1
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Horton NC, Lyumkis D. Structures, mechanisms, and kinetic advantages of the SgrAI filament forming mechanism. Crit Rev Biochem Mol Biol 2024:1-39. [PMID: 39699272 DOI: 10.1080/10409238.2024.2440315] [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: 09/27/2024] [Revised: 12/04/2024] [Accepted: 12/06/2024] [Indexed: 12/20/2024]
Abstract
This review documents investigations leading to the unprecedented discovery of filamentation as a mode of enzyme regulation in the type II restriction endonuclease SgrAI. Filamentation is defined here as linear or helical polymerization of a single enzyme as occurs for SgrAI, and has now been shown to occur in many other enzyme systems, including conserved metabolic enzymes. In the case of SgrAI, filamentation activates the DNA cleavage rate by up to 1000-fold and also alters the enzyme's DNA sequence specificity. The investigations began with the observation that SgrAI cleaves two types of recognition sequences, primary and secondary, but cleaves the secondary sequences only when present on the same DNA as at least one primary. DNA cleavage rate measurements showed how the primary sequence is both a substrate and an allosteric effector of SgrAI. Biophysical measurements indicated that the activated form of SgrAI, stimulated by binding to the primary sequence, consisted of varied numbers of the SgrAI bound to DNA. Structural studies revealed the activated state of SgrAI as a left-handed helical filament which stabilizes an altered enzyme conformation, which binds a second divalent cation in the active site. Efforts to determine the mechanism of DNA sequence specificity alteration are ongoing and current models are discussed. Finally, global kinetic modeling of the filament mediated DNA cleavage reaction and simulations of in vivo activity suggest that the filament mechanism evolved to rapidly cleave invading DNA while protecting the Streptomyces host genome.
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Affiliation(s)
- Nancy C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Dmitry Lyumkis
- The Salk Institute for Biological Studies, La Jolla, California, USA
- Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, California, USA
- Graduate School of Biological Sciences, Section of Molecular Biology, University of California San Diego, La Jolla, California, USA
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2
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Guo CJ, Zhang Z, Lu JL, Zhong J, Wu YF, Guo SY, Liu JL. Structural Basis of Bifunctional CTP/dCTP Synthase. J Mol Biol 2024; 436:168750. [PMID: 39173734 DOI: 10.1016/j.jmb.2024.168750] [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: 04/29/2024] [Revised: 08/16/2024] [Accepted: 08/17/2024] [Indexed: 08/24/2024]
Abstract
The final step in the de novo synthesis of cytidine 5'-triphosphate (CTP) is catalyzed by CTP synthase (CTPS), which can form cytoophidia in all three domains of life. Recently, we have discovered that CTPS binds to ribonucleotides (NTPs) to form filaments, and have successfully resolved the structures of Drosophila melanogaster CTPS bound with NTPs. Previous biochemical studies have shown that CTPS can bind to deoxyribonucleotides (dNTPs) to produce 2'-deoxycytidine-5'-triphosphate (dCTP). However, the structural basis of CTPS binding to dNTPs is still unclear. In this study, we find that Drosophila CTPS can also form filaments with dNTPs. Using cryo-electron microscopy, we are able to resolve the structure of Drosophila melanogaster CTPS bound to dNTPs with a resolution of up to 2.7 Å. By combining these structural findings with biochemical analysis, we compare the binding and reaction characteristics of NTPs and dNTPs with CTPS. Our results indicate that the same enzyme can act bifunctionally as CTP/dCTP synthase in vitro, and provide a structural basis for these activities.
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Affiliation(s)
- Chen-Jun Guo
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zherong Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Jia-Li Lu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jiale Zhong
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yu-Fen Wu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shu-Ying Guo
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - 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, United Kingdom.
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3
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Deng R, Li YL, Liu JL. Differential Cytoophidium Assembly between Saccharomyces cerevisiae and Schizosaccharomyces pombe. Int J Mol Sci 2024; 25:10092. [PMID: 39337578 PMCID: PMC11432714 DOI: 10.3390/ijms251810092] [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: 08/18/2024] [Revised: 09/09/2024] [Accepted: 09/16/2024] [Indexed: 09/30/2024] Open
Abstract
The de novo synthesis of cytidine 5'-triphosphate (CTP) is catalyzed by the enzyme CTP synthase (CTPS), which is known to form cytoophidia across all three domains of life. In this study, we use the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe as model organisms to compare cytoophidium assembly under external environmental and intracellular CTPS alterations. We observe that under low and high temperature conditions, cytoophidia in fission yeast gradually disassemble, while cytoophidia in budding yeast remain unaffected. The effect of pH changes on cytoophidia maintenance in the two yeast species is different. When cultured in the yeast-saturated cultured medium, cytoophidia in fission yeast disassemble, while cytoophidia in budding yeast gradually form. Overexpression of CTPS results in the presence and maintenance of cytoophidia in both yeast species from the log phase to the stationary phase. In summary, our results demonstrate differential cytoophidium assembly between Saccharomyces cerevisiae and Schizosaccharomyces pombe, the two most studied yeast species.
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Affiliation(s)
- Ruolan Deng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi-Lan Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - 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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4
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Zhang Y, Liu JL. The Impact of Developmental and Metabolic Cues on Cytoophidium Formation. Int J Mol Sci 2024; 25:10058. [PMID: 39337544 PMCID: PMC11432437 DOI: 10.3390/ijms251810058] [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: 08/28/2024] [Revised: 09/14/2024] [Accepted: 09/17/2024] [Indexed: 09/30/2024] Open
Abstract
The cytoophidium, composed mainly of CTP synthase (CTPS), is a newly discovered dynamic filamentous structure in various organisms such as archaea, bacteria, and humans. These filamentous structures represent a fascinating example of intracellular compartmentation and dynamic regulation of metabolic enzymes. Currently, cytoophidia have been proven to be tightly regulated and highly dynamic, responding rapidly to developmental and metabolic cues and playing a critical role in maintaining cellular homeostasis. In this review, we would like to discuss in detail the characteristics, mechanisms, functions, and potential applications of this conservative but promising organelle.
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Affiliation(s)
- Yuanbing Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Center for Experimental Medicine, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, China
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
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5
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Bearne SL. Biochemical communication between filament-forming enzymes: Potential Regulatory Roles of Metabolites in Enzyme Co-assemblies with CTP Synthase. Bioessays 2024; 46:e2400063. [PMID: 38975656 DOI: 10.1002/bies.202400063] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/05/2024] [Accepted: 05/08/2024] [Indexed: 07/09/2024]
Abstract
A host of metabolic enzymes reversibly self-assemble to form membrane-less, intracellular filaments under normal physiological conditions and in response to stress. Often, these enzymes reside at metabolic control points, suggesting that filament formation affords an additional regulatory mechanism. Examples include cytidine-5'-triphosphate (CTP) synthase (CTPS), which catalyzes the rate-limiting step for the de novo biosynthesis of CTP; inosine-5'-monophosphate dehydrogenase (IMPDH), which controls biosynthetic access to guanosine-5'-triphosphate (GTP); and ∆1-pyrroline-5-carboxylate (P5C) synthase (P5CS) that catalyzes the formation of P5C, which links the Krebs cycle, urea cycle, and proline metabolism. Intriguingly, CTPS can exist in co-assemblies with IMPDH or P5CS. Since GTP is an allosteric activator of CTPS, the association of CTPS and IMPDH filaments accords with the need to coordinate pyrimidine and purine biosynthesis. Herein, a hypothesis is presented furnishing a biochemical connection underlying co-assembly of CTPS and P5CS filaments - potent inhibition of CTPS by glutamate γ-semialdehyde, the open-chain form of P5C.
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Affiliation(s)
- Stephen L Bearne
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
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6
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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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7
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Hugener J, Xu J, Wettstein R, Ioannidi L, Velikov D, Wollweber F, Henggeler A, Matos J, Pilhofer M. FilamentID reveals the composition and function of metabolic enzyme polymers during gametogenesis. Cell 2024; 187:3303-3318.e18. [PMID: 38906101 DOI: 10.1016/j.cell.2024.04.026] [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: 08/11/2023] [Revised: 02/06/2024] [Accepted: 04/19/2024] [Indexed: 06/23/2024]
Abstract
Gamete formation and subsequent offspring development often involve extended phases of suspended cellular development or even dormancy. How cells adapt to recover and resume growth remains poorly understood. Here, we visualized budding yeast cells undergoing meiosis by cryo-electron tomography (cryoET) and discovered elaborate filamentous assemblies decorating the nucleus, cytoplasm, and mitochondria. To determine filament composition, we developed a "filament identification" (FilamentID) workflow that combines multiscale cryoET/cryo-electron microscopy (cryoEM) analyses of partially lysed cells or organelles. FilamentID identified the mitochondrial filaments as being composed of the conserved aldehyde dehydrogenase Ald4ALDH2 and the nucleoplasmic/cytoplasmic filaments as consisting of acetyl-coenzyme A (CoA) synthetase Acs1ACSS2. Structural characterization further revealed the mechanism underlying polymerization and enabled us to genetically perturb filament formation. Acs1 polymerization facilitates the recovery of chronologically aged spores and, more generally, the cell cycle re-entry of starved cells. FilamentID is broadly applicable to characterize filaments of unknown identity in diverse cellular contexts.
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Affiliation(s)
- Jannik Hugener
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland; Institute of Biochemistry, ETH Zürich, 8093 Zürich, Switzerland; Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Jingwei Xu
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - Rahel Wettstein
- Institute of Biochemistry, ETH Zürich, 8093 Zürich, Switzerland; Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Lydia Ioannidi
- Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Daniel Velikov
- Max Perutz Labs, University of Vienna, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Florian Wollweber
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - Adrian Henggeler
- Institute of Biochemistry, ETH Zürich, 8093 Zürich, Switzerland; Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Joao Matos
- Institute of Biochemistry, ETH Zürich, 8093 Zürich, Switzerland; Max Perutz Labs, University of Vienna, 1030 Vienna, Austria.
| | - Martin Pilhofer
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland.
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8
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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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9
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Ghadirian N, Morgan RD, Horton NC. DNA Sequence Control of Enzyme Filamentation and Activation of the SgrAI Endonuclease. Biochemistry 2024; 63:326-338. [PMID: 38207281 DOI: 10.1021/acs.biochem.3c00313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Enzyme polymerization (also known as filamentation) has emerged as a new layer of enzyme regulation. SgrAI is a sequence-dependent DNA endonuclease that forms polymeric filaments with enhanced DNA cleavage activity as well as altered DNA sequence specificity. To better understand this unusual regulatory mechanism, full global kinetic modeling of the reaction pathway, including the enzyme filamentation steps, has been undertaken. Prior work with the primary DNA recognition sequence cleaved by SgrAI has shown how the kinetic rate constants of each reaction step are tuned to maximize activation and DNA cleavage while minimizing the extent of DNA cleavage to the host genome. In the current work, we expand on our prior study by now including DNA cleavage of a secondary recognition sequence, to understand how the sequence of the bound DNA modulates filamentation and activation of SgrAI. The work shows that an allosteric equilibrium between low and high activity states is modulated by the sequence of bound DNA, with primary sequences more prone to activation and filament formation, while SgrAI bound to secondary recognition sequences favor the low (and nonfilamenting) state by up to 40-fold. In addition, the degree of methylation of secondary sequences in the host organism, Streptomyces griseus, is now reported for the first time and shows that as predicted, these sequences are left unprotected from the SgrAI endonuclease making sequence specificity critical in this unusual filament-forming enzyme.
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Affiliation(s)
- Niloofar Ghadirian
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Richard D Morgan
- New England Biolabs, Inc., Ipswich, Massachusetts 01938, United States
| | - Nancy C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, United States
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10
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Yin Y, Yu H, Wang X, Hu Q, Liu Z, Luo D, Yang X. Cytoophidia: a conserved yet promising mode of enzyme regulation in nucleotide metabolism. Mol Biol Rep 2024; 51:245. [PMID: 38300325 DOI: 10.1007/s11033-024-09208-y] [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: 10/17/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024]
Abstract
Nucleotide biosynthesis encompasses both de novo and salvage synthesis pathways, each characterized by significant material and procedural distinctions. Despite these differences, cells with elevated nucleotide demands exhibit a preference for the more intricate de novo synthesis pathway, intricately linked to modes of enzyme regulation. In this study, we primarily scrutinize the biological importance of a conserved yet promising mode of enzyme regulation in nucleotide metabolism-cytoophidia. Cytoophidia, comprising cytidine triphosphate synthase or inosine monophosphate dehydrogenase, is explored across diverse biological models, including yeasts, Drosophila, mice, and human cancer cell lines. Additionally, we delineate potential biomedical applications of cytoophidia. As our understanding of cytoophidia deepens, the roles of enzyme compartmentalization and polymerization in various biochemical processes will unveil, promising profound impacts on both research and the treatment of metabolism-related diseases.
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Affiliation(s)
- Yue Yin
- School of Queen Mary, Jiangxi Medical College, Nanchang University, Jiangxi, China
| | - Huanhuan Yu
- First School of Clinical Medicine, Jiangxi Medical College, Nanchang University, Jiangxi, China
| | - Xinyi Wang
- Thyroid Surgery Center, West China Hospital of Sichuan University, Chengdu, China
| | - Qiaohao Hu
- The 1st Affiliated Hospital, Jiangxi Medical College, Nanchang University, Jiangxi, China
| | - Zhuoqi Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Jiangxi Medical College, Nanchang University, Jiangxi, China
| | - Daya Luo
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Jiangxi Medical College, Nanchang University, Jiangxi, China.
| | - Xiaohong Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Jiangxi Medical College, Nanchang University, Jiangxi, China.
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11
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Jentoft IMA, Bäuerlein FJB, Welp LM, Cooper BH, Petrovic A, So C, Penir SM, Politi AZ, Horokhovskyi Y, Takala I, Eckel H, Moltrecht R, Lénárt P, Cavazza T, Liepe J, Brose N, Urlaub H, Fernández-Busnadiego R, Schuh M. Mammalian oocytes store proteins for the early embryo on cytoplasmic lattices. Cell 2023; 186:5308-5327.e25. [PMID: 37922900 DOI: 10.1016/j.cell.2023.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 08/01/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023]
Abstract
Mammalian oocytes are filled with poorly understood structures called cytoplasmic lattices. First discovered in the 1960s and speculated to correspond to mammalian yolk, ribosomal arrays, or intermediate filaments, their function has remained enigmatic to date. Here, we show that cytoplasmic lattices are sites where oocytes store essential proteins for early embryonic development. Using super-resolution light microscopy and cryoelectron tomography, we show that cytoplasmic lattices are composed of filaments with a high surface area, which contain PADI6 and subcortical maternal complex proteins. The lattices associate with many proteins critical for embryonic development, including proteins that control epigenetic reprogramming of the preimplantation embryo. Loss of cytoplasmic lattices by knocking out PADI6 or the subcortical maternal complex prevents the accumulation of these proteins and results in early embryonic arrest. Our work suggests that cytoplasmic lattices enrich maternally provided proteins to prevent their premature degradation and cellular activity, thereby enabling early mammalian development.
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Affiliation(s)
- Ida M A Jentoft
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Felix J B Bäuerlein
- Institute for Neuropathology, University Medical Center Göttingen, 37077 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37077 Göttingen, Germany
| | - Luisa M Welp
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany; Institute of Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Benjamin H Cooper
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, 37075 Göttingen, Germany
| | - Arsen Petrovic
- Institute for Neuropathology, University Medical Center Göttingen, 37077 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37077 Göttingen, Germany
| | - Chun So
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Sarah Mae Penir
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Antonio Z Politi
- Facility for Light Microscopy, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Yehor Horokhovskyi
- Quantitative and Systems Biology Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Iina Takala
- Quantitative and Systems Biology Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Heike Eckel
- Kinderwunschzentrum Göttingen, 37081 Göttingen, Germany
| | | | - Peter Lénárt
- Facility for Light Microscopy, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Tommaso Cavazza
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Juliane Liepe
- Quantitative and Systems Biology Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Nils Brose
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37077 Göttingen, Germany; Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, 37075 Göttingen, Germany
| | - Henning Urlaub
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37077 Göttingen, Germany; Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany; Institute of Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany; Göttingen Center for Molecular Biosciences, Georg-August University Göttingen, 37077 Göttingen, Germany
| | - Rubén Fernández-Busnadiego
- Institute for Neuropathology, University Medical Center Göttingen, 37077 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37077 Göttingen, Germany; Faculty of Physics, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37077 Göttingen, Germany.
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12
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Nasalingkhan C, Sirinonthanawech N, Noree C. Robust assembly of the aldehyde dehydrogenase Ald4p in Saccharomyces cerevisiae. Biol Open 2023; 12:bio060070. [PMID: 37767855 PMCID: PMC10602002 DOI: 10.1242/bio.060070] [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: 07/10/2023] [Accepted: 09/26/2023] [Indexed: 09/29/2023] Open
Abstract
As part of our studies of yeast aldehyde dehydrogenase (Ald4p) assembly, we identified a population of transformants (SWORD strain) that show more robust filament formation of GFP-tagged Ald4p (Ald4p-GFP) than that of a wild type ALD4::GFP strain. Sequencing of the ALD4 gene in the SWORD strain showed that the increased assembly was not due to changes to the ALD4 coding sequence, suggesting that a second mutation site was altering Ald4p assembly. Using short-read whole-genome sequencing, we identified spontaneous mutations in FLO9. Introduction of the SWORD allele of FLO9 into a wild-type ALD4::GFP yeast strain revealed that the changes to FLO9 were a contributor to the increased length of Ald4p-GFP filaments we observe in the SWORD strain and that this effect was not due to an increase in Ald4p protein levels. However, the expression of the FLO9 (SWORD) allele in wild-type yeast did not fully recapitulate the length control defect we observed in SWORD strains, arguing that there are additional genes contributing to the filament length phenotype. For our future work, this FLO9 from SWORD will be tested whether it could show global effect, promoting the assembly of some other filament-forming enzymes.
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Affiliation(s)
- Channarong Nasalingkhan
- Institute of Molecular Biosciences, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom 73170Thailand
| | - Naraporn Sirinonthanawech
- Institute of Molecular Biosciences, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom 73170Thailand
| | - Chalongrat Noree
- Institute of Molecular Biosciences, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom 73170Thailand
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13
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Paukštytė J, López Cabezas RM, Feng Y, Tong K, Schnyder D, Elomaa E, Gregorova P, Doudin M, Särkkä M, Sarameri J, Lippi A, Vihinen H, Juutila J, Nieminen A, Törönen P, Holm L, Jokitalo E, Krisko A, Huiskonen J, Sarin LP, Hietakangas V, Picotti P, Barral Y, Saarikangas J. Global analysis of aging-related protein structural changes uncovers enzyme-polymerization-based control of longevity. Mol Cell 2023; 83:3360-3376.e11. [PMID: 37699397 DOI: 10.1016/j.molcel.2023.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 05/18/2023] [Accepted: 08/11/2023] [Indexed: 09/14/2023]
Abstract
Aging is associated with progressive phenotypic changes. Virtually all cellular phenotypes are produced by proteins, and their structural alterations can lead to age-related diseases. However, we still lack comprehensive knowledge of proteins undergoing structural-functional changes during cellular aging and their contributions to age-related phenotypes. Here, we conducted proteome-wide analysis of early age-related protein structural changes in budding yeast using limited proteolysis-mass spectrometry (LiP-MS). The results, compiled in online ProtAge catalog, unraveled age-related functional changes in regulators of translation, protein folding, and amino acid metabolism. Mechanistically, we found that folded glutamate synthase Glt1 polymerizes into supramolecular self-assemblies during aging, causing breakdown of cellular amino acid homeostasis. Inhibiting Glt1 polymerization by mutating the polymerization interface restored amino acid levels in aged cells, attenuated mitochondrial dysfunction, and led to lifespan extension. Altogether, this comprehensive map of protein structural changes enables identifying mechanisms of age-related phenotypes and offers opportunities for their reversal.
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Affiliation(s)
- Jurgita Paukštytė
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Rosa María López Cabezas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Yuehan Feng
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Kai Tong
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA; Interdisciplinary Graduate Program in Quantitative Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Ellinoora Elomaa
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Pavlina Gregorova
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Matteo Doudin
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Meeri Särkkä
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Jesse Sarameri
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Alice Lippi
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Helena Vihinen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Juhana Juutila
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Anni Nieminen
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Petri Törönen
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Liisa Holm
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Eija Jokitalo
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Anita Krisko
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Juha Huiskonen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - L Peter Sarin
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Paola Picotti
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland; Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Yves Barral
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Juha Saarikangas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.
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14
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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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15
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Fischbach A, Johns A, Schneider KL, Hao X, Tessarz P, Nyström T. Artificial Hsp104-mediated systems for re-localizing protein aggregates. Nat Commun 2023; 14:2663. [PMID: 37160881 PMCID: PMC10169802 DOI: 10.1038/s41467-023-37706-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 03/28/2023] [Indexed: 05/11/2023] Open
Abstract
Spatial Protein Quality Control (sPQC) sequesters misfolded proteins into specific, organelle-associated inclusions within the cell to control their toxicity. To approach the role of sPQC in cellular fitness, neurodegenerative diseases and aging, we report on the construction of Hsp100-based systems in budding yeast cells, which can artificially target protein aggregates to non-canonical locations. We demonstrate that aggregates of mutant huntingtin (mHtt), the disease-causing agent of Huntington's disease can be artificially targeted to daughter cells as well as to eisosomes and endosomes with this approach. We find that the artificial removal of mHtt inclusions from mother cells protects them from cell death suggesting that even large mHtt inclusions may be cytotoxic, a trait that has been widely debated. In contrast, removing inclusions of endogenous age-associated misfolded proteins does not significantly affect the lifespan of mother cells. We demonstrate also that this approach is able to manipulate mHtt inclusion formation in human cells and has the potential to be useful as an alternative, complementary approach to study the role of sPQC, for example in aging and neurodegenerative disease.
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Affiliation(s)
- Arthur Fischbach
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg, Sweden.
- Max-Planck Research Group Chromatin and Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany.
| | - Angela Johns
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg, Sweden
| | - Kara L Schneider
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg, Sweden
| | - Xinxin Hao
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg, Sweden
| | - Peter Tessarz
- Max-Planck Research Group Chromatin and Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
- Cologne Excellence Cluster on Stress Responses in Ageing-Associated Diseases (CECAD), Cologne, Germany
| | - Thomas Nyström
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg, Sweden.
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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: 16] [Impact Index Per Article: 16.0] [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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The role of filamentation in activation and DNA sequence specificity of the sequence-specific endonuclease SgrAI. Biochem Soc Trans 2022; 50:1703-1714. [PMID: 36398769 PMCID: PMC9788392 DOI: 10.1042/bst20220547] [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: 08/17/2022] [Revised: 10/09/2022] [Accepted: 10/12/2022] [Indexed: 11/19/2022]
Abstract
Filament formation by metabolic, biosynthetic, and other enzymes has recently come into focus as a mechanism to fine-tune enzyme activity in the cell. Filamentation is key to the function of SgrAI, a sequence-specific DNA endonuclease that has served as a model system to provide some of the deepest insights into the biophysical characteristics of filamentation and its functional consequences. Structure-function analyses reveal that, in the filamentous state, SgrAI stabilizes an activated enzyme conformation that leads to accelerated DNA cleavage activity and expanded DNA sequence specificity. The latter is thought to be mediated by sequence-specific DNA structure, protein-DNA interactions, and a disorder-to-order transition in the protein, which collectively affect the relative stabilities of the inactive, non-filamentous conformation and the active, filamentous conformation of SgrAI bound to DNA. Full global kinetic modeling of the DNA cleavage pathway reveals a slow, rate-limiting, second-order association rate constant for filament assembly, and simulations of in vivo activity predict that filamentation is superior to non-filamenting mechanisms in ensuring rapid activation and sequestration of SgrAI's DNA cleavage activity on phage DNA and away from the host chromosome. In vivo studies demonstrate the critical requirement for accelerated DNA cleavage by SgrAI in its biological role to safeguard the bacterial host. Collectively, these data have advanced our understanding of how filamentation can regulate enzyme structure and function, while the experimental strategies used for SgrAI can be applied to other enzymatic systems to identify novel functional roles for filamentation.
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18
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Andreadis C, Li T, Liu JL. Ubiquitination regulates cytoophidium assembly in Schizosaccharomyces pombe. Exp Cell Res 2022; 420:113337. [PMID: 36087798 DOI: 10.1016/j.yexcr.2022.113337] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/26/2022] [Accepted: 08/27/2022] [Indexed: 12/30/2022]
Abstract
CTP synthase (CTPS), a metabolic enzyme responsible for the de novo synthesis of CTP, can form filamentous structures termed cytoophidia, which are evolutionarily conserved from bacteria to humans. Here we used Schizosaccharomyces pombe to study the cytoophidium assembly regulation by ubiquitination. We tested the CTP synthase's capacity to be post-translationally modified by ubiquitin or be affected by the ubiquitination state of the cell and showed that ubiquitination is important for the maintenance of the CTPS filamentous structure in fission yeast. We have identified proteins which are in complex with CTPS, including specific ubiquitination regulators which significantly affect CTPS filamentation, and mapped probable ubiquitination targets on CTPS. Furthermore, we discovered that a cohort of deubiquitinating enzymes is important for the regulation of cytoophidium's filamentous morphology. Our study provides a framework for the analysis of the effects that ubiquitination and deubiquitination have on the formation of cytoophidia.
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Affiliation(s)
- Christos Andreadis
- School of Life Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Tianhao Li
- School of Life Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, 201210, Shanghai, China; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom.
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19
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Fang YF, Li YL, Li XM, Liu JL. Super-Resolution Imaging Reveals Dynamic Reticular Cytoophidia. Int J Mol Sci 2022; 23:11698. [PMID: 36233000 PMCID: PMC9569780 DOI: 10.3390/ijms231911698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 11/16/2022] Open
Abstract
CTP synthase (CTPS) can form filamentous structures termed cytoophidia in cells in all three domains of life. In order to study the mesoscale structure of cytoophidia, we perform fluorescence recovery after photobleaching (FRAP) and stimulated emission depletion (STED) microscopy in human cells. By using an EGFP dimeric tag as a tool to explore the physical properties of cytoophidia, we find that cytoophidia are dynamic and reticular. The reticular structure of CTPS cytoophidia may provide space for other components, such as IMPDH. In addition, we observe CTPS granules with tentacles.
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Affiliation(s)
- Yi-Fan Fang
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Yi-Lan Li
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Xiao-Ming Li
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Ji-Long Liu
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
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20
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Jin X, Zhou M, Chen S, Li D, Cao X, Liu B. Effects of pH alterations on stress- and aging-induced protein phase separation. Cell Mol Life Sci 2022; 79:380. [PMID: 35750966 PMCID: PMC9232405 DOI: 10.1007/s00018-022-04393-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/26/2022] [Accepted: 05/21/2022] [Indexed: 01/18/2023]
Abstract
Upon stress challenges, proteins/RNAs undergo liquid–liquid phase separation (LLPS) to fine-tune cell physiology and metabolism to help cells adapt to adverse environments. The formation of LLPS has been recently linked with intracellular pH, and maintaining proper intracellular pH homeostasis is known to be essential for the survival of organisms. However, organisms are constantly exposed to diverse stresses, which are accompanied by alterations in the intracellular pH. Aging processes and human diseases are also intimately linked with intracellular pH alterations. In this review, we summarize stress-, aging-, and cancer-associated pH changes together with the mechanisms by which cells regulate cytosolic pH homeostasis. How critical cell components undergo LLPS in response to pH alterations is also discussed, along with the functional roles of intracellular pH fluctuation in the regulation of LLPS. Further studies investigating the interplay of pH with other stressors in LLPS regulation and identifying protein responses to different pH levels will provide an in-depth understanding of the mechanisms underlying pH-driven LLPS in cell adaptation. Moreover, deciphering aging and disease-associated pH changes that influence LLPS condensate formation could lead to a deeper understanding of the functional roles of biomolecular condensates in aging and aging-related diseases.
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Affiliation(s)
- Xuejiao Jin
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Min Zhou
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Shuxin Chen
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Danqi Li
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Xiuling Cao
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China.
| | - Beidong Liu
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China. .,Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 413 90, Goteborg, Sweden. .,Center for Large-Scale Cell-Based Screening, Faculty of Science, University of Gothenburg, Medicinaregatan 9C, 413 90, Goteborg, Sweden.
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21
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Hu HH, Lu GM, Chang CC, Li Y, Zhong J, Guo CJ, Zhou X, Yin B, Zhang T, Liu JL. Filamentation modulates allosteric regulation of PRPS. eLife 2022; 11:79552. [PMID: 35736577 PMCID: PMC9232217 DOI: 10.7554/elife.79552] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphoribosyl pyrophosphate (PRPP) is a key intermediate in the biosynthesis of purine and pyrimidine nucleotides, histidine, tryptophan, and cofactors NAD and NADP. Abnormal regulation of PRPP synthase (PRPS) is associated with human disorders, including Arts syndrome, retinal dystrophy, and gouty arthritis. Recent studies have demonstrated that PRPS can form filamentous cytoophidia in eukaryotes. Here, we show that PRPS forms cytoophidia in prokaryotes both in vitro and in vivo. Moreover, we solve two distinct filament structures of E. coli PRPS at near-atomic resolution using Cryo-EM. The formation of the two types of filaments is controlled by the binding of different ligands. One filament type is resistant to allosteric inhibition. The structural comparison reveals conformational changes of a regulatory flexible loop, which may regulate the binding of the allosteric inhibitor and the substrate ATP. A noncanonical allosteric AMP/ADP binding site is identified to stabilize the conformation of the regulatory flexible loop. Our findings not only explore a new mechanism of PRPS regulation with structural basis, but also propose an additional layer of cell metabolism through PRPS filamentation.
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Affiliation(s)
- Huan-Huan Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Guang-Ming Lu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Chia-Chun Chang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yilan Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jiale Zhong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Chen-Jun Guo
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xian Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Boqi Yin
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Tianyi 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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22
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Wu Z, Liu JL. CTP synthase does not form cytoophidia in Drosophila interfollicular stalks. Exp Cell Res 2022; 418:113250. [PMID: 35691380 DOI: 10.1016/j.yexcr.2022.113250] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/05/2022] [Accepted: 06/06/2022] [Indexed: 11/26/2022]
Abstract
CTP synthase (CTPS) catalyzes the final step of de novo synthesis of the nucleotide CTP. In 2010, CTPS has been found to form filamentous structures termed cytoophidia in Drosophila follicle cells and germline cells. Subsequently, cytoophidia have been reported in many species across three domains of life: bacteria, eukaryotes and archaea. Forming cytoophidia appears to be a highly conserved and ancient property of CTPS. To our surprise, here we find that polar cells and stalk cells, two specialized types of cells composing Drosophila interfollicular stalks, do not possess obvious cytoophidia. We show that Myc level is low in these two types of cells. Treatment with a glutamine analog, 6-diazo-5-oxo-l-norleucine (DON), increases cytoophidium assembly in main follicle cells, but not in polar cells or stalk cells. Moreover, overexpressing Myc induces cytoophidium formation in stalk cells. When CTPS is overexpressed, cytoophidia can be observed both in stalk cells and polar cells. Our findings provide an interesting paradigm for the in vivo study of cytoophidium assembly and disassembly among different populations of follicle cells.
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Affiliation(s)
- Zheng Wu
- School of Life Science and Technology, ShanghaiTech University, 230 Haike Road, 201210, Shanghai, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, 230 Haike Road, 201210, Shanghai, China; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3PT, United Kingdom.
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23
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Huang P, Chen S, Chiang W, Ho M, Wu K. Structural basis for the helical filament formation of Escherichia coli glutamine synthetase. Protein Sci 2022; 31:e4304. [PMID: 35481643 PMCID: PMC8996467 DOI: 10.1002/pro.4304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 02/01/2023]
Abstract
Escherichia coli glutamine synthetase (EcGS) spontaneously forms a dodecamer that catalytically converts glutamate to glutamine. EcGS stacks with other dodecamers to create a filament-like polymer visible under transmission electron microscopy. Filamentous EcGS is induced by environmental metal ions. We used cryo-electron microscopy (cryo-EM) to decipher the structure of metal ion (nickel)-induced EcGS helical filament at a sub-3Å resolution. EcGS filament formation involves stacking of native dodecamers by chelating nickel ions to residues His5 and His13 in the first N-terminal helix (H1). His5 and His13 from paired parallel H1 helices provide salt bridges and hydrogen bonds to tightly stack two dodecamers. One subunit of the EcGS filament hosts two nickel ions, whereas the dodecameric interface and the ATP/Mg-binding site both host a nickel ion each. We reveal that upon adding glutamate or ATP for catalytic reactions, nickel-induced EcGS filament reverts to individual dodecamers. Such tunable filament formation is often associated with stress responses. Our results provide detailed structural information on the mechanism underlying reversible and tunable EcGS filament formation.
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Affiliation(s)
- Pei‐Chi Huang
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
- Department of ChemistryNational Taiwan Normal UniversityTaipeiTaiwan
| | - Shao‐Kang Chen
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
| | - Wei‐Hung Chiang
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
| | - Meng‐Ru Ho
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
| | - Kuen‐Phon Wu
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
- Institute of Biochemical ScienceCollege of Life Science, National Taiwan UniversityTaipeiTaiwan
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24
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Shan Z, Ghadirian N, Lyumkis D, Horton NC. Pretransition state and apo structures of the filament-forming enzyme SgrAI elucidate mechanisms of activation and substrate specificity. J Biol Chem 2022; 298:101760. [PMID: 35202658 PMCID: PMC8960973 DOI: 10.1016/j.jbc.2022.101760] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 12/01/2022] Open
Abstract
Enzyme filamentation is a widespread phenomenon that mediates enzyme regulation and function. For the filament-forming sequence-specific DNA endonuclease SgrAI, the process of filamentation both accelerates its DNA cleavage activity and expands its DNA sequence specificity, thus allowing for many additional DNA sequences to be rapidly cleaved. Both outcomes-the acceleration of DNA cleavage and the expansion of sequence specificity-are proposed to regulate critical processes in bacterial innate immunity. However, the mechanistic bases underlying these events remain unclear. Herein, we describe two new structures of the SgrAI enzyme that shed light on its catalytic function. First, we present the cryo-EM structure of filamentous SgrAI bound to intact primary site DNA and Ca2+ resolved to ∼2.5 Å within the catalytic center, which represents the trapped enzyme-DNA complex prior to the DNA cleavage reaction. This structure reveals important conformational changes that contribute to the catalytic mechanism and the binding of a second divalent cation in the enzyme active site, which is expected to contribute to increased DNA cleavage activity of SgrAI in the filamentous state. Second, we present an X-ray crystal structure of DNA-free (apo) SgrAI resolved to 2.0 Å resolution, which reveals a disordered loop involved in DNA recognition. Collectively, these multiple new observations clarify the mechanism of expansion of DNA sequence specificity of SgrAI, including the indirect readout of sequence-dependent DNA structure, changes in protein-DNA interactions, and the disorder-to-order transition of a crucial DNA recognition element.
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Affiliation(s)
- Zelin Shan
- Laboratory of Genetics, The Salk Institute of Biological Sciences, La Jolla, California, USA
| | - Niloofar Ghadirian
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Dmitry Lyumkis
- Laboratory of Genetics, The Salk Institute of Biological Sciences, La Jolla, California, USA; Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.
| | - Nancy C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA.
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25
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Miura N. Condensate Formation by Metabolic Enzymes in Saccharomyces cerevisiae. Microorganisms 2022; 10:232. [PMID: 35208686 PMCID: PMC8876316 DOI: 10.3390/microorganisms10020232] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 12/31/2022] Open
Abstract
Condensate formation by a group of metabolic enzymes in the cell is an efficient way of regulating cell metabolism through the formation of "membrane-less organelles." Because of the use of green fluorescent protein (GFP) for investigating protein localization, various enzymes were found to form condensates or filaments in living Saccharomyces cerevisiae, mammalian cells, and in other organisms, thereby regulating cell metabolism in the certain status of the cells. Among different environmental stresses, hypoxia triggers the spatial reorganization of many proteins, including more than 20 metabolic enzymes, to form numerous condensates, including "Glycolytic body (G-body)" and "Purinosome." These individual condensates are collectively named "Metabolic Enzymes Transiently Assembling (META) body". This review overviews condensate or filament formation by metabolic enzymes in S. cerevisiae, focusing on the META body, and recent reports in elucidating regulatory machinery of META body formation.
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Affiliation(s)
- Natsuko Miura
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Japan
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26
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Hansen JM, Horowitz A, Lynch EM, Farrell DP, Quispe J, DiMaio F, Kollman JM. Cryo-EM structures of CTP synthase filaments reveal mechanism of pH-sensitive assembly during budding yeast starvation. eLife 2021; 10:73368. [PMID: 34734801 PMCID: PMC8641951 DOI: 10.7554/elife.73368] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/03/2021] [Indexed: 12/27/2022] Open
Abstract
Many metabolic enzymes self-assemble into micron-scale filaments to organize and regulate metabolism. The appearance of these assemblies often coincides with large metabolic changes as in development, cancer, and stress. Yeast undergo cytoplasmic acidification upon starvation, triggering the assembly of many metabolic enzymes into filaments. However, it is unclear how these filaments assemble at the molecular level and what their role is in the yeast starvation response. CTP Synthase (CTPS) assembles into metabolic filaments across many species. Here, we characterize in vitro polymerization and investigate in vivo consequences of CTPS assembly in yeast. Cryo-EM structures reveal a pH-sensitive assembly mechanism and highly ordered filament bundles that stabilize an inactive state of the enzyme, features unique to yeast CTPS. Disruption of filaments in cells with non-assembly or pH-insensitive mutations decreases growth rate, reflecting the importance of regulated CTPS filament assembly in homeotstasis.
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Affiliation(s)
- Jesse M Hansen
- Department of Biochemistry, University of Washington, Seattle, United States.,Graduate Program in Biological Physics, Structure, and Design, University of Washington, Seattle, United States
| | - Avital Horowitz
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Eric M Lynch
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Daniel P Farrell
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Joel Quispe
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, United States
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27
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Drosophila intestinal homeostasis requires CTP synthase. Exp Cell Res 2021; 408:112838. [PMID: 34560103 DOI: 10.1016/j.yexcr.2021.112838] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/12/2021] [Accepted: 09/17/2021] [Indexed: 11/22/2022]
Abstract
CTP synthase (CTPS) senses all four nucleotides and forms filamentous structures termed cytoophidia in all three domains of life. How CTPS and cytoophidia function in a developmental context, however, remains underexplored. We report that CTPS forms cytoophidia in a subset of cells in the Drosophila midgut. We found that cytoophidia exist in intestinal stem cells (ISC) and enteroblasts in similar proportions. Both refeeding after starvation and feeding with dextran sulfate sodium (DSS) induce ISC proliferation and elongate cytoophidia. Knockdown of CTPS inhibits ISC proliferation. Remarkably, disruption of CTPS cytoophidia inhibits DSS-induced ISC proliferation. Taken together, these data suggest that both the expression level and the filament-form property of CTPS are crucial for intestinal homeostasis in Drosophila.
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28
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Abstract
Hypoxia inhibits the tricarboxylic acid (TCA) cycle and leaves glycolysis as the primary metabolic pathway responsible for converting glucose into usable energy. However, the mechanisms that compensate for this loss in energy production due to TCA cycle inactivation remain poorly understood. Glycolysis enzymes are typically diffuse and soluble in the cytoplasm under normoxic conditions. In contrast, recent studies have revealed dynamic compartmentalization of glycolysis enzymes in response to hypoxic stress in yeast, C. elegans and mammalian cells. These messenger ribonucleoprotein (mRNP) structures, termed glycolytic (G) bodies in yeast, lack membrane enclosure and display properties of phase-separated biomolecular condensates. Disruption of condensate formation correlates with defects such as impaired synaptic function in C. elegans neurons and decreased glucose flux in yeast. Concentrating glycolysis enzymes into condensates may lead to their functioning as 'metabolons' that enhance rates of glucose utilization for increased energy production. Besides condensates, glycolysis enzymes functionally associate in other organisms and specific tissues through protein-protein interactions and membrane association. However, as discussed in this Review, the functional consequences of coalescing glycolytic machinery are only just beginning to be revealed. Through ongoing studies, we anticipate the physiological importance of metabolic regulation mediated by the compartmentalization of glycolysis enzymes will continue to emerge.
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Affiliation(s)
- Gregory G Fuller
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - John K Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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29
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Zhang B, Zhang Y, Liu JL. Highly effective proximate labeling in Drosophila. G3-GENES GENOMES GENETICS 2021; 11:6173991. [PMID: 33724396 PMCID: PMC8104946 DOI: 10.1093/g3journal/jkab077] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 02/05/2021] [Indexed: 12/16/2022]
Abstract
The protein-protein interaction (PPI) is a basic strategy for life to operate. The analysis of PPIs in multicellular organisms is very important but extremely challenging because PPIs are particularly dynamic and variable among different development stages, tissues, cells, and even organelles. Therefore, understanding PPI needs a good resolution of time and space. More importantly, understanding in vivo PPI needs to be realized in situ. Proximity-based biotinylation combined with mass spectrometry (MS) has emerged as a powerful approach to study PPI networks and protein subcellular compartmentation. TurboID, the newly engineered promiscuous ligase, has been reported to label proximate proteins effectively in various species. In Drosophila, we systematically apply TurboID-mediated biotinylation in a wide range of developmental stages and tissues, and demonstrate the feasibility of TurboID-mediated labeling system in desired cell types. For a proof-of-principle, we use the TurboID-mediated biotinylation coupled with MS to distinguish CTP synthase with or without the ability to form filamentous cytoophidia, retrieving two distinct sets of proximate proteomes. Therefore, this makes it possible to map PPIs in vivo and in situ at a defined spatiotemporal resolution, and demonstrates a referable resource for cytoophidium proteome in Drosophila.
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Affiliation(s)
- Bo Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanbing Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - 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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30
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Zhang S, Feng HC, Liu JL. ASNS disruption shortens CTPS cytoophidia in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2021; 11:6080684. [PMID: 33561249 PMCID: PMC8022725 DOI: 10.1093/g3journal/jkaa060] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Asparagine synthetase (ASNS) and CTP synthase (CTPS) are two metabolic enzymes that catalyze the biosynthesis of asparagine and CTP, respectively. Both CTPS and ASNS have been identified to form cytoophidia in Saccharomyces cerevisiae. Glutamine is a common substrate for both these enzymes, and they play an important role in glutamine homeostasis. Here, we find that the ASNS cytoophidia are shorter than the CTPS cytoophidia, and that disruption of ASNS shortens the length of CTPS cytoophidia. However, the deletion of CTPS has no effect on the formation and length of ASNS cytoophidia, or on the ASNS protein level. We also find that Asn1 overexpression induces the formation of a multi-dot structure in diauxic phase which suggests that the increased protein level may trigger cytoophidia formation. Collectively, our results reveal a connection between ASNS cytoophidia and CTPS cytoophidia.
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Affiliation(s)
- Shanshan Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Han-Chao Feng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - 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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31
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Simonet JC, Burrell AL, Kollman JM, Peterson JR. Freedom of assembly: metabolic enzymes come together. Mol Biol Cell 2021; 31:1201-1205. [PMID: 32463766 PMCID: PMC7353150 DOI: 10.1091/mbc.e18-10-0675] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Many different enzymes in intermediate metabolism dynamically assemble filamentous polymers in cells, often in response to changes in physiological conditions. Most of the enzyme filaments known to date have only been observed in cells, but in a handful of cases structural and biochemical studies have revealed the mechanisms and consequences of assembly. In general, enzyme polymerization functions as a mechanism to allosterically tune enzyme kinetics, and it may play a physiological role in integrating metabolic signaling. Here, we highlight some principles of metabolic filaments by focusing on two well-studied examples in nucleotide biosynthesis pathways—inosine-5’-monophosphate (IMP) dehydrogenase and cytosine triphosphate (CTP) synthase.
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Affiliation(s)
| | - Anika L Burrell
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
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32
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Keppeke GD, Chang CC, Antos CL, Peng M, Sung LY, Andrade LEC, Liu JL. IMPDH forms the cytoophidium in zebrafish. Dev Biol 2021; 478:89-101. [PMID: 34048735 DOI: 10.1016/j.ydbio.2021.05.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023]
Abstract
Inosine monophosphate dehydrogenase (IMPDH) catalyzes the rate-limiting step in de novo guanine nucleotide biosynthesis. Its activity is negatively regulated by the binding of GTP. IMPDH can form a membraneless subcellular structure termed the cytoophidium in response to certain changes in the metabolic status of the cell. The polymeric form of IMPDH, which is the subunit of the cytoophidium, has been shown to be more resistant to the inhibition by GTP at physiological concentrations, implying a functional correlation between cytoophidium formation and the upregulation of GTP biosynthesis. Herein we demonstrate that zebrafish IMPDH1b and IMPDH2 isoforms can assemble abundant cytoophidium in most of cultured cells under stimuli, while zebrafish IMPDH1a shows distinctive properties of forming the cytoophidium in different cell types. Point mutations that disrupt cytoophidium structure in mammalian models also prevent the aggregation of zebrafish IMPDHs. In addition, we discover the presence of the IMPDH cytoophidium in various tissues of larval and adult fish under normal growth conditions. Our results reveal that polymerization and cytoophidium assembly of IMPDH can be a regulatory machinery conserved among vertebrates, and with specific physiological purposes.
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Affiliation(s)
- 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
| | - Chia-Chun Chang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Christopher L Antos
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Min Peng
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan
| | - Li-Ying Sung
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan; Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Luis Eduardo Coelho Andrade
- Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Sao Paulo, SP, 04023-062, Brazil
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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33
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Peng M, Chang CC, Liu JL, Sung LY. CTPS and IMPDH form cytoophidia in developmental thymocytes. Exp Cell Res 2021; 405:112662. [PMID: 34022203 DOI: 10.1016/j.yexcr.2021.112662] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 02/06/2023]
Abstract
The cytoophidium, a filamentous structure formed by metabolic enzymes, has emerged as a novel regulatory machinery for certain proteins. The rate-limiting enzymes of de novo CTP and GTP synthesis, cytidine triphosphate synthase (CTPS) and inosine monophosphate dehydrogenase (IMPDH), are the most characterized cytoophidium-forming enzymes in mammalian models. Although the assembly of CTPS cytoophidia has been demonstrated in various organisms including multiple human cancers, a systemic survey for the presence of CTPS cytoophidia in mammalian tissues in normal physiological conditions has not yet been reported. Herein, we examine major organs of adult mouse and observe that CTPS cytoophidia are displayed by a specific thymocyte population ranging between DN3 to early DP stages. Most of these cytoophidium-presenting cells have both CTPS and IMPDH cytoophidia and undergo rapid cell proliferation. In addition, we show that cytoophidium formation is associated with active glycolytic metabolism as the cytoophidium-presenting cells exhibit higher levels of c-Myc, phospho-Akt and PFK. Inhibition of glycolysis with 2DG, however, disrupts most of cytoophidium structures and impairs cell proliferation. Our findings not only indicate that the regulation of CTPS and IMPDH cytoophidia are correlated with the metabolic switch triggered by pre-TCR signaling, but also suggest physiological roles of the cytoophidium in thymocyte development.
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Affiliation(s)
- Min Peng
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan
| | - Chia-Chun Chang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Li-Ying Sung
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan; Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan; Animal Resource Center, National Taiwan University, Taipei, 106, Taiwan.
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34
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Surasiang T, Noree C. Effects of A6E Mutation on Protein Expression and Supramolecular Assembly of Yeast Asparagine Synthetase. BIOLOGY 2021; 10:biology10040294. [PMID: 33916846 PMCID: PMC8065433 DOI: 10.3390/biology10040294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Certain mutations causing extremely low abundance of asparagine synthetase (the enzyme responsible for producing asparagine, one of the amino acids required for normal growth and development) have been identified in humans with neurological problems and small head and brain size. Currently, yeast is becoming more popular in modeling many human diseases. In this study, we incorporate a mutation, associated with human asparagine synthetase deficiency, into the yeast asparagine synthetase gene to demonstrate that this mutation can also show similar effects as those observed in humans, leading to very low abundance of yeast asparagine synthetase and slower yeast growth rate. This suggests that our yeast system can be alternatively used to initially screen for any drugs that can help rescue the protein levels of asparagine synthetase before applying them to further studies in mammals and humans. Furthermore, this mutation might specifically be introduced into the asparagine synthetase gene of the target cancer cells in order to suppress the overproduction of asparagine synthetase within these abnormal cells, therefore inhibiting the growth of cancer, which might be helpful for patients with blood cancer to prevent them developing any resistance to the conventional asparaginase treatment. Abstract Asparagine synthetase deficiency (ASD) has been found to be caused by certain mutations in the gene encoding human asparagine synthetase (ASNS). Among reported mutations, A6E mutation showed the greatest reduction in ASNS abundance. However, the effect of A6E mutation has not yet been tested with yeast asparagine synthetase (Asn1/2p). Here, we constructed a yeast strain by deleting ASN2 from its genome, introducing the A6E mutation codon to ASN1, along with GFP downstream of ASN1. Our mutant yeast construct showed a noticeable decrease of Asn1p(A6E)-GFP levels as compared to the control yeast expressing Asn1p(WT)-GFP. At the stationary phase, the A6E mutation also markedly lowered the assembly frequency of the enzyme. In contrast to Asn1p(WT)-GFP, Asn1p(A6E)-GFP was insensitive to changes in the intracellular energy levels upon treatment with sodium azide during the log phase or fresh glucose at the stationary phase. Our study has confirmed that the effect of A6E mutation on protein expression levels of asparagine synthetase is common in both unicellular and multicellular eukaryotes, suggesting that yeast could be a model of ASD. Furthermore, A6E mutation could be introduced to the ASNS gene of acute lymphoblastic leukemia patients to inhibit the upregulation of ASNS by cancer cells, reducing the risk of developing resistance to the asparaginase treatment.
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35
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Histone transcription regulator Slm9 is required for cytoophidium biogenesis. Exp Cell Res 2021; 403:112582. [PMID: 33812868 DOI: 10.1016/j.yexcr.2021.112582] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/25/2021] [Accepted: 03/28/2021] [Indexed: 11/23/2022]
Abstract
The cytoophidium, a subcellular structure composed of CTP synthase, can be observed during the division of Schizosaccharomyces pombe. Cytoophidium formation changes periodically with the cell cycle of yeast cells. Here, we find that histone chaperone Slm9 is required for the integrity of cytoophidia in fission yeast. When the slm9 gene is knocked out, we observe that morphological characteristics, the abundance of cytoophidia and the division of the yeast cells are significantly affected. Fragmented cytoophidia occur in slm9 mutant cells, a phenomenon rarely observed in wild-type cells. Our study reveals a potential link between a chromosomal regulatory factor and cytoophidium biogenesis.
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36
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Wang QQ, Zhao PA, Tastan ÖY, Liu JL. Polarised maintenance of cytoophidia in Drosophila follicle epithelia. Exp Cell Res 2021; 402:112564. [PMID: 33737069 DOI: 10.1016/j.yexcr.2021.112564] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 12/20/2022]
Abstract
The metabolic enzyme CTP synthase (CTPS) can form filamentous structures named cytoophidia in numerous types of cells, including follicle cells. However, the regulation of cytoophidium assembly remains elusive. The apicobasal polarity, a defining characteristic of Drosophila follicle epithelium, is established and regulated by a variety of membrane domains. Here we show that CTPS can form cytoophidia in Drosophila epithelial follicle cells. Cytoophidia localise to the basolateral side of follicle cells. If apical polarity regulators are knocked down, cytoophidia become unstable and distribute abnormally. Knockdown of basolateral polarity regulators has no significant effect on cytoophidia, even though the polarity is disturbed. Our results indicate that cytoophidia are maintained via polarised distribution on the basolateral side of Drosophila follicle epithelia, which is primarily achieved through the apical polarity regulators.
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Affiliation(s)
- Qiao-Qi Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Peiyao A Zhao
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom
| | - Ömür Y Tastan
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom.
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37
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Li YL, Liu JL. Hypoosmolality impedes cytoophidium integrity during nitrogen starvation. Yeast 2021; 38:276-289. [PMID: 33294993 DOI: 10.1002/yea.3542] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/18/2020] [Accepted: 12/03/2020] [Indexed: 12/26/2022] Open
Abstract
CTP synthase (CTPS) cytoophidia have been found in many species over domains of life in the past 10 years, implying the evolutionary conservation of these structures. However, there are differences in cytoophidia between species. The difference in CTPS cytoophidium properties between budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) inspires this research. We study the effects of culture environment on cytoophidia in S. cerevisiae by switching to the optimal medium for S. pombe. S. cerevisiae CTPS cytoophidium fragmentation and pseudohyphae formation are observed after treatment with S. pombe medium YES instead of S. cerevisiae medium YPD. By modifying the level of each ingredient of the media, we find that hypoosmolality impedes cytoophidium integrity during nitrogen starvation. Our study demonstrates the relationship between cytoophidium integrity and environmental stress, supporting the role of cytoophidia in stress resistance.
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Affiliation(s)
- Yi-Lan Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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38
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Abstract
Live-cell imaging is widely used by researchers to study cellular dynamics and obtain a deep understanding of cell biological processes. Keeping cells in the proper growing environment and immobilizing the cells are essential for the imaging of live yeast cells. Here we describe a protocol for monitoring cytoophidia in Saccharomyces cerevisiae and Schizosaccharomyces pombe using inverted confocal fluorescence microscopy. This protocol includes yeast culture, sample preparation, fluorescence imaging, and data analysis.
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Affiliation(s)
- Shanshan Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Hui Li
- School of Systems Science, Beijing Normal University, Beijing, China
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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39
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Noree C, Sirinonthanawech N. Nuclear targeted Saccharomyces cerevisiae asparagine synthetases associate with the mitotic spindle regardless of their enzymatic activity. PLoS One 2020; 15:e0243742. [PMID: 33347445 PMCID: PMC7751962 DOI: 10.1371/journal.pone.0243742] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/28/2020] [Indexed: 12/14/2022] Open
Abstract
Recently, human asparagine synthetase has been found to be associated with the mitotic spindle. However, this event cannot be seen in yeast because yeast takes a different cell division process via closed mitosis (there is no nuclear envelope breakdown to allow the association between any cytosolic enzyme and mitotic spindle). To find out if yeast asparagine synthetase can also (but hiddenly) have this feature, the coding sequences of green fluorescent protein (GFP) and nuclear localization signal (NLS) were introduced downstream of ASN1 and ASN2, encoding asparagine synthetases Asn1p and Asn2p, respectively, in the yeast genome having mCherrry coding sequence downstream of TUB1 encoding alpha-tubulin, a building block of the mitotic spindle. The genomically engineered yeast strains showed co-localization of Asn1p-GFP-NLS (or Asn2p-GFP-NLS) and Tub1p-mCherry in dividing nuclei. In addition, an activity-disrupted mutation was introduced to ASN1 (or ASN2). The yeast mutants still exhibited co-localization between defective asparagine synthetase and mitotic spindle, indicating that the biochemical activity of asparagine synthetase is not required for its association with the mitotic spindle. Furthermore, nocodazole treatment was used to depolymerize the mitotic spindle, resulting in lack of association between the enzyme and the mitotic spindle. Although yeast cell division undergoes closed mitosis, preventing the association of its asparagine synthetase with the mitotic spindle, however, by using yeast constructs with re-localized Asn1/2p have suggested the moonlighting role of asparagine synthetase in cell division of higher eukaryotes.
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Affiliation(s)
- Chalongrat Noree
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom, Thailand
| | - Naraporn Sirinonthanawech
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom, Thailand
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40
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Montrose K, López Cabezas RM, Paukštytė J, Saarikangas J. Winter is coming: Regulation of cellular metabolism by enzyme polymerization in dormancy and disease. Exp Cell Res 2020; 397:112383. [PMID: 33212148 DOI: 10.1016/j.yexcr.2020.112383] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/12/2020] [Accepted: 11/14/2020] [Indexed: 12/20/2022]
Abstract
Metabolism feeds growth. Accordingly, metabolism is regulated by nutrient-sensing pathways that converge growth promoting signals into biosynthesis by regulating the activity of metabolic enzymes. When the environment does not support growth, organisms invest in survival. For cells, this entails transitioning into a dormant, quiescent state (G0). In dormancy, the activity of biosynthetic pathways is dampened, and catabolic metabolism and stress tolerance pathways are activated. Recent work in yeast has demonstrated that dormancy is associated with alterations in the physicochemical properties of the cytoplasm, including changes in pH, viscosity and macromolecular crowding. Accompanying these changes, numerous metabolic enzymes transition from soluble to polymerized assemblies. These large-scale self-assemblies are dynamic and depolymerize when cells resume growth. Here we review how enzyme polymerization enables metabolic plasticity by tuning carbohydrate, nucleic acid, amino acid and lipid metabolic pathways, with particular focus on its potential adaptive value in cellular dormancy.
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Affiliation(s)
- Kristopher Montrose
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Finland; Research Programme in Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Rosa María López Cabezas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Finland; Research Programme in Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Jurgita Paukštytė
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Finland; Research Programme in Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Juha Saarikangas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Finland; Research Programme in Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland; Neuroscience Center, University of Helsinki, Finland.
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41
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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: 22] [Impact Index Per Article: 5.5] [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.
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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.
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42
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Zhang Y, Liu J, Liu JL. The atlas of cytoophidia in Drosophila larvae. J Genet Genomics 2020; 47:321-331. [PMID: 32912804 DOI: 10.1016/j.jgg.2020.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/07/2020] [Accepted: 06/21/2020] [Indexed: 02/08/2023]
Abstract
In 2010, cytidine 5'-triphosphate synthase (CTPS) was reported to form the filamentous or serpentine structure in Drosophila, which we termed the cytoophidium. In the last decade, CTPS filaments/cytoophidia have been found in bacteria, budding yeast, human cells, mice, fission yeast, plants, and archaea, indicating that this mechanism is highly conserved in evolution. In addition to CTPS, other metabolic enzymes have been identified to have the characteristics of forming cytoophidia or similar advanced structures, demonstrating that this is a basic strategy of cells. Nevertheless, our understanding of the physiological function of the cytoophidium remains incomplete and elusive. Here, we took the larva of Drosophila melanogaster as a model to systematically describe the localization and distribution of cytoophidia in different tissues during larval development. We found that the distribution pattern of CTPS cytoophidia is dynamic and heterogenic in larval tissues. Our study provides a road map for further understanding of the function and regulatory mechanism of cytoophidia.
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Affiliation(s)
- Yuanbing Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jingnan Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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43
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Lynch EM, Kollman JM, Webb BA. Filament formation by metabolic enzymes-A new twist on regulation. Curr Opin Cell Biol 2020; 66:28-33. [PMID: 32417394 DOI: 10.1016/j.ceb.2020.04.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 01/18/2023]
Abstract
Compartmentalization of metabolic enzymes through protein-protein interactions is an emerging mechanism for localizing and regulating metabolic activity. Self-assembly into linear filaments is a common strategy for cellular compartmentalization of enzymes. Polymerization is often driven by changes in the metabolic state of the cell, suggesting that it is a strategy for shifting metabolic flux in response to cellular demand. Although polymerization of metabolic enzymes is widespread, observed from bacteria to humans, we are just beginning to appreciate their role in regulating cellular metabolism. In most cases, one functional role of metabolic enzyme filaments is allosteric control of enzyme activity. Here, we highlight recent findings, providing insight into the structural and functional significance of filamentation of metabolic enzymes in cells.
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Affiliation(s)
- Eric M Lynch
- Department of Biochemistry, University of Washington, USA
| | | | - Bradley A Webb
- Department of Biochemistry, West Virginia University, USA.
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44
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Chakraborty A, Lin WC, Lin YT, Huang KJ, Wang PY, Chang IYF, Wang HI, Ma KT, Wang CY, Huang XR, Lee YH, Chen BC, Hsieh YJ, Chien KY, Lin TY, Liu JL, Sung LY, Yu JS, Chang YS, Pai LM. SNAP29 mediates the assembly of histidine-induced CTP synthase filaments in proximity to the cytokeratin network. J Cell Sci 2020; 133:jcs240200. [PMID: 32184263 DOI: 10.1242/jcs.240200] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/06/2020] [Indexed: 01/08/2023] Open
Abstract
Under metabolic stress, cellular components can assemble into distinct membraneless organelles for adaptation. One such example is cytidine 5'-triphosphate synthase (CTPS, for which there are CTPS1 and CTPS2 forms in mammals), which forms filamentous structures under glutamine deprivation. We have previously demonstrated that histidine (His)-mediated methylation regulates the formation of CTPS filaments to suppress enzymatic activity and preserve the CTPS protein under glutamine deprivation, which promotes cancer cell growth after stress alleviation. However, it remains unclear where and how these enigmatic structures are assembled. Using CTPS-APEX2-mediated in vivo proximity labeling, we found that synaptosome-associated protein 29 (SNAP29) regulates the spatiotemporal filament assembly of CTPS along the cytokeratin network in a keratin 8 (KRT8)-dependent manner. Knockdown of SNAP29 interfered with assembly and relaxed the filament-induced suppression of CTPS enzymatic activity. Furthermore, APEX2 proximity labeling of keratin 18 (KRT18) revealed a spatiotemporal association of SNAP29 with cytokeratin in response to stress. Super-resolution imaging suggests that during CTPS filament formation, SNAP29 interacts with CTPS along the cytokeratin network. This study links the cytokeratin network to the regulation of metabolism by compartmentalization of metabolic enzymes during nutrient deprivation.
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Affiliation(s)
- Archan Chakraborty
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Wei-Cheng Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Yu-Tsun Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Kuang-Jing Huang
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Pei-Yu Wang
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Ian Yi-Feng Chang
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
- Bioinformatics Core Laboratory, Chang Gung University, Taoyuan 33302, Taiwan
| | - Hsiang-Iu Wang
- Bioinformatics Core Laboratory, Chang Gung University, Taoyuan 33302, Taiwan
| | - Kung-Ting Ma
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Chun-Yen Wang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Xuan-Rong Huang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Yen-Hsien Lee
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Bi-Chang Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Ya-Ju Hsieh
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Kun-Yi Chien
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Clinical Proteomics Core laboratory, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Tzu-Yang Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Ji-Long Liu
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Li-Ying Sung
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan
| | - Jau-Song Yu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Yu-Sun Chang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Li-Mei Pai
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
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45
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The structure of helical lipoprotein lipase reveals an unexpected twist in lipase storage. Proc Natl Acad Sci U S A 2020; 117:10254-10264. [PMID: 32332168 DOI: 10.1073/pnas.1916555117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Lipases are enzymes necessary for the proper distribution and utilization of lipids in the human body. Lipoprotein lipase (LPL) is active in capillaries, where it plays a crucial role in preventing dyslipidemia by hydrolyzing triglycerides from packaged lipoproteins. Thirty years ago, the existence of a condensed and inactive LPL oligomer was proposed. Although recent work has shed light on the structure of the LPL monomer, the inactive oligomer remained opaque. Here we present a cryo-EM reconstruction of a helical LPL oligomer at 3.8-Å resolution. Helix formation is concentration-dependent, and helices are composed of inactive dihedral LPL dimers. Heparin binding stabilizes LPL helices, and the presence of substrate triggers helix disassembly. Superresolution fluorescent microscopy of endogenous LPL revealed that LPL adopts a filament-like distribution in vesicles. Mutation of one of the helical LPL interaction interfaces causes loss of the filament-like distribution. Taken together, this suggests that LPL is condensed into its inactive helical form for storage in intracellular vesicles.
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46
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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.
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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
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47
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Zhou S, Xiang H, Liu JL. CTP synthase forms cytoophidia in archaea. J Genet Genomics 2020; 47:213-223. [DOI: 10.1016/j.jgg.2020.03.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 03/12/2020] [Accepted: 03/18/2020] [Indexed: 12/14/2022]
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48
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Zhang B, Tastan ÖY, Zhou X, Guo CJ, Liu X, Thind A, Hu HH, Zhao S, Liu JL. The proline synthesis enzyme P5CS forms cytoophidia in Drosophila. J Genet Genomics 2020; 47:131-143. [PMID: 32317150 DOI: 10.1016/j.jgg.2020.02.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/25/2020] [Accepted: 02/29/2020] [Indexed: 01/26/2023]
Abstract
Compartmentation of enzymes via filamentation has arisen as a mechanism for the regulation of metabolism. In 2010, three groups independently reported that CTP synthase (CTPS) can assemble into a filamentous structure termed the cytoophidium. In searching for CTPS-interacting proteins, here we perform a yeast two-hybrid screening of Drosophila proteins and identify a putative CTPS-interacting protein, △1-pyrroline-5-carboxylate synthase (P5CS). Using the Drosophila follicle cell as the in vivo model, we confirm that P5CS forms cytoophidia, which are associated with CTPS cytoophidia. Overexpression of P5CS increases the length of CTPS cytoophidia. Conversely, filamentation of CTPS affects the morphology of P5CS cytoophidia. Finally, in vitro analyses confirm the filament-forming property of P5CS. Our work links CTPS with P5CS, two enzymes involved in the rate-limiting steps in pyrimidine and proline biosynthesis, respectively.
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Affiliation(s)
- Bo Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ömür Y Tastan
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom
| | - Xian Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Chen-Jun Guo
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Xuyang Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Aaron Thind
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom
| | - Huan-Huan Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Suwen Zhao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom.
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49
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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: 58] [Impact Index Per Article: 14.5] [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.
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Affiliation(s)
- Matthew C Johnson
- Department of BiochemistryUniversity of WashingtonSeattleUnited States
| | - Justin M Kollman
- Department of BiochemistryUniversity of WashingtonSeattleUnited States
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50
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Lynch EM, Kollman JM. Coupled structural transitions enable highly cooperative regulation of human CTPS2 filaments. Nat Struct Mol Biol 2019; 27:42-48. [PMID: 31873303 PMCID: PMC6954954 DOI: 10.1038/s41594-019-0352-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/15/2019] [Indexed: 01/26/2023]
Abstract
Many enzymes assemble into defined oligomers, providing a mechanism for cooperatively regulating activity. Recent studies have described a mode of regulation in which enzyme activity is modulated by polymerization into large-scale filaments. Here we describe an ultrasensitive form of polymerization-based regulation employed by human CTP synthase 2 (CTPS2). Cryo-EM structures reveal that CTPS2 filaments dynamically switch between active and inactive forms in response to changes in substrate and product levels. Linking the conformational state of many CTPS2 subunits in a filament results in highly cooperative regulation, greatly exceeding the limits of cooperativity for the CTPS2 tetramer alone. The structures reveal a link between conformation and control of ammonia channeling between the enzyme’s active sites, and explain differences in regulation of human CTPS isoforms. This filament-based mechanism of enhanced cooperativity demonstrates how the widespread phenomenon of enzyme polymerization can be adapted to achieve different regulatory outcomes.
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Affiliation(s)
- Eric M Lynch
- 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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