1
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Fonda BD, Kato M, Li Y, Murray DT. Cryo-EM and Solid State NMR Together Provide a More Comprehensive Structural Investigation of Protein Fibrils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.30.596698. [PMID: 38853912 PMCID: PMC11160737 DOI: 10.1101/2024.05.30.596698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
The Tropomyosin 1 isoform I/C C-terminal domain (Tm1-LC) fibril structure is studied jointly with cryogenic electron microscopy (cryo-EM) and solid state nuclear magnetic resonance (NMR). This study demonstrates the complementary nature of these two structural biology techniques. Chemical shift assignments from solid state NMR are used to determine the secondary structure at the level of individual amino acids, which is faithfully seen in cryo-EM reconstructions. Additionally, solid state NMR demonstrates that the region not observed in the reconstructed cryo-EM density is primarily in a highly mobile random coil conformation rather than adopting multiple rigid conformations. Overall, this study illustrates the benefit of investigations combining cryo-EM and solid state NMR to investigate protein fibril structure.
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Affiliation(s)
- Blake D. Fonda
- Department of Chemistry, University of California, Davis, California, 95616, United States of America
| | - Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, United States of America
| | - Yang Li
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, United States of America
| | - Dylan T. Murray
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, 06269, United States of America
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2
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Tsilafakis K, Mavroidis M. Are the Head and Tail Domains of Intermediate Filaments Really Unstructured Regions? Genes (Basel) 2024; 15:633. [PMID: 38790262 PMCID: PMC11121635 DOI: 10.3390/genes15050633] [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: 03/15/2024] [Revised: 05/01/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
Intermediate filaments (IFs) are integral components of the cytoskeleton which provide cells with tissue-specific mechanical properties and are involved in a plethora of cellular processes. Unfortunately, due to their intricate architecture, the 3D structure of the complete molecule of IFs has remained unresolved. Even though most of the rod domain structure has been revealed by means of crystallographic analyses, the flanked head and tail domains are still mostly unknown. Only recently have studies shed light on head or tail domains of IFs, revealing certainsecondary structures and conformational changes during IF assembly. Thus, a deeper understanding of their structure could provide insights into their function.
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Affiliation(s)
- Konstantinos Tsilafakis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece;
- Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece
| | - Manolis Mavroidis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece;
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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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Sanchez‐Martinez S, Nguyen K, Biswas S, Nicholson V, Romanyuk AV, Ramirez J, Kc S, Akter A, Childs C, Meese EK, Usher ET, Ginell GM, Yu F, Gollub E, Malferrari M, Francia F, Venturoli G, Martin EW, Caporaletti F, Giubertoni G, Woutersen S, Sukenik S, Woolfson DN, Holehouse AS, Boothby TC. Labile assembly of a tardigrade protein induces biostasis. Protein Sci 2024; 33:e4941. [PMID: 38501490 PMCID: PMC10949331 DOI: 10.1002/pro.4941] [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: 11/01/2023] [Revised: 02/01/2024] [Accepted: 02/09/2024] [Indexed: 03/20/2024]
Abstract
Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS D's fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.
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Affiliation(s)
| | - K. Nguyen
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - S. Biswas
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - V. Nicholson
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - A. V. Romanyuk
- School of ChemistryUniversity of BristolBristolUK
- Max Planck‐Bristol Centre for Minimal BiologyUniversity of BristolBristolUK
| | - J. Ramirez
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - S. Kc
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - A. Akter
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - C. Childs
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - E. K. Meese
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - E. T. Usher
- Department of Biochemistry and Molecular BiophysicsWashington University School of MedicineSt. LouisMissouriUSA
- Center for Biomolecular CondensatesWashington University in St. LouisSt. LouisMissouriUSA
| | - G. M. Ginell
- Department of Biochemistry and Molecular BiophysicsWashington University School of MedicineSt. LouisMissouriUSA
- Center for Biomolecular CondensatesWashington University in St. LouisSt. LouisMissouriUSA
| | - F. Yu
- Quantitative Systems Biology ProgramUniversity of California MercedMercedCaliforniaUSA
| | - E. Gollub
- Department of Chemistry and BiochemistryUniversity of California MercedMercedCaliforniaUSA
| | - M. Malferrari
- Dipartimento di Chimica “Giacomo Ciamician”Università di BolognaBolognaItaly
| | - F. Francia
- Laboratorio di Biochimica e Biofisica Molecolare, Dipartimento di Farmacia e Biotecnologie, FaBiTUniversità di BolognaBolognaItaly
| | - G. Venturoli
- Laboratorio di Biochimica e Biofisica Molecolare, Dipartimento di Farmacia e Biotecnologie, FaBiTUniversità di BolognaBolognaItaly
- Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), c/o Dipartimento di Fisica e Astronomia (DIFA)Università di BolognaBolognaItaly
| | - E. W. Martin
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTennesseeUSA
| | - F. Caporaletti
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamAmsterdamThe Netherlands
| | - G. Giubertoni
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamAmsterdamThe Netherlands
| | - S. Woutersen
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamAmsterdamThe Netherlands
| | - S. Sukenik
- Quantitative Systems Biology ProgramUniversity of California MercedMercedCaliforniaUSA
- Department of Chemistry and BiochemistryUniversity of California MercedMercedCaliforniaUSA
| | - D. N. Woolfson
- School of ChemistryUniversity of BristolBristolUK
- Max Planck‐Bristol Centre for Minimal BiologyUniversity of BristolBristolUK
- School of BiochemistryUniversity of Bristol, Biomedical Sciences BuildingBristolUK
| | - A. S. Holehouse
- Department of Biochemistry and Molecular BiophysicsWashington University School of MedicineSt. LouisMissouriUSA
- Center for Biomolecular CondensatesWashington University in St. LouisSt. LouisMissouriUSA
| | - T. C. Boothby
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
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5
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Sweeney KM, Chantarawong S, Barbieri EM, Cajka G, Liu M, Spruce L, Fazelinia H, Portz B, Copley K, Lapidot T, Duhamel L, Greenwald P, Saida N, Shalgi R, Shorter J, Shalem O. CRISPR screen for protein inclusion formation uncovers a role for SRRD in the regulation of intermediate filament dynamics and aggresome assembly. PLoS Genet 2024; 20:e1011138. [PMID: 38315730 PMCID: PMC10868785 DOI: 10.1371/journal.pgen.1011138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 02/15/2024] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
The presence of large protein inclusions is a hallmark of neurodegeneration, and yet the precise molecular factors that contribute to their formation remain poorly understood. Screens using aggregation-prone proteins have commonly relied on downstream toxicity as a readout rather than the direct formation of aggregates. Here, we combined a genome-wide CRISPR knockout screen with Pulse Shape Analysis, a FACS-based method for inclusion detection, to identify direct modifiers of TDP-43 aggregation in human cells. Our screen revealed both canonical and novel proteostasis genes, and unearthed SRRD, a poorly characterized protein, as a top regulator of protein inclusion formation. APEX biotin labeling reveals that SRRD resides in proximity to proteins that are involved in the formation and breakage of disulfide bonds and to intermediate filaments, suggesting a role in regulation of the spatial dynamics of the intermediate filament network. Indeed, loss of SRRD results in aberrant intermediate filament fibrils and the impaired formation of aggresomes, including blunted vimentin cage structure, during proteotoxic stress. Interestingly, SRRD also localizes to aggresomes and unfolded proteins, and rescues proteotoxicity in yeast whereby its N-terminal low complexity domain is sufficient to induce this affect. Altogether this suggests an unanticipated and broad role for SRRD in cytoskeletal organization and cellular proteostasis.
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Affiliation(s)
- Katelyn M. Sweeney
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sapanna Chantarawong
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Edward M. Barbieri
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Greg Cajka
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Matthew Liu
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Lynn Spruce
- Proteomics Core Facility, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Hossein Fazelinia
- Proteomics Core Facility, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Bede Portz
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Katie Copley
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Tomer Lapidot
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Lauren Duhamel
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Phoebe Greenwald
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Naseeb Saida
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Reut Shalgi
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ophir Shalem
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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6
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Ono S, Watabe E, Morisaki K, Ono K, Kuroyanagi H. Alternative splicing of a single exon causes a major impact on the affinity of Caenorhabditis elegans tropomyosin isoforms for actin filaments. Front Cell Dev Biol 2023; 11:1208913. [PMID: 37745299 PMCID: PMC10512467 DOI: 10.3389/fcell.2023.1208913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023] Open
Abstract
Tropomyosin is generally known as an actin-binding protein that regulates actomyosin interaction and actin filament stability. In metazoans, multiple tropomyosin isoforms are expressed, and some of them are involved in generating subpopulations of actin cytoskeleton in an isoform-specific manner. However, functions of many tropomyosin isoforms remain unknown. Here, we report identification of a novel alternative exon in the Caenorhabditis elegans tropomyosin gene and characterization of the effects of alternative splicing on the properties of tropomyosin isoforms. Previous studies have reported six tropomyosin isoforms encoded by the C. elegans lev-11 tropomyosin gene. We identified a seventh isoform, LEV-11U, that contained a novel alternative exon, exon 7c (E7c). LEV-11U is a low-molecular-weight tropomyosin isoform that differs from LEV-11T only at the exon 7-encoded region. In silico analyses indicated that the E7c-encoded peptide sequence was unfavorable for coiled-coil formation and distinct from other tropomyosin isoforms in the pattern of electrostatic surface potentials. In vitro, LEV-11U bound poorly to actin filaments, whereas LEV-11T bound to actin filaments in a saturable manner. When these isoforms were transgenically expressed in the C. elegans striated muscle, LEV-11U was present in the diffuse cytoplasm with tendency to form aggregates, whereas LEV-11T co-localized with sarcomeric actin filaments. Worms with a mutation in E7c showed reduced motility and brood size, suggesting that this exon is important for the optimal health. These results indicate that alternative splicing of a single exon can produce biochemically diverged tropomyosin isoforms and suggest that a tropomyosin isoform with poor actin affinity has a novel biological function.
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Affiliation(s)
- Shoichiro Ono
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, United States
| | - Eichi Watabe
- Laboratory of Gene Expression, Graduate School of Biomedical Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keita Morisaki
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Kanako Ono
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, United States
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Graduate School of Biomedical Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Biochemistry, University of the Ryukyus Graduate School of Medicine, Okinawa, Japan
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7
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Ogneva IV. The Mechanoreception in Drosophila melanogaster Oocyte under Modeling Micro- and Hypergravity. Cells 2023; 12:1819. [PMID: 37508484 PMCID: PMC10377865 DOI: 10.3390/cells12141819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 07/01/2023] [Accepted: 07/09/2023] [Indexed: 07/30/2023] Open
Abstract
The hypothesis about the role of the cortical cytoskeleton as the primary mechanosensor was tested. Drosophila melanogaster oocytes were exposed to simulated microgravity (by 3D clinorotation in random directions with 4 rotations per minute-sµg group) and hypergravity at the 2 g level (by centrifugal force from one axis rotation-hg group) for 30, 90, and 210 min without and with cytochalasin B, colchicine, acrylamide, and calyculin A. Cell stiffness was measured by atomic force microscopy, protein content in the membrane and cytoplasmic fractions by Western blotting, and cellular respiration by polarography. The obtained results indicate that the stiffness of the cortical cytoskeleton of Drosophila melanogaster oocytes decreases in simulated micro- (after 90 min) and hypergravity (after 30 min), possibly due to intermediate filaments. The cell stiffness recovered after 210 min in the hg group, but intact microtubules were required for this. Already after 30 min of exposure to sµg, the cross-sectional area of oocytes decreased, which indicates deformation, and the singed protein, which organizes microfilaments into longitudinal bundles, diffused from the cortical cytoskeleton into the cytoplasm. Under hg, after 30 min, the cross-sectional area of the oocytes increased, and the proteins that organize filament networks, alpha-actinin and spectrin, diffused from the cortical cytoskeleton.
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Affiliation(s)
- Irina V Ogneva
- Cell Biophysics Laboratory, State Scientific Center of the Russian Federation Institute of Biomedical Problems of the Russian Academy of Sciences, 76a, Khoroshevskoyoe Shosse, 123007 Moscow, Russia
- Medical and Biological Physics Department, I. M. Sechenov First Moscow State Medical University, 8-2 Trubetskaya Street, 119991 Moscow, Russia
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8
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Wittmer Y, Jami KM, Stowell RK, Le T, Hung I, Murray DT. Liquid Droplet Aging and Seeded Fibril Formation of the Cytotoxic Granule Associated RNA Binding Protein TIA1 Low Complexity Domain. J Am Chem Soc 2023; 145:1580-1592. [PMID: 36638831 PMCID: PMC9881004 DOI: 10.1021/jacs.2c08596] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Protein domains biased toward a few amino acid types are vital for the formation of biomolecular condensates in living cells. These membraneless compartments are formed by molecules exhibiting a range of molecular motions and structural order. Missense mutations increase condensate persistence lifetimes or structural order, properties that are thought to underlie pathological protein aggregation. In the context of stress granules associated with neurodegenerative diseases, this process involves the rigidification of protein liquid droplets into β-strand rich protein fibrils. Here, we characterize the molecular mechanism underlying the rigidification of liquid droplets for the low complexity domain of the Cytotoxic granule associated RNA binding protein TIA1 (TIA1) stress granule protein and the influence of a disease mutation linked to neurodegenerative diseases. A seeding procedure and solid state nuclear magnetic resonance measurements show that the low complexity domain converges on a β-strand rich fibril conformation composed of 21% of the sequence. Additional solid state nuclear magnetic resonance measurements and difference spectroscopy show that aged liquid droplets of wild type and a proline-to-leucine mutant low complexity domain are composed of fibril assemblies that are conformationally heterogeneous and structurally distinct from the seeded fibril preparation. Regarding low complexity domains, our data support the functional template-driven formation of conformationally homogeneous structures, that rigidification of liquid droplets into conformationally heterogenous structures promotes pathological interactions, and that the effect of disease mutations is more nuanced than increasing thermodynamic stability or increasing β-strand structure content.
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Affiliation(s)
- Yuuki Wittmer
- Department
of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Khaled M. Jami
- Department
of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Rachelle K. Stowell
- Department
of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Truc Le
- Department
of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Ivan Hung
- National
High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Dylan T. Murray
- Department
of Chemistry, University of California Davis, Davis, California 95616, United States,
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9
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Ogneva IV. Single Cell in a Gravity Field. Life (Basel) 2022; 12:1601. [PMID: 36295035 PMCID: PMC9604728 DOI: 10.3390/life12101601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/09/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023] Open
Abstract
The exploration of deep space or other bodies of the solar system, associated with a long stay in microgravity or altered gravity, requires the development of fundamentally new methods of protecting the human body. Most of the negative changes in micro- or hypergravity occur at the cellular level; however, the mechanism of reception of the altered gravity and transduction of this signal, leading to the formation of an adaptive pattern of the cell, is still poorly understood. At the same time, most of the negative changes that occur in early embryos when the force of gravity changes almost disappear by the time the new organism is born. This review is devoted to the responses of early embryos and stem cells, as well as terminally differentiated germ cells, to changes in gravity. An attempt was made to generalize the data presented in the literature and propose a possible unified mechanism for the reception by a single cell of an increase and decrease in gravity based on various deformations of the cortical cytoskeleton.
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Affiliation(s)
- Irina V Ogneva
- Cell Biophysics Laboratory, State Scientific Center of the Russian Federation Institute of Biomedical Problems of the Russian Academy of Sciences, 76a, Khoroshevskoyoe Shosse, 123007 Moscow, Russia
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10
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Zhou X, Sumrow L, Tashiro K, Sutherland L, Liu D, Qin T, Kato M, Liszczak G, McKnight SL. Mutations linked to neurological disease enhance self-association of low-complexity protein sequences. Science 2022; 377:eabn5582. [PMID: 35771920 PMCID: PMC9610444 DOI: 10.1126/science.abn5582] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Protein domains of low sequence complexity do not fold into stable, three-dimensional structures. Nevertheless, proteins with these sequences assist in many aspects of cell organization, including assembly of nuclear and cytoplasmic structures not surrounded by membranes. The dynamic nature of these cellular assemblies is caused by the ability of low-complexity domains (LCDs) to transiently self-associate through labile, cross-β structures. Mechanistic studies useful for the study of LCD self-association have evolved over the past decade in the form of simple assays of phase separation. Here, we have used such assays to demonstrate that the interactions responsible for LCD self-association can be dictated by labile protein structures poised close to equilibrium between the folded and unfolded states. Furthermore, missense mutations causing Charcot-Marie-Tooth disease, frontotemporal dementia, and Alzheimer's disease manifest their pathophysiology in vitro and in cultured cell systems by enhancing the stability of otherwise labile molecular structures formed upon LCD self-association.
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11
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Rosenberg GM, Murray KA, Salwinski L, Hughes MP, Abskharon R, Eisenberg DS. Bioinformatic identification of previously unrecognized amyloidogenic proteins. J Biol Chem 2022; 298:101920. [PMID: 35405097 PMCID: PMC9108986 DOI: 10.1016/j.jbc.2022.101920] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
Low-complexity domains (LCDs) of proteins have been shown to self-associate, and pathogenic mutations within these domains often drive the proteins into amyloid aggregation associated with disease. These domains may be especially susceptible to amyloidogenic mutations because they are commonly intrinsically disordered and function in self-association. The question therefore arises whether a search for pathogenic mutations in LCDs of the human proteome can lead to identification of other proteins associated with amyloid disease. Here, we take a computational approach to identify documented pathogenic mutations within LCDs that may favor amyloid formation. Using this approach, we identify numerous known amyloidogenic mutations, including several such mutations within proteins previously unidentified as amyloidogenic. Among the latter group, we focus on two mutations within the TRK-fused gene protein (TFG), known to play roles in protein secretion and innate immunity, which are associated with two different peripheral neuropathies. We show that both mutations increase the propensity of TFG to form amyloid fibrils. We therefore conclude that TFG is a novel amyloid protein and propose that the diseases associated with its mutant forms may be amyloidoses.
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Affiliation(s)
- Gregory M Rosenberg
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, California, USA
| | - Kevin A Murray
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, California, USA
| | - Lukasz Salwinski
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, California, USA
| | - Michael P Hughes
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, California, USA; Department of Cell and Molecular Biology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Romany Abskharon
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, California, USA
| | - David S Eisenberg
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, California, USA.
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12
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Li L, Casalini T, Arosio P, Salvalaglio M. Modeling the Structure and Interactions of Intrinsically Disordered Peptides with Multiple Replica, Metadynamics-Based Sampling Methods and Force-Field Combinations. J Chem Theory Comput 2022; 18:1915-1928. [PMID: 35174713 PMCID: PMC9097291 DOI: 10.1021/acs.jctc.1c00889] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Indexed: 01/08/2023]
Abstract
Intrinsically disordered proteins play a key role in many biological processes, including the formation of biomolecular condensates within cells. A detailed characterization of their configurational ensemble and structure-function paradigm is crucial for understanding their biological activity and for exploiting them as building blocks in material sciences. In this work, we incorporate bias-exchange metadynamics and parallel-tempering well-tempered metadynamics with CHARMM36m and CHARMM22* to explore the structural and thermodynamic characteristics of a short archetypal disordered sequence derived from a DEAD-box protein. The conformational landscapes emerging from our simulations are largely congruent across methods and force fields. Nevertheless, differences in fine details emerge from varying combinations of force-fields and sampling methods. For this protein, our analysis identifies features that help to explain the low propensity of this sequence to undergo self-association in vitro, which are common to all force-field/sampling method combinations. Overall, our work demonstrates the importance of using multiple force-field and sampling method combinations for accurate structural and thermodynamic information in the study of disordered proteins.
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Affiliation(s)
- Lunna Li
- Thomas
Young Centre and Department of Chemical Engineering, University College London, London WC1E 7JE, U.K.
| | - Tommaso Casalini
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, Zurich 8093, Switzerland
| | - Paolo Arosio
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, Zurich 8093, Switzerland
| | - Matteo Salvalaglio
- Thomas
Young Centre and Department of Chemical Engineering, University College London, London WC1E 7JE, U.K.
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13
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Murray KA, Evans D, Hughes MP, Sawaya MR, Hu CJ, Houk KN, Eisenberg D. Extended β-Strands Contribute to Reversible Amyloid Formation. ACS NANO 2022; 16:2154-2163. [PMID: 35132852 DOI: 10.1021/acsnano.1c08043] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The assembly of proteins into fibrillar amyloid structures was once considered to be pathologic and essentially irreversible. Recent studies reveal amyloid-like structures that form reversibly, derived from protein low-complexity domains which function in cellular metabolism. Here, by comparing atomic-level structures of reversible and irreversible amyloid fibrils, we find that the β-sheets of reversible fibrils are enriched in flattened (as opposed to pleated) β-sheets formed by stacking of extended β-strands. Quantum mechanical calculations show that glycine residues favor extended β-strands which may be stabilized by intraresidue interactions between the amide proton and the carbonyl oxygen, known as C5 hydrogen-bonds. Larger residue side chains favor shorter strands and pleated sheets. These findings highlight a structural element that may regulate reversible amyloid assembly.
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14
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Murray KA, Hughes MP, Hu CJ, Sawaya MR, Salwinski L, Pan H, French SW, Seidler PM, Eisenberg DS. Identifying amyloid-related diseases by mapping mutations in low-complexity protein domains to pathologies. Nat Struct Mol Biol 2022; 29:529-536. [PMID: 35637421 PMCID: PMC9205782 DOI: 10.1038/s41594-022-00774-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 04/08/2022] [Indexed: 01/19/2023]
Abstract
Proteins including FUS, hnRNPA2, and TDP-43 reversibly aggregate into amyloid-like fibrils through interactions of their low-complexity domains (LCDs). Mutations in LCDs can promote irreversible amyloid aggregation and disease. We introduce a computational approach to identify mutations in LCDs of disease-associated proteins predicted to increase propensity for amyloid aggregation. We identify several disease-related mutations in the intermediate filament protein keratin-8 (KRT8). Atomic structures of wild-type and mutant KRT8 segments confirm the transition to a pleated strand capable of amyloid formation. Biochemical analysis reveals KRT8 forms amyloid aggregates, and the identified mutations promote aggregation. Aggregated KRT8 is found in Mallory-Denk bodies, observed in hepatocytes of livers with alcoholic steatohepatitis (ASH). We demonstrate that ethanol promotes KRT8 aggregation, and KRT8 amyloids co-crystallize with alcohol. Lastly, KRT8 aggregation can be seeded by liver extract from people with ASH, consistent with the amyloid nature of KRT8 aggregates and the classification of ASH as an amyloid-related condition.
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Affiliation(s)
- Kevin A. Murray
- grid.19006.3e0000 0000 9632 6718Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA USA
| | - Michael P. Hughes
- grid.19006.3e0000 0000 9632 6718Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA USA
| | - Carolyn J. Hu
- grid.19006.3e0000 0000 9632 6718Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA USA
| | - Michael R. Sawaya
- grid.19006.3e0000 0000 9632 6718Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA USA
| | - Lukasz Salwinski
- grid.19006.3e0000 0000 9632 6718Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA USA
| | - Hope Pan
- grid.19006.3e0000 0000 9632 6718Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA USA
| | - Samuel W. French
- grid.19006.3e0000 0000 9632 6718Department of Pathology & Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA USA
| | - Paul M. Seidler
- grid.42505.360000 0001 2156 6853Department of Pharmacology and Pharmaceutical Science, University of Southern California, Los Angeles, CA USA
| | - David S. Eisenberg
- grid.19006.3e0000 0000 9632 6718Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, and Howard Hughes Medical Institute, UCLA, Los Angeles, CA USA
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15
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Ogunnigbagbe O, Bunick CG, Kaur K. Keratin 1 as a cell-surface receptor in cancer. Biochim Biophys Acta Rev Cancer 2022; 1877:188664. [PMID: 34890750 PMCID: PMC8818032 DOI: 10.1016/j.bbcan.2021.188664] [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: 08/19/2021] [Revised: 11/10/2021] [Accepted: 11/30/2021] [Indexed: 01/03/2023]
Abstract
Keratins are fibrous proteins that take part in several important cellular functions, including the formation of intermediate filaments. In addition, keratins serve as epithelial cell markers, which has made their role in cancer progression, diagnosis, and treatment an important focus of research. Keratin 1 (K1) is a type II keratin whose structure is comprised of a coiled-coil central domain flanked by flexible, glycine-rich loops in the N- and C-termini. While the structure of cytoplasmic K1 is established, the structure of cell-surface K1 is not known. Several transformed cells, such as cancerous cells and cells that have undergone oxidative stress, display increased levels of overall and/or cell-surface K1 expression. Cell-surface keratins (CSKs) may be modified or truncated, and their role is yet to be fully elucidated. Current studies suggest that CSKs are involved in receptor-mediated endocytosis and immune evasion. In this Review, we discuss findings relating to K1 structure, overexpression, and cell-surface expression in the context of utilizing CSK1 as a receptor for targeted drug delivery to cancer cells, and other strategies to develop novel treatments for cancer.
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Affiliation(s)
- Oluseye Ogunnigbagbe
- School of Pharmacy, Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California, 92618-1908, USA
| | - Christopher G. Bunick
- Department of Dermatology, Yale University, New Haven, Connecticut, 06520-8059, USA,corresponding author
| | - Kamaljit Kaur
- School of Pharmacy, Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California, 92618-1908, USA,corresponding author
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16
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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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17
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Fonda BD, Jami KM, Boulos NR, Murray DT. Identification of the Rigid Core for Aged Liquid Droplets of an RNA-Binding Protein Low Complexity Domain. J Am Chem Soc 2021; 143:6657-6668. [PMID: 33896178 DOI: 10.1021/jacs.1c02424] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The biomolecular condensation of proteins with low complexity sequences plays a functional role in RNA metabolism and a pathogenic role in neurodegenerative diseases. The formation of dynamic liquid droplets brings biomolecules together to achieve complex cellular functions. The rigidification of liquid droplets into β-strand-rich hydrogel structures composed of protein fibrils is thought to be purely pathological in nature. However, low complexity sequences often harbor multiple fibril-prone regions with delicately balanced functional and pathological interactions. Here, we investigate the maturation of liquid droplets formed by the low complexity domain of the TAR DNA-binding protein 43 (TDP-43). Solid state nuclear magnetic resonance measurements on the aged liquid droplets identify residues 365-400 as the structured core, which are squarely outside the region between residues 311-360 thought to be most important for pathological fibril formation and aggregation. The results of this study suggest that multiple segments of this low complexity domain are prone to form fibrils and that stabilization of β-strand-rich structure in one segment precludes the other region from adopting a rigid fibril structure.
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Affiliation(s)
- Blake D Fonda
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Khaled M Jami
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Natalie R Boulos
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Dylan T Murray
- Department of Chemistry, University of California, Davis, California 95616, United States
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18
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Dong X, Bera S, Qiao Q, Tang Y, Lao Z, Luo Y, Gazit E, Wei G. Liquid-Liquid Phase Separation of Tau Protein Is Encoded at the Monomeric Level. J Phys Chem Lett 2021; 12:2576-2586. [PMID: 33686854 DOI: 10.1021/acs.jpclett.1c00208] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Liquid-liquid phase separation (LLPS) is involved in both physiological and pathological processes. The intrinsically disordered protein Tau and its K18 construct can undergo LLPS in a distinct temperature-dependent manner, and the LLPS of Tau protein can initiate Tau aggregation. However, the underlying mechanism driving Tau LLPS remains largely elusive. To understand the temperature-dependent LLPS behavior of Tau at the monomeric level, we explored the conformational ensemble of Tau at different temperatures by performing all-atom replica-exchange molecular dynamic simulation on K18 monomer with an accumulated simulation time of 26.4 μs. Our simulation demonstrates that the compactness, β-structure propensity, and intramolecular interaction of K18 monomer exhibit nonlinear temperature-dependent behavior. 295DNIKHV300/326GNIHHK331/337VEVKSE342 make significant contributions to the temperature dependence of the β propensity of K18 monomer, while the two fibril-nucleating cores display relatively high β propensity at all temperatures. At a specific temperature, K18 monomer adopts the most collapsed state with exposed sites for both persistent and transient interactions. Given that more collapsed polypeptide chains were reported to be more prone to phase separate, our results suggest that K18 monomer inherently possesses conformational characteristics favoring LLPS. Our simulation predicts the importance of 295DNIKHV300/326GNIHHK331/337VEVKSE342 to the temperature-dependent conformational properties of K18, which is corroborated by CD spectra, turbidity assays, and DIC microscopy. Taken together, we offer a computational and experimental approach to comprehend the structural basis for LLPS by amyloidal building blocks.
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Affiliation(s)
- Xuewei Dong
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (Ministry of Education), Fudan University, Shanghai 200433, People's Republic of China
| | - Santu Bera
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Qin Qiao
- Digital Medical Research Center, School of Basic Medical Sciences, Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention, Fudan University, Shanghai 200032, People's Republic of China
| | - Yiming Tang
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (Ministry of Education), Fudan University, Shanghai 200433, People's Republic of China
| | - Zenghui Lao
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (Ministry of Education), Fudan University, Shanghai 200433, People's Republic of China
| | - Yin Luo
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (Ministry of Education), Fudan University, Shanghai 200433, People's Republic of China
| | - Ehud Gazit
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (Ministry of Education), Fudan University, Shanghai 200433, People's Republic of China
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19
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Kato M, Tu BP, McKnight SL. Redox-mediated regulation of low complexity domain self-association. Curr Opin Genet Dev 2021; 67:111-118. [PMID: 33454579 DOI: 10.1016/j.gde.2020.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/05/2020] [Accepted: 12/08/2020] [Indexed: 01/12/2023]
Abstract
Eukaryotic cells express thousands of protein domains long believed to function in the absence of molecular order. These intrinsically disordered protein (IDP) domains are typified by gibberish-like repeats of only a limited number of amino acids that we refer to as domains of low sequence complexity. A decade ago, it was observed that these low complexity (LC) domains can undergo phase transition out of aqueous solution to form either liquid-like droplets or hydrogels. The self-associative interactions responsible for phase transition involve the formation of specific cross-β structures that are unusual in being labile to dissociation. Here we give evidence that the LC domains of two RNA binding proteins, ataxin-2 and TDP43, form cross-β interactions that specify biologically relevant redox sensors.
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Affiliation(s)
- Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9152, United States; Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9152, United States
| | - Steven L McKnight
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9152, United States.
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