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Ji E, Pandey PR, Martindale JL, Yang X, Yang JH, Tsitsipatis D, Shin CH, Piao Y, Fan J, Mazan-Mamczarz K, Banskota N, De S, Gorospe M. FUS-Mediated Inhibition of Myogenesis Elicited by Suppressing TNNT1 Production. Mol Cell Biol 2024:1-19. [PMID: 39133076 DOI: 10.1080/10985549.2024.2383296] [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: 05/26/2024] [Revised: 07/17/2024] [Accepted: 07/17/2024] [Indexed: 08/13/2024] Open
Abstract
Myogenesis is a highly orchestrated process whereby muscle precursor cells, myoblasts, develop into muscle fibers to form skeletal muscle during embryogenesis and regenerate adult muscle. Here, we studied the RNA-binding protein FUS (fused in sarcoma), which has been implicated in muscular and neuromuscular pathologies but is poorly characterized in myogenesis. Given that FUS levels declined in human and mouse models of skeletal myogenesis, and that silencing FUS enhanced myogenesis, we hypothesized that FUS might be a repressor of myogenic differentiation. Interestingly, overexpression of FUS delayed myogenesis, accompanied by slower production of muscle differentiation markers. To identify the mechanisms through which FUS inhibits myogenesis, we uncovered RNA targets of FUS by ribonucleoprotein immunoprecipitation (RIP) followed by RNA-sequencing (RNA-seq) analysis. Stringent selection of the bound transcripts uncovered Tnnt1 mRNA, encoding troponin T1 (TNNT1), as a major effector of FUS influence on myogenesis. We found that in myoblasts, FUS retained Tnnt1 mRNA in the nucleus, preventing TNNT1 expression; however, reduction of FUS during myogenesis or by silencing FUS released Tnnt1 mRNA for export to the cytoplasm, enabling TNNT1 translation and promoting myogenesis. We propose that FUS inhibits myogenesis by suppressing TNNT1 expression through a mechanism of nuclear Tnnt1 mRNA retention.
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Affiliation(s)
- Eunbyul Ji
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Poonam R Pandey
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Jennifer L Martindale
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Xiaoling Yang
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Jen-Hao Yang
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Dimitrios Tsitsipatis
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Chang Hoon Shin
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Yulan Piao
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Jinshui Fan
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Krystyna Mazan-Mamczarz
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Nirad Banskota
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Supriyo De
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Myriam Gorospe
- Laboratory of Genetics and Genomics, National Institute on Aging (NIA) Intramural Research Program (IRP), National Institutes of Health (NIH), Baltimore, MD, USA
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2
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Ziaunys M, Sulskis D, Veiveris D, Kopustas A, Snieckute R, Mikalauskaite K, Sakalauskas A, Tutkus M, Smirnovas V. Liquid-liquid phase separation of alpha-synuclein increases the structural variability of fibrils formed during amyloid aggregation. FEBS J 2024. [PMID: 39116032 DOI: 10.1111/febs.17244] [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: 02/02/2024] [Revised: 04/25/2024] [Accepted: 07/25/2024] [Indexed: 08/10/2024]
Abstract
Protein liquid-liquid phase separation (LLPS) is a rapidly emerging field of study on biomolecular condensate formation. In recent years, this phenomenon has been implicated in the process of amyloid fibril formation, serving as an intermediate step between the native protein transition into their aggregated state. The formation of fibrils via LLPS has been demonstrated for a number of proteins related to neurodegenerative disorders, as well as other amyloidoses. Despite the surge in amyloid-related LLPS studies, the influence of protein condensate formation on the end-point fibril characteristics is still far from fully understood. In this work, we compare alpha-synuclein aggregation under different conditions, which promote or negate its LLPS and examine the differences between the formed aggregates. We show that alpha-synuclein phase separation generates a wide variety of assemblies with distinct secondary structures and morphologies. The LLPS-induced structures also possess higher levels of toxicity to cells, indicating that biomolecular condensate formation may be a critical step in the appearance of disease-related fibril variants.
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Affiliation(s)
- Mantas Ziaunys
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
| | - Darius Sulskis
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
| | - Dominykas Veiveris
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
| | - Aurimas Kopustas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Ruta Snieckute
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
| | | | - Andrius Sakalauskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
| | - Marijonas Tutkus
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Lithuania
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3
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Gatch AJ, Ding F. TDP-43 Promotes Amyloid-Beta Toxicity by Delaying Fibril Maturation via Direct Molecular Interaction. ACS Chem Neurosci 2024; 15:2936-2953. [PMID: 39073874 PMCID: PMC11323227 DOI: 10.1021/acschemneuro.4c00334] [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: 07/30/2024] Open
Abstract
Amyloid-β (Aβ) is a peptide that undergoes self-assembly into amyloid fibrils, which compose the hallmark plaques observed in Alzheimer's disease (AD). TAR DNA-binding protein 43 (TDP-43) is a protein with mislocalization and aggregation implicated in amyotrophic lateral sclerosis and other neurodegenerative diseases. Recent work suggests that TDP-43 may interact with Aβ, inhibiting the formation of amyloid fibrils and worsening AD pathology, but the molecular details of their interaction remain unknown. Using all-atom discrete molecular dynamics simulations, we systematically investigated the direct molecular interaction between Aβ and TDP-43. We found that Aβ monomers were able to bind near the flexible nuclear localization sequence of the N-terminal domain (NTD) of TDP-43, adopting β-sheet rich conformations that were promoted by the interaction. Furthermore, Aβ associated with the nucleic acid binding interface of the tandem RNA recognition motifs of TDP-43 via electrostatic interactions. Using the computational peptide array method, we found the strongest C-terminal domain interaction with Aβ to be within the amyloidogenic core region of TDP-43. With experimental evidence suggesting that the NTD is necessary for inhibiting Aβ fibril growth, we also simulated the NTD with an Aβ40 fibril seed. We found that the NTD was able to strongly bind the elongation surface of the fibril seed via extensive hydrogen bonding and could also diffuse along the lateral surface via electrostatic interactions. Our results suggest that TDP-43 binding to the elongation surface, thereby sterically blocking Aβ monomer addition, is responsible for the experimentally observed inhibition of fibril growth. We conclude that TDP-43 may promote Aβ toxicity by stabilizing the oligomeric state and kinetically delaying fibril maturation.
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Affiliation(s)
- Adam J. Gatch
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
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4
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Ikeda A, Meng H, Taniguchi D, Mio M, Funayama M, Nishioka K, Yoshida M, Li Y, Yoshino H, Inoshita T, Shiba-Fukushima K, Okubo Y, Sakurai T, Amo T, Aiba I, Saito Y, Saito Y, Murayama S, Atsuta N, Nakamura R, Tohnai G, Izumi Y, Morita M, Tamura A, Kano O, Oda M, Kuwabara S, Yamashita T, Sone J, Kaji R, Sobue G, Imai Y, Hattori N. CHCHD2 P14L, found in amyotrophic lateral sclerosis, exhibits cytoplasmic mislocalization and alters Ca 2+ homeostasis. PNAS NEXUS 2024; 3:pgae319. [PMID: 39131911 PMCID: PMC11316225 DOI: 10.1093/pnasnexus/pgae319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 07/22/2024] [Indexed: 08/13/2024]
Abstract
CHCHD2 and CHCHD10, linked to Parkinson's disease and amyotrophic lateral sclerosis-frontotemporal dementia (ALS), respectively, are mitochondrial intermembrane proteins that form a heterodimer. This study aimed to investigate the impact of the CHCHD2 P14L variant, implicated in ALS, on mitochondrial function and its subsequent effects on cellular homeostasis. The missense variant of CHCHD2, P14L, found in a cohort of patients with ALS, mislocalized CHCHD2 to the cytoplasm, leaving CHCHD10 in the mitochondria. Drosophila lacking the CHCHD2 ortholog exhibited mitochondrial degeneration. In contrast, human CHCHD2 P14L, but not wild-type human CHCHD2, failed to suppress this degeneration, suggesting that P14L is a pathogenic variant. The mitochondrial Ca2+ buffering capacity was reduced in Drosophila neurons expressing human CHCHD2 P14L. The altered Ca2+-buffering phenotype was also observed in cultured human neuroblastoma SH-SY5Y cells expressing CHCHD2 P14L. In these cells, transient elevation of cytoplasmic Ca2+ facilitated the activation of calpain and caspase-3, accompanied by the processing and insolubilization of TDP-43. These observations suggest that CHCHD2 P14L causes abnormal Ca2+ dynamics and TDP-43 aggregation, reflecting the pathophysiology of ALS.
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Affiliation(s)
- Aya Ikeda
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Hongrui Meng
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Daisuke Taniguchi
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Muneyo Mio
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Manabu Funayama
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Center for Genomic and Regenerative Medicine, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Kenya Nishioka
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Mari Yoshida
- Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Nagakute, Aichi 480-1195, Japan
| | - Yuanzhe Li
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Hiroyo Yoshino
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Tsuyoshi Inoshita
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Kahori Shiba-Fukushima
- Department of Drug Development for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Yohei Okubo
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Taku Amo
- Department of Applied Chemistry, National Defense Academy, Yokosuka, Kanagawa 239-8686, Japan
| | - Ikuko Aiba
- Department of Neurology, NHO Higashinagoya National Hospital, Meito-ku, Nagoya, Aichi 465-8620, Japan
| | - Yufuko Saito
- Department of Neurology, NHO Higashinagoya National Hospital, Meito-ku, Nagoya, Aichi 465-8620, Japan
| | - Yuko Saito
- Brain Bank for Aging Research (Department of Neuropathology), Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo 173-0015, Japan
| | - Shigeo Murayama
- Brain Bank for Aging Research (Department of Neuropathology), Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo 173-0015, Japan
- Brain Bank for Neurodevelopmental, Neurological and Psychiatric Disorders, United Graduate School of Child Development, Osaka University, Osaka 565-0871, Japan
| | - Naoki Atsuta
- Department of Neurology, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan
| | - Ryoichi Nakamura
- Department of Neurology, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan
| | - Genki Tohnai
- Division of ALS Research, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan
| | - Yuishin Izumi
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima 770-8503, Japan
| | - Mitsuya Morita
- Division of Neurology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan
| | - Asako Tamura
- Department of Neurology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
| | - Osamu Kano
- Department of Neurology, Toho University Faculty of Medicine, Ota-ku, Tokyo 143-8541, Japan
| | - Masaya Oda
- Department of Neurology, Vihara Hananosato Hospital, Miyoshi, Hiroshima 728-0001, Japan
| | - Satoshi Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba 260-8670, Japan
| | - Toru Yamashita
- Department of Neurology, Okayama University Graduate School of Medicine, Kita-ku, Okayama 700-8558, Japan
| | - Jun Sone
- Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Nagakute, Aichi 480-1195, Japan
| | - Ryuji Kaji
- Department of Clinical Neuroscience, Tokushima University, Tokushima 770-8503, Japan
| | - Gen Sobue
- Aichi Medical University, Nagakute, Aichi 480-1195, Japan
| | - Yuzuru Imai
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Drug Development for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Neurodegenerative Disorders Collaborative Laboratory, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
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Singh S, Bernal Astrain G, Hincapie AM, Goudreault M, Smith MJ. Complex interplay between RAS GTPases and RASSF effectors regulates subcellular localization of YAP. EMBO Rep 2024; 25:3574-3600. [PMID: 39009833 PMCID: PMC11316025 DOI: 10.1038/s44319-024-00203-9] [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: 12/06/2023] [Revised: 06/20/2024] [Accepted: 06/25/2024] [Indexed: 07/17/2024] Open
Abstract
RAS GTPases bind effectors to convert upstream cues to changes in cellular function. Effectors of classical H/K/NRAS are defined by RBD/RA domains which recognize the GTP-bound conformation of these GTPases, yet the specificity of RBD/RAs for over 160 RAS superfamily proteins remains poorly explored. We have systematically mapped interactions between BRAF and four RASSF effectors, the largest family of RA-containing proteins, with all RAS, RHO and ARF small GTPases. 39 validated complexes reveal plasticity in RASSF binding, while BRAF demonstrates tight specificity for classical H/K/NRAS. Complex between RASSF5 and diverse RAS GTPases at the plasma membrane can activate Hippo signalling and sequester YAP in the cytosol. RASSF8 undergoes liquid-liquid phase separation and resides in YAP-associated membraneless condensates, which also engage several RAS and RHO GTPases. The poorly studied RASSF3 has been identified as a first potential effector of mitochondrial MIRO proteins, and its co-expression with these GTPases impacts mitochondria and peroxisome distribution. These data reveal the complex nature of GTPase-effector interactions and show their systematic elucidation can reveal completely novel and biologically relevant cellular processes.
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Affiliation(s)
- Swati Singh
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Gabriela Bernal Astrain
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Ana Maria Hincapie
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QC, H3A 1A3, Canada
| | - Marilyn Goudreault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Matthew J Smith
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada.
- Department of Pathology and Cell Biology, Faculty of Medicine, Université de Montréal, Montréal, QC, H3T 1J4, Canada.
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6
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Lippi A, Krisko A. Protein aggregation: A detrimental symptom or an adaptation mechanism? J Neurochem 2024; 168:1426-1441. [PMID: 37694504 DOI: 10.1111/jnc.15955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/12/2023]
Abstract
Protein quality control mechanisms oversee numerous aspects of protein lifetime. From the point of protein synthesis, protein homeostasis machineries take part in folding, solubilization, and/or degradation of impaired proteins. Some proteins follow an alternative path upon loss of their solubility, thus are secluded from the cytosol and form protein aggregates. Protein aggregates differ in their function and composition, rendering protein aggregation a complex phenomenon that continues to receive plenty of attention in the scientific and medical communities. Traditionally, protein aggregates have been associated with aging and a large spectrum of protein folding diseases, such as neurodegenerative diseases, type 2 diabetes, or cataract. However, a body of evidence suggests that they may act as an adaptive mechanism to overcome transient stressful conditions, serving as a sink for the removal of misfolded proteins from the cytosol or storage compartments for machineries required upon stress release. In this review, we present examples and evidence elaborating different possible roles of protein aggregation and discuss their potential roles in stress survival, aging, and disease, as well as possible anti-aggregation interventions.
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Affiliation(s)
- Alice Lippi
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Anita Krisko
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
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7
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Geng Q, Keya JJ, Hotta T, Verhey KJ. The kinesin-3 KIF1C undergoes liquid-liquid phase separation for accumulation of specific transcripts at the cell periphery. EMBO J 2024; 43:3192-3213. [PMID: 38898313 PMCID: PMC11294625 DOI: 10.1038/s44318-024-00147-9] [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: 03/19/2024] [Revised: 04/30/2024] [Accepted: 05/17/2024] [Indexed: 06/21/2024] Open
Abstract
In cells, mRNAs are transported to and positioned at subcellular areas to locally regulate protein production. Recent studies have identified the kinesin-3 family member motor protein KIF1C as an RNA transporter. However, it is not clear how KIF1C interacts with RNA molecules. Here, we show that the KIF1C C-terminal tail domain contains an intrinsically disordered region (IDR) that drives liquid-liquid phase separation (LLPS). KIF1C forms dynamic puncta in cells that display physical properties of liquid condensates and incorporate RNA molecules in a sequence-selective manner. Endogenous KIF1C forms condensates in cellular protrusions, where mRNAs are enriched in an IDR-dependent manner. Purified KIF1C tail constructs undergo LLPS in vitro at near-endogenous nM concentrations and in the absence of crowding agents and can directly recruit RNA molecules. Overall, our work uncovers an intrinsic correlation between the LLPS activity of KIF1C and its role in mRNA positioning. In addition, the LLPS activity of KIF1C's tail represents a new mode of motor-cargo interaction that extends our current understanding of cytoskeletal motor proteins.
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Affiliation(s)
- Qi Geng
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jakia Jannat Keya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Takashi Hotta
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.
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8
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Staderini T, Bigi A, Lagrève C, Marzi I, Bemporad F, Chiti F. Biophysical characterization of the phase separation of TDP-43 devoid of the C-terminal domain. Cell Mol Biol Lett 2024; 29:104. [PMID: 38997630 PMCID: PMC11245819 DOI: 10.1186/s11658-024-00615-4] [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: 12/18/2023] [Accepted: 06/25/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND Frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-TDP), amyotrophic lateral sclerosis (ALS) and limbic-predominant age-related TDP-43 encephalopathy (LATE) are associated with deposition of cytoplasmic inclusions of TAR DNA-binding protein 43 (TDP-43) in neurons. One complexity of this process lies in the ability of TDP-43 to form liquid-phase membraneless organelles in cells. Previous work has shown that the recombinant, purified, prion-like domain (PrLD) forms liquid droplets in vitro, but the behaviour of the complementary fragment is uncertain. METHODS We have purified such a construct without the PrLD (PrLD-less TDP-43) and have induced its phase separation using a solution-jump method and an array of biophysical techniques to study the morphology, state of matter and structure of the TDP-43 assemblies. RESULTS The fluorescent TMR-labelled protein construct, imaged using confocal fluorescence, formed rapidly (< 1 min) round, homogeneous and 0.5-1.0 µm wide assemblies which then coalesced into larger, yet round, species. When labelled with AlexaFluor488, they initially exhibited fluorescence recovery after photobleaching (FRAP), showing a liquid behaviour distinct from full-length TDP-43 and similar to PrLD. The protein molecules did not undergo major structural changes, as determined with circular dichroism and intrinsic fluorescence spectroscopies. This process had a pH and salt dependence distinct from those of full-length TDP-43 and its PrLD, which can be rationalized on the grounds of electrostatic forces. CONCLUSIONS Similarly to PrLD, PrLD-less TDP-43 forms liquid droplets in vitro through liquid-liquid phase separation (LLPS), unlike the full-length protein that rather undergoes liquid-solid phase separation (LSPS). These results offer a rationale of the complex electrostatic forces governing phase separation of full-length TDP-43 and its fragments. On the one hand, PrLD-less TDP-43 has a low pI and oppositively charged domains, and LLPS is inhibited by salts, which attenuate inter-domain electrostatic attractions. On the other hand, PrLD is positively charged due to a high isoionic point (pI) and LLPS is therefore promoted by salts and pH increases as they both reduce electrostatic repulsions. By contrast, full-length TDP-43 undergoes LSPS most favourably at its pI, with positive and negative salt dependences at lower and higher pH, respectively, depending on whether repulsive or attractive forces dominate, respectively.
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Affiliation(s)
- Tommaso Staderini
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134, Florence, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, 50019, Florence, Italy
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, 50019, Florence, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134, Florence, Italy
| | - Clément Lagrève
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134, Florence, Italy
- Chimie ParisTech-PSL, École Nationale Supérieur de Chimie de Paris, 11 rue Pierre et Marie Curie, 75231, Paris, France
| | - Isabella Marzi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134, Florence, Italy
| | - Francesco Bemporad
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134, Florence, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134, Florence, Italy.
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9
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Chuang HY, He RY, Huang YA, Hsu WT, Cheng YJ, Guo ZR, Wali N, Hwang IS, Shie JJ, Huang JJT. Engineered droplet-forming peptide as photocontrollable phase modulator for fused in sarcoma protein. Nat Commun 2024; 15:5686. [PMID: 38971830 PMCID: PMC11227587 DOI: 10.1038/s41467-024-50025-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 06/27/2024] [Indexed: 07/08/2024] Open
Abstract
The assembly and disassembly of biomolecular condensates are crucial for the subcellular compartmentalization of biomolecules in the control of cellular reactions. Recently, a correlation has been discovered between the phase transition of condensates and their maturation (aggregation) process in diseases. Therefore, modulating the phase of condensates to unravel the roles of condensation has become a matter of interest. Here, we create a peptide-based phase modulator, JSF1, which forms droplets in the dark and transforms into amyloid-like fibrils upon photoinitiation, as evidenced by their distinctive nanomechanical and dynamic properties. JSF1 is found to effectively enhance the condensation of purified fused in sarcoma (FUS) protein and, upon light exposure, induce its fibrilization. We also use JSF1 to modulate the biophysical states of FUS condensates in live cells and elucidate the relationship between FUS phase transition and FUS proteinopathy, thereby shedding light on the effect of protein phase transition on cellular function and malfunction.
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Affiliation(s)
- Hao-Yu Chuang
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan
- Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, Taipei, 115, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu, 300, Taiwan
| | - Ruei-Yu He
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan
| | - Yung-An Huang
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan
| | - Wan-Ting Hsu
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan
| | - Ya-Jen Cheng
- Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, 115, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan
| | - Zheng-Rong Guo
- Institute of Physics, Academia Sinica, Taipei, 115, Taiwan
| | - Niaz Wali
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan
| | | | - Jiun-Jie Shie
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan
| | - Joseph Jen-Tse Huang
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan.
- Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, 115, Taiwan.
- Sustainable Chemical Science and Technology, Taiwan International Graduate Program, Academia Sinica, Taipei, 115, Taiwan.
- Department of Applied Chemistry, National Chiayi University, Chiayi City, 600, Taiwan.
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10
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Mendes LFS, Gimenes CO, da Silva MDO, Rout SK, Riek R, Costa‐Filho AJ. The potential role of liquid-liquid phase separation in the cellular fate of the compartments for unconventional protein secretion. Protein Sci 2024; 33:e5085. [PMID: 38923199 PMCID: PMC11201811 DOI: 10.1002/pro.5085] [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: 02/27/2024] [Revised: 04/30/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024]
Abstract
Eukaryotic cells have developed intricate mechanisms for biomolecule transport, particularly in stressful conditions. This interdisciplinary study delves into unconventional protein secretion (UPS) pathways activated during starvation, facilitating the export of proteins bypassing most of the components of the classical secretory machinery. Specifically, we focus on the underexplored mechanisms of the GRASP's role in UPS, particularly in biogenesis and cargo recruitment for the vesicular-like compartment for UPS. Our results show that liquid-liquid phase separation (LLPS) plays a key role in the coacervation of Grh1, the GRASP yeast homologue, under starvation-like conditions. This association seems a precursor to the Compartment for Unconventional Protein Secretion (CUPS) biogenesis. Grh1's self-association is regulated by electrostatic, hydrophobic, and hydrogen-bonding interactions. Importantly, our study demonstrates that phase-separated states of Grh1 can recruit UPS cargo under starvation-like situations. Additionally, we explore how the coacervate liquid-to-solid transition could impact cells' ability to return to normal post-stress states. Our findings offer insights into intracellular protein dynamics and cell adaptive responses to stress.
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Affiliation(s)
- Luis Felipe S. Mendes
- Group of Biophysics and Structural Biology "Sergio Mascarenhas". São Carlos Institute of PhysicsUniversity of São PauloSão CarlosSão PauloBrazil
- Department of Physics, Ribeirão Preto School of Philosophy, Science, and LiteratureUniversity of São PauloRibeirão PretoSão PauloBrazil
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH HönggerbergZürichSwitzerland
| | - Carolina O. Gimenes
- Department of Physics, Ribeirão Preto School of Philosophy, Science, and LiteratureUniversity of São PauloRibeirão PretoSão PauloBrazil
| | - Marília D. O. da Silva
- Group of Biophysics and Structural Biology "Sergio Mascarenhas". São Carlos Institute of PhysicsUniversity of São PauloSão CarlosSão PauloBrazil
| | - Saroj K. Rout
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH HönggerbergZürichSwitzerland
| | - Roland Riek
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH HönggerbergZürichSwitzerland
| | - Antonio J. Costa‐Filho
- Department of Physics, Ribeirão Preto School of Philosophy, Science, and LiteratureUniversity of São PauloRibeirão PretoSão PauloBrazil
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11
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Zhang X, Yuan L, Zhang W, Zhang Y, Wu Q, Li C, Wu M, Huang Y. Liquid-liquid phase separation in diseases. MedComm (Beijing) 2024; 5:e640. [PMID: 39006762 PMCID: PMC11245632 DOI: 10.1002/mco2.640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 07/16/2024] Open
Abstract
Liquid-liquid phase separation (LLPS), an emerging biophysical phenomenon, can sequester molecules to implement physiological and pathological functions. LLPS implements the assembly of numerous membraneless chambers, including stress granules and P-bodies, containing RNA and protein. RNA-RNA and RNA-protein interactions play a critical role in LLPS. Scaffolding proteins, through multivalent interactions and external factors, support protein-RNA interaction networks to form condensates involved in a variety of diseases, particularly neurodegenerative diseases and cancer. Modulating LLPS phenomenon in multiple pathogenic proteins for the treatment of neurodegenerative diseases and cancer could present a promising direction, though recent advances in this area are limited. Here, we summarize in detail the complexity of LLPS in constructing signaling pathways and highlight the role of LLPS in neurodegenerative diseases and cancers. We also explore RNA modifications on LLPS to alter diseases progression because these modifications can influence LLPS of certain proteins or the formation of stress granules, and discuss the possibility of proper manipulation of LLPS process to restore cellular homeostasis or develop therapeutic drugs for the eradication of diseases. This review attempts to discuss potential therapeutic opportunities by elaborating on the connection between LLPS, RNA modification, and their roles in diseases.
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Affiliation(s)
- Xinyue Zhang
- College of Life and Health Sciences Northeastern University Shenyang China
| | - Lin Yuan
- Laboratory of Research in Parkinson's Disease and Related Disorders Health Sciences Institute China Medical University Shenyang China
| | - Wanlu Zhang
- College of Life and Health Sciences Northeastern University Shenyang China
| | - Yi Zhang
- College of Life and Health Sciences Northeastern University Shenyang China
| | - Qun Wu
- Department of Pediatrics Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine Shanghai China
| | - Chunting Li
- College of Life and Health Sciences Northeastern University Shenyang China
| | - Min Wu
- Wenzhou Institute University of Chinese Academy of Sciences Wenzhou Zhejiang China
- The Joint Research Center Affiliated Xiangshan Hospital of Wenzhou Medical University Ningbo China
| | - Yongye Huang
- College of Life and Health Sciences Northeastern University Shenyang China
- Key Laboratory of Bioresource Research and Development of Liaoning Province College of Life and Health Sciences Northeastern University Shenyang China
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12
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Kitamura A, Fujimoto A, Kawashima R, Lyu Y, Sasaki K, Hamada Y, Moriya K, Kurata A, Takahashi K, Brielmann R, Bott LC, Morimoto RI, Kinjo M. Hetero-oligomerization of TDP-43 carboxy-terminal fragments with cellular proteins contributes to proteotoxicity. Commun Biol 2024; 7:743. [PMID: 38902525 PMCID: PMC11190292 DOI: 10.1038/s42003-024-06410-3] [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: 06/22/2022] [Accepted: 06/03/2024] [Indexed: 06/22/2024] Open
Abstract
Carboxy terminal fragments (CTFs) of TDP-43 contain an intrinsically disordered region (IDR) and form cytoplasmic condensates containing amyloid fibrils. Such condensates are toxic and associated with pathogenicity in amyotrophic lateral sclerosis. However, the molecular details of how the domain of TDP-43 CTFs leads to condensation and cytotoxicity remain elusive. Here, we show that truncated RNA/DNA-recognition motif (RRM) at the N-terminus of TDP-43 CTFs leads to the structural transition of the IDR, whereas the IDR itself of TDP-43 CTFs is difficult to assemble even if they are proximate intermolecularly. Hetero-oligomers of TDP-43 CTFs that have recruited other proteins are more toxic than homo-oligomers, implicating loss-of-function of the endogenous proteins by such oligomers is associated with cytotoxicity. Furthermore, such toxicity of TDP-43 CTFs was cell-nonautonomously affected in the nematodes. Therefore, misfolding and oligomeric characteristics of the truncated RRM at the N-terminus of TDP-43 CTFs define their condensation properties and toxicity.
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Affiliation(s)
- Akira Kitamura
- Laboratory of Cellular and Molecular Sciences, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan.
- PRIME, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo, 100-0004, Japan.
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan.
| | - Ai Fujimoto
- Laboratory of Cellular and Molecular Sciences, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Rei Kawashima
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Yidan Lyu
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Kotetsu Sasaki
- Laboratory of Cellular and Molecular Sciences, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Yuta Hamada
- Laboratory of Cellular and Molecular Sciences, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Kanami Moriya
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Ayumi Kurata
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Kazuho Takahashi
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
| | - Reneé Brielmann
- Department of Molecular Bioscience, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL, 60208, USA
| | - Laura C Bott
- Department of Molecular Bioscience, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL, 60208, USA
| | - Richard I Morimoto
- Department of Molecular Bioscience, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL, 60208, USA
| | - Masataka Kinjo
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo, 001-0021, Japan
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13
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Park S, Park SK, Liebman SW. Expression of Wild-Type and Mutant Human TDP-43 in Yeast Inhibits TOROID (TORC1 Organized in Inhibited Domain) Formation and Autophagy Proportionally to the Levels of TDP-43 Toxicity. Int J Mol Sci 2024; 25:6258. [PMID: 38892445 PMCID: PMC11172667 DOI: 10.3390/ijms25116258] [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: 04/05/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
TDP-43 forms aggregates in the neurons of patients with several neurodegenerative diseases. Human TDP-43 also aggregates and is toxic in yeast. Here, we used a yeast model to investigate (1) the nature of TDP-43 aggregates and (2) the mechanism of TDP-43 toxicity. Thioflavin T, which stains amyloid but not wild-type TDP-43 aggregates, also did not stain mutant TDP-43 aggregates made from TDP-43 with intragenic mutations that increase or decrease its toxicity. However, 1,6-hexanediol, which dissolves liquid droplets, dissolved wild-type or mutant TDP-43 aggregates. To investigate the mechanism of TDP-43 toxicity, the effects of TDP-43 mutations on the autophagy of the GFP-ATG8 reporter were examined. Mutations in TDP-43 that enhance its toxicity, but not mutations that reduce its toxicity, caused a larger reduction in autophagy. TOROID formation, which enhances autophagy, was scored as GFP-TOR1 aggregation. TDP-43 inhibited TOROID formation. TORC1 bound to both toxic and non-toxic TDP-43, and to TDP-43, with reduced toxicity due to pbp1Δ. However, extragenic modifiers and TDP-43 mutants that reduced TDP-43 toxicity, but not TDP-43 mutants that enhanced toxicity, restored TOROID formation. This is consistent with the hypothesis that TDP-43 is toxic in yeast because it reduces TOROID formation, causing the inhibition of autophagy. Whether TDP-43 exerts a similar effect in higher cells remains to be determined.
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Affiliation(s)
| | | | - Susan W. Liebman
- Department of Pharmacology, University of Nevada, Reno, NV 89557, USA
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14
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Shelkovnikova TA, Hautbergue GM. RNP granules in ALS and neurodegeneration: From multifunctional membraneless organelles to therapeutic opportunities. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 176:455-479. [PMID: 38802180 DOI: 10.1016/bs.irn.2024.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) and related neurodegenerative diseases are characterised by dysfunction of a host of RNA-binding proteins (RBPs) and a severely disrupted RNA metabolism. Recently, RBP-harbouring phase-separated complexes, ribonucleoprotein (RNP) granules, have come into the limelight as "crucibles" of neuronal pathology in ALS. RNP granules are indispensable for the multitude of regulatory processes underlying cellular RNA metabolism and serve as critical organisers of cellular biochemistry. Neurons, highly specialised cells, heavily rely on RNP granules for efficient trafficking, signalling and stress responses. Multiple RNP granule components, primarily RBPs such as TDP-43 and FUS, are affected by ALS mutations. However, even in the absence of mutations, RBP proteinopathies represent pathophysiological hallmarks of ALS. Given the high local concentrations of RBPs and RNAs, their weakened or enhanced interactions within RNP granules disrupt their homeostasis. Thus, the physiological process of phase separation and RNP granule formation, vital for maintaining the high-functioning state of neuronal cells, becomes their Achilles heel. Here, we will review the recent literature on the causes and consequences of abnormal RNP granule functioning in ALS and related disorders. In particular, we will summarise the evidence for the network-level dysfunction of RNP granules in these conditions and discuss considerations for therapeutic interventions to target RBPs, RNP granules and their network as a whole.
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Affiliation(s)
- Tatyana A Shelkovnikova
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom; Neuroscience Institute, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom.
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom; Neuroscience Institute, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom; Healthy Lifespan Institute (HELSI), University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom.
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15
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Zheng H, Sun H, Cai Q, Tai HC. The Enigma of Tau Protein Aggregation: Mechanistic Insights and Future Challenges. Int J Mol Sci 2024; 25:4969. [PMID: 38732197 PMCID: PMC11084794 DOI: 10.3390/ijms25094969] [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: 03/30/2024] [Revised: 04/20/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
Tau protein misfolding and aggregation are pathological hallmarks of Alzheimer's disease and over twenty neurodegenerative disorders. However, the molecular mechanisms of tau aggregation in vivo remain incompletely understood. There are two types of tau aggregates in the brain: soluble aggregates (oligomers and protofibrils) and insoluble filaments (fibrils). Compared to filamentous aggregates, soluble aggregates are more toxic and exhibit prion-like transmission, providing seeds for templated misfolding. Curiously, in its native state, tau is a highly soluble, heat-stable protein that does not form fibrils by itself, not even when hyperphosphorylated. In vitro studies have found that negatively charged molecules such as heparin, RNA, or arachidonic acid are generally required to induce tau aggregation. Two recent breakthroughs have provided new insights into tau aggregation mechanisms. First, as an intrinsically disordered protein, tau is found to undergo liquid-liquid phase separation (LLPS) both in vitro and inside cells. Second, cryo-electron microscopy has revealed diverse fibrillar tau conformations associated with different neurodegenerative disorders. Nonetheless, only the fibrillar core is structurally resolved, and the remainder of the protein appears as a "fuzzy coat". From this review, it appears that further studies are required (1) to clarify the role of LLPS in tau aggregation; (2) to unveil the structural features of soluble tau aggregates; (3) to understand the involvement of fuzzy coat regions in oligomer and fibril formation.
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Affiliation(s)
| | | | | | - Hwan-Ching Tai
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen 361102, China
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16
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Zacco E, Broglia L, Kurihara M, Monti M, Gustincich S, Pastore A, Plath K, Nagakawa S, Cerase A, Sanchez de Groot N, Tartaglia GG. RNA: The Unsuspected Conductor in the Orchestra of Macromolecular Crowding. Chem Rev 2024; 124:4734-4777. [PMID: 38579177 PMCID: PMC11046439 DOI: 10.1021/acs.chemrev.3c00575] [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: 08/14/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 04/07/2024]
Abstract
This comprehensive Review delves into the chemical principles governing RNA-mediated crowding events, commonly referred to as granules or biological condensates. We explore the pivotal role played by RNA sequence, structure, and chemical modifications in these processes, uncovering their correlation with crowding phenomena under physiological conditions. Additionally, we investigate instances where crowding deviates from its intended function, leading to pathological consequences. By deepening our understanding of the delicate balance that governs molecular crowding driven by RNA and its implications for cellular homeostasis, we aim to shed light on this intriguing area of research. Our exploration extends to the methodologies employed to decipher the composition and structural intricacies of RNA granules, offering a comprehensive overview of the techniques used to characterize them, including relevant computational approaches. Through two detailed examples highlighting the significance of noncoding RNAs, NEAT1 and XIST, in the formation of phase-separated assemblies and their influence on the cellular landscape, we emphasize their crucial role in cellular organization and function. By elucidating the chemical underpinnings of RNA-mediated molecular crowding, investigating the role of modifications, structures, and composition of RNA granules, and exploring both physiological and aberrant phase separation phenomena, this Review provides a multifaceted understanding of the intriguing world of RNA-mediated biological condensates.
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Affiliation(s)
- Elsa Zacco
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Laura Broglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Misuzu Kurihara
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Michele Monti
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Stefano Gustincich
- Central
RNA Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Annalisa Pastore
- UK
Dementia Research Institute at the Maurice Wohl Institute of King’s
College London, London SE5 9RT, U.K.
| | - Kathrin Plath
- Department
of Biological Chemistry, David Geffen School
of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
| | - Shinichi Nagakawa
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Andrea Cerase
- Blizard
Institute,
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, U.K.
- Unit
of Cell and developmental Biology, Department of Biology, Università di Pisa, 56123 Pisa, Italy
| | - Natalia Sanchez de Groot
- Unitat
de Bioquímica, Departament de Bioquímica i Biologia
Molecular, Universitat Autònoma de
Barcelona, 08193 Barcelona, Spain
| | - Gian Gaetano Tartaglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
- Catalan
Institution for Research and Advanced Studies, ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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17
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Jin SW, Seong Y, Yoon D, Kwon YS, Song H. Dissolution of ribonucleoprotein condensates by the embryonic stem cell protein L1TD1. Nucleic Acids Res 2024; 52:3310-3326. [PMID: 38165001 PMCID: PMC11014241 DOI: 10.1093/nar/gkad1244] [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: 04/24/2023] [Revised: 11/22/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024] Open
Abstract
L1TD1 is a cytoplasmic RNA-binding protein specifically expressed in pluripotent stem cells and, unlike its mouse ortholog, is essential for the maintenance of stemness in human cells. Although L1TD1 is the only known protein-coding gene domesticated from a LINE-1 (L1) retroelement, the functional legacy of its ancestral protein, ORF1p of L1, and how it is manifested in L1TD1 are still unknown. Here, we determined RNAs associated with L1TD1 and found that, like ORF1p, L1TD1 binds L1 RNAs and localizes to high-density ribonucleoprotein (RNP) condensates. Unexpectedly, L1TD1 enhanced the translation of a subset of mRNAs enriched in the condensates. L1TD1 depletion promoted the formation of stress granules in embryonic stem cells. In HeLa cells, ectopically expressed L1TD1 facilitated the dissolution of stress granules and granules formed by pathological mutations of TDP-43 and FUS. The glutamate-rich domain and the ORF1-homology domain of L1TD1 facilitated dispersal of the RNPs and induced autophagy, respectively. These results provide insights into how L1TD1 regulates gene expression in pluripotent stem cells. We propose that the ability of L1TD1 to dissolve stress granules may provide novel opportunities for treatment of neurodegenerative diseases caused by disturbed stress granule dynamics.
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Affiliation(s)
- Sang Woo Jin
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Youngmo Seong
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Dayoung Yoon
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Young-Soo Kwon
- Department of Integrative Bioscience & Biotechnology, Sejong University, Seoul 05006, Republic of Korea
| | - Hoseok Song
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
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18
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Haider R, Shipley B, Surewicz K, Hinczewski M, Surewicz WK. Pathological C-terminal phosphomimetic substitutions alter the mechanism of liquid-liquid phase separation of TDP-43 low complexity domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.21.586202. [PMID: 38585945 PMCID: PMC10996529 DOI: 10.1101/2024.03.21.586202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
C-terminally phosphorylated TAR DNA-binding protein of 43 kDa (TDP-43) marks the proteinaceous inclusions that characterize a number of age-related neurodegenerative diseases, including amyotrophic lateral sclerosis, frontotemporal lobar degeneration and Alzheimer's disease. TDP-43 phosphorylation at S403/S404, and especially at S409/S410, is in fact accepted as a biomarker of proteinopathy. These residues are located within the low complexity domain (LCD), which also drives the protein's liquid-liquid phase separation (LLPS). The impact of phosphorylation at these LCD sites on phase separation of the protein is a topic of great interest, as these post-translational modifications and LLPS are both implicated in proteinopathies. Here, we employed a combination of experimental and simulation-based approaches to explore this question on a phosphomimetic model of the TDP-43 LCD. Our turbidity and fluorescence microscopy data show that Ser-to-Asp substitutions at residues S403, S404, S409 and S410 alter the LLPS behavior of TDP-43 LCD. In particular, in contrast to the unmodified protein, the phosphomimetic variants display a biphasic dependence on salt concentration. Through coarse-grained modeling, we find that this biphasic salt dependence is derived from an altered mechanism of phase separation, in which LLPS-driving short-range intermolecular hydrophobic interactions are modulated by long-range attractive electrostatic interactions. Overall, this in vitro and in silico study provides a physiochemical foundation for understanding the impact of pathologically-relevant C-terminal phosphorylation on the LLPS of the TDP-43 in a more complex cellular environment.
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Affiliation(s)
- Raza Haider
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, United States
| | - Brandon Shipley
- Department of Physics, Case Western Reserve University, Cleveland, United States
| | - Krystyna Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, United States
| | - Michael Hinczewski
- Department of Physics, Case Western Reserve University, Cleveland, United States
| | - Witold K Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, United States
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19
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Giraud G, Rodà M, Huchon P, Michelet M, Maadadi S, Jutzi D, Montserret R, Ruepp MD, Parent R, Combet C, Zoulim F, Testoni B. G-quadruplexes control hepatitis B virus replication by promoting cccDNA transcription and phase separation in hepatocytes. Nucleic Acids Res 2024; 52:2290-2305. [PMID: 38113270 PMCID: PMC10954475 DOI: 10.1093/nar/gkad1200] [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: 04/05/2023] [Revised: 11/12/2023] [Accepted: 12/05/2023] [Indexed: 12/21/2023] Open
Abstract
Phase separation regulates fundamental processes in gene expression and is mediated by the local concentration of proteins and nucleic acids, as well as nucleic acid secondary structures such as G-quadruplexes (G4s). These structures play fundamental roles in both host gene expression and in viral replication due to their peculiar localisation in regulatory sequences. Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is an episomal minichromosome whose persistence is at the basis of chronic infection. Identifying the mechanisms controlling its transcriptional activity is indispensable to develop new therapeutic strategies against chronic hepatitis B. The aim of this study was to determine whether G4s are formed in cccDNA and regulate viral replication. Combining biochemistry and functional studies, we demonstrate that cccDNA indeed contains ten G4s structures. Furthermore, mutations disrupting two G4s located in the enhancer I HBV regulatory region altered cccDNA transcription and viral replication. Finally, we showed for the first time that cccDNA undergoes phase separation in a G4-dependent manner to promote its transcription in infected hepatocytes. Altogether, our data give new insight in the transcriptional regulation of the HBV minichromosome that might pave the way for the identification of novel targets to destabilize or silence cccDNA.
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Affiliation(s)
- Guillaume Giraud
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
| | - Mélanie Rodà
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
| | - Pélagie Huchon
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
- Université Claude-Bernard Lyon I, 69003 Lyon, France
| | - Maud Michelet
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
| | - Sarah Maadadi
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 lyon, france; université claude-bernard lyon i, 69003 Lyon, France
| | - Daniel Jutzi
- United Kingdom Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, WC2R 2LS London, UK
| | - Roland Montserret
- Molecular Microbiology and Structural Biochemistry (MMSB) UMR 5086 CNRS/Université de Lyon, Labex Ecofect, 7 Passage du Vercors 69367Lyon, France
| | - Marc-David Ruepp
- United Kingdom Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, WC2R 2LS London, UK
| | - Romain Parent
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
| | - Christophe Combet
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
| | - Fabien Zoulim
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
- Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Service, Hospices Civils de Lyon, 69004 Lyon, France
| | - Barbara Testoni
- INSERM U1052, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)-5286, Cancer Research Center of Lyon, 69003 Lyon, France; Université Claude-Bernard Lyon I, 69003 Lyon, France
- Hepatology Institute of Lyon, 69004 Lyon, France
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20
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Fakim H, Vande Velde C. The implications of physiological biomolecular condensates in amyotrophic lateral sclerosis. Semin Cell Dev Biol 2024; 156:176-189. [PMID: 37268555 DOI: 10.1016/j.semcdb.2023.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/13/2023] [Accepted: 05/16/2023] [Indexed: 06/04/2023]
Abstract
In recent years, there has been an emphasis on the role of phase-separated biomolecular condensates, especially stress granules, in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). This is largely due to several ALS-associated mutations occurring in genes involved in stress granule assembly and observations that pathological inclusions detected in ALS patient neurons contain stress granule proteins, including the ALS-linked proteins TDP-43 and FUS. However, protein components of stress granules are also found in numerous other phase-separated biomolecular condensates under physiological conditions which are inadequately discussed in the context of ALS. In this review, we look beyond stress granules and describe the roles of TDP-43 and FUS in physiological condensates occurring in the nucleus and neurites, such as the nucleolus, Cajal bodies, paraspeckles and neuronal RNA transport granules. We also discuss the consequences of ALS-linked mutations in TDP-43 and FUS on their ability to phase separate into these stress-independent biomolecular condensates and perform their respective functions. Importantly, biomolecular condensates sequester multiple overlapping protein and RNA components, and their dysregulation could contribute to the observed pleiotropic effects of both sporadic and familial ALS on RNA metabolism.
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Affiliation(s)
- Hana Fakim
- Department of Neurosciences, Université de Montréal, and CHUM Research Center, Montréal, QC, Canada
| | - Christine Vande Velde
- Department of Neurosciences, Université de Montréal, and CHUM Research Center, Montréal, QC, Canada.
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21
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Jagaraj CJ, Shadfar S, Kashani SA, Saravanabavan S, Farzana F, Atkin JD. Molecular hallmarks of ageing in amyotrophic lateral sclerosis. Cell Mol Life Sci 2024; 81:111. [PMID: 38430277 PMCID: PMC10908642 DOI: 10.1007/s00018-024-05164-9] [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: 12/05/2023] [Revised: 01/21/2024] [Accepted: 02/06/2024] [Indexed: 03/03/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, severely debilitating and rapidly progressing disorder affecting motor neurons in the brain, brainstem, and spinal cord. Unfortunately, there are few effective treatments, thus there remains a critical need to find novel interventions that can mitigate against its effects. Whilst the aetiology of ALS remains unclear, ageing is the major risk factor. Ageing is a slowly progressive process marked by functional decline of an organism over its lifespan. However, it remains unclear how ageing promotes the risk of ALS. At the molecular and cellular level there are specific hallmarks characteristic of normal ageing. These hallmarks are highly inter-related and overlap significantly with each other. Moreover, whilst ageing is a normal process, there are striking similarities at the molecular level between these factors and neurodegeneration in ALS. Nine ageing hallmarks were originally proposed: genomic instability, loss of telomeres, senescence, epigenetic modifications, dysregulated nutrient sensing, loss of proteostasis, mitochondrial dysfunction, stem cell exhaustion, and altered inter-cellular communication. However, these were recently (2023) expanded to include dysregulation of autophagy, inflammation and dysbiosis. Hence, given the latest updates to these hallmarks, and their close association to disease processes in ALS, a new examination of their relationship to pathophysiology is warranted. In this review, we describe possible mechanisms by which normal ageing impacts on neurodegenerative mechanisms implicated in ALS, and new therapeutic interventions that may arise from this.
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Affiliation(s)
- Cyril Jones Jagaraj
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sina Shadfar
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sara Assar Kashani
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sayanthooran Saravanabavan
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Fabiha Farzana
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Julie D Atkin
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia.
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC, 3086, Australia.
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22
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Man J, Zhang Q, Zhao T, Sun D, Sun W, Long K, Zhang Z. Oxidative Stress Induced by Arsenite is Involved in YTHDF2 Phase Separation. Biol Trace Elem Res 2024; 202:885-899. [PMID: 37310554 DOI: 10.1007/s12011-023-03728-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/05/2023] [Indexed: 06/14/2023]
Abstract
YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) undergoes phase separation in response to the stimulation of high concentration of arsenite, suggesting that oxidative stress, the major mechanism of arsenite toxicity, may play a role in YTHDF2 phase separation. However, whether arsenite-induced oxidative stress is involved in phase separation of YTHDF2 has yet to be established. To explore the effect of arsenite-induced oxidative stress on YTHDF2 phase separation, the levels of oxidative stress, YTHDF2 phase separation, and N6-methyladenosine (m6A) in human keratinocytes were detected after exposure to various concentrations of sodium arsenite (0-500 µM; 1 h) and antioxidant N-acetylcysteine (0-10 mM; 2 h). We found that arsenite promoted oxidative stress and YTHDF2 phase separation in a concentration-dependent manner. In contrast, pretreatment with N-acetylcysteine significantly relieved arsenate-induced oxidative stress and inhibited YTHDF2 phase separation. As one of the key factors to YTHDF2 phase separation, N6-methyladenosine (m6A) levels in human keratinocytes were significantly increased after arsenite exposure, accompanied by upregulation of m6A methylesterase levels and downregulation of m6A demethylases levels. On the contrary, N-acetylcysteine mitigated the arsenite-induced increase of m6A and m6A methylesterase and the arsenite-induced decrease in m6A demethylase. Collectively, our study firstly revealed that oxidative stress induced by arsenite plays an important role in YTHDF2 phase separation driven by m6A modification, which provides new insights into the arsenite toxicity from the phase-separation perspective.
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Affiliation(s)
- Jin Man
- Department of Environmental and Occupational Health, West China School of Public Health, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Qian Zhang
- Department of Environmental and Occupational Health, West China School of Public Health, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Tianhe Zhao
- Department of Environmental and Occupational Health, West China School of Public Health, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Donglei Sun
- Department of Environmental and Occupational Health, West China School of Public Health, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Weilian Sun
- Department of Environmental and Occupational Health, West China School of Public Health, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Keyan Long
- Department of Environmental and Occupational Health, West China School of Public Health, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Zunzhen Zhang
- Department of Environmental and Occupational Health, West China School of Public Health, Sichuan University, Chengdu, 610041, Sichuan, China.
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23
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Huang Y, Chen J, Hsiung CH, Bai Y, Tan Z, Ye S, Zhang X. Detecting protein-protein interaction during liquid-liquid phase separation using fluorogenic protein sensors. Mol Biol Cell 2024; 35:ar41. [PMID: 38231854 PMCID: PMC10916855 DOI: 10.1091/mbc.e23-11-0442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/04/2024] [Accepted: 01/09/2024] [Indexed: 01/19/2024] Open
Abstract
The formation of cellular condensates, akin to membraneless organelles, is typically mediated by liquid-liquid phase separation (LLPS), during which proteins and RNA molecules interact with each other via multivalent interactions. Gaining a comprehensive understanding of these interactions holds significance in unraveling the mechanisms underlying condensate formation and the pathology of related diseases. In an attempt toward this end, fluorescence microscopy is often used to examine the colocalization of target proteins/RNAs. However, fluorescence colocalization is inadequate to reliably identify protein interaction due to the diffraction limit of traditional fluorescence microscopy. In this study, we achieve this goal through adopting a novel chemical biology approach via the dimerization-dependent fluorescent proteins (ddFPs). We succeeded in utilizing ddFPs to detect protein interaction during LLPS both in vitro and in living cells. The ddFPs allow us to investigate the interaction between two important LLPS-associated proteins, FUS and TDP-43, as cellular condensates formed. Importantly, we revealed that their interaction was associated with RNA binding upon LLPS, indicating that RNA plays a critical role in mediating interactions between RBPs. More broadly, we envision that utilization of ddFPs would reveal previously unknown protein-protein interaction and uncover their functional roles in the formation and disassembly of biomolecular condensates.
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Affiliation(s)
- Yanan Huang
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Junlin Chen
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Chia-Heng Hsiung
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Yulong Bai
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Zizhu Tan
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Songtao Ye
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Xin Zhang
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang Province, China
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24
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Li S, Zhang Y, Chen J. Backbone interactions and secondary structures in phase separation of disordered proteins. Biochem Soc Trans 2024; 52:319-329. [PMID: 38348795 DOI: 10.1042/bst20230618] [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: 11/29/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/29/2024]
Abstract
Intrinsically disordered proteins (IDPs) are one of the major drivers behind the formation and characteristics of biomolecular condensates. Due to their inherent flexibility, the backbones of IDPs are significantly exposed, rendering them highly influential and susceptible to biomolecular phase separation. In densely packed condensates, exposed backbones have a heightened capacity to interact with neighboring protein chains, which might lead to strong coupling between the secondary structures and phase separation and further modulate the subsequent transitions of the condensates, such as aging and fibrillization. In this mini-review, we provide an overview of backbone-mediated interactions and secondary structures within biomolecular condensates to underscore the importance of protein backbones in phase separation. We further focus on recent advances in experimental techniques and molecular dynamics simulation methods for probing and exploring the roles of backbone interactions and secondary structures in biomolecular phase separation involving IDPs.
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Affiliation(s)
- Shanlong Li
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A
| | - Yumeng Zhang
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A
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25
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Haider R, Penumutchu S, Boyko S, Surewicz WK. Phosphomimetic substitutions in TDP-43's transiently α-helical region suppress phase separation. Biophys J 2024; 123:361-373. [PMID: 38178578 PMCID: PMC10870169 DOI: 10.1016/j.bpj.2024.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 11/10/2023] [Accepted: 01/02/2024] [Indexed: 01/06/2024] Open
Abstract
Phosphorylated TAR DNA-binding protein of 43 kDa (TDP-43) is present within the aggregates of several age-related neurodegenerative disorders, such as amyotrophic lateral sclerosis, frontotemporal lobar degeneration, and Alzheimer's disease, to the point that the presence of phosphorylated TDP-43 is considered a hallmark of some of these diseases. The majority of known TDP-43 phosphorylation sites detected in amyotrophic lateral sclerosis and frontotemporal lobar degeneration patients is located in the low-complexity domain (LCD), the same domain that has been shown to be critical for TDP-43 liquid-liquid phase separation (LLPS). However, the effect of these LCD phosphorylation sites on TDP-43 LLPS has been largely unexplored, and any work that has been done has mainly focused on sites near the C-terminal end of the LCD. Here, we used a phosphomimetic approach to explore the impact of phosphorylation at residues S332 and S333, sites located within the transiently α-helical region of TDP-43 that have been observed to be phosphorylated in disease, on protein LLPS. Our turbidimetry and fluorescence microscopy data demonstrate that these phosphomimetic substitutions greatly suppress LLPS, and solution NMR data strongly suggest that this effect is at least in part due to the loss of α-helical propensity of the phosphomimetic protein variant. We also show that the S332D and S333D substitutions slow TDP-43 LCD droplet aging and fibrillation of the protein. Overall, these findings provide a biophysical basis for understanding the effect of phosphorylation within the transiently α-helical region of TDP-43 LCD on protein LLPS and fibrillation, suggesting that phosphorylation at residues 332 and 333 is not necessarily directly related to the pathogenic process.
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Affiliation(s)
- Raza Haider
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
| | - Srinivasa Penumutchu
- Northeast Ohio High Field NMR Facility, Case Western Reserve University, Cleveland, Ohio
| | - Solomiia Boyko
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
| | - Witold K Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio.
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26
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Gregorich ZR, Yanghai Z, Kamp TJ, Granzier H, Guo W. Mechanisms of RBM20 Cardiomyopathy: Insights From Model Systems. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2024; 17:e004355. [PMID: 38288598 PMCID: PMC10923161 DOI: 10.1161/circgen.123.004355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
RBM20 (RNA-binding motif protein 20) is a vertebrate- and muscle-specific RNA-binding protein that belongs to the serine-arginine-rich family of splicing factors. The RBM20 gene was first identified as a dilated cardiomyopathy-linked gene over a decade ago. Early studies in Rbm20 knockout rodents implicated disrupted splicing of RBM20 target genes as a causative mechanism. Clinical studies show that pathogenic variants in RBM20 are linked to aggressive dilated cardiomyopathy with early onset heart failure and high mortality. Subsequent studies employing pathogenic variant knock-in animal models revealed that variants in a specific portion of the arginine-serine-rich domain in RBM20 not only disrupt splicing but also hinder nucleocytoplasmic transport and lead to the formation of RBM20 biomolecular condensates in the sarcoplasm. Conversely, mice harboring a disease-associated variant in the RRM (RNA recognition motif) do not show evidence of adverse remodeling or exhibit sudden death despite disrupted splicing of RBM20 target genes. Thus, whether disrupted splicing, biomolecular condensates, or both contribute to dilated cardiomyopathy is under debate. Beyond this, additional questions remain, such as whether there is sexual dimorphism in the presentation of RBM20 cardiomyopathy. What are the clinical features of RBM20 cardiomyopathy and why do some individuals develop more severe disease than others? In this review, we summarize the reported observations and discuss potential mechanisms of RBM20 cardiomyopathy derived from studies employing in vivo animal models and in vitro human-induced pluripotent stem cell-derived cardiomyocytes. Potential therapeutic strategies to treat RBM20 cardiomyopathy are also discussed.
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Affiliation(s)
- Zachery R. Gregorich
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
| | - Zhang Yanghai
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
| | - Timothy J. Kamp
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
- Cardiovascular Research Center, University of Wisconsin-Madison, Madison, WI
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Wei Guo
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
- Cardiovascular Research Center, University of Wisconsin-Madison, Madison, WI
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27
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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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28
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Zhang Y, Li S, Gong X, Chen J. Toward Accurate Simulation of Coupling between Protein Secondary Structure and Phase Separation. J Am Chem Soc 2024; 146:342-357. [PMID: 38112495 PMCID: PMC10842759 DOI: 10.1021/jacs.3c09195] [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: 12/21/2023]
Abstract
Intrinsically disordered proteins (IDPs) frequently mediate phase separation that underlies the formation of a biomolecular condensate. Together with theory and experiment, efficient coarse-grained (CG) simulations have been instrumental in understanding the sequence-specific phase separation of IDPs. However, the widely used Cα-only models are limited in capturing the peptide nature of IDPs, particularly backbone-mediated interactions and effects of secondary structures, in phase separation. Here, we describe a hybrid resolution (HyRes) protein model toward a more accurate description of the backbone and transient secondary structures in phase separation. With an atomistic backbone and coarse-grained side chains, HyRes can semiquantitatively capture the residue helical propensity and overall chain dimension of monomeric IDPs. Using GY-23 as a model system, we show that HyRes is efficient enough for the direct simulation of spontaneous phase separation and, at the same time, appears accurate enough to resolve the effects of single His to Lys mutations. HyRes simulations also successfully predict increased β-structure formation in the condensate, consistent with available experimental CD data. We further utilize HyRes to study the phase separation of TPD-43, where several disease-related mutants in the conserved region (CR) have been shown to affect residual helicities and modulate the phase separation propensity as measured by the saturation concentration. The simulations successfully recapitulate the effect of these mutants on the helicity and phase separation propensity of TDP-43 CR. Analyses reveal that the balance between backbone and side chain-mediated interactions, but not helicity itself, actually determines phase separation propensity. These results support that HyRes represents an effective protein model for molecular simulation of IDP phase separation and will help to elucidate the coupling between transient secondary structures and phase separation.
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Affiliation(s)
| | | | - Xiping Gong
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
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29
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Raguseo F, Wang Y, Li J, Petrić Howe M, Balendra R, Huyghebaert A, Vadukul DM, Tanase DA, Maher TE, Malouf L, Rubio-Sánchez R, Aprile FA, Elani Y, Patani R, Di Michele L, Di Antonio M. The ALS/FTD-related C9orf72 hexanucleotide repeat expansion forms RNA condensates through multimolecular G-quadruplexes. Nat Commun 2023; 14:8272. [PMID: 38092738 PMCID: PMC10719400 DOI: 10.1038/s41467-023-43872-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 11/21/2023] [Indexed: 12/17/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that exist on a clinico-pathogenetic spectrum, designated ALS/FTD. The most common genetic cause of ALS/FTD is expansion of the intronic hexanucleotide repeat (GGGGCC)n in C9orf72. Here, we investigate the formation of nucleic acid secondary structures in these expansion repeats, and their role in generating condensates characteristic of ALS/FTD. We observe significant aggregation of the hexanucleotide sequence (GGGGCC)n, which we associate to the formation of multimolecular G-quadruplexes (mG4s) by using a range of biophysical techniques. Exposing the condensates to G4-unfolding conditions leads to prompt disassembly, highlighting the key role of mG4-formation in the condensation process. We further validate the biological relevance of our findings by detecting an increased prevalence of G4-structures in C9orf72 mutant human motor neurons when compared to healthy motor neurons by staining with a G4-selective fluorescent probe, revealing signal in putative condensates. Our findings strongly suggest that RNA G-rich repetitive sequences can form protein-free condensates sustained by multimolecular G-quadruplexes, highlighting their potential relevance as therapeutic targets for C9orf72 mutation-related ALS/FTD.
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Affiliation(s)
- Federica Raguseo
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
- University of Cambridge, Department of Chemical Engineering and Biotechnology, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
- Imperial College London, Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
| | - Yiran Wang
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Jessica Li
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Marija Petrić Howe
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Rubika Balendra
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Anouk Huyghebaert
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
- Imperial College London, Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
| | - Devkee M Vadukul
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
| | - Diana A Tanase
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
- University of Cambridge, Department of Chemical Engineering and Biotechnology, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Thomas E Maher
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
- Imperial College London, Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
| | - Layla Malouf
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
- University of Cambridge, Department of Chemical Engineering and Biotechnology, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Roger Rubio-Sánchez
- University of Cambridge, Department of Chemical Engineering and Biotechnology, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Francesco A Aprile
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
- Imperial College London, Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK
| | - Yuval Elani
- Imperial College London, Department of Chemical Engineering, South Kensington, London, SW7 2AZ, UK
| | - Rickie Patani
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK.
| | - Lorenzo Di Michele
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK.
- University of Cambridge, Department of Chemical Engineering and Biotechnology, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK.
| | - Marco Di Antonio
- Imperial College London, Department of Chemistry, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK.
- Imperial College London, Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London, W12 0BZ, UK.
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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Wang S, Chen J, Li P, Chen Y. LINC01133 can induce acquired ferroptosis resistance by enhancing the FSP1 mRNA stability through forming the LINC01133-FUS-FSP1 complex. Cell Death Dis 2023; 14:767. [PMID: 38007473 PMCID: PMC10676390 DOI: 10.1038/s41419-023-06311-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 11/08/2023] [Accepted: 11/15/2023] [Indexed: 11/27/2023]
Abstract
Due to a lack of research on the critical non-coding RNAs in regulating ferroptosis, our study aimed to uncover the crucial ones involved in the process. We found that LINC01133 could make pancreatic cancer cells more resistant to ferroptosis. A higher expression of LINC01133 was associated with a higher IC50 of sorafenib in clinical samples. Furthermore, we discovered that LINC01133 induced this process through enhancing the mRNA stability of FSP1. CEBPB was the transcription factor to increase the expression of LINC01133. A higher CEBPB could also indicate a higher IC50 of sorafenib in patients with cancer. Moreover, we confirmed that LINC01133 could form a triple complex with FUS and FSP1 to increase the mRNA stability of FSP1.
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Affiliation(s)
- Shaowen Wang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
- Neuromedicine Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, Guangdong, 518053, China
| | - Jionghuang Chen
- Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310000, China
| | - Pengping Li
- Department of Thyroid & Breast Surgery, The First People's Hospital of Xiaoshan District, Xiaoshan Affiliated Hospital of Wenzhou Medical University, Hangzhou, Zhejiang, China
| | - Yangchao Chen
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518087, China.
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31
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Song J. Molecular mechanisms of phase separation and amyloidosis of ALS/FTD-linked FUS and TDP-43. Aging Dis 2023:AD.2023.1118. [PMID: 38029395 DOI: 10.14336/ad.2023.1118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/18/2023] [Indexed: 12/01/2023] Open
Abstract
FUS and TDP-43, two RNA-binding proteins from the heterogeneous nuclear ribonucleoprotein family, have gained significant attention in the field of neurodegenerative diseases due to their association with amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). They possess folded domains for binding ATP and various nucleic acids including DNA and RNA, as well as substantial intrinsically disordered regions (IDRs) including prion-like domains (PLDs) and RG-/RGG-rich regions. They play vital roles in various cellular processes, including transcription, splicing, microRNA maturation, RNA stability and transport and DNA repair. In particular, they are key components for forming ribonucleoprotein granules and stress granules (SGs) through homotypic or heterotypic liquid-liquid phase separation (LLPS). Strikingly, liquid-like droplets formed by FUS and TDP-43 may undergo aging to transform into less dynamic assemblies such as hydrogels, inclusions, and amyloid fibrils, which are the pathological hallmarks of ALS and FTD. This review aims to synthesize and consolidate the biophysical knowledge of the sequences, structures, stability, dynamics, and inter-domain interactions of FUS and TDP-43 domains, so as to shed light on the molecular mechanisms underlying their liquid-liquid phase separation (LLPS) and amyloidosis. The review further delves into the mechanisms through which ALS-causing mutants of the well-folded hPFN1 disrupt the dynamics of LLPS of FUS prion-like domain, providing key insights into a potential mechanism for misfolding/aggregation-prone proteins to cause neurodegenerative diseases and aging by gain of functions. With better understanding of different biophysical aspects of FUS and TDP-43, the ultimate goal is to develop drugs targeting LLPS and amyloidosis, which could mediate protein homeostasis within cells and lead to new treatments for currently intractable diseases, particularly neurodegenerative diseases such as ALS, FTD and aging. However, the study of membrane-less organelles and condensates is still in its infancy and therefore the review also highlights key questions that require future investigation.
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Pelaez MC, Desmeules A, Gelon PA, Glasson B, Marcadet L, Rodgers A, Phaneuf D, Pozzi S, Dutchak PA, Julien JP, Sephton CF. Neuronal dysfunction caused by FUSR521G promotes ALS-associated phenotypes that are attenuated by NF-κB inhibition. Acta Neuropathol Commun 2023; 11:182. [PMID: 37974279 PMCID: PMC10652582 DOI: 10.1186/s40478-023-01671-1] [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: 08/04/2023] [Accepted: 10/09/2023] [Indexed: 11/19/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are related neurodegenerative diseases that belong to a common disease spectrum based on overlapping clinical, pathological and genetic evidence. Early pathological changes to the morphology and synapses of affected neuron populations in ALS/FTD suggest a common underlying mechanism of disease that requires further investigation. Fused in sarcoma (FUS) is a DNA/RNA-binding protein with known genetic and pathological links to ALS/FTD. Expression of ALS-linked FUS mutants in mice causes cognitive and motor defects, which correlate with loss of motor neuron dendritic branching and synapses, in addition to other pathological features of ALS/FTD. The role of ALS-linked FUS mutants in causing ALS/FTD-associated disease phenotypes is well established, but there are significant gaps in our understanding of the cell-autonomous role of FUS in promoting structural changes to motor neurons, and how these changes relate to disease progression. Here we generated a neuron-specific FUS-transgenic mouse model expressing the ALS-linked human FUSR521G variant, hFUSR521G/Syn1, to investigate the cell-autonomous role of FUSR521G in causing loss of dendritic branching and synapses of motor neurons, and to understand how these changes relate to ALS-associated phenotypes. Longitudinal analysis of mice revealed that cognitive impairments in juvenile hFUSR521G/Syn1 mice coincide with reduced dendritic branching of cortical motor neurons in the absence of motor impairments or changes in the neuromorphology of spinal motor neurons. Motor impairments and dendritic attrition of spinal motor neurons developed later in aged hFUSR521G/Syn1 mice, along with FUS cytoplasmic mislocalisation, mitochondrial abnormalities and glial activation. Neuroinflammation promotes neuronal dysfunction and drives disease progression in ALS/FTD. The therapeutic effects of inhibiting the pro-inflammatory nuclear factor kappa B (NF-κB) pathway with an analog of Withaferin A, IMS-088, were assessed in symptomatic hFUSR521G/Syn1 mice and were found to improve cognitive and motor function, increase dendritic branches and synapses of motor neurons, and attenuate other ALS/FTD-associated pathological features. Treatment of primary cortical neurons expressing FUSR521G with IMS-088 promoted the restoration of dendritic mitochondrial numbers and mitochondrial activity to wild-type levels, suggesting that inhibition of NF-κB permits the restoration of mitochondrial stasis in our models. Collectively, this work demonstrates that FUSR521G has a cell-autonomous role in causing early pathological changes to dendritic and synaptic structures of motor neurons, and that these changes precede motor defects and other well-known pathological features of ALS/FTD. Finally, these findings provide further support that modulation of the NF-κB pathway in ALS/FTD is an important therapeutic approach to attenuate disease.
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Affiliation(s)
- Mari Carmen Pelaez
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Antoine Desmeules
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Pauline A Gelon
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Bastien Glasson
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Laetitia Marcadet
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Alicia Rodgers
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Daniel Phaneuf
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Silvia Pozzi
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Paul A Dutchak
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Jean-Pierre Julien
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Chantelle F Sephton
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada.
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Wang YL, Zhao WW, Shi J, Wan XB, Zheng J, Fan XJ. Liquid-liquid phase separation in DNA double-strand breaks repair. Cell Death Dis 2023; 14:746. [PMID: 37968256 PMCID: PMC10651886 DOI: 10.1038/s41419-023-06267-0] [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: 12/26/2022] [Revised: 10/23/2023] [Accepted: 11/01/2023] [Indexed: 11/17/2023]
Abstract
DNA double-strand breaks (DSBs) are the fatal type of DNA damage mostly induced by exposure genome to ionizing radiation or genotoxic chemicals. DSBs are mainly repaired by homologous recombination (HR) and nonhomologous end joining (NHEJ). To repair DSBs, a large amount of DNA repair factors was observed to be concentrated at the end of DSBs in a specific spatiotemporal manner to form a repair center. Recently, this repair center was characterized as a condensate derived from liquid-liquid phase separation (LLPS) of key DSBs repair factors. LLPS has been found to be the mechanism of membraneless organelles formation and plays key roles in a variety of biological processes. In this review, the recent advances and mechanisms of LLPS in the formation of DSBs repair-related condensates are summarized.
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Affiliation(s)
- Yun-Long Wang
- Henan Provincial Key Laboratory of Radiation Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, PR China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, 450052, PR China
- Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, PR China
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
| | - Wan-Wen Zhao
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
- GuangDong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
| | - Jie Shi
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
- GuangDong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
| | - Xiang-Bo Wan
- Henan Provincial Key Laboratory of Radiation Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, PR China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, 450052, PR China
- Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, PR China
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
| | - Jian Zheng
- Department of Radiation Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
- GuangDong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China
| | - Xin-Juan Fan
- Henan Provincial Key Laboratory of Radiation Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, PR China.
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, 450052, PR China.
- GuangDong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China.
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, PR China.
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Geng Q, Keya JJ, Hotta T, Verhey KJ. KIF1C, an RNA transporting kinesin-3, undergoes liquid-liquid phase separation through its C-terminal disordered domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563538. [PMID: 37961614 PMCID: PMC10634753 DOI: 10.1101/2023.10.23.563538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The spatial distribution of mRNA is critical for local control of protein production. Recent studies have identified the kinesin-3 family member KIF1C as an RNA transporter. However, it is not clear how KIF1C interacts with RNA molecules. Here, we show that KIF1C's C-terminal tail domain is an intrinsically disordered region (IDR) containing a prion-like domain (PLD) that is unique compared to the C-terminal tails of other kinesin family members. In cells, KIF1C constructs undergo reversible formation of dynamic puncta that display physical properties of liquid condensates and incorporate RNA molecules in a sequence-selective manner. The IDR is necessary and sufficient for driving liquid-liquid phase separation (LLPS) but the condensate properties can be modulated by adjacent coiled-coil segments. The purified KIF1C IDR domain undergoes LLPS in vitro at near-endogenous nM concentrations in a salt-dependent manner. Deletion of the IDR abolished the ability of KIF1C to undergo LLPS and disrupted the distribution of mRNA cargoes to the cell periphery. Our work thus uncovers an intrinsic correlation between the LLPS activity of KIF1C and its role as an RNA transporter. In addition, as the first kinesin motor reported to undergo LLPS, our work reveals a previously uncharacterized mode of motor-cargo interaction that extends our understanding of the behavior of cytoskeletal motor proteins.
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Affiliation(s)
- Qi Geng
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jakia Jannat Keya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Takashi Hotta
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
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35
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Sudhakar S, Manohar A, Mani E. Liquid-Liquid Phase Separation (LLPS)-Driven Fibrilization of Amyloid-β Protein. ACS Chem Neurosci 2023; 14:3655-3664. [PMID: 37718544 DOI: 10.1021/acschemneuro.3c00286] [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] [Indexed: 09/19/2023] Open
Abstract
Amyloid-β [Aβ(1-40)] aggregation into a fibrillar network is one of the major hallmarks of Alzheimer's disease (AD). Recently, a few studies reported that polyphosphate (polyP), an anionic biopolymer that participates in various cellular physiological processes in humans, induces fibrilization in many amyloidogenic proteins [ 2020 Alzheimer's Disease Facts and Figures; John Wiley and Sons Inc., 2020; Tanzi, R. E.; Bertram, L. Cell 2005, 120, 545-555; Selkoe, D. J. Proc. Natl. Acad. Sci. U.S.A. 1995, 275, 630-631; and Rambaran, R. N.; Serpell, L. C. Prion 2008, 2, 112-117]. However, the role of polyP in Aβ(1-40) fibrilization and the underlying mechanism are unclear. In this study, we report experimental investigations on the role of polyP in the fibrilization kinetics of Aβ(1-40). It is found that polyP exhibits a dual effect depending upon the pH value. At pH = 7 (neutral), polyP inhibits amyloid fibrilization in a dose-dependent manner similar to negatively charged nanoparticles. On the contrary, at pH = 3 (acidic), polyP accelerates amyloid fibrilization kinetics via liquid-liquid phase separation (LLPS), wherein the protein-rich droplets contain mature fibrils. In the parameter space spanned by concentrations of Aβ(1-40) and polyP, a phase diagram is constructed to demark the domain where LLPS is observed at pH = 3. Characterization of the protein aggregates, secondary structure content in the aggregates, and cell viability studies in the presence of aggregates are discussed at both pH values. This study reveals that anionic biopolymers can modulate amyloid fibrilization kinetics, linked to neurodegenerative diseases, depending upon their local concentrations and pH.
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Affiliation(s)
- Swathi Sudhakar
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India
- Center for Soft and Biological Matter, Indian Institute of Technology Madras, Chennai 600036, India
| | - Anagha Manohar
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ethayaraja Mani
- Polymer Engineering and Colloid Science Lab, Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
- Center for Soft and Biological Matter, Indian Institute of Technology Madras, Chennai 600036, India
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36
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Gastelum S, Michael AF, Bolger TA. Saccharomyces cerevisiae as a research tool for RNA-mediated human disease. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 15:e1814. [PMID: 37671427 DOI: 10.1002/wrna.1814] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 09/07/2023]
Abstract
The budding yeast, Saccharomyces cerevisiae, has been used for decades as a powerful genetic tool to study a broad spectrum of biological topics. With its ease of use, economic utility, well-studied genome, and a highly conserved proteome across eukaryotes, it has become one of the most used model organisms. Due to these advantages, it has been used to study an array of complex human diseases. From broad, complex pathological conditions such as aging and neurodegenerative disease to newer uses such as SARS-CoV-2, yeast continues to offer new insights into how cellular processes are affected by disease and how affected pathways might be targeted in therapeutic settings. At the same time, the roles of RNA and RNA-based processes have become increasingly prominent in the pathology of many of these same human diseases, and yeast has been utilized to investigate these mechanisms, from aberrant RNA-binding proteins in amyotrophic lateral sclerosis to translation regulation in cancer. Here we review some of the important insights that yeast models have yielded into the molecular pathology of complex, RNA-based human diseases. This article is categorized under: RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Stephanie Gastelum
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Allison F Michael
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Timothy A Bolger
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
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Zhang Y, Li S, Gong X, Chen J. Accurate Simulation of Coupling between Protein Secondary Structure and Liquid-Liquid Phase Separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554378. [PMID: 37662293 PMCID: PMC10473686 DOI: 10.1101/2023.08.22.554378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Intrinsically disordered proteins (IDPs) frequently mediate liquid-liquid phase separation (LLPS) that underlies the formation of membraneless organelles. Together with theory and experiment, efficient coarse-grained (CG) simulations have been instrumental in understanding sequence-specific phase separation of IDPs. However, the widely-used Cα-only models are severely limited in capturing the peptide nature of IDPs, including backbone-mediated interactions and effects of secondary structures, in LLPS. Here, we describe a hybrid resolution (HyRes) protein model for accurate description of the backbone and transient secondary structures in LLPS. With an atomistic backbone and coarse-grained side chains, HyRes accurately predicts the residue helical propensity and chain dimension of monomeric IDPs. Using GY-23 as a model system, we show that HyRes is efficient enough for direct simulation of spontaneous phase separation, and at the same time accurate enough to resolve the effects of single mutations. HyRes simulations also successfully predict increased beta-sheet formation in the condensate, consistent with available experimental data. We further utilize HyRes to study the phase separation of TPD-43, where several disease-related mutants in the conserved region (CR) have been shown to affect residual helicities and modulate LLPS propensity. The simulations successfully recapitulate the effect of these mutants on the helicity and LLPS propensity of TDP-43 CR. Analyses reveal that the balance between backbone and sidechain-mediated interactions, but not helicity itself, actually determines LLPS propensity. We believe that the HyRes model represents an important advance in the molecular simulation of LLPS and will help elucidate the coupling between IDP transient secondary structures and phase separation.
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Affiliation(s)
| | | | - Xiping Gong
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
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38
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Xiang L, Wang Y, Liu S, Liu B, Jin X, Cao X. Targeting Protein Aggregates with Natural Products: An Optional Strategy for Neurodegenerative Diseases. Int J Mol Sci 2023; 24:11275. [PMID: 37511037 PMCID: PMC10379780 DOI: 10.3390/ijms241411275] [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: 05/31/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Protein aggregation is one of the hallmarks of aging and aging-related diseases, especially for the neurodegenerative diseases (NDs) such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS), and others. In these diseases, many pathogenic proteins, such as amyloid-β, tau, α-Syn, Htt, and FUS, form aggregates that disrupt the normal physiological function of cells and lead to associated neuronal lesions. Protein aggregates in NDs are widely recognized as one of the important targets for the treatment of these diseases. Natural products, with their diverse biological activities and rich medical history, represent a great treasure trove for the development of therapeutic strategies to combat disease. A number of in vitro and in vivo studies have shown that natural products, by virtue of their complex molecular scaffolds that specifically bind to pathogenic proteins and their aggregates, can inhibit the formation of aggregates, disrupt the structure of aggregates and destabilize them, thereby alleviating conditions associated with NDs. Here, we systematically reviewed studies using natural products to improve disease-related symptoms by reducing or inhibiting the formation of five pathogenic protein aggregates associated with NDs. This information should provide valuable insights into new directions and ideas for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Lingzhi Xiang
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
| | - Yanan Wang
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
| | - Shenkui Liu
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
| | - Beidong Liu
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41390 Gothenburg, Sweden
| | - Xuejiao Jin
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
| | - Xiuling Cao
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, China
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Swasthi HM, Basalla JL, Dudley CE, Vecchiarelli AG, Chapman MR. Cell surface-localized CsgF condensate is a gatekeeper in bacterial curli subunit secretion. Nat Commun 2023; 14:2392. [PMID: 37100792 PMCID: PMC10133297 DOI: 10.1038/s41467-023-38089-1] [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: 10/23/2022] [Accepted: 04/14/2023] [Indexed: 04/28/2023] Open
Abstract
Curli are functional amyloids present on the outer membrane of E. coli. CsgF is required for the proper assembly of curli. Here, we found that the CsgF phase separates in vitro and that the ability of CsgF variants to phase-separate is tightly correlated with CsgF function during curli biogenesis. Substitution of phenylalanine residues in the CsgF N-terminus both reduced the propensity of CsgF to phase-separate and impaired curli assembly. Exogenous addition of purified CsgF complemented csgF - cells. This exogenous addition assay was used to assess the ability of CsgF variants to complement csgF ‒ cells. CsgF on the cell surface modulated the secretion of CsgA, the curli major subunit, to the cell surface. We also found that the CsgB nucleator protein can form SDS-insoluble aggregates within the dynamic CsgF condensate. We propose that these multicomponent CsgF-B condensates form a nucleation-competent complex that templates CsgA amyloid formation on the cell surface.
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Affiliation(s)
- Hema M Swasthi
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048, USA
| | - Joseph L Basalla
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048, USA
| | - Claire E Dudley
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048, USA
| | - Anthony G Vecchiarelli
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048, USA
| | - Matthew R Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048, USA.
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40
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Piol D, Robberechts T, Da Cruz S. Lost in local translation: TDP-43 and FUS in axonal/neuromuscular junction maintenance and dysregulation in amyotrophic lateral sclerosis. Neuron 2023; 111:1355-1380. [PMID: 36963381 DOI: 10.1016/j.neuron.2023.02.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/21/2022] [Accepted: 02/16/2023] [Indexed: 03/26/2023]
Abstract
Key early features of amyotrophic lateral sclerosis (ALS) are denervation of neuromuscular junctions and axonal degeneration. Motor neuron homeostasis relies on local translation through controlled regulation of axonal mRNA localization, transport, and stability. Yet the composition of the local transcriptome, translatome (mRNAs locally translated), and proteome during health and disease remains largely unexplored. This review covers recent discoveries on axonal translation as a critical mechanism for neuronal maintenance/survival. We focus on two RNA binding proteins, transactive response DNA binding protein-43 (TDP-43) and fused in sarcoma (FUS), whose mutations cause ALS and frontotemporal dementia (FTD). Emerging evidence points to their essential role in the maintenance of axons and synapses, including mRNA localization, transport, and local translation, and whose dysfunction may contribute to ALS. Finally, we describe recent advances in omics-based approaches mapping compartment-specific local RNA and protein compositions, which will be invaluable to elucidate fundamental local processes and identify key targets for therapy development.
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Affiliation(s)
- Diana Piol
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Tessa Robberechts
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Sandrine Da Cruz
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium.
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Kumar MS, Stallworth KM, Murthy AC, Lim SM, Li N, Jain A, Munro JB, Fawzi NL, Lagier-Tourenne C, Bosco DA. Interactions between FUS and the C-terminal Domain of Nup62 are Sufficient for their Co-phase Separation into Amorphous Assemblies. J Mol Biol 2023; 435:167972. [PMID: 36690069 PMCID: PMC10329203 DOI: 10.1016/j.jmb.2023.167972] [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: 09/08/2022] [Revised: 12/29/2022] [Accepted: 01/15/2023] [Indexed: 01/22/2023]
Abstract
Deficient nucleocytoplasmic transport is emerging as a pathogenic feature of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), including in ALS caused by mutations in Fused in Sarcoma (FUS). Recently, both wild-type and ALS-linked mutant FUS were shown to directly interact with the phenylalanine-glycine (FG)-rich nucleoporin 62 (Nup62) protein, where FUS WT/ Nup62 interactions were enriched within the nucleus but ALS-linked mutant FUS/ Nup62 interactions were enriched within the cytoplasm of cells. Nup62 is a central channel Nup that has a prominent role in forming the selectivity filter within the nuclear pore complex and in regulating effective nucleocytoplasmic transport. Under conditions where FUS phase separates into liquid droplets in vitro, the addition of Nup62 caused the synergistic formation of amorphous assemblies containing both FUS and Nup62. Here, we examined the molecular determinants of this process using recombinant FUS and Nup62 proteins and biochemical approaches. We demonstrate that the structured C-terminal domain of Nup62 containing an alpha-helical coiled-coil region plays a dominant role in binding FUS and is sufficient for inducing the formation of FUS/Nup62 amorphous assemblies. In contrast, the natively unstructured, F/G repeat-rich N-terminal domain of Nup62 modestly contributed to FUS/Nup62 phase separation behavior. Expression of individual Nup62 domain constructs in human cells confirmed that the Nup62 C-terminal domain is essential for localization of the protein to the nuclear envelope. Our results raise the possibility that interactions between FUS and the C-terminal domain of Nup62 can influence the function of Nup62 under physiological and/or pathological conditions.
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Affiliation(s)
- Meenakshi Sundaram Kumar
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, MA 01605, USA; Biochemistry and Molecular Biotechnology Program, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Karly M Stallworth
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, MA 01605, USA
| | - Anastasia C Murthy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Su Min Lim
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Nan Li
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Aastha Jain
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - James B Munro
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Nicolas L Fawzi
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Clotilde Lagier-Tourenne
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Daryl A Bosco
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, MA 01605, USA.
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Fare CM, Rhine K, Lam A, Myong S, Shorter J. A minimal construct of nuclear-import receptor Karyopherin-β2 defines the regions critical for chaperone and disaggregation activity. J Biol Chem 2023; 299:102806. [PMID: 36529289 PMCID: PMC9860449 DOI: 10.1016/j.jbc.2022.102806] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
Karyopherin-β2 (Kapβ2) is a nuclear-import receptor that recognizes proline-tyrosine nuclear localization signals of diverse cytoplasmic cargo for transport to the nucleus. Kapβ2 cargo includes several disease-linked RNA-binding proteins with prion-like domains, such as FUS, TAF15, EWSR1, hnRNPA1, and hnRNPA2. These RNA-binding proteins with prion-like domains are linked via pathology and genetics to debilitating degenerative disorders, including amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy. Remarkably, Kapβ2 prevents and reverses aberrant phase transitions of these cargoes, which is cytoprotective. However, the molecular determinants of Kapβ2 that enable these activities remain poorly understood, particularly from the standpoint of nuclear-import receptor architecture. Kapβ2 is a super-helical protein comprised of 20 HEAT repeats. Here, we design truncated variants of Kapβ2 and assess their ability to antagonize FUS aggregation and toxicity in yeast and FUS condensation at the pure protein level and in human cells. We find that HEAT repeats 8 to 20 of Kapβ2 recapitulate all salient features of Kapβ2 activity. By contrast, Kapβ2 truncations lacking even a single cargo-binding HEAT repeat display reduced activity. Thus, we define a minimal Kapβ2 construct for delivery in adeno-associated viruses as a potential therapeutic for amyotrophic lateral sclerosis/frontotemporal dementia, multisystem proteinopathy, and related disorders.
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Affiliation(s)
- Charlotte M Fare
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin Rhine
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, Baltimore, Maryland, USA; Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Andrew Lam
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sua Myong
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, Baltimore, Maryland, USA; Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Yang Y, Fritzsching KJ, He S, McDermott AE. Zinc Alters the Supramolecular Organization of Nucleic Acid Complexes with Full-Length TIA1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.25.525508. [PMID: 36747652 PMCID: PMC9900833 DOI: 10.1101/2023.01.25.525508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
T-Cell Intracellular Antigen-1 (TIA1) is a 43 kDa multi-domain RNA-binding protein involved in stress granule formation during eukaryotic stress response, and has been implicated in neurodegenerative diseases including Welander distal myopathy and amyotrophic lateral sclerosis. TIA1 contains three RNA recognition motifs (RRMs), which are capable of binding nucleic acids and a C-terminal Q/N-rich prion-related domain (PRD) which has been variously described as intrinsically disordered or prion inducing and is believed to play a role in promoting liquid-liquid phase separation connected with the assembly of stress granule formation. Motivated by the fact that our prior work shows RRMs 2 and 3 are well-ordered in an oligomeric full-length form, while RRM1 and the PRD appear to phase separate, the present work addresses whether the oligomeric form is functional and competent for binding, and probes the consequences of nucleic acid binding for oligomerization and protein conformation change. New SSNMR data show that ssDNA binds to full-length oligomeric TIA1 primarily at the RRM2 domain, but also weakly at the RRM3 domain, and Zn 2+ binds primarily to RRM3. Binding of Zn 2+ and DNA was reversible for the full-length wild type oligomeric form, and did not lead to formation of amyloid fibrils, despite the presence of the C-terminal prion-related domain. While TIA1:DNA complexes appear as long "daisy chained" structures, the addition of Zn 2+ caused the structures to collapse. We surmise that this points to a regulatory role for Zn 2+ . By occupying various "half" binding sites on RRM3 Zn 2+ may shift the nucleic acid binding off RRM3 and onto RRM2. More importantly, the use of different half sites on different monomers may introduce a mesh of crosslinks in the supramolecular complex rendering it compact and markedly reducing the access to the nucleic acids (including transcripts) from solution.
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Liquid-liquid Phase Separation of α-Synuclein: A New Mechanistic Insight for α-Synuclein Aggregation Associated with Parkinson's Disease Pathogenesis. J Mol Biol 2023; 435:167713. [PMID: 35787838 DOI: 10.1016/j.jmb.2022.167713] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 02/04/2023]
Abstract
Aberrant aggregation of the misfolded presynaptic protein, α-Synuclein (α-Syn) into Lewy body (LB) and Lewy neuritis (LN) is a major pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. Numerous studies have suggested that prefibrillar and fibrillar species of the misfolded α-Syn aggregates are responsible for cell death in PD pathogenesis. However, the precise molecular events during α-Syn aggregation, especially in the early stages, remain elusive. Emerging evidence has demonstrated that liquid-liquid phase separation (LLPS) of α-Syn occurs in the nucleation step of α-Syn aggregation, which offers an alternate non-canonical aggregation pathway in the crowded microenvironment. The liquid-like α-Syn droplets gradually undergo an irreversible liquid-to-solid phase transition into amyloid-like hydrogel entrapping oligomers and fibrils. This new mechanism of α-Syn LLPS and gel formation might represent the molecular basis of cellular toxicity associated with PD. This review aims to demonstrate the recent development of α-Syn LLPS, the underlying mechanism along with the microscopic events of aberrant phase transition. This review further discusses how several intrinsic and extrinsic factors regulate the thermodynamics and kinetics of α-Syn LLPS and co-LLPS with other proteins, which might explain the pathophysiology of α-Syn in various neurodegenerative diseases.
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45
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Włodarczyk P, Witczak M, Gajewska A, Chady T, Piotrowski I. The role of TDP-43 protein in amyotrophic lateral sclerosis. JOURNAL OF MEDICAL SCIENCE 2022. [DOI: 10.20883/medical.e710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease where both upper and lower motoneurons are damaged. Even though the pathogenesis of ALS is unclear, the TDP-43 aggregations and non-nuclear localization may be crucial to understanding this process. Despite intensive research on ALS therapies, only two lifespan-prolonging medications have been approved: Riluzole and Edaravone. Unravelling the TDP-43 pathology could help develop new ALS therapies using mechanisms such as inhibition of nuclear export, autophagy, chaperones, or antisense oligonucleotides. Selective inhibitors of nuclear export (SINEs) are drugs that block Exportin 1 (XPO1) and cause the accumulation of not exported molecules inside the nucleus. SINEs that target XPO1 are shown to slightly extend the survival of neurons and soften motor symptoms. Dysfunctional proteins, including TDP-43, can be eliminated through autophagocytosis, which is regulated by the mTOR kinase. Stimulating the elimination of protein deposits may be an effective ALS therapy. Antisense oligonucleotides (ASO) are single-stranded, synthetic oligonucleotides that can bind and modulate specific RNA: via ribonuclease H, inducing their degradation or inducing alternative splicing via blocking primary RNA transcripts. Current ASOs therapies used in ALS focus on SOD1, C9ORF72, FUS, and ATXN2, and they may be used to slow the ALS progression. Reversing the aggregation is a promising therapeutic strategy. Chaperones control other proteins' quality and protect them against stress factors. Due to the irreversible character of ALS, it is essential to understand its complicated pathology better and to seek new therapies.
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46
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Khalil B, Chhangani D, Wren MC, Smith CL, Lee JH, Li X, Puttinger C, Tsai CW, Fortin G, Morderer D, Gao J, Liu F, Lim CK, Chen J, Chou CC, Croft CL, Gleixner AM, Donnelly CJ, Golde TE, Petrucelli L, Oskarsson B, Dickson DW, Zhang K, Shorter J, Yoshimura SH, Barmada SJ, Rincon-Limas DE, Rossoll W. Nuclear import receptors are recruited by FG-nucleoporins to rescue hallmarks of TDP-43 proteinopathy. Mol Neurodegener 2022; 17:80. [PMID: 36482422 PMCID: PMC9733332 DOI: 10.1186/s13024-022-00585-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD) disease spectrum, causing both nuclear loss-of-function and cytoplasmic toxic gain-of-function phenotypes. While TDP-43 proteinopathy has been associated with defects in nucleocytoplasmic transport, this process is still poorly understood. Here we study the role of karyopherin-β1 (KPNB1) and other nuclear import receptors in regulating TDP-43 pathology. METHODS We used immunostaining, immunoprecipitation, biochemical and toxicity assays in cell lines, primary neuron and organotypic mouse brain slice cultures, to determine the impact of KPNB1 on the solubility, localization, and toxicity of pathological TDP-43 constructs. Postmortem patient brain and spinal cord tissue was stained to assess KPNB1 colocalization with TDP-43 inclusions. Turbidity assays were employed to study the dissolution and prevention of aggregation of recombinant TDP-43 fibrils in vitro. Fly models of TDP-43 proteinopathy were used to determine the effect of KPNB1 on their neurodegenerative phenotype in vivo. RESULTS We discovered that several members of the nuclear import receptor protein family can reduce the formation of pathological TDP-43 aggregates. Using KPNB1 as a model, we found that its activity depends on the prion-like C-terminal region of TDP-43, which mediates the co-aggregation with phenylalanine and glycine-rich nucleoporins (FG-Nups) such as Nup62. KPNB1 is recruited into these co-aggregates where it acts as a molecular chaperone that reverses aberrant phase transition of Nup62 and TDP-43. These findings are supported by the discovery that Nup62 and KPNB1 are also sequestered into pathological TDP-43 aggregates in ALS/FTD postmortem CNS tissue, and by the identification of the fly ortholog of KPNB1 as a strong protective modifier in Drosophila models of TDP-43 proteinopathy. Our results show that KPNB1 can rescue all hallmarks of TDP-43 pathology, by restoring its solubility and nuclear localization, and reducing neurodegeneration in cellular and animal models of ALS/FTD. CONCLUSION Our findings suggest a novel NLS-independent mechanism where, analogous to its canonical role in dissolving the diffusion barrier formed by FG-Nups in the nuclear pore, KPNB1 is recruited into TDP-43/FG-Nup co-aggregates present in TDP-43 proteinopathies and therapeutically reverses their deleterious phase transition and mislocalization, mitigating neurodegeneration.
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Affiliation(s)
- Bilal Khalil
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Deepak Chhangani
- Department of Neurology, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, 32610, USA
| | - Melissa C Wren
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Courtney L Smith
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
- Mayo Clinic Graduate School of Biomedical Sciences, Neuroscience Track, Mayo Clinic, Jacksonville, FL, USA
| | - Jannifer H Lee
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
- Mayo Clinic Graduate School of Biomedical Sciences, Neuroscience Track, Mayo Clinic, Jacksonville, FL, USA
| | - Xingli Li
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | | | - Chih-Wei Tsai
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Gael Fortin
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Dmytro Morderer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Junli Gao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Feilin Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Chun Kim Lim
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto, Japan
| | - Jingjiao Chen
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
- Geriatric Department, Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Ching-Chieh Chou
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Cara L Croft
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA
- UK Dementia Research Institute at University College London, London, UK
| | - Amanda M Gleixner
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, 15261, USA
| | - Christopher J Donnelly
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, 15261, USA
| | - Todd E Golde
- Department of Neurology, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, 32610, USA
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA
| | | | | | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Ke Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Shige H Yoshimura
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto, Japan
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Diego E Rincon-Limas
- Department of Neurology, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, 32610, USA
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
| | - Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA.
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47
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Phase separation and other forms of α-Synuclein self-assemblies. Essays Biochem 2022; 66:987-1000. [DOI: 10.1042/ebc20220055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022]
Abstract
Abstract
α-Synuclein (α-Syn) is a natively unstructured protein, which self-assembles into higher-order aggregates possessing serious pathophysiological implications. α-Syn aberrantly self-assembles into protein aggregates, which have been widely implicated in Parkinson’s disease (PD) pathogenesis and other synucleinopathies. The self-assembly of α-Syn involves the structural conversion of soluble monomeric protein into oligomeric intermediates and eventually fibrillar aggregates of amyloids with cross-β-sheet rich conformation. These aggregated α-Syn species majorly constitute the intraneuronal inclusions, which is a hallmark of PD neuropathology. Self-assembly/aggregation of α-Syn is not a single-state conversion process as unfolded protein can access multiple conformational states through the formation of metastable, transient pre-fibrillar intermediate species. Recent studies have indicated that soluble oligomers are the potential neurotoxic species responsible for cell death in PD pathogenesis. The heterogeneous and transient nature of oligomers formed during the early stage of aggregation pathway limit their detailed study in understanding the structure–toxicity relationship. Moreover, the precise molecular events occurring in the early stage of α-Syn aggregation process majorly remain unsolved. Recently, liquid–liquid phase separation (LLPS) of α-Syn has been designated as an alternate nucleation mechanism, which occurs in the early lag phase of the aggregation pathway leading to the formation of dynamic supramolecular assemblies. The stronger self-association among the protein molecules triggers the irreversible liquid-to-solid transition of these supramolecular assemblies into the amyloid-like hydrogel, which may serve as a reservoir entrapping toxic oligomeric intermediates and fibrils. This review strives to provide insights into different modes of α-Syn self-assemblies including LLPS-mediated self-assembly and its recent advancements.
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Gordon-Kim C, Rha A, Poppitz GA, Smith-Carpenter J, Luu R, Roberson AB, Conklin R, Blake A, Lynn DG. Polyanion order controls liquid-to-solid phase transition in peptide/nucleic acid co-assembly. Front Mol Biosci 2022; 9:991728. [PMID: 36452451 PMCID: PMC9702359 DOI: 10.3389/fmolb.2022.991728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/25/2022] [Indexed: 01/06/2024] Open
Abstract
The Central Dogma highlights the mutualistic functions of protein and nucleic acid biopolymers, and this synergy appears prominently in the membraneless organelles widely distributed throughout prokaryotic and eukaryotic organisms alike. Ribonucleoprotein granules (RNPs), which are complex coacervates of RNA with proteins, are a prime example of these membranelles organelles and underly multiple essential cellular functions. Inspired by the highly dynamic character of these organelles and the recent studies that ATP both inhibits and templates phase separation of the fused in sarcoma (FUS) protein implicated in several neurodegenerative diseases, we explored the RNA templated ordering of a single motif of the Aβ peptide of Alzheimer's disease. We now know that this strong cross-β propensity motif alone assembles through a liquid-like coacervate phase that can be externally templated to form distinct supramolecular assemblies. Now we provide evidence that structured phosphates, ranging from complex structures like double stranded and quadraplex DNA to simple trimetaphosphate, differentially impact the liquid to solid phase transition necessary for paracrystalline assembly. The results from this simple model illustrate the potential of ordered environmental templates in the transition to potentially irreversible pathogenic assemblies and provides insight into the ordering dynamics necessary for creating functional synthetic polymer co-assemblies.
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Affiliation(s)
| | - Allisandra Rha
- Children’s Health of Orange County, Research Institute, Orange, CA, United States
| | - George A. Poppitz
- Department of Chemistry, Emory University, Atlanta, GA, United States
| | | | - Regina Luu
- Department of Chemistry, Emory University, Atlanta, GA, United States
| | | | - Russell Conklin
- Department of Chemistry, Emory University, Atlanta, GA, United States
| | - Alexis Blake
- Department of Chemistry, Emory University, Atlanta, GA, United States
| | - David G. Lynn
- Department of Chemistry, Emory University, Atlanta, GA, United States
- Department of Biology, Emory University, Atlanta, GA, United States
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49
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Different states and the associated fates of biomolecular condensates. Essays Biochem 2022; 66:849-862. [PMID: 36350032 DOI: 10.1042/ebc20220054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/20/2022] [Accepted: 10/07/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Biomolecular condensates are functional assemblies, which can enrich intrinsically disordered proteins (IDPs) and/or RNAs at concentrations that are orders of magnitude higher than the bulk. In their native functional state, these structures can exist in multiple physical states including liquid-droplet phase, hydrogels, and solid assemblies. On the other hand, an aberrant transition between these physical states can result in loss-of-function or a gain-of-toxic-function. A prime example of such an aberrant transition is droplet aging—a phenomenon where some condensates may progressively transition into less dynamic material states at biologically relevant timescales. In this essay, we review structural and viscoelastic roots of aberrant liquid–solid transitions. Also, we highlight the different checkpoints and experimentally tunable handles, both active (ATP-dependent enzymes, post-translational modifications) and passive (colocalization of RNA molecules), that could alter the material state of assemblies.
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50
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Gelon PA, Dutchak PA, Sephton CF. Synaptic dysfunction in ALS and FTD: anatomical and molecular changes provide insights into mechanisms of disease. Front Mol Neurosci 2022; 15:1000183. [PMID: 36263379 PMCID: PMC9575515 DOI: 10.3389/fnmol.2022.1000183] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/01/2022] [Indexed: 11/29/2022] Open
Abstract
Synaptic loss is a pathological feature of all neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). ALS is a disease of the cortical and spinal motor neurons resulting in fatal paralysis due to denervation of muscles. FTD is a form of dementia that primarily affects brain regions controlling cognition, language and behavior. Once classified as two distinct diseases, ALS and FTD are now considered as part of a common disease spectrum based on overlapping clinical, pathological and genetic evidence. At the cellular level, aggregation of common proteins and overlapping gene susceptibilities are shared in both ALS and FTD. Despite the convergence of these two fields of research, the underlying disease mechanisms remain elusive. However, recent discovers from ALS and FTD patient studies and models of ALS/FTD strongly suggests that synaptic dysfunction is an early event in the disease process and a unifying hallmark of these diseases. This review provides a summary of the reported anatomical and cellular changes that occur in cortical and spinal motor neurons in ALS and FTD tissues and models of disease. We also highlight studies that identify changes in the proteome and transcriptome of ALS and FTD models and provide a conceptual overview of the processes that contribute to synaptic dysfunction in these diseases. Due to space limitations and the vast number of publications in the ALS and FTD fields, many articles have not been discussed in this review. As such, this review focuses on the three most common shared mutations in ALS and FTD, the hexanucleuotide repeat expansion within intron 1 of chromosome 9 open reading frame 72 (C9ORF72), transactive response DNA binding protein 43 (TARDBP or TDP-43) and fused in sarcoma (FUS), with the intention of highlighting common pathways that promote synaptic dysfunction in the ALS-FTD disease spectrum.
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