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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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52
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Wimmi S, Balinovic A, Jeckel H, Selinger L, Lampaki D, Eisemann E, Meuskens I, Linke D, Drescher K, Endesfelder U, Diepold A. Dynamic relocalization of cytosolic type III secretion system components prevents premature protein secretion at low external pH. Nat Commun 2021; 12:1625. [PMID: 33712575 PMCID: PMC7954860 DOI: 10.1038/s41467-021-21863-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 02/12/2021] [Indexed: 01/31/2023] Open
Abstract
Many bacterial pathogens use a type III secretion system (T3SS) to manipulate host cells. Protein secretion by the T3SS injectisome is activated upon contact to any host cell, and it has been unclear how premature secretion is prevented during infection. Here we report that in the gastrointestinal pathogens Yersinia enterocolitica and Shigella flexneri, cytosolic injectisome components are temporarily released from the proximal interface of the injectisome at low external pH, preventing protein secretion in acidic environments, such as the stomach. We show that in Yersinia enterocolitica, low external pH is detected in the periplasm and leads to a partial dissociation of the inner membrane injectisome component SctD, which in turn causes the dissociation of the cytosolic T3SS components. This effect is reversed upon restoration of neutral pH, allowing a fast activation of the T3SS at the native target regions within the host. These findings indicate that the cytosolic components form an adaptive regulatory interface, which regulates T3SS activity in response to environmental conditions.
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Affiliation(s)
- Stephan Wimmi
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Alexander Balinovic
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Hannah Jeckel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Lisa Selinger
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Dimitrios Lampaki
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Max-Planck-Institut für Immunbiologie und Epigenetik, Freiburg, Germany
| | - Emma Eisemann
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- James Madison University, Harrisonburg, VA, USA
| | - Ina Meuskens
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Ulrike Endesfelder
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.
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53
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Goetz SK, Mahamid J. Visualizing Molecular Architectures of Cellular Condensates: Hints of Complex Coacervation Scenarios. Dev Cell 2021; 55:97-107. [PMID: 33049214 DOI: 10.1016/j.devcel.2020.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/15/2020] [Accepted: 09/05/2020] [Indexed: 02/09/2023]
Abstract
In the last decade, liquid-liquid phase separation has emerged as a fundamental principle in the organization of crowded cellular environments into functionally distinct membraneless compartments. It is now established that biomolecules can condense into various physical phases, traditionally defined for simple polymer systems, and more recently elucidated by techniques employed in life sciences. We review pioneering cryo-electron tomography studies that have begun to unravel a wide spectrum of molecular architectures, ranging from amorphous to crystalline assemblies, that underlie cellular condensates. These observations bring into question current interpretations of microscopic phase behavior. Furthermore, by examining emerging concepts of non-classical phase separation pathways in small-molecule crystallization, we draw parallels with biomolecular condensation that highlight aspects not yet fully explored. In particular, transient and metastable intermediates that might be challenging to capture experimentally inside cells could be probed through computational simulations and enable a multi-scale understanding of the subcellular organization governed by distinct phases.
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Affiliation(s)
- Sara Kathrin Goetz
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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54
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Kofuji S, Sasaki AT. GTP metabolic reprogramming by IMPDH2: unlocking cancer cells' fuelling mechanism. J Biochem 2021; 168:319-328. [PMID: 32702086 DOI: 10.1093/jb/mvaa085] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/16/2020] [Indexed: 12/15/2022] Open
Abstract
Growing cells increase multiple biosynthetic processes in response to the high metabolic demands needed to sustain proliferation. The even higher metabolic requirements in the setting of cancer provoke proportionately greater biosynthesis. Underappreciated key aspects of this increased metabolic demand are guanine nucleotides and adaptive mechanisms to regulate their concentration. Using the malignant brain tumour, glioblastoma, as a model, we have demonstrated that one of the rate-limiting enzymes for guanosine triphosphate (GTP) synthesis, inosine monophosphate dehydrogenase-2 (IMPDH2), is increased and IMPDH2 expression is necessary for the activation of de novo GTP biosynthesis. Moreover, increased IMPDH2 enhances RNA polymerase I and III transcription directly linking GTP metabolism to both anabolic capacity as well as nucleolar enlargement historically observed as associated with cancer. In this review, we will review in detail the basis of these new discoveries and, more generally, summarize the current knowledge on the role of GTP metabolism in cancer.
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Affiliation(s)
- Satoshi Kofuji
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, 3125 Eden Ave., Cincinnati, OH 45267-0508, USA.,Department of Cancer Biology, University of Cincinnati College of Medicine, 3125 Eden Ave., OH 45267-0508, USA.,Department of Neurosurgery, Brain Tumor Center at UC Gardner Neuroscience Institute, 3113 Bellevue Ave, Cincinnati, OH 45267-0508, USA.,Institute for Advanced Biosciences, Keio University, Kakuganji 246-2, Mizukami, Tsuruoka City, Yamagata 997-0052, Japan
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55
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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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56
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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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57
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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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58
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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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59
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Maire T, Allertz T, Betjes MA, Youk H. Dormancy-to-death transition in yeast spores occurs due to gradual loss of gene-expressing ability. Mol Syst Biol 2020; 16:e9245. [PMID: 33206464 PMCID: PMC7673291 DOI: 10.15252/msb.20199245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 11/28/2022] Open
Abstract
Dormancy is colloquially considered as extending lifespan by being still. Starved yeasts form dormant spores that wake-up (germinate) when nutrients reappear but cannot germinate (die) after some time. What sets their lifespans and how they age are open questions because what processes occur-and by how much-within each dormant spore remains unclear. With single-cell-level measurements, we discovered how dormant yeast spores age and die: spores have a quantifiable gene-expressing ability during dormancy that decreases over days to months until it vanishes, causing death. Specifically, each spore has a different probability of germinating that decreases because its ability to-without nutrients-express genes decreases, as revealed by a synthetic circuit that forces GFP expression during dormancy. Decreasing amounts of molecules required for gene expression-including RNA polymerases-decreases gene-expressing ability which then decreases chances of germinating. Spores gradually lose these molecules because they are produced too slowly compared with their degradations, causing gene-expressing ability to eventually vanish and, thus, death. Our work provides a systems-level view of dormancy-to-death transition.
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Affiliation(s)
- Théo Maire
- Kavli Institute of NanoscienceDelftThe Netherlands
- Department of BionanoscienceDelft University of TechnologyDelftThe Netherlands
| | - Tim Allertz
- Kavli Institute of NanoscienceDelftThe Netherlands
- Department of BionanoscienceDelft University of TechnologyDelftThe Netherlands
| | - Max A Betjes
- Kavli Institute of NanoscienceDelftThe Netherlands
- Department of BionanoscienceDelft University of TechnologyDelftThe Netherlands
| | - Hyun Youk
- Kavli Institute of NanoscienceDelftThe Netherlands
- CIFARCIFAR Azrieli Global Scholars ProgramTorontoONCanada
- Program in Molecular MedicineUniversity of Massachusetts Medical SchoolWorcesterMAUSA
- Program in Systems BiologyUniversity of Massachusetts Medical SchoolWorcesterMAUSA
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60
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ATP hydrolysis by yeast Hsp104 determines protein aggregate dissolution and size in vivo. Nat Commun 2020; 11:5226. [PMID: 33067463 PMCID: PMC7568574 DOI: 10.1038/s41467-020-19104-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/28/2020] [Indexed: 12/23/2022] Open
Abstract
Signs of proteostasis failure often entwine with those of metabolic stress at the cellular level. Here, we study protein sequestration during glucose deprivation-induced ATP decline in Saccharomyces cerevisiae. Using live-cell imaging, we find that sequestration of misfolded proteins and nascent polypeptides into two distinct compartments, stress granules, and Q-bodies, is triggered by the exhaustion of ATP. Both compartments readily dissolve in a PKA-dependent manner within minutes of glucose reintroduction and ATP level restoration. We identify the ATP hydrolase activity of Hsp104 disaggregase as the critical ATP-consuming process determining compartments abundance and size, even in optimal conditions. Sequestration of proteins into distinct compartments during acute metabolic stress and their retrieval during the recovery phase provide a competitive fitness advantage, likely promoting cell survival during stress. The sequestration of misfolded protein into insoluble aggregates occurs under conditions of proteotoxic stress. Here the authors observe that a reduction in cellular ATP promotes protein sequestration into two separate compartments: Q-bodies and stress granules; and identify Hsp104 as a critical ATP-consuming process that determines those compartments abundance and size.
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61
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Vibhute MA, Schaap MH, Maas RJM, Nelissen FHT, Spruijt E, Heus HA, Hansen MMK, Huck WTS. Transcription and Translation in Cytomimetic Protocells Perform Most Efficiently at Distinct Macromolecular Crowding Conditions. ACS Synth Biol 2020; 9:2797-2807. [PMID: 32976714 PMCID: PMC7573978 DOI: 10.1021/acssynbio.0c00330] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
![]()
The formation of
cytomimetic protocells that capture the physicochemical
aspects of living cells is an important goal in bottom-up synthetic
biology. Here, we recreated the crowded cytoplasm in liposome-based
protocells and studied the kinetics of cell-free gene expression in
these crowded containers. We found that diffusion of key components
is affected not only by macromolecular crowding but also by enzymatic
activity in the protocell. Surprisingly, size-dependent diffusion
in crowded conditions yielded two distinct maxima for protein synthesis,
reflecting the differential impact of crowding on transcription and
translation. Our experimental data show, for the first time, that
macromolecular crowding induces a switch from reaction to diffusion
control and that this switch depends on the sizes of the macromolecules
involved. These results highlight the need to control the physical
environment in the design of synthetic cells.
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Affiliation(s)
- Mahesh A. Vibhute
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Mark H. Schaap
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Roel J. M. Maas
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Frank H. T. Nelissen
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Evan Spruijt
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hans A. Heus
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Maike M. K. Hansen
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Wilhelm T. S. Huck
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Bagamery LE, Justman QA, Garner EC, Murray AW. A Putative Bet-Hedging Strategy Buffers Budding Yeast against Environmental Instability. Curr Biol 2020; 30:4563-4578.e4. [PMID: 32976801 DOI: 10.1016/j.cub.2020.08.092] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/20/2020] [Accepted: 08/26/2020] [Indexed: 12/19/2022]
Abstract
To grow and divide, cells must extract resources from dynamic and unpredictable environments. Many organisms use different metabolic strategies for distinct contexts. Budding yeast can produce ATP from carbon sources by mechanisms that prioritize either speed (fermentation) or yield (respiration). Withdrawing glucose from exponentially growing cells reveals variability in their ability to switch from fermentation to respiration. We observe two subpopulations of glucose-starved cells: recoverers, which rapidly adapt and resume growth, and arresters, which enter a shock state characterized by deformation of many cellular structures, including mitochondria. These states are heritable, and on high glucose, arresters grow and divide faster than recoverers. Recoverers have a fitness advantage during a carbon source shift but are less fit in a constant, high-glucose environment, and we observe natural variation in the frequency of the two states across wild yeast strains. These experiments suggest that bet hedging has evolved in budding yeast.
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Affiliation(s)
- Laura E Bagamery
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Quincey A Justman
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
| | - Andrew W Murray
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
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63
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Pattanayak GK, Liao Y, Wallace EWJ, Budnik B, Drummond DA, Rust MJ. Daily Cycles of Reversible Protein Condensation in Cyanobacteria. Cell Rep 2020; 32:108032. [PMID: 32814039 PMCID: PMC10005845 DOI: 10.1016/j.celrep.2020.108032] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/08/2020] [Accepted: 07/23/2020] [Indexed: 12/21/2022] Open
Abstract
An emerging principle of cell biology is the regulated conversion of macromolecules between soluble and condensed states. To screen for such regulation of the cyanobacterial proteome, we use quantitative mass spectrometry to identify proteins that change solubility during the day-night cycle. We find a set of night-insoluble proteins that includes many enzymes in essential metabolic pathways. Using time-lapse microscopy and isotope labeling, we show that these proteins reversibly transition between punctate structures at night and a soluble state during the day without substantial degradation. We find that the cyanobacterial circadian clock regulates the kinetics of puncta formation during the night and that the appearance of puncta indicates the metabolic status of the cell. Reversible condensation of specific enzymes is thus a regulated response to the day-night cycle and may reflect a general bacterial strategy used in fluctuating growth conditions.
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Affiliation(s)
- Gopal K Pattanayak
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Yi Liao
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Edward W J Wallace
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Bogdan Budnik
- Mass Spectrometry and Proteomics Resource Laboratory, FAS Division of Science, Harvard University, Cambridge, MA 02138, USA
| | - D Allan Drummond
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Michael J Rust
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA; Department of Physics, University of Chicago, Chicago, IL 60637, USA.
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64
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Triandafillou CG, Katanski CD, Dinner AR, Drummond DA. Transient intracellular acidification regulates the core transcriptional heat shock response. eLife 2020; 9:e54880. [PMID: 32762843 PMCID: PMC7449696 DOI: 10.7554/elife.54880] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 08/07/2020] [Indexed: 01/18/2023] Open
Abstract
Heat shock induces a conserved transcriptional program regulated by heat shock factor 1 (Hsf1) in eukaryotic cells. Activation of this heat shock response is triggered by heat-induced misfolding of newly synthesized polypeptides, and so has been thought to depend on ongoing protein synthesis. Here, using the budding yeast Saccharomyces cerevisiae, we report the discovery that Hsf1 can be robustly activated when protein synthesis is inhibited, so long as cells undergo cytosolic acidification. Heat shock has long been known to cause transient intracellular acidification which, for reasons which have remained unclear, is associated with increased stress resistance in eukaryotes. We demonstrate that acidification is required for heat shock response induction in translationally inhibited cells, and specifically affects Hsf1 activation. Physiological heat-triggered acidification also increases population fitness and promotes cell cycle reentry following heat shock. Our results uncover a previously unknown adaptive dimension of the well-studied eukaryotic heat shock response.
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Affiliation(s)
| | - Christopher D Katanski
- Department of Biochemistry and Molecular Biology and Department of Medicine, Section of Genetic Medicine, The University of ChicagoChicagoUnited States
| | - Aaron R Dinner
- Department of Chemistry and the James Franck Institute, The University of ChicagoChicagoUnited States
| | - D Allan Drummond
- Department of Biochemistry and Molecular Biology and Department of Medicine, Section of Genetic Medicine, The University of ChicagoChicagoUnited States
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65
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Nüske E, Marini G, Richter D, Leng W, Bogdanova A, Franzmann TM, Pigino G, Alberti S. Filament formation by the translation factor eIF2B regulates protein synthesis in starved cells. Biol Open 2020; 9:bio046391. [PMID: 32554487 PMCID: PMC7358136 DOI: 10.1242/bio.046391] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/26/2020] [Indexed: 12/11/2022] Open
Abstract
Cells exposed to starvation have to adjust their metabolism to conserve energy and protect themselves. Protein synthesis is one of the major energy-consuming processes and as such has to be tightly controlled. Many mechanistic details about how starved cells regulate the process of protein synthesis are still unknown. Here, we report that the essential translation initiation factor eIF2B forms filaments in starved budding yeast cells. We demonstrate that filamentation is triggered by starvation-induced acidification of the cytosol, which is caused by an influx of protons from the extracellular environment. We show that filament assembly by eIF2B is necessary for rapid and efficient downregulation of translation. Importantly, this mechanism does not require the kinase Gcn2. Furthermore, analysis of site-specific variants suggests that eIF2B assembly results in enzymatically inactive filaments that promote stress survival and fast recovery of cells from starvation. We propose that translation regulation through filament assembly is an efficient mechanism that allows yeast cells to adapt to fluctuating environments.
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Affiliation(s)
- Elisabeth Nüske
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Guendalina Marini
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Doris Richter
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Weihua Leng
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Aliona Bogdanova
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Titus M Franzmann
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
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66
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Stoddard PR, Lynch EM, Farrell DP, Dosey AM, DiMaio F, Williams TA, Kollman JM, Murray AW, Garner EC. Polymerization in the actin ATPase clan regulates hexokinase activity in yeast. Science 2020; 367:1039-1042. [PMID: 32108112 DOI: 10.1126/science.aay5359] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 01/27/2020] [Indexed: 01/03/2023]
Abstract
The actin fold is found in cytoskeletal polymers, chaperones, and various metabolic enzymes. Many actin-fold proteins, such as the carbohydrate kinases, do not polymerize. We found that Glk1, a Saccharomyces cerevisiae glucokinase, forms two-stranded filaments with ultrastructure that is distinct from that of cytoskeletal polymers. In cells, Glk1 polymerized upon sugar addition and depolymerized upon sugar withdrawal. Polymerization inhibits enzymatic activity; the Glk1 monomer-polymer equilibrium sets a maximum rate of glucose phosphorylation regardless of Glk1 concentration. A mutation that eliminated Glk1 polymerization alleviated concentration-dependent enzyme inhibition. Yeast containing nonpolymerizing Glk1 were less fit when growing on sugars and more likely to die when refed glucose. Glk1 polymerization arose independently from other actin-related filaments and may allow yeast to rapidly modulate glucokinase activity as nutrient availability changes.
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Affiliation(s)
- Patrick R Stoddard
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.,Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Eric M Lynch
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Daniel P Farrell
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Annie M Dosey
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Andrew W Murray
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA. .,Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA. .,Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
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67
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Iserman C, Desroches Altamirano C, Jegers C, Friedrich U, Zarin T, Fritsch AW, Mittasch M, Domingues A, Hersemann L, Jahnel M, Richter D, Guenther UP, Hentze MW, Moses AM, Hyman AA, Kramer G, Kreysing M, Franzmann TM, Alberti S. Condensation of Ded1p Promotes a Translational Switch from Housekeeping to Stress Protein Production. Cell 2020; 181:818-831.e19. [PMID: 32359423 PMCID: PMC7237889 DOI: 10.1016/j.cell.2020.04.009] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 11/16/2019] [Accepted: 04/06/2020] [Indexed: 11/24/2022]
Abstract
Cells sense elevated temperatures and mount an adaptive heat shock response that involves changes in gene expression, but the underlying mechanisms, particularly on the level of translation, remain unknown. Here we report that, in budding yeast, the essential translation initiation factor Ded1p undergoes heat-induced phase separation into gel-like condensates. Using ribosome profiling and an in vitro translation assay, we reveal that condensate formation inactivates Ded1p and represses translation of housekeeping mRNAs while promoting translation of stress mRNAs. Testing a variant of Ded1p with altered phase behavior as well as Ded1p homologs from diverse species, we demonstrate that Ded1p condensation is adaptive and fine-tuned to the maximum growth temperature of the respective organism. We conclude that Ded1p condensation is an integral part of an extended heat shock response that selectively represses translation of housekeeping mRNAs to promote survival under conditions of severe heat stress.
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Affiliation(s)
- Christiane Iserman
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Christine Desroches Altamirano
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; BIOTEC and CMCB, Technische Universität Dresden, Tatzberg 47/48, 01307 Dresden, Germany
| | - Ceciel Jegers
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Ulrike Friedrich
- Center for Molecular Biology of the University of Heidelberg, German Cancer Research Center, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Taraneh Zarin
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Anatol W Fritsch
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Matthäus Mittasch
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Antonio Domingues
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Lena Hersemann
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Marcus Jahnel
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; BIOTEC and CMCB, Technische Universität Dresden, Tatzberg 47/48, 01307 Dresden, Germany
| | - Doris Richter
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; BIOTEC and CMCB, Technische Universität Dresden, Tatzberg 47/48, 01307 Dresden, Germany
| | - Ulf-Peter Guenther
- DKMS Life Science Lab GmbH, St. Petersburger Str. 2, 01069 Dresden, Germany
| | - Matthias W Hentze
- EMBL Heidelberg, Director's Research Unit, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Alan M Moses
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Günter Kramer
- Center for Molecular Biology of the University of Heidelberg, German Cancer Research Center, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Titus M Franzmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; BIOTEC and CMCB, Technische Universität Dresden, Tatzberg 47/48, 01307 Dresden, Germany
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; BIOTEC and CMCB, Technische Universität Dresden, Tatzberg 47/48, 01307 Dresden, Germany.
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68
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Noree C, Sirinonthanawech N. Coupled regulations of enzymatic activity and structure formation of aldehyde dehydrogenase Ald4p. Biol Open 2020; 9:bio051110. [PMID: 32295831 PMCID: PMC7197708 DOI: 10.1242/bio.051110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/31/2020] [Indexed: 11/20/2022] Open
Abstract
Previously, we have developed an extramitochondrial assembly system, where mitochondrial targeting signal (MTS) can be removed from a given mitochondrial enzyme, which could be used to characterize the regulatory factors involved in enzyme assembly/disassembly in vivo Here, we demonstrate that addition of exogenous acetaldehyde can quickly induce the supramolecular assembly of MTS-deleted aldehyde dehydrogenase Ald4p in yeast cytoplasm. Also, by using PCR-based modification of the yeast genome, cytoplasmically targeted Ald4p cannot polymerize into long filaments when key functional amino acid residues are substituted, as shown by N192D, S269A, E290K and C324A mutations. This study has confirmed that extramitochondrial assembly could be a powerful external system for studying mitochondrial enzyme assembly, and its regulatory factors outside the mitochondria. In addition, we propose that mitochondrial enzyme assembly/disassembly is coupled to the regulation of a given mitochondrial enzyme activity.
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Affiliation(s)
- Chalongrat Noree
- Institute of Molecular Biosciences, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand
| | - Naraporn Sirinonthanawech
- Institute of Molecular Biosciences, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand
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69
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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: 19] [Impact Index Per Article: 4.8] [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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70
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Marini G, Nüske E, Leng W, Alberti S, Pigino G. Reorganization of budding yeast cytoplasm upon energy depletion. Mol Biol Cell 2020; 31:1232-1245. [PMID: 32293990 PMCID: PMC7353153 DOI: 10.1091/mbc.e20-02-0125] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Yeast cells, when exposed to stress, can enter a protective state in which cell division, growth, and metabolism are down-regulated. They remain viable in this state until nutrients become available again. How cells enter this protective survival state and what happens at a cellular and subcellular level are largely unknown. In this study, we used electron tomography to investigate stress-induced ultrastructural changes in the cytoplasm of yeast cells. After ATP depletion, we observed significant cytosolic compaction and extensive cytoplasmic reorganization, as well as the emergence of distinct membrane-bound and membraneless organelles. Using correlative light and electron microscopy, we further demonstrated that one of these membraneless organelles was generated by the reversible polymerization of eukaryotic translation initiation factor 2B, an essential enzyme in the initiation of protein synthesis, into large bundles of filaments. The changes we observe are part of a stress-induced survival strategy, allowing yeast cells to save energy, protect proteins from degradation, and inhibit protein functionality by forming assemblies of proteins.
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Affiliation(s)
- Guendalina Marini
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
| | - Elisabeth Nüske
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
| | - Weihua Leng
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
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71
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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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72
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Heat-shock proteases promote survival of Pseudomonas aeruginosa during growth arrest. Proc Natl Acad Sci U S A 2020; 117:4358-4367. [PMID: 32029587 DOI: 10.1073/pnas.1912082117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
When nutrients in their environment are exhausted, bacterial cells become arrested for growth. During these periods, a primary challenge is maintaining cellular integrity with a reduced capacity for renewal or repair. Here, we show that the heat-shock protease FtsH is generally required for growth arrest survival of Pseudomonas aeruginosa, and that this requirement is independent of a role in regulating lipopolysaccharide synthesis, as has been suggested for Escherichia coli We find that ftsH interacts with diverse genes during growth and overlaps functionally with the other heat-shock protease-encoding genes hslVU, lon, and clpXP to promote survival during growth arrest. Systematic deletion of the heat-shock protease-encoding genes reveals that the proteases function hierarchically during growth arrest, with FtsH and ClpXP having primary, nonredundant roles, and HslVU and Lon deploying a secondary response to aging stress. This hierarchy is partially conserved during growth at high temperature and alkaline pH, suggesting that heat, pH, and growth arrest effectively impose a similar type of proteostatic stress at the cellular level. In support of this inference, heat and growth arrest act synergistically to kill cells, and protein aggregation appears to occur more rapidly in protease mutants during growth arrest and correlates with the onset of cell death. Our findings suggest that protein aggregation is a major driver of aging and cell death during growth arrest, and that coordinated activity of the heat-shock response is required to ensure ongoing protein quality control in the absence of growth.
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73
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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: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/29/2020] [Indexed: 02/06/2023] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) mediates the first committed step in guanine nucleotide biosynthesis and plays important roles in cellular proliferation and the immune response. IMPDH reversibly polymerizes in cells and tissues in response to changes in metabolic demand. Self-assembly of metabolic enzymes is increasingly recognized as a general mechanism for regulating activity, typically by stabilizing specific conformations of an enzyme, but the regulatory role of IMPDH filaments has remained unclear. Here, we report a series of human IMPDH2 cryo-EM structures in both active and inactive conformations. The structures define the mechanism of filament assembly, and reveal how filament-dependent allosteric regulation of IMPDH2 makes the enzyme less sensitive to feedback inhibition, explaining why assembly occurs under physiological conditions that require expansion of guanine nucleotide pools. Tuning sensitivity to an allosteric inhibitor distinguishes IMPDH from other metabolic filaments, and highlights the diversity of regulatory outcomes that can emerge from self-assembly.
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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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74
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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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75
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Spannl S, Tereshchenko M, Mastromarco GJ, Ihn SJ, Lee HO. Biomolecular condensates in neurodegeneration and cancer. Traffic 2019; 20:890-911. [PMID: 31606941 DOI: 10.1111/tra.12704] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 10/03/2019] [Accepted: 10/06/2019] [Indexed: 12/14/2022]
Abstract
The intracellular environment is partitioned into functionally distinct compartments containing specific sets of molecules and reactions. Biomolecular condensates, also referred to as membrane-less organelles, are diverse and abundant cellular compartments that lack membranous enclosures. Molecules assemble into condensates by phase separation; multivalent weak interactions drive molecules to separate from their surroundings and concentrate in discrete locations. Biomolecular condensates exist in all eukaryotes and in some prokaryotes, and participate in various essential house-keeping, stress-response and cell type-specific processes. An increasing number of recent studies link abnormal condensate formation, composition and material properties to a number of disease states. In this review, we discuss current knowledge and models describing the regulation of condensates and how they become dysregulated in neurodegeneration and cancer. Further research on the regulation of biomolecular phase separation will help us to better understand their role in cell physiology and disease.
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Affiliation(s)
- Stephanie Spannl
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Maria Tereshchenko
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | | | - Sean J Ihn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hyun O Lee
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Canada Research Chairs Program, University of Toronto, Toronto, Ontario, Canada
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76
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Park CK, Horton NC. Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation. Biophys Rev 2019; 11:927-994. [PMID: 31734826 PMCID: PMC6874960 DOI: 10.1007/s12551-019-00602-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.
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Affiliation(s)
- Chad K. Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Nancy C. Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
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77
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Zhou X, Guo CJ, Hu HH, Zhong J, Sun Q, Liu D, Zhou S, Chang CC, Liu JL. Drosophila CTP synthase can form distinct substrate- and product-bound filaments. J Genet Genomics 2019; 46:537-545. [PMID: 31902586 DOI: 10.1016/j.jgg.2019.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/07/2019] [Accepted: 11/10/2019] [Indexed: 01/26/2023]
Abstract
Intracellular compartmentation is a key strategy for the functioning of a cell. In 2010, several studies revealed that the metabolic enzyme CTP synthase (CTPS) can form filamentous structures termed cytoophidia in prokaryotic and eukaryotic cells. However, recent structural studies showed that CTPS only forms inactive product-bound filaments in bacteria while forming active substrate-bound filaments in eukaryotic cells. In this study, using negative staining and cryo-electron microscopy, we demonstrate that Drosophila CTPS, whether in substrate-bound or product-bound form, can form filaments. Our results challenge the previous model and indicate that substrate-bound and product-bound filaments can coexist in the same species. We speculate that the ability to switch between active and inactive cytoophidia in the same cells provides an additional layer of metabolic regulation.
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Affiliation(s)
- 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
| | - Huan-Huan Hu
- 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
| | - Jiale Zhong
- 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
| | - Qianqian Sun
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Dandan Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - Shuang Zhou
- 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
| | - 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.
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78
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Mudogo CN, Falke S, Brognaro H, Duszenko M, Betzel C. Protein phase separation and determinants of in cell crystallization. Traffic 2019; 21:220-230. [DOI: 10.1111/tra.12711] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 10/21/2019] [Accepted: 10/27/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Celestin N. Mudogo
- Laboratory for Structural Biology of Infection and InflammationInstitute of Biochemistry and Molecular Biology, University of Hamburg Hamburg Germany
- Department of Basic Sciences, School of MedicineUniversity of Kinshasa Kinshasa Democratic Republic of Congo
| | - Sven Falke
- Laboratory for Structural Biology of Infection and InflammationInstitute of Biochemistry and Molecular Biology, University of Hamburg Hamburg Germany
| | - Hévila Brognaro
- Laboratory for Structural Biology of Infection and InflammationInstitute of Biochemistry and Molecular Biology, University of Hamburg Hamburg Germany
- Centre for Free‐Electron‐Laser Science Hamburg Germany
| | - Michael Duszenko
- Institute of Neurophysiology, University of Tübingen Tübingen Germany
| | - Christian Betzel
- Laboratory for Structural Biology of Infection and InflammationInstitute of Biochemistry and Molecular Biology, University of Hamburg Hamburg Germany
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79
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Prabhakar A, Vadaie N, Krzystek T, Cullen PJ. Proteins That Interact with the Mucin-Type Glycoprotein Msb2p Include a Regulator of the Actin Cytoskeleton. Biochemistry 2019; 58:4842-4856. [PMID: 31710471 DOI: 10.1021/acs.biochem.9b00725] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Transmembrane mucin-type glycoproteins can regulate signal transduction pathways. In yeast, signaling mucins regulate mitogen-activated protein kinase (MAPK) pathways that induce cell differentiation to filamentous growth (fMAPK pathway) and the response to osmotic stress (HOG pathway). To explore regulatory aspects of signaling mucin function, protein microarrays were used to identify proteins that interact with the cytoplasmic domain of the mucin-like glycoprotein Msb2p. Eighteen proteins were identified that comprised functional categories of metabolism, actin filament capping and depolymerization, aerobic and anaerobic growth, chromatin organization and bud growth, sporulation, ribosome biogenesis, protein modification by iron-sulfur clusters, RNA catabolism, and DNA replication and DNA repair. A subunit of actin capping protein, Cap2p, interacted with the cytoplasmic domain of Msb2p. Cells lacking Cap2p showed altered localization of Msb2p and increased levels of shedding of Msb2p's N-terminal glycosylated domain. Consistent with its role in regulating the actin cytoskeleton, Cap2p was required for enhanced cell polarization during filamentous growth. Our study identifies proteins that connect a signaling mucin to diverse cellular processes and may provide insight into new aspects of mucin function.
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Affiliation(s)
- Aditi Prabhakar
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
| | - Nadia Vadaie
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
| | - Thomas Krzystek
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
| | - Paul J Cullen
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
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80
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Heimlicher MB, Bächler M, Liu M, Ibeneche-Nnewihe C, Florin EL, Hoenger A, Brunner D. Reversible solidification of fission yeast cytoplasm after prolonged nutrient starvation. J Cell Sci 2019; 132:jcs.231688. [PMID: 31558680 PMCID: PMC6857596 DOI: 10.1242/jcs.231688] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 09/20/2019] [Indexed: 12/19/2022] Open
Abstract
Cells depend on a highly ordered organisation of their content and must develop strategies to maintain the anisotropic distribution of organelles during periods of nutrient shortage. One of these strategies is to solidify the cytoplasm, which was observed in bacteria and yeast cells with acutely interrupted energy production. Here, we describe a different type of cytoplasm solidification fission yeast cells switch to, after having run out of nutrients during multiple days in culture. It provides the most profound reversible cytoplasmic solidification of yeast cells described to date. Our data exclude the previously proposed mechanisms for cytoplasm solidification in yeasts and suggest a mechanism that immobilises cellular components in a size-dependent manner. We provide experimental evidence that, in addition to time, cells use intrinsic nutrients and energy sources to reach this state. Such cytoplasmic solidification may provide a robust means to protect cellular architecture in dormant cells. Summary: After prolonged quiescence, fission yeast cell populations switch state to immobilise subcellular components much more profoundly than cells experiencing acute energy depletion.
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Affiliation(s)
- Maria B Heimlicher
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Mirjam Bächler
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Minghua Liu
- Dept. of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, UCB-0347, Boulder, CO 80309, USA
| | - Chieze Ibeneche-Nnewihe
- Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
| | - Ernst-Ludwig Florin
- Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
| | - Andreas Hoenger
- Dept. of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, UCB-0347, Boulder, CO 80309, USA
| | - Damian Brunner
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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81
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Zhang J, Liu JL. Temperature-sensitive cytoophidium assembly in Schizosaccharomyces pombe. J Genet Genomics 2019; 46:423-432. [PMID: 31611173 PMCID: PMC6868507 DOI: 10.1016/j.jgg.2019.09.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 08/29/2019] [Accepted: 09/09/2019] [Indexed: 12/15/2022]
Abstract
The metabolic enzyme CTP synthase (CTPS) is able to compartmentalize into filaments, termed cytoophidia, in a variety of organisms including bacteria, budding yeast, fission yeast, fruit flies and mammals. A previous study in budding yeast shows that the filament-forming process of CTPS is not sensitive to temperature shift. Here we study CTPS filamentation in the fission yeast Schizosaccharomyces pombe. To our surprise, we find that both the length and the occurrence of cytoophidia in S. pombe decrease upon cold shock or heat shock. The temperature-dependent changes of cytoophidia are fast and reversible. Taking advantage of yeast genetics, we demonstrate that heat-shock proteins are required for cytoophidium assembly in S. pombe. Temperature sensitivity of cytoophidia makes S. pombe an attractive model system for future investigations of this novel membraneless organelle.
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Affiliation(s)
- Jing Zhang
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom
| | - Ji-Long Liu
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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82
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Anti-Tumor Potential of IMP Dehydrogenase Inhibitors: A Century-Long Story. Cancers (Basel) 2019; 11:cancers11091346. [PMID: 31514446 PMCID: PMC6770829 DOI: 10.3390/cancers11091346] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/01/2019] [Accepted: 09/02/2019] [Indexed: 01/15/2023] Open
Abstract
The purine nucleotides ATP and GTP are essential precursors to DNA and RNA synthesis and fundamental for energy metabolism. Although de novo purine nucleotide biosynthesis is increased in highly proliferating cells, such as malignant tumors, it is not clear if this is merely a secondary manifestation of increased cell proliferation. Suggestive of a direct causative effect includes evidence that, in some cancer types, the rate-limiting enzyme in de novo GTP biosynthesis, inosine monophosphate dehydrogenase (IMPDH), is upregulated and that the IMPDH inhibitor, mycophenolic acid (MPA), possesses anti-tumor activity. However, historically, enthusiasm for employing IMPDH inhibitors in cancer treatment has been mitigated by their adverse effects at high treatment doses and variable response. Recent advances in our understanding of the mechanistic role of IMPDH in tumorigenesis and cancer progression, as well as the development of IMPDH inhibitors with selective actions on GTP synthesis, have prompted a reappraisal of targeting this enzyme for anti-cancer treatment. In this review, we summarize the history of IMPDH inhibitors, the development of new inhibitors as anti-cancer drugs, and future directions and strategies to overcome existing challenges.
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83
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Noree C, Begovich K, Samilo D, Broyer R, Monfort E, Wilhelm JE. A quantitative screen for metabolic enzyme structures reveals patterns of assembly across the yeast metabolic network. Mol Biol Cell 2019; 30:2721-2736. [PMID: 31483745 PMCID: PMC6761767 DOI: 10.1091/mbc.e19-04-0224] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Despite the proliferation of proteins that can form filaments or phase-separated condensates, it remains unclear how this behavior is distributed over biological networks. We have found that 60 of the 440 yeast metabolic enzymes robustly form structures, including 10 that assemble within mitochondria. Additionally, the ability to assemble is enriched at branch points on several metabolic pathways. The assembly of enzymes at the first branch point in de novo purine biosynthesis is coordinated, hierarchical, and based on their position within the pathway, while the enzymes at the second branch point are recruited to RNA stress granules. Consistent with distinct classes of structures being deployed at different control points in a pathway, we find that the first enzyme in the pathway, PRPP synthetase, forms evolutionarily conserved filaments that are sequestered in the nucleus in higher eukaryotes. These findings provide a roadmap for identifying additional conserved features of metabolic regulation by condensates/filaments.
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Affiliation(s)
- Chalongrat Noree
- Howard Hughes Medical Institute Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543.,Institute of Molecular Biosciences, Mahidol University, Phuttamonthon, Nakhon Pathom 73170, Thailand
| | - Kyle Begovich
- Howard Hughes Medical Institute Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543.,Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Dane Samilo
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Risa Broyer
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Elena Monfort
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - James E Wilhelm
- Howard Hughes Medical Institute Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543.,Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
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84
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van Leeuwen W, Rabouille C. Cellular stress leads to the formation of membraneless stress assemblies in eukaryotic cells. Traffic 2019; 20:623-638. [PMID: 31152627 PMCID: PMC6771618 DOI: 10.1111/tra.12669] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/10/2019] [Accepted: 05/30/2019] [Indexed: 12/28/2022]
Abstract
In cells at steady state, two forms of cell compartmentalization coexist: membrane-bound organelles and phase-separated membraneless organelles that are present in both the nucleus and the cytoplasm. Strikingly, cellular stress is a strong inducer of the reversible membraneless compartments referred to as stress assemblies. Stress assemblies play key roles in survival during cell stress and in thriving of cells upon stress relief. The two best studied stress assemblies are the RNA-based processing-bodies (P-bodies) and stress granules that form in response to oxidative, endoplasmic reticulum (ER), osmotic and nutrient stress as well as many others. Interestingly, P-bodies and stress granules are heterogeneous with respect to both the pathways that lead to their formation and their protein and RNA content. Furthermore, in yeast and Drosophila, nutrient stress also leads to the formation of many other types of prosurvival cytoplasmic stress assemblies, such as metabolic enzymes foci, proteasome storage granules, EIF2B bodies, U-bodies and Sec bodies, some of which are not RNA-based. Nutrient stress leads to a drop in cytoplasmic pH, which combined with posttranslational modifications of granule contents, induces phase separation.
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Affiliation(s)
- Wessel van Leeuwen
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciencesand University Medical Center UtrechtUtrechtthe Netherlands
| | - Catherine Rabouille
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciencesand University Medical Center UtrechtUtrechtthe Netherlands
- Department of Biomedical Science of Cells and SystemsUniversity Medical Center GroningenGroningenthe Netherlands
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85
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Zhang C, Rabouille C. Membrane-Bound Meet Membraneless in Health and Disease. Cells 2019; 8:cells8091000. [PMID: 31470564 PMCID: PMC6770257 DOI: 10.3390/cells8091000] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 12/12/2022] Open
Abstract
Membraneless organelles (MLOs) are defined as cellular structures that are not sealed by a lipidic membrane and are shown to form by phase separation. They exist in both the nucleus and the cytoplasm that is also heavily populated by numerous membrane-bound organelles. Even though the name membraneless suggests that MLOs are free of membrane, both membrane and factors regulating membrane trafficking steps are emerging as important components of MLO formation and function. As a result, we name them biocondensates. In this review, we examine the relationships between biocondensates and membrane. First, inhibition of membrane trafficking in the early secretory pathway leads to the formation of biocondensates (P-bodies and Sec bodies). In the same vein, stress granules have a complex relationship with the cyto-nuclear transport machinery. Second, membrane contributes to the regulated formation of phase separation in the cells and we will present examples including clustering at the plasma membrane and at the synapse. Finally, the whole cell appears to transit from an interphase phase-separated state to a mitotic diffuse state in a DYRK3 dependent manner. This firmly establishes a crosstalk between the two types of cell organization that will need to be further explored.
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Affiliation(s)
- Chujun Zhang
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences, and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Catherine Rabouille
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences, and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands.
- Department of Biomedical Science of Cells and Systems, University Medical Center Groningen, 9713 AV Groningen, The Netherlands.
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86
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Lee WH, Oh JY, Maeng PJ. The NADP +-dependent glutamate dehydrogenase Gdh1 is subjected to glucose starvation-induced reversible aggregation that affects stress resistance in yeast. J Microbiol 2019; 57:884-892. [PMID: 31376105 DOI: 10.1007/s12275-019-9065-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 11/28/2022]
Abstract
The yeast Saccharomyces cerevisiae has two isoforms of NADP+-dependent glutamate dehydrogenase (Gdh1 and Gdh3) that catalyze the synthesis of glutamate from α-ketoglutarate and NH4+. In the present study, we confirmed that Gdh3, but not Gdh1, mainly contributes to the oxidative stress resistance of stationary-phase cells and found evidence suggesting that the insignificance of Gdh1 to stress resistance is possibly resulted from conditional and reversible aggregation of Gdh1 into punctuate foci initiated in parallel with post-diauxic growth. Altered localization to the mitochondria or peroxisomes prevented Gdh1, which was originally localized in the cytoplasm, from stationary phase-specific aggregation, suggesting that some cytosolic factors are involved in the process of Gdh1 aggregation. Glucose starvation triggered the transition of the soluble form of Gdh1 into the insoluble aggregate form, which could be redissolved by replenishing glucose, without any requirement for protein synthesis. Mutational analysis showed that the N-terminal proximal region of Gdh1 (NTP1, aa 21-26, TLFEQH) is essential for glucose starvation-induced aggregation. We also found that the substitution of NTP1 with the corresponding region of Gdh3 (NTP3) significantly increased the contribution of the mutant Gdh1 to the stress resistance of stationary-phase cells. Thus, this suggests that NTP1 is responsible for the negligible role of Gdh1 in maintaining the oxidative stress resistance of stationary-phase cells and the stationary phase-specific stresssensitive phenotype of the mutants lacking Gdh3.
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Affiliation(s)
- Woo Hyun Lee
- Department of Microbiology and Molecular Biology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Ju Yeong Oh
- Department of Microbiology and Molecular Biology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Pil Jae Maeng
- Department of Microbiology and Molecular Biology, Chungnam National University, Daejeon, 34134, Republic of Korea.
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87
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Owen MC, Gnutt D, Gao M, Wärmländer SKTS, Jarvet J, Gräslund A, Winter R, Ebbinghaus S, Strodel B. Effects of in vivo conditions on amyloid aggregation. Chem Soc Rev 2019; 48:3946-3996. [PMID: 31192324 DOI: 10.1039/c8cs00034d] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the grand challenges of biophysical chemistry is to understand the principles that govern protein misfolding and aggregation, which is a highly complex process that is sensitive to initial conditions, operates on a huge range of length- and timescales, and has products that range from protein dimers to macroscopic amyloid fibrils. Aberrant aggregation is associated with more than 25 diseases, which include Alzheimer's, Parkinson's, Huntington's, and type II diabetes. Amyloid aggregation has been extensively studied in the test tube, therefore under conditions that are far from physiological relevance. Hence, there is dire need to extend these investigations to in vivo conditions where amyloid formation is affected by a myriad of biochemical interactions. As a hallmark of neurodegenerative diseases, these interactions need to be understood in detail to develop novel therapeutic interventions, as millions of people globally suffer from neurodegenerative disorders and type II diabetes. The aim of this review is to document the progress in the research on amyloid formation from a physicochemical perspective with a special focus on the physiological factors influencing the aggregation of the amyloid-β peptide, the islet amyloid polypeptide, α-synuclein, and the hungingtin protein.
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Affiliation(s)
- Michael C Owen
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - David Gnutt
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany and Lead Discovery Wuppertal, Bayer AG, 42096 Wuppertal, Germany
| | - Mimi Gao
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany and Sanofi-Aventis Deutschland GmbH, R&D, Industriepark Höchst, 65926 Frankfurt, Germany
| | - Sebastian K T S Wärmländer
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 42525 Jülich, Germany. and Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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88
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89
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Alexandrov AI, Grosfeld EV, Dergalev AA, Kushnirov VV, Chuprov-Netochin RN, Tyurin-Kuzmin PA, Kireev II, Ter-Avanesyan MD, Leonov SV, Agaphonov MO. Analysis of novel hyperosmotic shock response suggests 'beads in liquid' cytosol structure. Biol Open 2019; 8:bio044529. [PMID: 31285266 PMCID: PMC6679407 DOI: 10.1242/bio.044529] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 06/25/2019] [Indexed: 12/11/2022] Open
Abstract
Proteins can aggregate in response to stresses, including hyperosmotic shock. Formation and disassembly of aggregates is a relatively slow process. We describe a novel instant response of the cell to hyperosmosis, during which chaperones and other proteins form numerous foci with properties uncharacteristic of classical aggregates. These foci appeared/disappeared seconds after shock onset/removal, in close correlation with cell volume changes. Genome-wide and targeted testing revealed chaperones, metabolic enzymes, P-body components and amyloidogenic proteins in the foci. Most of these proteins can form large assemblies and for some, the assembled state was pre-requisite for participation in foci. A genome-wide screen failed to identify genes whose absence prevented foci participation by Hsp70. Shapes of and interconnections between foci, revealed by super-resolution microscopy, indicated that the foci were compressed between other entities. Based on our findings, we suggest a new model of cytosol architecture as a collection of numerous gel-like regions suspended in a liquid network. This network is reduced in volume in response to hyperosmosis and forms small pockets between the gel-like regions.
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Affiliation(s)
- Alexander I Alexandrov
- Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Bach Institute of Biochemistry, Leninsky Ave. 33, bld. 2, Moscow 119071, Russia
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Leninskie gori 1, bldg 40, Moscow 119234, Russia
| | - Erika V Grosfeld
- Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Bach Institute of Biochemistry, Leninsky Ave. 33, bld. 2, Moscow 119071, Russia
- Chair of Molecular and Cell Biology, Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, Dolgoprudny, Moscow Region 141701, Russia
| | - Alexander A Dergalev
- Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Bach Institute of Biochemistry, Leninsky Ave. 33, bld. 2, Moscow 119071, Russia
| | - Vitaly V Kushnirov
- Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Bach Institute of Biochemistry, Leninsky Ave. 33, bld. 2, Moscow 119071, Russia
| | - Roman N Chuprov-Netochin
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, Dolgoprudny, Moscow Region 141701, Russia
| | - Pyotr A Tyurin-Kuzmin
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, M.V. Lomonosov Moscow State University, Lomonosovskiy pr., 27 bldg 1, Moscow 119192, Russia
| | - Igor I Kireev
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Leninskie gori 1, bldg 40, Moscow 119234, Russia
- V. I. Kulakov National Medical Research Center for Obstetrics, Gynecology, and Perinatology, Moscow 117198, Russia
- Faculty of Biology, M. V. Lomonosov Moscow State University, Moscow 119234, Russia
| | - Michael D Ter-Avanesyan
- Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Bach Institute of Biochemistry, Leninsky Ave. 33, bld. 2, Moscow 119071, Russia
| | - Sergey V Leonov
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, Dolgoprudny, Moscow Region 141701, Russia
- Institute of Cell Biophysics of the Russian Academy of Sciences, Institutskaya str., 3, Moscow Region, 142290 Puschino, Russia
| | - Michael O Agaphonov
- Federal Research Center "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Bach Institute of Biochemistry, Leninsky Ave. 33, bld. 2, Moscow 119071, Russia
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90
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Dolz‐Edo L, van der Deen M, Brul S, Smits GJ. Caloric restriction controls stationary phase survival through Protein Kinase A (PKA) and cytosolic pH. Aging Cell 2019; 18:e12921. [PMID: 30790427 PMCID: PMC6516148 DOI: 10.1111/acel.12921] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 12/30/2018] [Accepted: 01/23/2019] [Indexed: 11/28/2022] Open
Abstract
Calorie restriction is the only physiological intervention that extends lifespan throughout all kingdoms of life. In the budding yeast Saccharomyces cerevisiae, cytosolic pH (pHc) controls growth and responds to nutrient availability, decreasing upon glucose depletion. We investigated the interactions between glucose availability, pHc and the central nutrient signalling cAMP‐Protein Kinase A (PKA) pathway. Glucose abundance during the growth phase enhanced acidification upon glucose depletion, via modulation of PKA activity. This actively controlled reduction in starvation pHc correlated with reduced stationary phase survival. Whereas changes in PKA activity affected both acidification and survival, targeted manipulation of starvation pHc showed that cytosolic acidification was downstream of PKA and the causal agent of the reduced chronological lifespan. Thus, caloric restriction controls stationary phase survival through PKA and cytosolic pH.
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Affiliation(s)
- Laura Dolz‐Edo
- Department of Molecular Biology and Microbial Food Safety Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam The Netherlands
| | - Margaretha van der Deen
- Department of Molecular Biology and Microbial Food Safety Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam The Netherlands
| | - Stanley Brul
- Department of Molecular Biology and Microbial Food Safety Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam The Netherlands
| | - Gertien Jacoba Smits
- Department of Molecular Biology and Microbial Food Safety Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam The Netherlands
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91
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Garcia‐Seisdedos H, Villegas JA, Levy ED. Infinite Assembly of Folded Proteins in Evolution, Disease, and Engineering. Angew Chem Int Ed Engl 2019; 58:5514-5531. [PMID: 30133878 PMCID: PMC6471489 DOI: 10.1002/anie.201806092] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/06/2018] [Indexed: 12/14/2022]
Abstract
Mutations and changes in a protein's environment are well known for their potential to induce misfolding and aggregation, including amyloid formation. Alternatively, such perturbations can trigger new interactions that lead to the polymerization of folded proteins. In contrast to aggregation, this process does not require misfolding and, to highlight this difference, we refer to it as agglomeration. This term encompasses the amorphous assembly of folded proteins as well as the polymerization in one, two, or three dimensions. We stress the remarkable potential of symmetric homo-oligomers to agglomerate even by single surface point mutations, and we review the double-edged nature of this potential: how aberrant assemblies resulting from agglomeration can lead to disease, but also how agglomeration can serve in cellular adaptation and be exploited for the rational design of novel biomaterials.
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Affiliation(s)
| | - José A. Villegas
- Department of Structural BiologyWeizmann Institute of ScienceRehovot7610001Israel
| | - Emmanuel D. Levy
- Department of Structural BiologyWeizmann Institute of ScienceRehovot7610001Israel
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92
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Sanchez de Groot N, Torrent Burgas M, Ravarani CN, Trusina A, Ventura S, Babu MM. The fitness cost and benefit of phase-separated protein deposits. Mol Syst Biol 2019; 15:e8075. [PMID: 30962358 PMCID: PMC6452874 DOI: 10.15252/msb.20178075] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Phase separation of soluble proteins into insoluble deposits is associated with numerous diseases. However, protein deposits can also function as membrane-less compartments for many cellular processes. What are the fitness costs and benefits of forming such deposits in different conditions? Using a model protein that phase-separates into deposits, we distinguish and quantify the fitness contribution due to the loss or gain of protein function and deposit formation in yeast. The environmental condition and the cellular demand for the protein function emerge as key determinants of fitness. Protein deposit formation can influence cell-to-cell variation in free protein abundance between individuals of a cell population (i.e., gene expression noise). This results in variable manifestation of protein function and a continuous range of phenotypes in a cell population, favoring survival of some individuals in certain environments. Thus, protein deposit formation by phase separation might be a mechanism to sense protein concentration in cells and to generate phenotypic variability. The selectable phenotypic variability, previously described for prions, could be a general property of proteins that can form phase-separated assemblies and may influence cell fitness.
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Affiliation(s)
- Natalia Sanchez de Groot
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK .,Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Marc Torrent Burgas
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.,Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | - Ala Trusina
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Salvador Ventura
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - M Madan Babu
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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93
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Yoo H, Triandafillou C, Drummond DA. Cellular sensing by phase separation: Using the process, not just the products. J Biol Chem 2019; 294:7151-7159. [PMID: 30877200 DOI: 10.1074/jbc.tm118.001191] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Phase separation creates two distinct liquid phases from a single mixed liquid phase, like oil droplets separating from water. Considerable attention has focused on how the products of phase separation-the resulting condensates-might act as biological compartments, bioreactors, filters, and membraneless organelles in cells. Here, we expand this perspective, reviewing recent results showing how cells instead use the process of phase separation to sense intracellular and extracellular changes. We review case studies in phase separation-based sensing and discuss key features, such as extraordinary sensitivity, which make the process of phase separation ideally suited to meet a range of sensory challenges cells encounter.
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Affiliation(s)
- Haneul Yoo
- From the Department of Biochemistry and Molecular Biology
| | | | - D Allan Drummond
- From the Department of Biochemistry and Molecular Biology, .,Department of Human Genetics, University of Chicago, Chicago, Illinois 60637
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94
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Barahona CJ, Basantes LE, Tompkins KJ, Heitman DM, Chukwu BI, Sanchez J, Sanchez JL, Ghadirian N, Park CK, Horton NC. The Need for Speed: Run-On Oligomer Filament Formation Provides Maximum Speed with Maximum Sequestration of Activity. J Virol 2019; 93:e01647-18. [PMID: 30518649 PMCID: PMC6384071 DOI: 10.1128/jvi.01647-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/26/2018] [Indexed: 01/29/2023] Open
Abstract
Here, we investigate an unusual antiviral mechanism developed in the bacterium Streptomyces griseus SgrAI is a type II restriction endonuclease that forms run-on oligomer filaments when activated and possesses both accelerated DNA cleavage activity and expanded DNA sequence specificity. Mutations disrupting the run-on oligomer filament eliminate the robust antiphage activity of wild-type SgrAI, and the observation that even relatively modest disruptions completely abolish this anti-viral activity shows that the greater speed imparted by the run-on oligomer filament mechanism is critical to its biological function. Simulations of DNA cleavage by SgrAI uncover the origins of the kinetic advantage of this newly described mechanism of enzyme regulation over more conventional mechanisms, as well as the origin of the sequestering effect responsible for the protection of the host genome against damaging DNA cleavage activity of activated SgrAI.IMPORTANCE This work is motivated by an interest in understanding the characteristics and advantages of a relatively newly discovered enzyme mechanism involving filament formation. SgrAI is an enzyme responsible for protecting against viral infections in its host bacterium and was one of the first such enzymes shown to utilize such a mechanism. In this work, filament formation by SgrAI is disrupted, and the effects on the speed of the purified enzyme as well as its function in cells are measured. It was found that even small disruptions, which weaken but do not destroy filament formation, eliminate the ability of SgrAI to protect cells from viral infection, its normal biological function. Simulations of enzyme activity were also performed and show how filament formation can greatly speed up an enzyme's activation compared to that of other known mechanisms, as well as to better localize its action to molecules of interest, such as invading phage DNA.
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Affiliation(s)
- Claudia J Barahona
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - L Emilia Basantes
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Kassidy J Tompkins
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Desirae M Heitman
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Barbara I Chukwu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Juan Sanchez
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Jonathan L Sanchez
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Niloofar Ghadirian
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Chad K Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - N C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
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95
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Gnutt D, Timr S, Ahlers J, König B, Manderfeld E, Heyden M, Sterpone F, Ebbinghaus S. Stability Effect of Quinary Interactions Reversed by Single Point Mutations. J Am Chem Soc 2019; 141:4660-4669. [DOI: 10.1021/jacs.8b13025] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- David Gnutt
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, Braunschweig 38106, Germany
- Department of Physical Chemistry II, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany
| | - Stepan Timr
- CNRS Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique, Université Paris Denis Diderot, Sorbonne Paris Cité, PSL Research University, 13 rue Pierre et Marie Curie, Paris 75005, France
| | - Jonas Ahlers
- Department of Physical Chemistry II, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany
| | - Benedikt König
- Department of Physical Chemistry II, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany
| | - Emily Manderfeld
- Department of Physical Chemistry II, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany
| | - Matthias Heyden
- School of Molecular Sciences, Arizona State University, 551 East University Drive, Tempe, Arizona 85287, United States
| | - Fabio Sterpone
- CNRS Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique, Université Paris Denis Diderot, Sorbonne Paris Cité, PSL Research University, 13 rue Pierre et Marie Curie, Paris 75005, France
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, Braunschweig 38106, Germany
- Department of Physical Chemistry II, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany
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96
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Liu M, Heimlicher MB, Bächler M, Ibeneche-Nnewihe CC, Florin EL, Brunner D, Hoenger A. Glucose starvation triggers filamentous septin assemblies in an S. pombe septin-2 deletion mutant. Biol Open 2019; 8:8/1/bio037622. [PMID: 30602528 PMCID: PMC6361201 DOI: 10.1242/bio.037622] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Using correlative light and electron microscopy (CLEM), we studied the intracellular organization by of glucose-starved fission yeast cells (Schizosaccharomyces pombe) with regards to the localization of septin proteins throughout the cytoplasm. Thereby, we found that for cells carrying a deletion of the gene encoding septin-2 (spn2Δ), starvation causes a GFP-tagged version of septin-3 (spn3-GFP) and family members, to assemble into a single, prominent filamentous structure. It was previously shown that during exponential growth, spn2Δ cells form septin-3 polymers. However, the polymers we observed during exponential growth are different from the spn3p-GFP structure we observed in starved cells. Using CLEM, in combination with anti-GFP immunolabeling on plastic-sections, we could assign spn3p-GFP to the filaments we have found in EM pictures. Besides septin-3, these filamentous assemblies most likely also contain septin-1 as an RFP-tagged version of this protein forms a very similar structure in starved spn2Δ cells. Our data correlate phase-contrast and fluorescence microscopy with electron micrographs of plastic-embedded cells, and further on with detailed views of tomographic 3D reconstructions. Cryo-electron microscopy of spn2Δ cells in vitrified sections revealed a very distinct overall morphology of the spn3p-GFP assembly. The fine-structured, regular density pattern suggests the presence of assembled septin-3 filaments that are clearly different from F-actin bundles. Furthermore, we found that starvation causes substantial mitochondria fission, together with massive decoration of their outer membrane by ribosomes.
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Affiliation(s)
- Minghua Liu
- University of Colorado at Boulder, Department of Molecular, Cellular and Developmental Biology, UCB-0347, Boulder, CO 80309, USA
| | - Maria B Heimlicher
- University of Zürich, Department of Molecular Life Sciences, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Mirjam Bächler
- University of Zürich, Department of Molecular Life Sciences, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Chieze C Ibeneche-Nnewihe
- University of Texas at Austin, Center for Nonlinear Dynamics and Department of Physics, Austin, TX 78712, USA
| | - Ernst-Ludwig Florin
- University of Texas at Austin, Center for Nonlinear Dynamics and Department of Physics, Austin, TX 78712, USA
| | - Damian Brunner
- University of Zürich, Department of Molecular Life Sciences, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Andreas Hoenger
- University of Colorado at Boulder, Department of Molecular, Cellular and Developmental Biology, UCB-0347, Boulder, CO 80309, USA
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97
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Sagot I, Laporte D. The cell biology of quiescent yeast – a diversity of individual scenarios. J Cell Sci 2019; 132:132/1/jcs213025. [DOI: 10.1242/jcs.213025] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
ABSTRACT
Most cells, from unicellular to complex organisms, spend part of their life in quiescence, a temporary non-proliferating state. Although central for a variety of essential processes including tissue homeostasis, development and aging, quiescence is poorly understood. In fact, quiescence encompasses various cellular situations depending on the cell type and the environmental niche. Quiescent cell properties also evolve with time, adding another layer of complexity. Studying quiescence is, above all, limited by the fact that a quiescent cell can be recognized as such only after having proved that it is capable of re-proliferating. Recent cellular biology studies in yeast have reported the relocalization of hundreds of proteins and the reorganization of several cellular machineries upon proliferation cessation. These works have revealed that quiescent cells can display various properties, shedding light on a plethora of individual behaviors. The deciphering of the molecular mechanisms beyond these reorganizations, together with the understanding of their cellular functions, have begun to provide insights into the physiology of quiescent cells. In this Review, we discuss recent findings and emerging concepts in Saccharomyces cerevisiae quiescent cell biology.
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Affiliation(s)
- Isabelle Sagot
- Centre National de la Recherche Scientifique, Université de Bordeaux-Institut de Biochimie et Génétique Cellulaires, UMR5095-33077 Bordeaux cedex, France
| | - Damien Laporte
- Centre National de la Recherche Scientifique, Université de Bordeaux-Institut de Biochimie et Génétique Cellulaires, UMR5095-33077 Bordeaux cedex, France
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98
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Noree C, Monfort E, Shotelersuk V. Human asparagine synthetase associates with the mitotic spindle. Biol Open 2018; 7:bio.038307. [PMID: 30464009 PMCID: PMC6310878 DOI: 10.1242/bio.038307] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cancer cells are characterized by extensive reprogramming of metabolic pathways in order to promote cell division and survival. However, the growth promotion effects of metabolic reprogramming can be due to moonlighting functions of metabolic enzymes as well as the redirection of flux through particular pathways. To identify metabolic enzymes that might have potential moonlighting functions in oncogenesis, we have examined recent screens of the yeast GFP strain collection for metabolic enzymes that have been implicated in cancer metabolism with an unusual subcellular localization. Asparagine synthetase forms filaments in yeast in response to nutrient limitation and is part of a pathway that is a chemotherapy target in acute lymphoblastic leukemia. Interestingly, while yeast asparagine synthetase forms cytoplasmic filaments in response to nutrient stress, human asparagine synthetase is associated with the centrosomes and mitotic spindles. This localization is disrupted by both nocodazole and asparaginase treatments. This failure to localize occurs even though asparagine synthetase is highly upregulated in response to asparaginase treatment. Together, these results argue that human asparagine synthetase undergoes regulated recruitment to the mitotic spindles and that it may have acquired a second role in mitosis similar to other metabolic enzymes that contribute to metabolic reprogramming in cancer cells. Summary: While yeast Asn1p/ASN2p forms cytoplasmic filaments in response to nutrient limitation, hASNS is associated with centrosomes and mitotic spindles in actively dividing cells, suggesting its additional role in cell division.
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Affiliation(s)
- Chalongrat Noree
- Institute of Molecular Biosciences, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand
| | - Elena Monfort
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive (MC 0347), La Jolla, CA 92093-0347, USA
| | - Vorasuk Shotelersuk
- Center of Excellence for Medical Genomics, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
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99
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Pillai M, Jha SK. The Folding and Aggregation Energy Landscapes of Tethered RRM Domains of Human TDP-43 Are Coupled via a Metastable Molten Globule-like Oligomer. Biochemistry 2018; 58:608-620. [DOI: 10.1021/acs.biochem.8b01013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Meenakshi Pillai
- Physical and Materials Chemistry Division, Academy of Scientific and Innovative Research (AcSIR), CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division, Academy of Scientific and Innovative Research (AcSIR), CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
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100
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Prouteau M, Loewith R. Regulation of Cellular Metabolism through Phase Separation of Enzymes. Biomolecules 2018; 8:biom8040160. [PMID: 30513998 PMCID: PMC6316564 DOI: 10.3390/biom8040160] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 01/21/2023] Open
Abstract
Metabolism is the sum of the life-giving chemical processes that occur within a cell. Proper regulation of these processes is essential for all organisms to thrive and prosper. When external factors are too extreme, or if internal regulation is corrupted through genetic or epigenetic changes, metabolic homeostasis is no longer achievable and diseases such as metabolic syndrome or cancer, aging, and, ultimately, death ensue. Metabolic reactions are catalyzed by proteins, and the in vitro kinetic properties of these enzymes have been studied by biochemists for many decades. These efforts led to the appreciation that enzyme activities can be acutely regulated and that this regulation is critical to metabolic homeostasis. Regulation can be mediated through allosteric interactions with metabolites themselves or via post-translational modifications triggered by intracellular signal transduction pathways. More recently, enzyme regulation has attracted the attention of cell biologists who noticed that change in growth conditions often triggers the condensation of diffusely localized enzymes into one or more discrete foci, easily visible by light microscopy. This reorganization from a soluble to a condensed state is best described as a phase separation. As summarized in this review, stimulus-induced phase separation has now been observed for dozens of enzymes suggesting that this could represent a widespread mode of activity regulation, rather than, or in addition to, a storage form of temporarily superfluous enzymes. Building on our recent structure determination of TOROIDs (TORc1 Organized in Inhibited Domain), the condensate formed by the protein kinase Target Of Rapamycin Complex 1 (TORC1), we will highlight that the molecular organization of enzyme condensates can vary dramatically and that future work aimed at the structural characterization of enzyme condensates will be critical to understand how phase separation regulates enzyme activity and consequently metabolic homeostasis. This information may ultimately facilitate the design of strategies to target the assembly or disassembly of specific enzymes condensates as a therapeutic approach to restore metabolic homeostasis in certain diseases.
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Affiliation(s)
- Manoël Prouteau
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, CH1211 Geneva, Switzerland.
- Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, 30 Quai Ernest-Ansermet, CH1211 Geneva, Switzerland.
| | - Robbie Loewith
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, CH1211 Geneva, Switzerland.
- Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, 30 Quai Ernest-Ansermet, CH1211 Geneva, Switzerland.
- Swiss National Centre for Competence in Research (NCCR) in Chemical Biology, University of Geneva, Sciences II, Room 3-308, 30 Quai Ernest-Ansermet, CH1211 Geneva, Switzerland.
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