiation induced upregulation of FGL1 in ESCC cells through FOXO4, intensifying ESCC cell invasion and migration. Targeted knockdown of FGL1 effectively alleviated these characteristics both in vitro and in vivo. FGL1 depletion concurrently suppressed IMPDH1 expression. Rescue experiments underscored that IMPDH1 knockdown robustly reversed the pro-invasive effects induced by FGL1 in ESCC cells. ESCC tissues exhibited heightened IMPDH1 mRNA levels, demonstrating a correlation with patient survival. CONCLUSIONS Radiation-induced upregulation of FGL1 propels ESCC metastasis through IMPDH1, proposing a potential therapeutic target to mitigate post-radiotherapy metastasis in ESCC patients.
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Affiliation(s)
- Shan Huang
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China.
| | - Jiayi Zhang
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Pu He
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Xinyue Cui
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Yuzhu Hou
- Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, ShaanXi, China
| | - Wanghui Su
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Fang Li
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
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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.
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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
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7
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Zhu M, Wu N, Zhong J, Chen C, Liu W, Ren Y, Wang X, Jin H. N 6-methyladenosine modification of the mRNA for a key gene in purine nucleotide metabolism regulates virus proliferation in an insect vector. Cell Rep 2024; 43:113821. [PMID: 38368611 DOI: 10.1016/j.celrep.2024.113821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/10/2024] [Accepted: 02/02/2024] [Indexed: 02/20/2024] Open
Abstract
The titer of viruses that persist and propagate in their insect vector must be high enough for transmission yet not harm the insect, but the mechanism of this dynamic balance is unclear. Here, expression of inosine monophosphate dehydrogenase (LsIMPDH), a rate-limiting enzyme for guanosine triphosphate (GTP) synthesis, is shown to be downregulated by increased levels of N6-methyladenosine (m6A) on LsIMPDH mRNA in rice stripe virus (RSV)-infected small brown planthoppers (SBPHs; Laodelphax striatellus), the RSV vector, which decreases GTP content, thus limiting viral proliferation. Moreover, planthopper methyltransferase-like protein 3 (LsMETTL3) and m6A reader protein LsYTHDF3 are found to catalyze and recognize the m6A on LsIMPDH mRNA, respectively, and cooperate in destabilizing LsIMPDH transcripts. Co-silencing assays show that negative regulation of viral proliferation by both LsMETTL3 and LsYTHDF3 is partially dependent on LsIMPDH. This distinct mechanism limits virus replication in an insect vector, providing a potential gene target to block viral transmission.
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Affiliation(s)
- Mengjie Zhu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Nan Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jiayi Zhong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Chen Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wenwen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yingdang Ren
- Institute of Plant Protection, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Xifeng Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Huaibing Jin
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Ayoub N, Gedeon A, Munier-Lehmann H. A journey into the regulatory secrets of the de novo purine nucleotide biosynthesis. Front Pharmacol 2024; 15:1329011. [PMID: 38444943 PMCID: PMC10912719 DOI: 10.3389/fphar.2024.1329011] [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: 10/27/2023] [Accepted: 02/01/2024] [Indexed: 03/07/2024] Open
Abstract
De novo purine nucleotide biosynthesis (DNPNB) consists of sequential reactions that are majorly conserved in living organisms. Several regulation events take place to maintain physiological concentrations of adenylate and guanylate nucleotides in cells and to fine-tune the production of purine nucleotides in response to changing cellular demands. Recent years have seen a renewed interest in the DNPNB enzymes, with some being highlighted as promising targets for therapeutic molecules. Herein, a review of two newly revealed modes of regulation of the DNPNB pathway has been carried out: i) the unprecedent allosteric regulation of one of the limiting enzymes of the pathway named inosine 5'-monophosphate dehydrogenase (IMPDH), and ii) the supramolecular assembly of DNPNB enzymes. Moreover, recent advances that revealed the therapeutic potential of DNPNB enzymes in bacteria could open the road for the pharmacological development of novel antibiotics.
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Affiliation(s)
- Nour Ayoub
- Institut Pasteur, Université Paris Cité, INSERM UMRS-1124, Paris, France
| | - Antoine Gedeon
- Sorbonne Université, École Normale Supérieure, Université PSL, CNRS UMR7203, Laboratoire des Biomolécules, LBM, Paris, France
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9
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Hassan AMS, Elfiky AA, Elgohary AM. Triple in silico targeting of IMPDH enzyme and RNA-dependent RNA polymerase of both SARS-CoV-2 and Rhizopus oryzae. Future Microbiol 2024; 19:9-19. [PMID: 38294272 DOI: 10.2217/fmb-2023-0103] [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: 05/03/2023] [Accepted: 08/23/2023] [Indexed: 02/01/2024] Open
Abstract
Aim: Mucormycosis has been associated with SARS-CoV-2 infections during the last year. The aim of this study was to triple-hit viral and fungal RNA-dependent RNA polymerases (RdRps) and human inosine monophosphate dehydrogenase (IMPDH). Materials & methods: Molecular docking and molecular dynamics simulation were used to test nucleotide inhibitors (NIs) against the RdRps of SARS-CoV-2 and Rhizopus oryzae RdRp. These same inhibitors targeted IMPDH. Results: Four NIs revealed a comparable binding affinity to the two drugs, remdesivir and sofosbuvir. Binding energies were calculated using the most abundant conformations of the RdRps after 100-ns molecular dynamics simulation. Conclusion: We suggest the triple-inhibition potential of four NIs against pathogenic RdRps and IMPDH, which is worth experimental validation.
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Affiliation(s)
| | - Abdo A Elfiky
- Biophysics Department, Faculty of Sciences, Cairo University, Giza, Dokki, 12613, Egypt
| | - Alaa M Elgohary
- Biophysics Department, Faculty of Sciences, Cairo University, Giza, Dokki, 12613, Egypt
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10
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Gao G, Xue Q, He J, Wu M, Jiang Y, Li Q, Zhang Y, Shi W. Single-cell RNA sequencing in double-hit lymphoma: IMPDH2 induces the progression of lymphoma by activating the PI3K/AKT/mTOR signaling pathway. Int Immunopharmacol 2023; 125:111125. [PMID: 37907047 DOI: 10.1016/j.intimp.2023.111125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 10/14/2023] [Accepted: 10/20/2023] [Indexed: 11/02/2023]
Abstract
BACKGROUND IMPDH2 is the rate-limiting enzyme of the de novo GTP synthesis pathway and has a key role in tumors; however, the specific mechanism underlying IMPDH2 activity in diffuse large B cell lymphoma (DLBCL) is still undetermined. This study aims to explore the potential mechanism of IMPDH2 in DLBCL, and its possible involvement in double-hit lymphoma (DHL), i.e., cases with translocations involving MYC and BCL2 and/or BCL6. METHODS Using single-cell sequencing and bioinformatics analysis to screen for IMPDH2. Exploring the differential expression of IMPDH2 and its correlation with prognosis through multiplexed immunofluorescence analysis. Using CCK8, EdU, clone formation assay, and animal model to analyze biological behavior changes after inhibiting IMPDH2. Explaining the potential mechanism of IMPDH2 in DLBCL by Western blot and multiplexed immunofluorescence. RESULTS Prognostic risk model was constructed by single-cell sequencing, which identified IMPDH2 as a DHL-related gene. IMPDH2 was highly expressed in cell lines and tissues, associated with poor patient prognosis and an independent prognostic factor. In vitro and in vivo experiments showed that IMPDH2 inhibition significantly inhibited DHL cell proliferation. Flow cytometry showed apoptosis and cycle arrest. Western blot results suggested that c-Myc regulated the activation of PI3K/AKT/mTOR signaling pathway by IMPDH2 to promote tumor development in DHL. Moreover, multiplex immunofluorescence revealed decreased T-cell infiltration within the tumor microenvironment exhibiting concurrent high expression of IMPDH2 and PD-L1. CONCLUSIONS Our results suggest that IMPDH2 functions as a tumor-promoting factor in DHL. This finding is expected to generate novel insights into the pathogenesis of these patients, thereby identifying potential therapeutic targets.
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Affiliation(s)
- Guangcan Gao
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong 226001, Jiangsu, China; Nantong University Medical School, 19, Qixiu Road, Nantong 226001, Jiangsu, China; Department of Clinical Biobank & Institute of Oncology, Nantong University Affiliated Hospital, Nantong 226001, Jiangsu, China
| | - Qingfeng Xue
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong 226001, Jiangsu, China; Nantong University Medical School, 19, Qixiu Road, Nantong 226001, Jiangsu, China; Department of Clinical Biobank & Institute of Oncology, Nantong University Affiliated Hospital, Nantong 226001, Jiangsu, China
| | - Jing He
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong 226001, Jiangsu, China; Nantong University Medical School, 19, Qixiu Road, Nantong 226001, Jiangsu, China; Department of Clinical Biobank & Institute of Oncology, Nantong University Affiliated Hospital, Nantong 226001, Jiangsu, China
| | - Meng Wu
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong 226001, Jiangsu, China
| | - Yongning Jiang
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong 226001, Jiangsu, China; Nantong University Medical School, 19, Qixiu Road, Nantong 226001, Jiangsu, China; Department of Clinical Biobank & Institute of Oncology, Nantong University Affiliated Hospital, Nantong 226001, Jiangsu, China
| | - Quanqing Li
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong 226001, Jiangsu, China; Nantong University Medical School, 19, Qixiu Road, Nantong 226001, Jiangsu, China; Department of Clinical Biobank & Institute of Oncology, Nantong University Affiliated Hospital, Nantong 226001, Jiangsu, China
| | - Yaping Zhang
- Nantong University Medical School, 19, Qixiu Road, Nantong 226001, Jiangsu, China; Department of Clinical Biobank & Institute of Oncology, Nantong University Affiliated Hospital, Nantong 226001, Jiangsu, China; Department of Hematology, Affiliated Hospital of Nantong University, 20, Xisi Road, Nantong 226001, Jiangsu, China.
| | - Wenyu Shi
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong 226001, Jiangsu, China; Nantong University Medical School, 19, Qixiu Road, Nantong 226001, Jiangsu, China; Department of Clinical Biobank & Institute of Oncology, Nantong University Affiliated Hospital, Nantong 226001, Jiangsu, China.
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Sakti DH, Cornish EE, Nash BM, Jamieson RV, Grigg JR. IMPDH1-associated autosomal dominant retinitis pigmentosa: natural history of novel variant Lys314Gln and a comprehensive literature search. Ophthalmic Genet 2023; 44:437-455. [PMID: 37259572 DOI: 10.1080/13816810.2023.2215310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/11/2023] [Accepted: 05/14/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND Inosine monophosphate dehydrogenase (IMPDH) is a key regulatory enzyme in the de novo synthesis of the purine base guanine. Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) are causative for RP10 autosomal dominant retinitis pigmentosa (adRP). This study reports a novel variant in a family with IMPDH1-associated retinopathy. We also performed a comprehensive review of all reported IMPDH1 disease causing variants with their associated phenotype. MATERIALS AND METHODS Multimodal imaging and functional studies documented the phenotype including best-corrected visual acuity (BCVA), fundus photograph, fundus autofluorescence (FAF), full field electroretinogram (ffERG), optical coherence tomography (OCT) and visual field (VF) data were collected. A literature search was performed in the PubMed and LOVD repositories. RESULTS We report 3 cases from a 2-generation family with a novel heterozygous likely pathogenic variant p. (Lys314Gln) (exon 10). The ophthalmic phenotype showed diffuse outer retinal atrophy with mild pigmentary changes with sparse pigmentary changes. FAF showed early macular involvement with macular hyperautofluorescence (hyperAF) surrounded by hypoAF. Foveal ellipsoid zone island can be found in the youngest patient but not in the older ones. The literature review identified a further 56 heterozygous, 1 compound heterozygous, and 2 homozygous variant. The heterozygous group included 43 missense, 3 in-frame, 1 nonsense, 2 frameshift, 1 synonymous, and 6 intronic variants. Exon 10 was noted as a hotspot harboring 18 variants. CONCLUSIONS We report a novel IMPDH1 variant. IMPDH1-associated retinopathy presents most frequently in the first decade of life with early macular involvement.
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Affiliation(s)
- Dhimas H Sakti
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Elisa E Cornish
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Benjamin M Nash
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children's Hospitals Network, Sydney, New South Wales, Australia
| | - Robyn V Jamieson
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - John R Grigg
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
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12
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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.
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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
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13
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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.
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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
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14
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Camici M, Garcia-Gil M, Allegrini S, Pesi R, Bernardini G, Micheli V, Tozzi MG. Inborn Errors of Purine Salvage and Catabolism. Metabolites 2023; 13:787. [PMID: 37512494 PMCID: PMC10383617 DOI: 10.3390/metabo13070787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Cellular purine nucleotides derive mainly from de novo synthesis or nucleic acid turnover and, only marginally, from dietary intake. They are subjected to catabolism, eventually forming uric acid in humans, while bases and nucleosides may be converted back to nucleotides through the salvage pathways. Inborn errors of the purine salvage pathway and catabolism have been described by several researchers and are usually referred to as rare diseases. Since purine compounds play a fundamental role, it is not surprising that their dysmetabolism is accompanied by devastating symptoms. Nevertheless, some of these manifestations are unexpected and, so far, have no explanation or therapy. Herein, we describe several known inborn errors of purine metabolism, highlighting their unexplained pathological aspects. Our intent is to offer new points of view on this topic and suggest diagnostic tools that may possibly indicate to clinicians that the inborn errors of purine metabolism may not be very rare diseases after all.
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Affiliation(s)
- Marcella Camici
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy
| | - Mercedes Garcia-Gil
- Unità di Fisiologia Generale, Dipartimento di Biologia, Università di Pisa, Via San Zeno 31, 56127 Pisa, Italy
- CISUP, Centro per l'Integrazione Della Strumentazione Dell'Università di Pisa, 56127 Pisa, Italy
- Centro di Ricerca Interdipartimentale Nutrafood "Nutraceuticals and Food for Health", Università di Pisa, 56126 Pisa, Italy
| | - Simone Allegrini
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy
- CISUP, Centro per l'Integrazione Della Strumentazione Dell'Università di Pisa, 56127 Pisa, Italy
- Centro di Ricerca Interdipartimentale Nutrafood "Nutraceuticals and Food for Health", Università di Pisa, 56126 Pisa, Italy
| | - Rossana Pesi
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy
| | - Giulia Bernardini
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Vanna Micheli
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100 Siena, Italy
- LND Famiglie Italiane ODV-Via Giovanetti 15-20, 16149 Genova, Italy
| | - Maria Grazia Tozzi
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy
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15
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Singh S, Anand R. Diverse strategies adopted by nature for regulating purine biosynthesis via fine-tuning of purine metabolic enzymes. Curr Opin Chem Biol 2023; 73:102261. [PMID: 36682088 DOI: 10.1016/j.cbpa.2022.102261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/18/2022] [Accepted: 12/21/2022] [Indexed: 01/24/2023]
Abstract
Purine nucleotides, generated by de novo synthesis and salvage pathways, are essential for metabolism and act as building blocks of genetic material. To avoid an imbalance in the nucleotide pool, nature has devised several strategies to regulate/tune the catalytic performance of key purine metabolic enzymes. Here, we discuss some recent examples, such as stress-regulating alarmones that bind to select pathway enzymes, huge ensembles like dynamic metabolons and self-assembled filaments that highlight the layered fine-control prevalent in the purine metabolic pathway to fulfill requisite purine demands. Examples of enzymes that turn-on only under allosteric control, are regulated via long-distance communication that facilitates transient conduits have additionally been explored.
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Affiliation(s)
- Sukhwinder Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Ruchi Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India; DBT-Wellcome Trust India Alliance Senior Fellow, Mumbai 400076, India.
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16
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Hvorecny KL, Kollman JM. Greater than the sum of parts: Mechanisms of metabolic regulation by enzyme filaments. Curr Opin Struct Biol 2023; 79:102530. [PMID: 36709625 PMCID: PMC10023394 DOI: 10.1016/j.sbi.2023.102530] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/28/2022] [Accepted: 12/19/2022] [Indexed: 01/28/2023]
Abstract
Recent work in structural biology is shedding light on how many of the enzymes of intermediary metabolism are self- and co-assembling into large, filamentous polymers or agglomerates to organize and regulate the complex and essential biochemical pathways in cells. Filament assembly provides an additional layer of regulation by modulating the intrinsic allostery of the enzyme protomers which tunes activity in response to a variety of environmental cues. Enzyme filaments dynamically assemble and disassemble in response to changes in metabolite levels and environmental cues, shifting metabolic flux on a more rapid timescale than transcriptional or translational reprogramming. Here we present recent examples of high-resolution structures of filaments from proteins in intermediary metabolism and we discuss how filament assembly modulates the activities of these and other proteins.
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Affiliation(s)
- Kelli L Hvorecny
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
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17
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Cellular and Molecular Mechanisms of Pathogenesis Underlying Inherited Retinal Dystrophies. Biomolecules 2023; 13:biom13020271. [PMID: 36830640 PMCID: PMC9953031 DOI: 10.3390/biom13020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation.
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18
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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: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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.
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Affiliation(s)
- Rubén M. Buey
- Metabolic Engineering Group, Department of Microbiology and GeneticsUniversidad de SalamancaSalamancaSpain
| | - David Fernández‐Justel
- Metabolic Engineering Group, Department of Microbiology and GeneticsUniversidad de SalamancaSalamancaSpain
| | - Alberto Jiménez
- Metabolic Engineering Group, Department of Microbiology and GeneticsUniversidad de SalamancaSalamancaSpain
| | - José L. Revuelta
- Metabolic Engineering Group, Department of Microbiology and GeneticsUniversidad de SalamancaSalamancaSpain
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19
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Wang T, Cao Y, Zhang H, Wang Z, Man CH, Yang Y, Chen L, Xu S, Yan X, Zheng Q, Wang Y. COVID-19 metabolism: Mechanisms and therapeutic targets. MedComm (Beijing) 2022; 3:e157. [PMID: 35958432 PMCID: PMC9363584 DOI: 10.1002/mco2.157] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 01/18/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dysregulates antiviral signaling, immune response, and cell metabolism in human body. Viral genome and proteins hijack host metabolic network to support viral biogenesis and propagation. However, the regulatory mechanism of SARS-CoV-2-induced metabolic dysfunction has not been elucidated until recently. Multiomic studies of coronavirus disease 2019 (COVID-19) revealed an intensive interaction between host metabolic regulators and viral proteins. SARS-CoV-2 deregulated cellular metabolism in blood, intestine, liver, pancreas, fat, and immune cells. Host metabolism supported almost every stage of viral lifecycle. Strikingly, viral proteins were found to interact with metabolic enzymes in different cellular compartments. Biochemical and genetic assays also identified key regulatory nodes and metabolic dependencies of viral replication. Of note, cholesterol metabolism, lipid metabolism, and glucose metabolism are broadly involved in viral lifecycle. Here, we summarized the current understanding of the hallmarks of COVID-19 metabolism. SARS-CoV-2 infection remodels host cell metabolism, which in turn modulates viral biogenesis and replication. Remodeling of host metabolism creates metabolic vulnerability of SARS-CoV-2 replication, which could be explored to uncover new therapeutic targets. The efficacy of metabolic inhibitors against COVID-19 is under investigation in several clinical trials. Ultimately, the knowledge of SARS-CoV-2-induced metabolic reprogramming would accelerate drug repurposing or screening to combat the COVID-19 pandemic.
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Affiliation(s)
- Tianshi Wang
- Shanghai Key Laboratory for Tumor Microenvironment and InflammationDepartment of Biochemistry and Molecular Cell BiologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Ying Cao
- State Key Laboratory of Oncogenes and Related GenesShanghai Cancer InstituteRenji HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Haiyan Zhang
- Bai Jia Obstetrics and Gynecology HospitalShanghaiChina
| | - Zihao Wang
- Fudan University Shanghai Cancer CenterKey Laboratory of Breast Cancer in ShanghaiShanghai Key Laboratory of Radiation OncologyCancer Instituteand The Shanghai Key Laboratory of Medical EpigeneticsInstitutes of Biomedical SciencesShanghai Medical CollegeFudan UniversityShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- The International Co‐laboratory of Medical Epigenetics and MetabolismMinistry of Science and TechnologyShanghaiChina
| | - Cheuk Him Man
- Division of HematologyDepartment of MedicineUniversity of Hong KongPokfulamHong Kong, China
| | - Yunfan Yang
- Department of Cell BiologySchool of Basic Medical SciencesCheeloo College of MedicineShandong UniversityJinanChina
| | - Lingchao Chen
- Department of NeurosurgeryHuashan HospitalShanghai Medical CollegeFudan UniversityNational Center for Neurological DisordersShanghai Key Laboratory of Brain Function and Restoration and Neural RegenerationNeurosurgical Institute of Fudan UniversityShanghai Clinical Medical Center of NeurosurgeryShanghaiChina
| | - Shuangnian Xu
- Department of HematologySouthwest HospitalArmy Medical UniversityChongqingChina
| | - Xiaojing Yan
- Department of HematologyThe First Affiliated Hospital of China Medical UniversityShenyangChina
| | - Quan Zheng
- Center for Single‐Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yi‐Ping Wang
- Fudan University Shanghai Cancer CenterKey Laboratory of Breast Cancer in ShanghaiShanghai Key Laboratory of Radiation OncologyCancer Instituteand The Shanghai Key Laboratory of Medical EpigeneticsInstitutes of Biomedical SciencesShanghai Medical CollegeFudan UniversityShanghaiChina
- Department of OncologyShanghai Medical CollegeFudan UniversityShanghaiChina
- The International Co‐laboratory of Medical Epigenetics and MetabolismMinistry of Science and TechnologyShanghaiChina
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20
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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.
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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.
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