1
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Fare CM, Rothstein JD. Nuclear pore dysfunction and disease: a complex opportunity. Nucleus 2024; 15:2314297. [PMID: 38383349 PMCID: PMC10883112 DOI: 10.1080/19491034.2024.2314297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/30/2024] [Indexed: 02/23/2024] Open
Abstract
The separation of genetic material from bulk cytoplasm has enabled the evolution of increasingly complex organisms, allowing for the development of sophisticated forms of life. However, this complexity has created new categories of dysfunction, including those related to the movement of material between cellular compartments. In eukaryotic cells, nucleocytoplasmic trafficking is a fundamental biological process, and cumulative disruptions to nuclear integrity and nucleocytoplasmic transport are detrimental to cell survival. This is particularly true in post-mitotic neurons, where nuclear pore injury and errors to nucleocytoplasmic trafficking are strongly associated with neurodegenerative disease. In this review, we summarize the current understanding of nuclear pore biology in physiological and pathological contexts and discuss potential therapeutic approaches for addressing nuclear pore injury and dysfunctional nucleocytoplasmic transport.
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Affiliation(s)
- Charlotte M Fare
- Department of Neurology and Brain Science Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Jeffrey D Rothstein
- Department of Neurology and Brain Science Institute, Johns Hopkins University, Baltimore, MD, USA
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2
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Ibáñez de Opakua A, Pantoja CF, Cima-Omori MS, Dienemann C, Zweckstetter M. Impact of distinct FG nucleoporin repeats on Nup98 self-association. Nat Commun 2024; 15:3797. [PMID: 38714656 PMCID: PMC11076500 DOI: 10.1038/s41467-024-48194-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 04/24/2024] [Indexed: 05/10/2024] Open
Abstract
Nucleoporins rich in phenylalanine/glycine (FG) residues form the permeability barrier within the nuclear pore complex and are implicated in several pathological cellular processes, including oncogenic fusion condensates. The self-association of FG-repeat proteins and interactions between FG-repeats play a critical role in these activities by forming hydrogel-like structures. Here we show that mutation of specific FG repeats of Nup98 can strongly decrease the protein's self-association capabilities. We further present a cryo-electron microscopy structure of a Nup98 peptide fibril with higher stability per residue compared with previous Nup98 fibril structures. The high-resolution structure reveals zipper-like hydrophobic patches which contain a GLFG motif and are less compatible for binding to nuclear transport receptors. The identified distinct molecular properties of different regions of the nucleoporin may contribute to spatial variations in the self-association of FG-repeats, potentially influencing transport processes through the nuclear pore.
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Affiliation(s)
- Alain Ibáñez de Opakua
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany
| | - Christian F Pantoja
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany
| | - Maria-Sol Cima-Omori
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany
| | - Christian Dienemann
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-based Structural Biology, Am Fassberg 11, Göttingen, Germany.
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3
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McKnight SL. Protein domains of low sequence complexity-dark matter of the proteome. Genes Dev 2024; 38:205-212. [PMID: 38503517 PMCID: PMC11065162 DOI: 10.1101/gad.351465.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
This perspective begins with a speculative consideration of the properties of the earliest proteins to appear during evolution. What did these primitive proteins look like, and how were they of benefit to early forms of life? I proceed to hypothesize that primitive proteins have been preserved through evolution and now serve diverse functions important to the dynamics of cell morphology and biological regulation. The primitive nature of these modern proteins is easy to spot. They are composed of a limited subset of the 20 amino acids used by traditionally evolved proteins and thus are of low sequence complexity. This chemical simplicity limits protein domains of low sequence complexity to forming only a crude and labile type of protein structure currently hidden from the computational powers of machine learning. I conclude by hypothesizing that this structural weakness represents the underlying virtue of proteins that, at least for the moment, constitute the dark matter of the proteome.
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Affiliation(s)
- Steven L McKnight
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75390-9152, USA
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4
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Khalil B, Linsenmeier M, Smith CL, Shorter J, Rossoll W. Nuclear-import receptors as gatekeepers of pathological phase transitions in ALS/FTD. Mol Neurodegener 2024; 19:8. [PMID: 38254150 PMCID: PMC10804745 DOI: 10.1186/s13024-023-00698-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 12/13/2023] [Indexed: 01/24/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative disorders on a disease spectrum that are characterized by the cytoplasmic mislocalization and aberrant phase transitions of prion-like RNA-binding proteins (RBPs). The common accumulation of TAR DNA-binding protein-43 (TDP-43), fused in sarcoma (FUS), and other nuclear RBPs in detergent-insoluble aggregates in the cytoplasm of degenerating neurons in ALS/FTD is connected to nuclear pore dysfunction and other defects in the nucleocytoplasmic transport machinery. Recent advances suggest that beyond their canonical role in the nuclear import of protein cargoes, nuclear-import receptors (NIRs) can prevent and reverse aberrant phase transitions of TDP-43, FUS, and related prion-like RBPs and restore their nuclear localization and function. Here, we showcase the NIR family and how they recognize cargo, drive nuclear import, and chaperone prion-like RBPs linked to ALS/FTD. We also discuss the promise of enhancing NIR levels and developing potentiated NIR variants as therapeutic strategies for ALS/FTD and related neurodegenerative proteinopathies.
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Affiliation(s)
- Bilal Khalil
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, U.S.A
| | - Miriam Linsenmeier
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, U.S.A
| | - Courtney L Smith
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, U.S.A
- Mayo Clinic Graduate School of Biomedical Sciences, Neuroscience Track, Mayo Clinic, Jacksonville, FL, 32224, U.S.A
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, U.S.A..
| | - Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, U.S.A..
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5
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Barrientos ECR, Otto TA, Mouton SN, Steen A, Veenhoff LM. A survey of the specificity and mechanism of 1,6 hexanediol-induced disruption of nuclear transport. Nucleus 2023; 14:2240139. [PMID: 37498221 PMCID: PMC10376917 DOI: 10.1080/19491034.2023.2240139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/17/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023] Open
Abstract
Selective transport through the nuclear pore complex (NPC) depends on the dynamic binding of FG-repeat containing nucleoporins, the FG-nups, with each other and with Karyopherins (Kaps). Here, we assessed the specificity and mechanism by which the aliphatic alcohol 1,6-hexanediol (1,6HD) disrupts the permeability barrier of NPCs in live baker's yeast cells. After a 10-minute exposure to 5% 1,6HD, no notable changes were observed in cell growth, cytosolic pH and ATP levels, or the appearance of organelles. However, effects on the cytoskeleton and Hsp104 were noted. 1,6HD clearly affected the NPC permeability barrier, allowing passive nuclear entry of a 177kDa reporter protein that is normally confined to the cytosol. Moreover, multiple Kaps were displaced from NPCs, and the displacement of Kap122-GFP correlated with the observed passive permeability changes. 1,6HD thus temporarily permeates NPCs, and in line with Kap-centric models, the mechanism includes the release of numerous Kaps from the NPCs.
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Affiliation(s)
- Elizabeth C Riquelme Barrientos
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Tegan A Otto
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Sara N Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Anton Steen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
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6
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Yang J, Ding W, Zhu B, Zhen S, Kuang S, Yang J, Zhang C, Wang P, Yang F, Yang L, Yin W, Tanzi RE, Shen S, Ran C. Bioluminescence Imaging with Functional Amyloid Reservoirs in Alzheimer's Disease Models. Anal Chem 2023; 95:14261-14270. [PMID: 37712902 DOI: 10.1021/acs.analchem.3c02358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Bioluminescence imaging has changed the daily practice of preclinical research on cancer and other diseases over the last few decades; however, it has rarely been applied in preclinical research on Alzheimer's disease (AD). In this Article, we demonstrated that bioluminescence imaging could be used to report the levels of amyloid beta (Aβ) species in vivo. We hypothesized that AkaLumine, a newly discovered substrate for luciferase, could bind to Aβ aggregates and plaques. We further speculated that the Aβ aggregates/fibrils/plaques could be considered as "functional amyloids", which have a reservoir function to sequester and release AkaLumine to control the bioluminescence intensity, which could be used to report the levels of Aβs. Our hypotheses have been validated via in vitro solution tests, mimic studies with brain tissues and mice, two-photon imaging with AD mice, and in vivo bioluminescence imaging using transgenic AD mice that were virally transduced with AkaLuciferase (AkaLuc), a new luciferase that generates bioluminescence in the near-infrared window. As expected, compared to the control group, we observed that the Aβ group showed lower bioluminescence intensity due to AkaLumine sequestering at early time points, while higher intensity was due to AkaLumine releasing at later time points. Lastly, we demonstrated that this method could be used to monitor AD progression and the therapeutic effectiveness of avagacestat, a well-studied gamma-secretase inhibitor. Importantly, a good correlation (R2 = 0.81) was established between in vivo bioluminescence signals and Aβ burdens of the tested AD mice. We believe that our approach can be easily implemented into daily imaging experiments and has tremendous potential to change the daily practice of preclinical AD research.
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Affiliation(s)
- Jing Yang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China
| | - Weihua Ding
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Biyue Zhu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
| | - Sherri Zhen
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Shi Kuang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
| | - Jun Yang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
| | - Can Zhang
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Peng Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
- School of Engineering, China Pharmaceutical University, Nanjing 210009, China
| | - Fan Yang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
| | - Liuyue Yang
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Wei Yin
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Shiqian Shen
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Building 149, Charlestown, Boston, Massachusetts 02129,United States
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7
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McGoldrick P, Robertson J. Unraveling the impact of disrupted nucleocytoplasmic transport systems in C9orf72-associated ALS. Front Cell Neurosci 2023; 17:1247297. [PMID: 37720544 PMCID: PMC10501458 DOI: 10.3389/fncel.2023.1247297] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 08/08/2023] [Indexed: 09/19/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two adult-onset neurodegenerative diseases that are part of a common disease spectrum due to clinical, genetic, and pathological overlap. A prominent genetic factor contributing to both diseases is a hexanucleotide repeat expansion in a non-coding region of the C9orf72 gene. This mutation in C9orf72 leads to nuclear depletion and cytoplasmic aggregation of Tar DNA-RNA binding protein 43 (TDP-43). TDP-43 pathology is characteristic of the majority of ALS cases, irrespective of disease causation, and is present in ~50% of FTD cases. Defects in nucleocytoplasmic transport involving the nuclear pore complex, the Ran-GTPase cycle, and nuclear transport factors have been linked with the mislocalization of TDP-43. Here, we will explore and discuss the implications of these system abnormalities of nucleocytoplasmic transport in C9orf72-ALS/FTD, as well as in other forms of familial and sporadic ALS.
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Affiliation(s)
- Philip McGoldrick
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Janice Robertson
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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8
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Dekker M, Van der Giessen E, Onck PR. Phase separation of intrinsically disordered FG-Nups is driven by highly dynamic FG motifs. Proc Natl Acad Sci U S A 2023; 120:e2221804120. [PMID: 37307457 PMCID: PMC10288634 DOI: 10.1073/pnas.2221804120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 05/09/2023] [Indexed: 06/14/2023] Open
Abstract
The intrinsically disordered FG-Nups in the central channel of the nuclear pore complex (NPC) form a selective permeability barrier, allowing small molecules to traverse by passive diffusion, while large molecules can only translocate with the help of nuclear transport receptors. The exact phase state of the permeability barrier remains elusive. In vitro experiments have shown that some FG-Nups can undergo phase separation into condensates that display NPC-like permeability barrier properties. Here, we use molecular dynamics simulations at amino acid resolution to study the phase separation characteristics of each of the disordered FG-Nups of the yeast NPC. We find that GLFG-Nups undergo phase separation and reveal that the FG motifs act as highly dynamic hydrophobic stickers that are essential for the formation of FG-Nup condensates featuring droplet-spanning percolated networks. Additionally, we study phase separation in an FG-Nup mixture that resembles the NPC stoichiometry and observe that an NPC condensate is formed containing multiple GLFG-Nups. We find that the phase separation of this NPC condensate is also driven by FG-FG interactions, similar to the homotypic FG-Nup condensates. Based on the observed phase separation behavior, the different FG-Nups of the yeast NPC can be divided into two classes: The FG-Nups (mostly GLFG-type) located in the central channel of the NPC form a highly dynamic percolated network formed by many short-lived FG-FG interactions, while the peripheral FG-Nups (mostly FxFG-type) at the entry and exit of the NPC channel likely form an entropic brush.
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Affiliation(s)
- Maurice Dekker
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Erik Van der Giessen
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Patrick R. Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
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9
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Danilov LG, Sukhanova XV, Rogoza TM, Antonova EY, Trubitsina NP, Zhouravleva GA, Bondarev SA. Identification of New FG-Repeat Nucleoporins with Amyloid Properties. Int J Mol Sci 2023; 24:ijms24108571. [PMID: 37239918 DOI: 10.3390/ijms24108571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
Amyloids are fibrillar protein aggregates with a cross-β structure. More than two hundred different proteins with amyloid or amyloid-like properties are already known. Functional amyloids with conservative amyloidogenic regions were found in different organisms. Protein aggregation appears to be beneficial for the organism in these cases. Therefore, this property might be conservative for orthologous proteins. The amyloid aggregates of the CPEB protein were suggested to play an important role in the long-term memory formation in Aplysia californica, Drosophila melanogaster, and Mus musculus. Moreover, the FXR1 protein demonstrates amyloid properties among the Vertebrates. A few nucleoporins (e.g., yeast Nup49, Nup100, Nup116, and human Nup153 and Nup58), are supposed or proved to form amyloid fibrils. In this study, we performed wide-scale bioinformatic analysis of nucleoporins with FG-repeats (phenylalanine-glycine repeats). We demonstrated that most of the barrier nucleoporins possess potential amyloidogenic properties. Furthermore, the aggregation-prone properties of several Nsp1 and Nup100 orthologs in bacteria and yeast cells were analyzed. Only two new nucleoporins, Drosophila melanogaster Nup98 and Schizosaccharomyces pombe Nup98, aggregated in different experiments. At the same time, Taeniopygia guttata Nup58 only formed amyloids in bacterial cells. These results rather contradict the hypothesis about the functional aggregation of nucleoporins.
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Affiliation(s)
- Lavrentii G Danilov
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Xenia V Sukhanova
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Tatiana M Rogoza
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
- St. Petersburg Branch, Vavilov Institute of General Genetics, Russian Academy of Sciences, 194064 St. Petersburg, Russia
| | - Ekaterina Y Antonova
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Nina P Trubitsina
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Galina A Zhouravleva
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Stanislav A Bondarev
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
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10
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Sontag EM, Morales-Polanco F, Chen JH, McDermott G, Dolan PT, Gestaut D, Le Gros MA, Larabell C, Frydman J. Nuclear and cytoplasmic spatial protein quality control is coordinated by nuclear-vacuolar junctions and perinuclear ESCRT. Nat Cell Biol 2023; 25:699-713. [PMID: 37081164 DOI: 10.1038/s41556-023-01128-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/14/2023] [Indexed: 04/22/2023]
Abstract
Effective protein quality control (PQC), essential for cellular health, relies on spatial sequestration of misfolded proteins into defined inclusions. Here we reveal the coordination of nuclear and cytoplasmic spatial PQC. Cytoplasmic misfolded proteins concentrate in a cytoplasmic juxtanuclear quality control compartment, while nuclear misfolded proteins sequester into an intranuclear quality control compartment (INQ). Particle tracking reveals that INQ and the juxtanuclear quality control compartment converge to face each other across the nuclear envelope at a site proximal to the nuclear-vacuolar junction marked by perinuclear ESCRT-II/III protein Chm7. Strikingly, convergence at nuclear-vacuolar junction contacts facilitates VPS4-dependent vacuolar clearance of misfolded cytoplasmic and nuclear proteins, the latter entailing extrusion of nuclear INQ into the vacuole. Finding that nuclear-vacuolar contact sites are cellular hubs of spatial PQC to facilitate vacuolar clearance of nuclear and cytoplasmic inclusions highlights the role of cellular architecture in proteostasis maintenance.
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Affiliation(s)
- Emily M Sontag
- Department of Biology, Stanford University, Stanford, CA, USA.
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.
| | | | - Jian-Hua Chen
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Gerry McDermott
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Patrick T Dolan
- Department of Biology, Stanford University, Stanford, CA, USA
- Quantitative Virology and Evolution Unit, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Daniel Gestaut
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Mark A Le Gros
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Carolyn Larabell
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA, USA.
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11
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Cowburn D, Rout M. Improving the hole picture: towards a consensus on the mechanism of nuclear transport. Biochem Soc Trans 2023; 51:871-886. [PMID: 37099395 PMCID: PMC10212546 DOI: 10.1042/bst20220494] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 04/27/2023]
Abstract
Nuclear pore complexes (NPCs) mediate the exchange of materials between the nucleoplasm and cytoplasm, playing a key role in the separation of nucleic acids and proteins into their required compartments. The static structure of the NPC is relatively well defined by recent cryo-EM and other studies. The functional roles of dynamic components in the pore of the NPC, phenylalanyl-glycyl (FG) repeat rich nucleoporins, is less clear because of our limited understanding of highly dynamic protein systems. These proteins form a 'restrained concentrate' which interacts with and concentrates nuclear transport factors (NTRs) to provide facilitated nucleocytoplasmic transport of cargoes. Very rapid on- and off-rates among FG repeats and NTRs supports extremely fast facilitated transport, close to the rate of macromolecular diffusion in cytoplasm, while complexes without specific interactions are entropically excluded, though details on several aspects of the transport mechanism and FG repeat behaviors remain to be resolved. However, as discussed here, new technical approaches combined with more advanced modeling methods will likely provide an improved dynamic description of NPC transport, potentially at the atomic level in the near future. Such advances are likely to be of major benefit in comprehending the roles the malfunctioning NPC plays in cancer, ageing, viral diseases, and neurodegeneration.
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Affiliation(s)
- David Cowburn
- Departments of Biochemistry and Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, U.S.A
| | - Michael Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, U.S.A
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12
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Kozai T, Fernandez-Martinez J, van Eeuwen T, Gallardo P, Kapinos LE, Mazur A, Zhang W, Tempkin J, Panatala R, Delgado-Izquierdo M, Raveh B, Sali A, Chait BT, Veenhoff LM, Rout MP, Lim RYH. Dynamic molecular mechanism of the nuclear pore complex permeability barrier. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535055. [PMID: 37066338 PMCID: PMC10103940 DOI: 10.1101/2023.03.31.535055] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Nuclear pore complexes (NPCs) mediate nucleocytoplasmic transport of specific macromolecules while impeding the exchange of unsolicited material. However, key aspects of this gating mechanism remain controversial. To address this issue, we determined the nanoscopic behavior of the permeability barrier directly within yeast S. cerevisiae NPCs at transport-relevant timescales. We show that the large intrinsically disordered domains of phenylalanine-glycine repeat nucleoporins (FG Nups) exhibit highly dynamic fluctuations to create transient voids in the permeability barrier that continuously shape-shift and reseal, resembling a radial polymer brush. Together with cargo-carrying transport factors the FG domains form a feature called the central plug, which is also highly dynamic. Remarkably, NPC mutants with longer FG domains show interweaving meshwork-like behavior that attenuates nucleocytoplasmic transport in vivo. Importantly, the bona fide nanoscale NPC behaviors and morphologies are not recapitulated by in vitro FG domain hydrogels. NPCs also exclude self-assembling FG domain condensates in vivo, thereby indicating that the permeability barrier is not generated by a self-assembling phase condensate, but rather is largely a polymer brush, organized by the NPC scaffold, whose dynamic gating selectivity is strongly enhanced by the presence of transport factors.
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Affiliation(s)
- Toshiya Kozai
- Biozentrum, University of Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Switzerland
| | - Javier Fernandez-Martinez
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, U.S.A
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
| | - Trevor van Eeuwen
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, U.S.A
| | - Paola Gallardo
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Netherlands
| | | | - Adam Mazur
- Biozentrum, University of Basel, Switzerland
| | - Wenzhu Zhang
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, U.S.A
| | - Jeremy Tempkin
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, U.S.A. Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA. Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | | | | | - Barak Raveh
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Israel
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, U.S.A. Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA. Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, U.S.A
| | - Liesbeth M. Veenhoff
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Netherlands
| | - Michael P. Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, U.S.A
| | - Roderick Y. H. Lim
- Biozentrum, University of Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Switzerland
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13
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Yang H, Yuan P, Wu Y, Shi M, Caro CD, Tengeiji A, Yamanoi S, Inoue M, DeGrado WF, Condello C. EMBER multidimensional spectral microscopy enables quantitative determination of disease- and cell-specific amyloid strains. Proc Natl Acad Sci U S A 2023; 120:e2300769120. [PMID: 36927157 PMCID: PMC10041141 DOI: 10.1073/pnas.2300769120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/08/2023] [Indexed: 03/18/2023] Open
Abstract
In neurodegenerative diseases, proteins fold into amyloid structures with distinct conformations (strains) that are characteristic of different diseases. However, there is a need to rapidly identify amyloid conformations in situ. Here, we use machine learning on the full information available in fluorescent excitation/emission spectra of amyloid-binding dyes to identify six distinct different conformational strains in vitro, as well as amyloid-β (Aβ) deposits in different transgenic mouse models. Our EMBER (excitation multiplexed bright emission recording) imaging method rapidly identifies conformational differences in Aβ and tau deposits from Down syndrome, sporadic and familial Alzheimer's disease human brain slices. EMBER has in situ identified distinct conformational strains of tau inclusions in astrocytes, oligodendrocytes, and neurons from Pick's disease. In future studies, EMBER should enable high-throughput measurements of the fidelity of strain transmission in cellular and animal neurodegenerative diseases models, time course of amyloid strain propagation, and identification of pathogenic versus benign strains.
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Affiliation(s)
- Hyunjun Yang
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA94143
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA94158
| | - Peng Yuan
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA94143
| | - Yibing Wu
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA94158
| | - Marie Shi
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA94143
| | - Christoffer D. Caro
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA94143
| | | | | | | | - William F. DeGrado
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA94143
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA94158
| | - Carlo Condello
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA94143
- Department of Neurology, University of California, San Francisco, CA94143
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14
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Ng SC, Biswas A, Huyton T, Schünemann J, Reber S, Görlich D. Barrier properties of Nup98 FG phases ruled by FG motif identity and inter-FG spacer length. Nat Commun 2023; 14:747. [PMID: 36765044 PMCID: PMC9918544 DOI: 10.1038/s41467-023-36331-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/24/2023] [Indexed: 02/12/2023] Open
Abstract
Nup98 FG repeat domains comprise hydrophobic FG motifs linked through uncharged spacers. FG motifs capture nuclear transport receptors (NTRs) during nuclear pore complex (NPC) passage, confer inter-repeat cohesion, and condense the domains into a selective phase with NPC-typical barrier properties. We show that shortening inter-FG spacers enhances cohesion, increases phase density, and tightens such barrier - all consistent with a sieve-like phase. Phase separation tolerates mutating the Nup98-typical GLFG motifs, provided domain-hydrophobicity remains preserved. NTR-entry, however, is sensitive to (certain) deviations from canonical FG motifs, suggesting co-evolutionary adaptation. Unexpectedly, we observed that arginines promote FG-phase-entry apparently also by hydrophobic interactions/ hydrogen-bonding and not just through cation-π interactions. Although incompatible with NTR·cargo complexes, a YG phase displays remarkable transport selectivity, particularly for engineered GFPNTR-variants. GLFG to FSFG mutations make the FG phase hypercohesive, precluding NTR-entry. Extending spacers relaxes this hypercohesion. Thus, antagonism between cohesion and NTR·FG interactions is key to transport selectivity.
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Affiliation(s)
- Sheung Chun Ng
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Abin Biswas
- Quantitative Biology, IRI Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Department of Biological Optomechanics, Max Planck Institute for the Science of Light, Erlangen, Germany
| | - Trevor Huyton
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Jürgen Schünemann
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Simone Reber
- Quantitative Biology, IRI Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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15
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Yang H, Yuan P, Wu Y, Shi M, Caro CD, Tengeiji A, Yamanoi S, Inoue M, DeGrado WF, Condello C. EMBER multi-dimensional spectral microscopy enables quantitative determination of disease- and cell-specific amyloid strains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.01.526692. [PMID: 36778268 PMCID: PMC9915571 DOI: 10.1101/2023.02.01.526692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
In neurodegenerative diseases proteins fold into amyloid structures with distinct conformations (strains) that are characteristic of different diseases. However, there is a need to rapidly identify amyloid conformations in situ . Here we use machine learning on the full information available in fluorescent excitation/emission spectra of amyloid binding dyes to identify six distinct different conformational strains in vitro , as well as Aβ deposits in different transgenic mouse models. Our EMBER (excitation multiplexed bright emission recording) imaging method rapidly identifies conformational differences in Aβ and tau deposits from Down syndrome, sporadic and familial Alzheimer's disease human brain slices. EMBER has in situ identified distinct conformational strains of tau inclusions in astrocytes, oligodendrocytes, and neurons from Pick's disease. In future studies, EMBER should enable high-throughput measurements of the fidelity of strain transmission in cellular and animal neurodegenerative diseases models, time course of amyloid strain propagation, and identification of pathogenic versus benign strains. Significance In neurodegenerative diseases proteins fold into amyloid structures with distinct conformations (strains) that are characteristic of different diseases. There is a need to rapidly identify these amyloid conformations in situ . Here we use machine learning on the full information available in fluorescent excitation/emission spectra of amyloid binding dyes to identify six distinct different conformational strains in vitro , as well as Aβ deposits in different transgenic mouse models. Our imaging method rapidly identifies conformational differences in Aβ and tau deposits from Down syndrome, sporadic and familial Alzheimer's disease human brain slices. We also identified distinct conformational strains of tau inclusions in astrocytes, oligodendrocytes, and neurons from Pick's disease. These findings will facilitate the identification of pathogenic protein aggregates to guide research and treatment of protein misfolding diseases.
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Affiliation(s)
- Hyunjun Yang
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94158
| | - Peng Yuan
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143
| | - Yibing Wu
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94158
| | - Marie Shi
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143
| | - Christoffer D Caro
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143
| | | | | | | | - William F DeGrado
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94158
| | - Carlo Condello
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143
- Department of Neurology, University of California, San Francisco, CA 94143
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16
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Doll SG, Cingolani G. Importin α/β and the tug of war to keep TDP-43 in solution: quo vadis? Bioessays 2022; 44:e2200181. [PMID: 36253101 PMCID: PMC9969346 DOI: 10.1002/bies.202200181] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 09/29/2022] [Accepted: 10/05/2022] [Indexed: 11/10/2022]
Abstract
The transactivation response-DNA binding protein of 43 kDa (TDP-43) is an aggregation-prone nucleic acid-binding protein linked to the etiology of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). These conditions feature the accumulation of insoluble TDP-43 aggregates in the neuronal cytoplasm that lead to cell death. The dynamics between cytoplasmic and nuclear TDP-43 are altered in the disease state where TDP-43 mislocalizes to the cytoplasm, disrupting Nuclear Pore Complexes (NPCs), and ultimately forming large fibrils stabilized by the C-terminal prion-like domain. Here, we review three emerging and poorly understood aspects of TDP-43 biology linked to its aggregation. First, how post-translational modifications in the proximity of TDP-43 N-terminal domain (NTD) promote aggregation. Second, how TDP-43 engages FG-nucleoporins in the NPC, disrupting the pore permeability and function. Third, how the importin α/β heterodimer prevents TDP-43 aggregation, serving both as a nuclear import transporter and a cytoplasmic chaperone.
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Affiliation(s)
- Steven G. Doll
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Gino Cingolani
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA,Corresponding author: Gino Cingolani,
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17
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Andersson J, Svirelis J, Medin J, Järlebark J, Hailes R, Dahlin A. Pore performance: artificial nanoscale constructs that mimic the biomolecular transport of the nuclear pore complex. NANOSCALE ADVANCES 2022; 4:4925-4937. [PMID: 36504753 PMCID: PMC9680827 DOI: 10.1039/d2na00389a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/12/2022] [Indexed: 06/17/2023]
Abstract
The nuclear pore complex is a nanoscale assembly that achieves shuttle-cargo transport of biomolecules: a certain cargo molecule can only pass the barrier if it is attached to a shuttle molecule. In this review we summarize the most important efforts aiming to reproduce this feature in artificial settings. This can be achieved by solid state nanopores that have been functionalized with the most important proteins found in the biological system. Alternatively, the nanopores are chemically modified with synthetic polymers. However, only a few studies have demonstrated a shuttle-cargo transport mechanism and due to cargo leakage, the selectivity is not comparable to that of the biological system. Other recent approaches are based on DNA origami, though biomolecule transport has not yet been studied with these. The highest selectivity has been achieved with macroscopic gels, but they are yet to be scaled down to nano-dimensions. It is concluded that although several interesting studies exist, we are still far from achieving selective and efficient artificial shuttle-cargo transport of biomolecules. Besides being of fundamental interest, such a system could be potentially useful in bioanalytical devices.
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Affiliation(s)
- John Andersson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Justas Svirelis
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Jesper Medin
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Julia Järlebark
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Rebekah Hailes
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
| | - Andreas Dahlin
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology 41296 Gothenburg Sweden
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18
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Expanding the Landscape of Amino Acid-Rich Antimicrobial Peptides: Definition, Deployment in Nature, Implications for Peptide Design and Therapeutic Potential. Int J Mol Sci 2022; 23:ijms232112874. [PMID: 36361660 PMCID: PMC9658076 DOI: 10.3390/ijms232112874] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/18/2022] [Accepted: 10/20/2022] [Indexed: 11/25/2022] Open
Abstract
Unlike the α-helical and β-sheet antimicrobial peptides (AMPs), our knowledge on amino acid-rich AMPs is limited. This article conducts a systematic study of rich AMPs (>25%) from different life kingdoms based on the Antimicrobial Peptide Database (APD) using the program R. Of 3425 peptides, 724 rich AMPs were identified. Rich AMPs are more common in animals and bacteria than in plants. In different animal classes, a unique set of rich AMPs is deployed. While histidine, proline, and arginine-rich AMPs are abundant in mammals, alanine, glycine, and leucine-rich AMPs are common in amphibians. Ten amino acids (Ala, Cys, Gly, His, Ile, Lys, Leu, Pro, Arg, and Val) are frequently observed in rich AMPs, seven (Asp, Glu, Phe, Ser, Thr, Trp, and Tyr) are occasionally observed, and three (Met, Asn, and Gln) were not yet found. Leucine is much more frequent in forming rich AMPs than either valine or isoleucine. To date, no natural AMPs are simultaneously rich in leucine and lysine, while proline, tryptophan, and cysteine-rich peptides can simultaneously be rich in arginine. These findings can be utilized to guide peptide design. Since multiple candidates are potent against antibiotic-resistant bacteria, rich AMPs stand out as promising future antibiotics.
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19
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A simple thermodynamic description of phase separation of Nup98 FG domains. Nat Commun 2022; 13:6172. [PMID: 36257947 PMCID: PMC9579204 DOI: 10.1038/s41467-022-33697-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/28/2022] [Indexed: 12/24/2022] Open
Abstract
The permeability barrier of nuclear pore complexes (NPCs) controls nucleocytoplasmic transport. It retains inert macromolecules but allows facilitated passage of nuclear transport receptors that shuttle cargoes into or out of nuclei. The barrier can be described as a condensed phase assembled from cohesive FG repeat domains, including foremost the charge-depleted FG domain of Nup98. We found that Nup98 FG domains show an LCST-type phase separation, and we provide comprehensive and orthogonal experimental datasets for a quantitative description of this behaviour. A derived thermodynamic model correlates saturation concentration with repeat number, temperature, and ionic strength. It allows estimating the enthalpy, entropy, and ΔG (0.2 kJ/mol, 0.1 kB·T) contributions per repeat to phase separation and inter-repeat cohesion. While changing the cohesion strength strongly impacts the strictness of barrier, these numbers provide boundary conditions for in-depth modelling not only of barrier assembly but also of NPC passage.
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20
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Ibáñez de Opakua A, Geraets JA, Frieg B, Dienemann C, Savastano A, Rankovic M, Cima-Omori MS, Schröder GF, Zweckstetter M. Molecular interactions of FG nucleoporin repeats at high resolution. Nat Chem 2022; 14:1278-1285. [PMID: 36138110 PMCID: PMC9630130 DOI: 10.1038/s41557-022-01035-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 08/02/2022] [Indexed: 12/01/2022]
Abstract
Proteins that contain repeat phenylalanine-glycine (FG) residues phase separate into oncogenic transcription factor condensates in malignant leukaemias, form the permeability barrier of the nuclear pore complex and mislocalize in neurodegenerative diseases. Insights into the molecular interactions of FG-repeat nucleoporins have, however, remained largely elusive. Using a combination of NMR spectroscopy and cryoelectron microscopy, we have identified uniformly spaced segments of transient β-structure and a stable preformed α-helix recognized by messenger RNA export factors in the FG-repeat domain of human nucleoporin 98 (Nup98). In addition, we have determined at high resolution the molecular organization of reversible FG–FG interactions in amyloid fibrils formed by a highly aggregation-prone segment in Nup98. We have further demonstrated that amyloid-like aggregates of the FG-repeat domain of Nup98 have low stability and are reversible. Our results provide critical insights into the molecular interactions underlying the self-association and phase separation of FG-repeat nucleoporins in physiological and pathological cell activities. ![]()
Proteins rich in phenylalanine-glycine (FG) repeats can phase separate through FG–FG interactions. The molecular interactions of an important FG-repeat protein, nucleoporin 98, have now been studied in liquid-like transient and amyloid-like cohesive states. These interactions underlie the behaviour of FG-repeat proteins and their function in physiological and pathological cell activities.
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Affiliation(s)
| | - James A Geraets
- Institute of Biological Information Processing (Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Benedikt Frieg
- Institute of Biological Information Processing (Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Christian Dienemann
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Göttingen, Germany
| | | | - Marija Rankovic
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-based Structural Biology, Göttingen, Germany
| | | | - Gunnar F Schröder
- Institute of Biological Information Processing (Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany. .,Physics Department, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases, Göttingen, Germany. .,Max Planck Institute for Multidisciplinary Sciences, Department of NMR-based Structural Biology, Göttingen, Germany.
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21
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Michieletto D, Marenda M. Rheology and Viscoelasticity of Proteins and Nucleic Acids Condensates. JACS AU 2022; 2:1506-1521. [PMID: 35911447 PMCID: PMC9326828 DOI: 10.1021/jacsau.2c00055] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Phase separation is as familiar as watching vinegar separating from oil in vinaigrette. The observation that phase separation of proteins and nucleic acids is widespread in living cells has opened an entire field of research into the biological significance and the biophysical mechanisms of phase separation and protein condensation in biology. Recent evidence indicates that certain proteins and nucleic acids condensates are not simple liquids and instead display both viscous and elastic behaviors, which in turn may have biological significance. The aim of this Perspective is to review the state-of-the-art of this quickly emerging field focusing on the material and rheological properties of protein condensates. Finally, we discuss the different techniques that can be employed to quantify the viscoelasticity of condensates and highlight potential future directions and opportunities for interdisciplinary cross-talk between chemists, physicists, and biologists.
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Affiliation(s)
- Davide Michieletto
- School
of Physics and Astronomy, University of
Edinburgh, Peter Guthrie
Tait Road, Edinburgh EH9
3FD, U.K.
- MRC
Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, U.K.
| | - Mattia Marenda
- School
of Physics and Astronomy, University of
Edinburgh, Peter Guthrie
Tait Road, Edinburgh EH9
3FD, U.K.
- MRC
Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, U.K.
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22
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Mycoprotein as novel functional ingredient: Mapping of functionality, composition and structure throughout the Quorn fermentation process. Food Chem 2022; 396:133736. [PMID: 35872494 DOI: 10.1016/j.foodchem.2022.133736] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 07/08/2022] [Accepted: 07/15/2022] [Indexed: 11/21/2022]
Abstract
This study provides the first mapping of mycoprotein functionality, composition and structure throughout the Quorn fermentation process. The fermentation broth, RNA-reduced broth (RNA-broth), centrate and their centrifugation deposits and supernatants were characterised. The broth, RNA-broth and their deposits displayed high concentrations of fungal filaments, which contributed to their high gelling properties (with a 5,320 Pa elastic modulus reported for RNA-broth deposits gels). Foams prepared with RNA-broth and centrate supernatants via frothing exhibited high stability (380 min), with high concentrations of a foam-positive cerato-platanin reported in these samples. Emulsions prepared with the broth and broth supernatant showed high emulsifying activity and stability indexes (12.80 m2/g and 15.84 mins for the broth supernatant) and low oil droplet sizes (18.09 µm for the broth). This study identified previously unreported gelling, foaming and/or emulsifying properties for the different Quorn streams, highlighting opportunities to develop novel sustainable alternatives to animal-derived functional ingredients using mycoprotein material.
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23
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Maccaroni K, La Torre M, Burla R, Saggio I. Phase Separation in the Nucleus and at the Nuclear Periphery during Post-Mitotic Nuclear Envelope Reformation. Cells 2022; 11:1749. [PMID: 35681444 PMCID: PMC9179440 DOI: 10.3390/cells11111749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023] Open
Abstract
Membrane-enclosed organelle compartmentalization is not the only way by which cell processes are spatially organized. Phase separation is emerging as a new driver in the organization of membrane-less compartments and biological processes. Liquid-liquid phase separation has been indicated as a new way to control the kinetics of molecular reactions and is based on weak multivalent interactions affecting the stoichiometry of the molecules involved. In the nucleus, liquid-liquid phase separation may represent an ancestral means of controlling genomic activity by forming discrete chromatin regions, regulating transcriptional activity, contributing to the assembly of DNA damage response foci, and controlling the organization of chromosomes. Liquid-liquid phase separation also contributes to chromatin function through its role in the reorganization of the nuclear periphery in the post-mitotic phase. Herein, we describe the basic principles regulating liquid-liquid phase separation, analyze examples of phase separation occurring in the nucleus, and dedicate attention to the implication of liquid-liquid phase separation in the reorganization of the nuclear periphery by the endosomal sorting complexes required for transport (ESCRT) machinery. Although some caution is warranted, current scientific knowledge allows for the hypothesis that many factors and processes in the cell are yet to be discovered which are functionally associated with phase separation.
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Affiliation(s)
- Klizia Maccaroni
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
| | - Mattia La Torre
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
| | - Romina Burla
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
- CNR Institute of Molecular Biology and Pathology, 00185 Rome, Italy
| | - Isabella Saggio
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
- CNR Institute of Molecular Biology and Pathology, 00185 Rome, Italy
- Institute of Structural Biology, Nanyang Technological University, Singapore 639798, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore
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24
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Dultz E, Wojtynek M, Medalia O, Onischenko E. The Nuclear Pore Complex: Birth, Life, and Death of a Cellular Behemoth. Cells 2022; 11:1456. [PMID: 35563762 PMCID: PMC9100368 DOI: 10.3390/cells11091456] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 02/01/2023] Open
Abstract
Nuclear pore complexes (NPCs) are the only transport channels that cross the nuclear envelope. Constructed from ~500-1000 nucleoporin proteins each, they are among the largest macromolecular assemblies in eukaryotic cells. Thanks to advances in structural analysis approaches, the construction principles and architecture of the NPC have recently been revealed at submolecular resolution. Although the overall structure and inventory of nucleoporins are conserved, NPCs exhibit significant compositional and functional plasticity even within single cells and surprising variability in their assembly pathways. Once assembled, NPCs remain seemingly unexchangeable in post-mitotic cells. There are a number of as yet unresolved questions about how the versatility of NPC assembly and composition is established, how cells monitor the functional state of NPCs or how they could be renewed. Here, we review current progress in our understanding of the key aspects of NPC architecture and lifecycle.
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Affiliation(s)
- Elisa Dultz
- Institute of Biochemistry, Department of Biology, ETHZ Zurich, 8093 Zurich, Switzerland;
| | - Matthias Wojtynek
- Institute of Biochemistry, Department of Biology, ETHZ Zurich, 8093 Zurich, Switzerland;
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland;
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland;
| | - Evgeny Onischenko
- Department of Biological Sciences, University of Bergen, 5020 Bergen, Norway
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25
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Nag N, Sasidharan S, Uversky VN, Saudagar P, Tripathi T. Phase separation of FG-nucleoporins in nuclear pore complexes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119205. [PMID: 34995711 DOI: 10.1016/j.bbamcr.2021.119205] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/14/2021] [Accepted: 12/23/2021] [Indexed: 12/11/2022]
Abstract
The nuclear envelope (NE) is a bilayer membrane that separates and physically isolates the genetic material from the cytoplasm. Nuclear pore complexes (NPCs) are cylindrical structures embedded in the NE and remain the sole channel of communication between the nucleus and the cytoplasm. The interior of NPCs contains densely packed intrinsically disordered FG-nucleoporins (FG-Nups), consequently forming a permeability barrier. This barrier facilitates the selection and specificity of the cargoes that are imported, exported, or shuttled through the NPCs. Recent studies have revealed that FG-Nups undergo the process of liquid-liquid phase separation into liquid droplets. Moreover, these liquid droplets mimic the permeability barrier observed in the interior of NPCs. This review highlights the phase separation of FG-Nups occurring inside the NPCs rooted in the NE. We discuss the phase separation of FG-Nups and compare the different aspects contributing to their phase separation. Furthermore, several diseases caused by the aberrant phase separation of the proteins are examined with respect to NEs. By understanding the fundamental process of phase separation at the nuclear membrane, the review seeks to explore the parameters influencing this phenomenon as well as its importance, ultimately paving the way for better research on the structure-function relationship of biomolecular condensates.
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Affiliation(s)
- Niharika Nag
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Santanu Sasidharan
- Department of Biotechnology, National Institute of Technology Warangal, Warangal 506004, India
| | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33620, United States; Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, Moscow Region 141700, Russia
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology Warangal, Warangal 506004, India.
| | - Timir Tripathi
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India.
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Najbauer EE, Ng SC, Griesinger C, Görlich D, Andreas LB. Atomic resolution dynamics of cohesive interactions in phase-separated Nup98 FG domains. Nat Commun 2022; 13:1494. [PMID: 35314668 PMCID: PMC8938434 DOI: 10.1038/s41467-022-28821-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/09/2022] [Indexed: 01/02/2023] Open
Abstract
Cohesive FG domains assemble into a condensed phase forming the selective permeability barrier of nuclear pore complexes. Nanoscopic insight into fundamental cohesive interactions has long been hampered by the sequence heterogeneity of native FG domains. We overcome this challenge by utilizing an engineered perfectly repetitive sequence and a combination of solution and magic angle spinning NMR spectroscopy. We map the dynamics of cohesive interactions in both phase-separated and soluble states at atomic resolution using TROSY for rotational correlation time (TRACT) measurements. We find that FG repeats exhibit nanosecond-range rotational correlation times and remain disordered in both states, although FRAP measurements show slow translation of phase-separated FG domains. NOESY measurements enable the direct detection of contacts involved in cohesive interactions. Finally, increasing salt concentration and temperature enhance phase separation and decrease local mobility of FG repeats. This lower critical solution temperature (LCST) behaviour indicates that cohesive interactions are driven by entropy. The permeability barrier of nuclear pores is formed by disordered and yet self-interacting FG repeat domains, whose sequence heterogeneity is a challenge for mechanistic insights. Here the authors overcome this challenge and characterize the protein’s dynamics by applying NMR techniques to an FG phase system that has been simplified to its essentials.
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27
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Raices M, D'Angelo MA. Structure, Maintenance, and Regulation of Nuclear Pore Complexes: The Gatekeepers of the Eukaryotic Genome. Cold Spring Harb Perspect Biol 2022; 14:a040691. [PMID: 34312247 PMCID: PMC8789946 DOI: 10.1101/cshperspect.a040691] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In eukaryotic cells, the genetic material is segregated inside the nucleus. This compartmentalization of the genome requires a transport system that allows cells to move molecules across the nuclear envelope, the membrane-based barrier that surrounds the chromosomes. Nuclear pore complexes (NPCs) are the central component of the nuclear transport machinery. These large protein channels penetrate the nuclear envelope, creating a passage between the nucleus and the cytoplasm through which nucleocytoplasmic molecule exchange occurs. NPCs are one of the largest protein assemblies of eukaryotic cells and, in addition to their critical function in nuclear transport, these structures also play key roles in many cellular processes in a transport-independent manner. Here we will review the current knowledge of the NPC structure, the cellular mechanisms that regulate their formation and maintenance, and we will provide a brief description of a variety of processes that NPCs regulate.
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Affiliation(s)
- Marcela Raices
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA
| | - Maximiliano A D'Angelo
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA
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28
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Musacchio A. On the role of phase separation in the biogenesis of membraneless compartments. EMBO J 2022; 41:e109952. [PMID: 35107832 PMCID: PMC8886532 DOI: 10.15252/embj.2021109952] [Citation(s) in RCA: 99] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 12/16/2022] Open
Abstract
Molecular mechanistic biology has ushered us into the world of life’s building blocks, revealing their interactions in macromolecular complexes and inspiring strategies for detailed functional interrogations. The biogenesis of membraneless cellular compartments, functional mesoscale subcellular locales devoid of strong internal order and delimiting membranes, is among mechanistic biology’s most demanding current challenges. A developing paradigm, biomolecular phase separation, emphasizes solvation of the building blocks through low‐affinity, weakly adhesive unspecific interactions as the driver of biogenesis of membraneless compartments. Here, I discuss the molecular underpinnings of the phase separation paradigm and demonstrate that validating its assumptions is much more challenging than hitherto appreciated. I also discuss that highly specific interactions, rather than unspecific ones, appear to be the main driver of biogenesis of subcellular compartments, while phase separation may be harnessed locally in selected instances to generate material properties tailored for specific functions, as exemplified by nucleocytoplasmic transport.
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Affiliation(s)
- Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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29
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Lüdeke S, Lohner P, Stühn LG, Betschart MU, Huber MC, Schreiber A, Schiller SM. Dynamische Strukturänderung und Thermodynamik von Phasentrennprozessen eines Proteinmodells mit intrinsisch ungeordneter/geordneter Struktur. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Steffen Lüdeke
- Institut für Pharmazeutische und Biomedizinische Wissenschaften (IPBW) Johannes Gutenberg-Universität Mainz Staudinger Weg 5 55128 Mainz Deutschland
- Institut für Pharmazeutische Wissenschaften Albert-Ludwigs-Universität Freiburg Albertstraße 25 79104 Freiburg Deutschland
| | - Philipp Lohner
- Institut für Pharmazeutische Wissenschaften Albert-Ludwigs-Universität Freiburg Albertstraße 25 79104 Freiburg Deutschland
| | - Lara G. Stühn
- Zentrum für Biosystemanalyse (ZBSA) Albert-Ludwigs-Universität Freiburg Habsburgerstraße 49 79104 Freiburg Deutschland
| | - Martin U. Betschart
- Institut für Pharmazeutische Wissenschaften Albert-Ludwigs-Universität Freiburg Albertstraße 25 79104 Freiburg Deutschland
| | - Matthias C. Huber
- Cluster of Excellence livMatS @ FIT – Freiburg Center for Interactive Materials and Bioinspired Technologies Albert-Ludwigs-Universität Freiburg Georges-Köhler-Allee 105 79104 Freiburg Deutschland
| | - Andreas Schreiber
- Zentrum für Biosystemanalyse (ZBSA) Albert-Ludwigs-Universität Freiburg Habsburgerstraße 49 79104 Freiburg Deutschland
| | - Stefan M. Schiller
- Zentrum für Biosystemanalyse (ZBSA) Albert-Ludwigs-Universität Freiburg Habsburgerstraße 49 79104 Freiburg Deutschland
- Cluster of Excellence livMatS @ FIT – Freiburg Center for Interactive Materials and Bioinspired Technologies Albert-Ludwigs-Universität Freiburg Georges-Köhler-Allee 105 79104 Freiburg Deutschland
- IMTEK – Institut für Mikrosystemtechnik Albert-Ludwigs-Universität Freiburg Georges-Köhler-Allee 103 79104 Freiburg Deutschland
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30
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Lüdeke S, Lohner P, Stühn LG, Betschart MU, Huber MC, Schreiber A, Schiller SM. Dynamic Structural Changes and Thermodynamics in Phase Separation Processes of an Intrinsically Disordered-Ordered Protein Model. Angew Chem Int Ed Engl 2022; 61:e202112738. [PMID: 34806270 PMCID: PMC9299898 DOI: 10.1002/anie.202112738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/21/2021] [Indexed: 01/03/2023]
Abstract
Elastin-like proteins (ELPs) are biologically important proteins and models for intrinsically disordered proteins (IDPs) and dynamic structural transitions associated with coacervates and liquid-liquid phase transitions. However, the conformational status below and above coacervation temperature and its role in the phase separation process is still elusive. Employing matrix least-squares global Boltzmann fitting of the circular dichroism spectra of the ELPs (VPGVG)20 , (VPGVG)40 , and (VPGVG)60 , we found that coacervation occurs sharply when a certain number of repeat units has acquired β-turn conformation (in our sequence setting a threshold of approx. 20 repeat units). The character of the differential scattering of the coacervate suspensions indicated that this fraction of β-turn structure is still retained after polypeptide assembly. Such conformational thresholds may also have a role in other protein assembly processes with implications for the design of protein-based smart materials.
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Affiliation(s)
- Steffen Lüdeke
- Institut für Pharmazeutische und Biomedizinische Wissenschaften (IPBW)Johannes Gutenberg-Universität MainzStaudinger Weg 555128MainzGermany
- Institut für Pharmazeutische WissenschaftenAlbert-Ludwigs-Universität FreiburgAlbertstrasse 2579104FreiburgGermany
| | - Philipp Lohner
- Institut für Pharmazeutische WissenschaftenAlbert-Ludwigs-Universität FreiburgAlbertstrasse 2579104FreiburgGermany
| | - Lara G. Stühn
- Zentrum für Biosystemanalyse (ZBSA)Albert-Ludwigs-Universität FreiburgHabsburgerstrasse 4979104FreiburgGermany
| | - Martin U. Betschart
- Institut für Pharmazeutische WissenschaftenAlbert-Ludwigs-Universität FreiburgAlbertstrasse 2579104FreiburgGermany
| | - Matthias C. Huber
- Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired TechnologiesAlbert-Ludwigs-Universität FreiburgGeorges-Köhler-Allee 10579104FreiburgGermany
| | - Andreas Schreiber
- Zentrum für Biosystemanalyse (ZBSA)Albert-Ludwigs-Universität FreiburgHabsburgerstrasse 4979104FreiburgGermany
| | - Stefan M. Schiller
- Zentrum für Biosystemanalyse (ZBSA)Albert-Ludwigs-Universität FreiburgHabsburgerstrasse 4979104FreiburgGermany
- Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired TechnologiesAlbert-Ludwigs-Universität FreiburgGeorges-Köhler-Allee 10579104FreiburgGermany
- IMTEK—Institut für MikrosystemtechnikAlbert-Ludwigs-Universität FreiburgGeorges-Köhler-Allee 10379104FreiburgGermany
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31
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Abstract
This review covers research findings reported over the past decade concerning the ability of low complexity (LC) domains to self-associate in a manner leading to their phase separation from aqueous solution. We focus our message upon the reductionist use of two forms of phase separation as biochemical assays to study how LC domains might function in living cells. Cells and their varied compartments represent extreme examples of material condensates. Over the past half century, biochemists, structural biologists, and molecular biologists have resolved the mechanisms driving innumerable forms of macromolecular condensation. In contrast, we remain largely ignorant as to how 10%-20% of our proteins actually work to assist in cell organization. This enigmatic 10%-20% of the proteome corresponds to gibberish-like LC sequences. We contend that many of these LC sequences move in and out of a structurally ordered, self-associated state as a means of offering a combination of organizational specificity and dynamic pliability to living cells. Finally, we speculate that ancient proteins may have behaved similarly, helping to condense, organize, and protect RNA early during evolution.
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Affiliation(s)
- Masato Kato
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Xiaoming Zhou
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Steven L McKnight
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75390, USA
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32
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Corti HR, Appignanesi GA, Barbosa MC, Bordin JR, Calero C, Camisasca G, Elola MD, Franzese G, Gallo P, Hassanali A, Huang K, Laria D, Menéndez CA, de Oca JMM, Longinotti MP, Rodriguez J, Rovere M, Scherlis D, Szleifer I. Structure and dynamics of nanoconfined water and aqueous solutions. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:136. [PMID: 34779954 DOI: 10.1140/epje/s10189-021-00136-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
This review is devoted to discussing recent progress on the structure, thermodynamic, reactivity, and dynamics of water and aqueous systems confined within different types of nanopores, synthetic and biological. Currently, this is a branch of water science that has attracted enormous attention of researchers from different fields interested to extend the understanding of the anomalous properties of bulk water to the nanoscopic domain. From a fundamental perspective, the interactions of water and solutes with a confining surface dramatically modify the liquid's structure and, consequently, both its thermodynamical and dynamical behaviors, breaking the validity of the classical thermodynamic and phenomenological description of the transport properties of aqueous systems. Additionally, man-made nanopores and porous materials have emerged as promising solutions to challenging problems such as water purification, biosensing, nanofluidic logic and gating, and energy storage and conversion, while aquaporin, ion channels, and nuclear pore complex nanopores regulate many biological functions such as the conduction of water, the generation of action potentials, and the storage of genetic material. In this work, the more recent experimental and molecular simulations advances in this exciting and rapidly evolving field will be reported and critically discussed.
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Affiliation(s)
- Horacio R Corti
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina.
| | - Gustavo A Appignanesi
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - Marcia C Barbosa
- Institute of Physics, Federal University of Rio Grande do Sul, 91501-970, Porto Alegre, Brazil
| | - J Rafael Bordin
- Department of Physics, Institute of Physics and Mathematics, 96050-500, Pelotas, RS, Brazil
| | - Carles Calero
- Secció de Física Estadística i Interdisciplinària - Departament de Física de la Matèria Condensada, Universitat de Barcelona & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Gaia Camisasca
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - M Dolores Elola
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
| | - Giancarlo Franzese
- Secció de Física Estadística i Interdisciplinària - Departament de Física de la Matèria Condensada, Universitat de Barcelona & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Paola Gallo
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - Ali Hassanali
- Condensed Matter and Statistical Physics Section (CMSP), The International Center for Theoretical Physics (ICTP), Trieste, Italy
| | - Kai Huang
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong, China
| | - Daniel Laria
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cintia A Menéndez
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - Joan M Montes de Oca
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - M Paula Longinotti
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Javier Rodriguez
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
- Escuela de Ciencia y Tecnología, Universidad Nacional de General San Martín, San Martín, Buenos Aires, Argentina
| | - Mauro Rovere
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - Damián Scherlis
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Igal Szleifer
- Biomedical Engineering Department, Northwestern University, Evanston, USA
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Fassler JS, Skuodas S, Weeks DL, Phillips BT. Protein Aggregation and Disaggregation in Cells and Development. J Mol Biol 2021; 433:167215. [PMID: 34450138 PMCID: PMC8530975 DOI: 10.1016/j.jmb.2021.167215] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 08/01/2021] [Accepted: 08/18/2021] [Indexed: 12/12/2022]
Abstract
Protein aggregation is a feature of numerous neurodegenerative diseases. However, regulated, often reversible, formation of protein aggregates, also known as condensates, helps control a wide range of cellular activities including stress response, gene expression, memory, cell development and differentiation. This review presents examples of aggregates found in biological systems, how they are used, and cellular strategies that control aggregation and disaggregation. We include features of the aggregating proteins themselves, environmental factors, co-aggregates, post-translational modifications and well-known aggregation-directed activities that influence their formation, material state, stability and dissolution. We highlight the emerging roles of biomolecular condensates in early animal development, and disaggregation processing proteins that have recently been shown to play key roles in gametogenesis and embryogenesis.
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Affiliation(s)
- Jan S Fassler
- Department of Biology, University of Iowa, Iowa City, IA 52242, United States.
| | - Sydney Skuodas
- Department of Biology, University of Iowa, Iowa City, IA 52242, United States. https://twitter.com/@sskuodas
| | - Daniel L Weeks
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Bryan T Phillips
- Department of Biology, University of Iowa, Iowa City, IA 52242, United States. https://twitter.com/@bt4phillips
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34
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Danilov LG, Moskalenko SE, Matveenko AG, Sukhanova XV, Belousov MV, Zhouravleva GA, Bondarev SA. The Human NUP58 Nucleoporin Can Form Amyloids In Vitro and In Vivo. Biomedicines 2021; 9:biomedicines9101451. [PMID: 34680573 PMCID: PMC8533070 DOI: 10.3390/biomedicines9101451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/05/2021] [Accepted: 10/08/2021] [Indexed: 12/20/2022] Open
Abstract
Amyloids are fibrillar protein aggregates with a cross-β structure and unusual features, including high resistance to detergent or protease treatment. More than two hundred different proteins with amyloid or amyloid-like properties are already known. Several examples of nucleoporins (e.g., yeast Nup49, Nup100, Nup116, and human NUP153) are supposed to form amyloid fibrils. In this study, we demonstrated an ability of the human NUP58 nucleoporin to form amyloid aggregates in vivo and in vitro. Moreover, we found two forms of NUP58 aggregates: oligomers and polymers stabilized by disulfide bonds. Bioinformatic analysis revealed that all known orthologs of this protein are potential amyloids which possess several regions with conserved ability to aggregation. The biological role of nucleoporin amyloid formation is debatable. We suggest that it is a rather abnormal process, which is characteristic for many proteins implicated in phase separation.
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Affiliation(s)
- Lavrentii G. Danilov
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (L.G.D.); (S.E.M.); (A.G.M.); (X.V.S.); (M.V.B.)
| | - Svetlana E. Moskalenko
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (L.G.D.); (S.E.M.); (A.G.M.); (X.V.S.); (M.V.B.)
- St. Petersburg Branch, Vavilov Institute of General Genetics, Russian Academy of Sciences, 199034 St. Petersburg, Russia
| | - Andrew G. Matveenko
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (L.G.D.); (S.E.M.); (A.G.M.); (X.V.S.); (M.V.B.)
| | - Xenia V. Sukhanova
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (L.G.D.); (S.E.M.); (A.G.M.); (X.V.S.); (M.V.B.)
| | - Mikhail V. Belousov
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (L.G.D.); (S.E.M.); (A.G.M.); (X.V.S.); (M.V.B.)
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology, 196608 St. Petersburg, Russia
| | - Galina A. Zhouravleva
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (L.G.D.); (S.E.M.); (A.G.M.); (X.V.S.); (M.V.B.)
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Correspondence: or (G.A.Z.); or (S.A.B.)
| | - Stanislav A. Bondarev
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (L.G.D.); (S.E.M.); (A.G.M.); (X.V.S.); (M.V.B.)
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Correspondence: or (G.A.Z.); or (S.A.B.)
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35
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Sawaya MR, Hughes MP, Rodriguez JA, Riek R, Eisenberg DS. The expanding amyloid family: Structure, stability, function, and pathogenesis. Cell 2021; 184:4857-4873. [PMID: 34534463 PMCID: PMC8772536 DOI: 10.1016/j.cell.2021.08.013] [Citation(s) in RCA: 164] [Impact Index Per Article: 54.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/26/2021] [Accepted: 08/11/2021] [Indexed: 02/05/2023]
Abstract
The hidden world of amyloid biology has suddenly snapped into atomic-level focus, revealing over 80 amyloid protein fibrils, both pathogenic and functional. Unlike globular proteins, amyloid proteins flatten and stack into unbranched fibrils. Stranger still, a single protein sequence can adopt wildly different two-dimensional conformations, yielding distinct fibril polymorphs. Thus, an amyloid protein may define distinct diseases depending on its conformation. At the heart of this conformational variability lies structural frustrations. In functional amyloids, evolution tunes frustration levels to achieve either stability or sensitivity according to the fibril's biological function, accounting for the vast versatility of the amyloid fibril scaffold.
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Affiliation(s)
- Michael R Sawaya
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA; UCLA-DOE Institute, UCLA, Los Angeles, CA 90095, USA; Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
| | - Michael P Hughes
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA; UCLA-DOE Institute, UCLA, Los Angeles, CA 90095, USA; Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
| | - Jose A Rodriguez
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA; UCLA-DOE Institute, UCLA, Los Angeles, CA 90095, USA; Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
| | - Roland Riek
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir Prelog Weg 2, CH-8093 Zurich, Switzerland
| | - David S Eisenberg
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA; UCLA-DOE Institute, UCLA, Los Angeles, CA 90095, USA; Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA.
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36
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Multifunctionality of F-rich nucleoporins. Biochem Soc Trans 2021; 48:2603-2614. [PMID: 33336681 DOI: 10.1042/bst20200357] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/13/2020] [Accepted: 12/01/2020] [Indexed: 01/11/2023]
Abstract
Nucleoporins (Nups) represent a range of proteins most known for composing the macromolecular assembly of the nuclear pore complex (NPC). Among them, the family of intrinsically disordered proteins (IDPs) phenylalanine-glycine (FG) rich Nups, form the permeability barrier and coordinate the high-speed nucleocytoplasmic transport in a selective way. Those FG-Nups have been demonstrated to participate in various biological processes besides nucleocytoplasmic transport. The high number of accessible hydrophobic motifs of FG-Nups potentially gives rise to this multifunctionality, enabling them to form unique microenvironments. In this review, we discuss the multifunctionality of disordered and F-rich Nups and the diversity of their localizations, emphasizing the important roles of those Nups in various regulatory and metabolic processes.
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Shen Q, Tian T, Xiong Q, Ellis Fisher PD, Xiong Y, Melia TJ, Lusk CP, Lin C. DNA-Origami NanoTrap for Studying the Selective Barriers Formed by Phenylalanine-Glycine-Rich Nucleoporins. J Am Chem Soc 2021; 143:12294-12303. [PMID: 34324340 DOI: 10.1021/jacs.1c05550] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
DNA nanotechnology provides a versatile and powerful tool to dissect the structure-function relationship of biomolecular machines like the nuclear pore complex (NPC), an enormous protein assembly that controls molecular traffic between the nucleus and cytoplasm. To understand how the intrinsically disordered, Phe-Gly-rich nucleoporins (FG-nups) within the NPC establish a selective barrier to macromolecules, we built a DNA-origami NanoTrap. The NanoTrap comprises precisely arranged FG-nups in an NPC-like channel, which sits on a baseplate that captures macromolecules that pass through the FG network. Using this biomimetic construct, we determined that the FG-motif type, grafting density, and spatial arrangement are critical determinants of an effective diffusion barrier. Further, we observed that diffusion barriers formed with cohesive FG interactions dominate in mixed-FG-nup scenarios. Finally, we demonstrated that the nuclear transport receptor, Ntf2, can selectively transport model cargo through NanoTraps composed of FxFG but not GLFG Nups. Our NanoTrap thus recapitulates the NPC's fundamental biological activities, providing a valuable tool for studying nuclear transport.
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Affiliation(s)
- Qi Shen
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States.,Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States.,Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06511, United States
| | - Taoran Tian
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States.,Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Qiancheng Xiong
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States.,Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Patrick D Ellis Fisher
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States.,Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06511, United States
| | - Thomas J Melia
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
| | - C Patrick Lusk
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
| | - Chenxiang Lin
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States.,Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
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38
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Hoogenboom BW, Hough LE, Lemke EA, Lim RYH, Onck PR, Zilman A. Physics of the Nuclear Pore Complex: Theory, Modeling and Experiment. PHYSICS REPORTS 2021; 921:1-53. [PMID: 35892075 PMCID: PMC9306291 DOI: 10.1016/j.physrep.2021.03.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The hallmark of eukaryotic cells is the nucleus that contains the genome, enclosed by a physical barrier known as the nuclear envelope (NE). On the one hand, this compartmentalization endows the eukaryotic cells with high regulatory complexity and flexibility. On the other hand, it poses a tremendous logistic and energetic problem of transporting millions of molecules per second across the nuclear envelope, to facilitate their biological function in all compartments of the cell. Therefore, eukaryotes have evolved a molecular "nanomachine" known as the Nuclear Pore Complex (NPC). Embedded in the nuclear envelope, NPCs control and regulate all the bi-directional transport between the cell nucleus and the cytoplasm. NPCs combine high molecular specificity of transport with high throughput and speed, and are highly robust with respect to molecular noise and structural perturbations. Remarkably, the functional mechanisms of NPC transport are highly conserved among eukaryotes, from yeast to humans, despite significant differences in the molecular components among various species. The NPC is the largest macromolecular complex in the cell. Yet, despite its significant complexity, it has become clear that its principles of operation can be largely understood based on fundamental physical concepts, as have emerged from a combination of experimental methods of molecular cell biology, biophysics, nanoscience and theoretical and computational modeling. Indeed, many aspects of NPC function can be recapitulated in artificial mimics with a drastically reduced complexity compared to biological pores. We review the current physical understanding of the NPC architecture and function, with the focus on the critical analysis of experimental studies in cells and artificial NPC mimics through the lens of theoretical and computational models. We also discuss the connections between the emerging concepts of NPC operation and other areas of biophysics and bionanotechnology.
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Affiliation(s)
- Bart W. Hoogenboom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Loren E. Hough
- Department of Physics and BioFrontiers Institute, University of Colorado, Boulder CO 80309, United States of America
| | - Edward A. Lemke
- Biocenter Mainz, Departments of Biology and Chemistry, Johannes Gutenberg University and Institute of Molecular Biology, 55128 Mainz, Germany
| | - Roderick Y. H. Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Patrick R. Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Anton Zilman
- Department of Physics and Institute for Biomedical Engineering (IBME), University of Toronto, Toronto, ON M5S 1A7, Canada
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Shinkai Y, Kuramochi M, Miyafusa T. New Family Members of FG Repeat Proteins and Their Unexplored Roles During Phase Separation. Front Cell Dev Biol 2021; 9:708702. [PMID: 34322491 PMCID: PMC8311347 DOI: 10.3389/fcell.2021.708702] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/17/2021] [Indexed: 12/26/2022] Open
Abstract
The condensation and compartmentalization of biomacromolecules in the cell are driven by the process of phase separation. The main effectors of phase separation are intrinsically disordered proteins, which include proteins with a phenylalanine-glycine (FG) repeat domain. Our understanding of the biological function of FG repeat proteins during phase separation has been mainly derived from recent research on a member of the nuclear pore complex proteins, nucleoporins containing FG repeat domain (FG-NUPs). FG-NUPs form meshwork structures by inter- and intra-molecular FG domain interactions, which confine the nucleo-cytoplasmic exchange. Whereas FG-NUPs localize in the nuclear membrane, other FG repeat proteins reside in the cytoplasm and the nucleoplasm, and the biological function of the FG repeat domain of these proteins is not well described. In the present review, we list the FG repeat proteins that are known to phase separate in the cell, and review their biological functions. We extract the unraveled features of FG repeat proteins as an activator of barrier formation and homotypic cell-cell interactions. Understanding the regulatory mechanisms of FG repeat proteins will provide a potential delivery tool for therapeutic reagents.
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Affiliation(s)
- Yoichi Shinkai
- Molecular Neurobiology Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Masahiro Kuramochi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan
| | - Takamitsu Miyafusa
- Bio-System Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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40
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Ng SC, Güttler T, Görlich D. Recapitulation of selective nuclear import and export with a perfectly repeated 12mer GLFG peptide. Nat Commun 2021; 12:4047. [PMID: 34193851 PMCID: PMC8245513 DOI: 10.1038/s41467-021-24292-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/11/2021] [Indexed: 12/04/2022] Open
Abstract
The permeability barrier of nuclear pore complexes (NPCs) controls nucleocytoplasmic transport. It retains inert macromolecules while allowing facilitated passage of importins and exportins, which in turn shuttle cargo into or out of cell nuclei. The barrier can be described as a condensed phase assembled from cohesive FG repeat domains. NPCs contain several distinct FG domains, each comprising variable repeats. Nevertheless, we now found that sequence heterogeneity is no fundamental requirement for barrier function. Instead, we succeeded in engineering a perfectly repeated 12mer GLFG peptide that self-assembles into a barrier of exquisite transport selectivity and fast transport kinetics. This barrier recapitulates RanGTPase-controlled importin- and exportin-mediated cargo transport and thus represents an ultimately simplified experimental model system. An alternative proline-free sequence forms an amyloid FG phase. Finally, we discovered that FG phases stain bright with ‘DNA-specific’ DAPI/ Hoechst probes, and that such dyes allow for a photo-induced block of nuclear transport. The permeability barrier of nuclear pore complexes blocks passage of inert macromolecules but allows rapid, receptor-mediated, and RanGTPase-driven transport of cargoes up to ribosome size. The authors now show that such a barrier can be faithfully recapitulated by an ultimately simplified FG phase assembled solely from a tandemly repeated 12mer GLFG peptide.
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Affiliation(s)
- Sheung Chun Ng
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Thomas Güttler
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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41
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Orti F, Navarro AM, Rabinovich A, Wodak SJ, Marino-Buslje C. Insight into membraneless organelles and their associated proteins: Drivers, Clients and Regulators. Comput Struct Biotechnol J 2021; 19:3964-3977. [PMID: 34377363 PMCID: PMC8318826 DOI: 10.1016/j.csbj.2021.06.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/26/2021] [Accepted: 06/27/2021] [Indexed: 02/06/2023] Open
Abstract
In recent years, attention has been devoted to proteins forming immiscible liquid phases within the liquid intracellular medium, commonly referred to as membraneless organelles (MLO). These organelles enable the spatiotemporal associations of cellular components that exchange dynamically with the cellular milieu. The dysregulation of these liquid-liquid phase separation processes (LLPS) may cause various diseases including neurodegenerative pathologies and cancer, among others. Until very recently, databases containing information on proteins forming MLOs, as well as tools and resources facilitating their analysis, were missing. This has recently changed with the publication of 4 databases that focus on different types of experiments, sets of proteins, inclusion criteria, and levels of annotation or curation. In this study we integrate and analyze the information across these databases, complement their records, and produce a consolidated set of proteins that enables the investigation of the LLPS phenomenon. To gain insight into the features that characterize different types of MLOs and the roles of their associated proteins, they were grouped into categories: High Confidence MLO associated (including Drivers and reviewed proteins), Potential Clients and Regulators, according to their annotated functions. We show that none of the databases taken alone covers the data sufficiently to enable meaningful analysis, validating our integration effort as essential for gaining better understanding of phase separation and laying the foundations for the discovery of new proteins potentially involved in this important cellular process. Lastly, we developed a server, enabling customized selections of different sets of proteins based on MLO location, database, disorder content, among other attributes (https://forti.shinyapps.io/mlos/).
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Affiliation(s)
- Fernando Orti
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Alvaro M. Navarro
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Andres Rabinovich
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Shoshana J. Wodak
- VIB-VUB Center for Structural Biology, Flemish Institute for Biotechnology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Cristina Marino-Buslje
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
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42
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Yoshizawa T, Guo L. Karyopherin-βs play a key role as a phase separation regulator. J Biochem 2021; 170:15-23. [PMID: 34223614 DOI: 10.1093/jb/mvab072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
Recent studies have revealed that cells utilize liquid-liquid phase separation (LLPS) as a mechanism in assembly of membrane-less organelles, such as RNP granules. The nucleus is a well-known membrane-bound organelle surrounded by the nuclear envelope; the nuclear pore complex on the nuclear envelope likely applies LLPS in the central channel to facilitate selective biological macromolecule exchange. Karyopherin-β family proteins exclusively pass through the central channel with cargos by dissolving the phase separated hydrogel formed by the phenylalanine-glycine (FG) repeats-containing nucleoporins. Karyopherin-βs also exhibit dissolution activity for the phase separation of cargo proteins. Many cargos, including RNA-binding proteins containing intrinsically disordered regions (IDRs), undergo phase separation; however, aberrant phase separation is linked to fatal neurodegenerative diseases. Multiple weak interactions between karyopherin-βs and phase separation-prone proteins, such as FG repeats-containing nucleoporins or IDR-containing karyopherin-β cargos, are likely to be important for passing through the nuclear pore complex and maintaining the soluble state of cargo, respectively. In this review, we discuss how karyopherin-βs regulate phase separation to function.
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Affiliation(s)
- Takuya Yoshizawa
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu-shi, Shiga 525-8577, Japan
| | - Lin Guo
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA 19107, USA
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43
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Real-time observation of structure and dynamics during the liquid-to-solid transition of FUS LC. Biophys J 2021; 120:1276-1287. [PMID: 33607084 DOI: 10.1016/j.bpj.2021.02.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/21/2021] [Accepted: 02/08/2021] [Indexed: 12/11/2022] Open
Abstract
A subset of the proteins found in pathological protein fibrils also exhibit tendencies for liquid-liquid phase separation (LLPS) both in vitro and in cells. The mechanisms underlying the connection between these phase transitions have been challenging to study due to the heterogeneous and dynamic nature of the states formed during the maturation of LLPS protein droplets into gels and solid aggregates. Here, we interrogate the liquid-to-solid transition of the low-complexity domain of the RNA-binding protein FUS (FUS LC), which has been shown to adopt LLPS, gel-like, and amyloid states. We employ magic-angle-spinning NMR spectroscopy, which has allowed us to follow these transitions in real time and with residue-specific resolution. We observe the development of β-sheet structure through the maturation process and show that the final state of FUS LC fibrils produced after LLPS is distinct from that grown from fibrillar seeds. We also apply our methodology to FUS LC G156E, a clinically relevant FUS mutant that exhibits accelerated fibrillization rates. We observe significant changes in dynamics during the transformation of the FUS LC G156E construct and begin to unravel the sequence specific contributions to this phenomenon with computational studies of the phase-separated state of FUS LC and FUS LC G156E.
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44
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Yang YJ, Mai DJ, Li S, Morris MA, Olsen BD. Tuning Selective Transport of Biomolecules through Site-Mutated Nucleoporin-like Protein (NLP) Hydrogels. Biomacromolecules 2021; 22:289-298. [PMID: 33428378 DOI: 10.1021/acs.biomac.0c01083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Natural selective filtering systems (e.g., the extracellular matrix, nuclear pores, and mucus) separate molecules selectively and efficiently, and the detailed understanding of transport mechanisms exploited in these systems provides important bioinspired design principles for selective filters. In particular, nucleoporins consist of consensus repeat sequences that are readily utilized for engineering repeat proteins. Here, the consensus repeat sequence of Nsp1, a yeast nucleoporin, is polymerized to form a nucleoporin-like protein (NLP) and mutated to understand the effect of sequence on selective transport. The hydrophilic spacers of the NLPs were redesigned considering net charge, charge distribution, and polarity. Mutations were made near to and far from the FSFG interacting domain to explore the role of highly conserved residues as a function of spatial proximity. A nuclear transport receptor-cargo complex, nuclear transport factor 2-green fluorescent protein (NTF2-GFP), was used as a model for changes in transport. For mutations of the charged spacer, some mutations of highly conserved charged residues were possible without knocking out selective transport of the NTF2, but the formation of regions of clustered negative charge has an unfavorable effect on nuclear transporter permeation. Thus, positive net charge and alternating positive and negative charge within the hydrophilic spacer are advantageous for recognition and selective transport. In the polarity panel, mutations that increased the interaction between NTF2-GFP and the gel led to decreased permeation of the NTF2-GFP due to blocking of the interface and inability of the NTF2-GFP to transport into the gel. Therefore, these results provide a strategy for tuning selective permeability of biomolecules using the artificially designed consensus repeat-based hydrogels.
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Affiliation(s)
- Yun Jung Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Biological Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | - Danielle J Mai
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Shuaili Li
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Melody A Morris
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Bradley D Olsen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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45
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Hardenberg MC, Sinnige T, Casford S, Dada ST, Poudel C, Robinson EA, Fuxreiter M, Kaminksi CF, Kaminski Schierle GS, Nollen EAA, Dobson CM, Vendruscolo M. Observation of an α-synuclein liquid droplet state and its maturation into Lewy body-like assemblies. J Mol Cell Biol 2021; 13:282-294. [PMID: 33386842 DOI: 10.1093/jmcb/mjaa075] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/09/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
Misfolded α-synuclein is a major component of Lewy bodies, which are a hallmark of Parkinson's disease (PD). A large body of evidence shows that α-synuclein can aggregate into amyloid fibrils, but the relationship between α-synuclein self-assembly and Lewy body formation remains unclear. Here, we show, both in vitro and in a Caenorhabditis elegans model of PD, that α-synuclein undergoes liquid‒liquid phase separation by forming a liquid droplet state, which converts into an amyloid-rich hydrogel with Lewy-body-like properties. This maturation process towards the amyloid state is delayed in the presence of model synaptic vesicles in vitro. Taken together, these results suggest that the formation of Lewy bodies may be linked to the arrested maturation of α-synuclein condensates in the presence of lipids and other cellular components.
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Affiliation(s)
- Maarten C Hardenberg
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Tessa Sinnige
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Sam Casford
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Samuel T Dada
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Chetan Poudel
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, UK
| | - Elizabeth A Robinson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Monika Fuxreiter
- MTA-DE Laboratory of Protein Dynamics, Department of Biochemistry and Molecular Biology, University of Debrecen, Hungary
| | - Clemens F Kaminksi
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, UK
| | | | - Ellen A A Nollen
- European Research Institute for the Biology of Aging, University Medical Center Groningen, University of Groningen, Groningen 9713 AV, The Netherlands
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
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46
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le Paige UB, Xiang S, Hendrix MMRM, Zhang Y, Folkers GE, Weingarth M, Bonvin AMJJ, Kutateladze TG, Voets IK, Baldus M, van Ingen H. Characterization of nucleosome sediments for protein interaction studies by solid-state NMR spectroscopy. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:187-202. [PMID: 35647606 PMCID: PMC9135053 DOI: 10.5194/mr-2-187-2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Regulation of DNA-templated processes such as gene transcription and DNA repair depend on the interaction of a wide range of proteins with the nucleosome, the fundamental building block of chromatin. Both solution and solid-state NMR spectroscopy have become an attractive approach to study the dynamics and interactions of nucleosomes, despite their high molecular weight of ~ 200 kDa. For solid-state NMR (ssNMR) studies, dilute solutions of nucleosomes are converted to a dense phase by sedimentation or precipitation. Since nucleosomes are known to self-associate, these dense phases may induce extensive interactions between nucleosomes, which could interfere with protein-binding studies. Here, we characterized the packing of nucleosomes in the dense phase created by sedimentation using NMR and small-angle X-ray scattering (SAXS) experiments. We found that nucleosome sediments are gels with variable degrees of solidity, have nucleosome concentration close to that found in crystals, and are stable for weeks under high-speed magic angle spinning (MAS). Furthermore, SAXS data recorded on recovered sediments indicate that there is no pronounced long-range ordering of nucleosomes in the sediment. Finally, we show that the sedimentation approach can also be used to study low-affinity protein interactions with the nucleosome. Together, our results give new insights into the sample characteristics of nucleosome sediments for ssNMR studies and illustrate the broad applicability of sedimentation-based NMR studies.
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Affiliation(s)
- Ulric B. le Paige
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - ShengQi Xiang
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Marco M. R. M. Hendrix
- Laboratory of Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, the Netherlands
| | - Yi Zhang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Gert E. Folkers
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Markus Weingarth
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Alexandre M. J. J. Bonvin
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Tatiana G. Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Ilja K. Voets
- Laboratory of Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, the Netherlands
| | - Marc Baldus
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Hugo van Ingen
- Utrecht NMR Group, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH, Utrecht, the Netherlands
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47
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Belwal VK, Chaudhary N. Amyloids and their untapped potential as hydrogelators. SOFT MATTER 2020; 16:10013-10028. [PMID: 33146652 DOI: 10.1039/d0sm01578d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Amyloid fibrils are cross-β-sheet-rich fibrous aggregates. They were originally identified as disease-associated protein/peptide deposits. The cross-β motif was consequently labelled as an alien and pathogenic fold. Subsequent research revealed that the fibrillar aggregates were benign, and the cytotoxicity in the amyloid diseases was attributed to the pre-fibrillar structures. Research in the past two decades has identified the native functional amyloids in organisms ranging from bacteria to human. The amyloid-like fibrils, therefore, are not necessarily pathogenic, and the cross-β motif is very much native. This premise makes way for the amyloids to be used as biocompatible materials. Many naturally occurring amyloidogenic proteins/peptides or their fragments have been reported in the literature to form hydrogels. Hydrogels constitute one of the most interesting classes of soft materials that find application in diverse fields such as environmental, electronic, and biomedical engineering. Applications of hydrogels in medicine are particularly extensive. Among various classes of peptides that form hydrogels, the potential of amyloids is largely untapped. In this review, we have attempted to compile the literature on amyloid hydrogels and discuss their potential applications.
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Affiliation(s)
- Vinay Kumar Belwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati - 781 039, India.
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48
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Theoretical Modeling of Chemical Equilibrium in Weak Polyelectrolyte Layers on Curved Nanosystems. Polymers (Basel) 2020; 12:polym12102282. [PMID: 33027995 PMCID: PMC7601300 DOI: 10.3390/polym12102282] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022] Open
Abstract
Surface functionalization with end-tethered weak polyelectrolytes (PE) is a versatile way to modify and control surface properties, given their ability to alter their degree of charge depending on external cues like pH and salt concentration. Weak PEs find usage in a wide range of applications, from colloidal stabilization, lubrication, adhesion, wetting to biomedical applications such as drug delivery and theranostics applications. They are also ubiquitous in many biological systems. Here, we present an overview of some of the main theoretical methods that we consider key in the field of weak PE at interfaces. Several applications involving engineered nanoparticles, synthetic and biological nanopores, as well as biological macromolecules are discussed to illustrate the salient features of systems involving weak PE near an interface or under (nano)confinement. The key feature is that by confining weak PEs near an interface the degree of charge is different from what would be expected in solution. This is the result of the strong coupling between structural organization of weak PE and its chemical state. The responsiveness of engineered and biological nanomaterials comprising weak PE combined with an adequate level of modeling can provide the keys to a rational design of smart nanosystems.
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Dynamic structural order of a low-complexity domain facilitates assembly of intermediate filaments. Proc Natl Acad Sci U S A 2020; 117:23510-23518. [PMID: 32907935 PMCID: PMC7519307 DOI: 10.1073/pnas.2010000117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The main point of our manuscript is focused on the structure of the low-complexity (LC) domain of the Tm1-I/C intermediate filament protein in the context of assembled intermediate filaments. We found that the LC tail domain of Tm1-I/C exists in precisely the same cross-β conformation within its proper biologic assembly as it does in labile, amyloid-like polymers made from the tail domain alone. This science represents a conceptually distinct advance that may form the cornerstone understanding of how the thousands of LC domains expressed in eukaryotic cells operate in a mechanistic sense, and stands in conflict with previous research claiming that LC domains function in the absence of molecular structure. The coiled-coil domains of intermediate filament (IF) proteins are flanked by regions of low sequence complexity. Whereas IF coiled-coil domains assume dimeric and tetrameric conformations on their own, maturation of eight tetramers into cylindrical IFs is dependent on either “head” or “tail” domains of low sequence complexity. Here we confirm that the tail domain required for assembly of Drosophila Tm1-I/C IFs functions by forming labile cross-β interactions. These interactions are seen in polymers made from the tail domain alone, as well as in assembled IFs formed by the intact Tm1-I/C protein. The ability to visualize such interactions in situ within the context of a discrete cellular assembly lends support to the concept that equivalent interactions may be used in organizing other dynamic aspects of cell morphology.
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Singh K, Rabin Y. Sequence effects on internal structure of droplets of associative polymers. Biophys J 2020; 120:1210-1218. [PMID: 32937111 DOI: 10.1016/j.bpj.2020.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/31/2020] [Accepted: 08/21/2020] [Indexed: 11/29/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) can form liquid-like membraneless organelles, gels, and fibers in cells and in vitro. In this study, we propose a simple model of IDPs as associative polymers in poor solvent and explore the formation of transient liquid droplets and their transformation into solid-like aggregates. We use Langevin dynamics simulations of short polymers with two stickers placed symmetrically along their contour to study the effect of the primary sequence of these polymers on their organization inside condensed droplets. We observe that the shape, size, and number of sticker clusters inside the droplet change from a long cylindrical fiber to many compact clusters as one varies the location of stickers along the chain contour. Aging caused by the conversion of intramoleclular to intermolecular associations is observed in droplets of telechelic polymers but not for other sequences of associating polymers. The relevance of our results to condensates of IDPs is discussed.
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Affiliation(s)
- Kulveer Singh
- Institute of Nanotechnology and Advanced Materials, Department of Physics, Bar-Ilan University, Ramat Gan, Israel.
| | - Yitzhak Rabin
- Institute of Nanotechnology and Advanced Materials, Department of Physics, Bar-Ilan University, Ramat Gan, Israel.
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