1
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Borgert L, Becker T, den Brave F. Conserved quality control mechanisms of mitochondrial protein import. J Inherit Metab Dis 2024. [PMID: 38790152 DOI: 10.1002/jimd.12756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/15/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024]
Abstract
Mitochondria carry out essential functions for the cell, including energy production, various biosynthesis pathways, formation of co-factors and cellular signalling in apoptosis and inflammation. The functionality of mitochondria requires the import of about 900-1300 proteins from the cytosol in baker's yeast Saccharomyces cerevisiae and human cells, respectively. The vast majority of these proteins pass the outer membrane in a largely unfolded state through the translocase of the outer mitochondrial membrane (TOM) complex. Subsequently, specific protein translocases sort the precursor proteins into the outer and inner membranes, the intermembrane space and matrix. Premature folding of mitochondrial precursor proteins, defects in the mitochondrial protein translocases or a reduction of the membrane potential across the inner mitochondrial membrane can cause stalling of precursors at the protein import apparatus. Consequently, the translocon is clogged and non-imported precursor proteins accumulate in the cell, which in turn leads to proteotoxic stress and eventually cell death. To prevent such stress situations, quality control mechanisms remove non-imported precursor proteins from the TOM channel. The highly conserved ubiquitin-proteasome system of the cytosol plays a critical role in this process. Thus, the surveillance of protein import via the TOM complex involves the coordinated activity of mitochondria-localized and cytosolic proteins to prevent proteotoxic stress in the cell.
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Affiliation(s)
- Lion Borgert
- Faculty of Medicine, Institute of Biochemistry and Molecular Biology, University of Bonn, Bonn, Germany
| | - Thomas Becker
- Faculty of Medicine, Institute of Biochemistry and Molecular Biology, University of Bonn, Bonn, Germany
| | - Fabian den Brave
- Faculty of Medicine, Institute of Biochemistry and Molecular Biology, University of Bonn, Bonn, Germany
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2
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Hipp MS, Hartl FU. Interplay of Proteostasis Capacity and Protein Aggregation: Implications for Cellular Function and Disease. J Mol Biol 2024:168615. [PMID: 38759929 DOI: 10.1016/j.jmb.2024.168615] [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: 02/08/2024] [Revised: 05/13/2024] [Accepted: 05/13/2024] [Indexed: 05/19/2024]
Abstract
Eukaryotic cells are equipped with an intricate proteostasis network (PN), comprising nearly 3,000 components dedicated to preserving proteome integrity and sustaining protein homeostasis. This protective system is particularly important under conditions of external and intrinsic cell stress, where inherently dynamic proteins may unfold and lose functionality. A decline in proteostasis capacity is associated with the aging process, resulting in a reduced folding efficiency of newly synthesized proteins and a deficit in the cellular capacity to degrade misfolded proteins. A critical consequence of PN insufficiency is the accumulation of cytotoxic protein aggregates that underlie various age-related neurodegenerative conditions and other pathologies. By interfering with specific proteostasis components, toxic aggregates place an excessive burden on the PN's ability to maintain proteome integrity. This initiates a feed-forward loop, wherein the generation of misfolded and aggregated proteins ultimately leads to proteostasis collapse and cellular demise.
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Affiliation(s)
- Mark S Hipp
- Department of Biomedical Sciences, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan, 1, 9713 AV Groningen, the Netherlands; Research School of Behavioural and Cognitive Neurosciences, University of Groningen, Groningen, the Netherlands; School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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3
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Bertgen L, Bökenkamp JE, Schneckmann T, Koch C, Räschle M, Storchová Z, Herrmann JM. Distinct types of intramitochondrial protein aggregates protect mitochondria against proteotoxic stress. Cell Rep 2024; 43:114018. [PMID: 38551959 DOI: 10.1016/j.celrep.2024.114018] [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: 10/02/2023] [Revised: 02/27/2024] [Accepted: 03/14/2024] [Indexed: 04/28/2024] Open
Abstract
Mitochondria consist of hundreds of proteins, most of which are inaccessible to the proteasomal quality control system of the cytosol. How cells stabilize the mitochondrial proteome during challenging conditions remains poorly understood. Here, we show that mitochondria form spatially defined protein aggregates as a stress-protecting mechanism. Two different types of intramitochondrial protein aggregates can be distinguished. The mitoribosomal protein Var1 (uS3m) undergoes a stress-induced transition from a soluble, chaperone-stabilized protein that is prevalent under benign conditions to an insoluble, aggregated form upon acute stress. The formation of Var1 bodies stabilizes mitochondrial proteostasis, presumably by sequestration of aggregation-prone proteins. The AAA chaperone Hsp78 is part of a second type of intramitochondrial aggregate that transiently sequesters proteins and promotes their folding or Pim1-mediated degradation. Thus, mitochondrial proteins actively control the formation of distinct types of intramitochondrial protein aggregates, which cooperate to stabilize the mitochondrial proteome during proteotoxic stress conditions.
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Affiliation(s)
- Lea Bertgen
- Cell Biology, University of Kaiserslautern, RPTU, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany
| | - Jan-Eric Bökenkamp
- Molecular Genetics, University of Kaiserslautern, RPTU, Paul-Ehrlich-Strasse 24, 67663 Kaiserslautern, Germany
| | - Tim Schneckmann
- Cell Biology, University of Kaiserslautern, RPTU, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany
| | - Christian Koch
- Cell Biology, University of Kaiserslautern, RPTU, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany
| | - Markus Räschle
- Molecular Genetics, University of Kaiserslautern, RPTU, Paul-Ehrlich-Strasse 24, 67663 Kaiserslautern, Germany
| | - Zuzana Storchová
- Molecular Genetics, University of Kaiserslautern, RPTU, Paul-Ehrlich-Strasse 24, 67663 Kaiserslautern, Germany
| | - Johannes M Herrmann
- Cell Biology, University of Kaiserslautern, RPTU, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany.
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4
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Kumar A, Mathew V, Stirling PC. Dynamics of DNA damage-induced nuclear inclusions are regulated by SUMOylation of Btn2. Nat Commun 2024; 15:3215. [PMID: 38615096 PMCID: PMC11016081 DOI: 10.1038/s41467-024-47615-8] [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: 08/16/2023] [Accepted: 04/05/2024] [Indexed: 04/15/2024] Open
Abstract
Spatial compartmentalization is a key facet of protein quality control that serves to store disassembled or non-native proteins until triage to the refolding or degradation machinery can occur in a regulated manner. Yeast cells sequester nuclear proteins at intranuclear quality control bodies (INQ) in response to various stresses, although the regulation of this process remains poorly understood. Here we reveal the SUMO modification of the small heat shock protein Btn2 under DNA damage and place Btn2 SUMOylation in a pathway promoting protein clearance from INQ structures. Along with other chaperones, and degradation machinery, Btn2-SUMO promotes INQ clearance from cells recovering from genotoxic stress. These data link small heat shock protein post-translational modification to the regulation of protein sequestration in the yeast nucleus.
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Affiliation(s)
- Arun Kumar
- Terry Fox Laboratory, BC Cancer, 675 West 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6T1Z4, Canada
| | - Veena Mathew
- Terry Fox Laboratory, BC Cancer, 675 West 10th Avenue, Vancouver, BC, V5Z1L3, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, BC Cancer, 675 West 10th Avenue, Vancouver, BC, V5Z1L3, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6T1Z4, Canada.
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5
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Foroutan Kalourazi A, Nazemi SA, Unniram Parambil AR, Muñoz-Tafalla R, Vidal P, Shahangian SS, Guallar V, Ferrer M, Shahgaldian P. Exploiting cyclodextrins as artificial chaperones to enhance enzyme protection through supramolecular engineering. NANOSCALE 2024; 16:5123-5129. [PMID: 38349359 DOI: 10.1039/d3nr06044f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
We report a method of enzyme stabilisation exploiting the artificial protein chaperone properties of β-cyclodextrin (β-CD) covalently embedded in an ultrathin organosilica layer. Putative interaction points of this artificial chaperone system with the surface of the selected enzyme were studied in silico using a protein energy landscape exploration simulation algorithm. We show that this enzyme shielding method allows for drastic enhancement of enzyme stability under thermal and chemical stress conditions, along with broadening the optimal temperature range of the biocatalyst. The presence of the β-CD macrocycle within the protective layer supports protein refolding after treatment with a surfactant.
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Affiliation(s)
- Ali Foroutan Kalourazi
- School of Life Science, University of Applied Sciences and Arts Northwestern Switzerland, Hofackerstrasse 30, Muttenz CH-4132, Switzerland.
- Department of Biology, Faculty of Sciences, University of Guilan, Rasht, Iran.
| | - Seyed Amirabbas Nazemi
- School of Life Science, University of Applied Sciences and Arts Northwestern Switzerland, Hofackerstrasse 30, Muttenz CH-4132, Switzerland.
| | - Ajmal Roshan Unniram Parambil
- School of Life Science, University of Applied Sciences and Arts Northwestern Switzerland, Hofackerstrasse 30, Muttenz CH-4132, Switzerland.
- Swiss Nanoscience Institute, Klingelbergstrasse 82, Basel CH-4056, Switzerland
| | - Ruben Muñoz-Tafalla
- Barcelona Supercomputing Center (BSC), 08034 Barcelona, Spain
- Faculty of Pharmacy and Food Science, Universitat de Barcelona (UB), 08007 Barcelona, Spain
| | - Paula Vidal
- Instituto de Catalisis y Petroleoquimica (ICP), CSIC, 28049 Madrid, Spain
| | - S Shirin Shahangian
- Department of Biology, Faculty of Sciences, University of Guilan, Rasht, Iran.
| | - Victor Guallar
- Barcelona Supercomputing Center (BSC), 08034 Barcelona, Spain
- Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
| | - Manuel Ferrer
- Instituto de Catalisis y Petroleoquimica (ICP), CSIC, 28049 Madrid, Spain
| | - Patrick Shahgaldian
- School of Life Science, University of Applied Sciences and Arts Northwestern Switzerland, Hofackerstrasse 30, Muttenz CH-4132, Switzerland.
- Swiss Nanoscience Institute, Klingelbergstrasse 82, Basel CH-4056, Switzerland
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6
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Lehmann CP, González-Fernández P, Tercero J. Spatial regulation of DNA damage tolerance protein Rad5 interconnects genome stability maintenance and proteostasis networks. Nucleic Acids Res 2024; 52:1156-1172. [PMID: 38055836 PMCID: PMC10853803 DOI: 10.1093/nar/gkad1176] [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: 08/22/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/08/2023] Open
Abstract
The Rad5/HLTF protein has a central role in the tolerance to DNA damage by mediating an error-free mode of bypassing unrepaired DNA lesions, and is therefore critical for the maintenance of genome stability. We show in this work that, following cellular stress, Rad5 is regulated by relocalization into two types of nuclear foci that coexist within the same cell, which we termed 'S' and 'I'. Rad5 S-foci form in response to genotoxic stress and are associated with Rad5's function in maintaining genome stability, whereas I-foci form in the presence of proteotoxic stress and are related to Rad5's own proteostasis. Rad5 accumulates into S-foci at DNA damage tolerance sites by liquid-liquid phase separation, while I-foci constitute sites of chaperone-mediated sequestration of Rad5 at the intranuclear quality control compartment (INQ). Relocalization of Rad5 into each type of foci involves different pathways and recruitment mechanisms, but in both cases is driven by the evolutionarily conserved E2 ubiquitin-conjugating enzyme Rad6. This coordinated differential relocalization of Rad5 interconnects DNA damage response and proteostasis networks, highlighting the importance of studying these homeostasis mechanisms in tandem. Spatial regulation of Rad5 under cellular stress conditions thus provides a useful biological model to study cellular homeostasis as a whole.
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Affiliation(s)
- Carl P Lehmann
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Cantoblanco. 28049-Madrid, Spain
| | | | - José Antonio Tercero
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Cantoblanco. 28049-Madrid, Spain
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7
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Ruger-Herreros C, Svoboda L, Mogk A, Bukau B. Role of J-domain Proteins in Yeast Physiology and Protein Quality Control. J Mol Biol 2024:168484. [PMID: 38331212 DOI: 10.1016/j.jmb.2024.168484] [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: 10/20/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 02/10/2024]
Abstract
The Hsp70 chaperone system is a central component of cellular protein quality control (PQC) by acting in a multitude of protein folding processes ranging from the folding of newly synthesized proteins to the disassembly and refolding of protein aggregates. This multifunctionality of Hsp70 is governed by J-domain proteins (JDPs), which act as indispensable co-chaperones that target specific substrates to Hsp70. The number of distinct JDPs present in a species always outnumbers Hsp70, documenting JDP function in functional diversification of Hsp70. In this review, we describe the physiological roles of JDPs in the Saccharomyces cerevisiae PQC system, with a focus on the abundant JDP generalists, Zuo1, Ydj1 and Sis1, which function in fundamental cellular processes. Ribosome-bound Zuo1 cooperates with the Hsp70 chaperones Ssb1/2 in folding and assembly of nascent polypeptides. Ydj1 and Sis1 cooperate with the Hsp70 members Ssa1 to Ssa4 to exert overlapping functions in protein folding and targeting of newly synthesized proteins to organelles including mitochondria and facilitating the degradation of aberrant proteins by E3 ligases. Furthermore, they act in protein disaggregation reactions, though Ydj1 and Sis1 differ in their modes of Hsp70 cooperation and substrate specificities. This results in functional specialization as seen in prion propagation and the underlying dominant role of Sis1 in targeting Hsp70 for shearing of prion amyloid fibrils.
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Affiliation(s)
- Carmen Ruger-Herreros
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany; Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avda. Manuel Siurot, s/n, E-41013 Sevilla, Spain
| | - Lucia Svoboda
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Axel Mogk
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
| | - Bernd Bukau
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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8
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den Brave F, Pfanner N, Becker T. Mitochondrial entry gate as regulatory hub. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119529. [PMID: 37951505 DOI: 10.1016/j.bbamcr.2023.119529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/18/2023] [Accepted: 06/23/2023] [Indexed: 11/14/2023]
Abstract
Mitochondria import 1000-1300 different precursor proteins from the cytosol. The main mitochondrial entry gate is formed by the translocase of the outer membrane (TOM complex). Molecular coupling and modification of TOM subunits control and modulate protein import in response to cellular signaling. The TOM complex functions as regulatory hub to integrate mitochondrial protein biogenesis and quality control into the cellular proteostasis network.
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Affiliation(s)
- Fabian den Brave
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany.
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9
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Kohler V, Kohler A, Berglund LL, Hao X, Gersing S, Imhof A, Nyström T, Höög JL, Ott M, Andréasson C, Büttner S. Nuclear Hsp104 safeguards the dormant translation machinery during quiescence. Nat Commun 2024; 15:315. [PMID: 38182580 PMCID: PMC10770042 DOI: 10.1038/s41467-023-44538-8] [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: 06/01/2023] [Accepted: 12/15/2023] [Indexed: 01/07/2024] Open
Abstract
The resilience of cellular proteostasis declines with age, which drives protein aggregation and compromises viability. The nucleus has emerged as a key quality control compartment that handles misfolded proteins produced by the cytosolic protein biosynthesis system. Here, we find that age-associated metabolic cues target the yeast protein disaggregase Hsp104 to the nucleus to maintain a functional nuclear proteome during quiescence. The switch to respiratory metabolism and the accompanying decrease in translation rates direct cytosolic Hsp104 to the nucleus to interact with latent translation initiation factor eIF2 and to suppress protein aggregation. Hindering Hsp104 from entering the nucleus in quiescent cells results in delayed re-entry into the cell cycle due to compromised resumption of protein synthesis. In sum, we report that cytosolic-nuclear partitioning of the Hsp104 disaggregase is a critical mechanism to protect the latent protein synthesis machinery during quiescence in yeast, ensuring the rapid restart of translation once nutrients are replenished.
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Affiliation(s)
- Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691, Stockholm, Sweden
- Institute of Molecular Biosciences, University of Graz, 8010, Graz, Austria
- Department of Molecular Biology, Umeå University, 90187, Umeå, Sweden
| | - Andreas Kohler
- Institute of Molecular Biosciences, University of Graz, 8010, Graz, Austria
- Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187, Umeå, Sweden
| | - Lisa Larsson Berglund
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Xinxin Hao
- Department of Microbiology and Immunology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Sarah Gersing
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, 1165, Copenhagen, Denmark
| | - Axel Imhof
- Biomedical Center Munich, Faculty of Medicine, Ludwig Maximilian University of Munich, 82152, Planegg-Martinsried, Germany
| | - Thomas Nyström
- Department of Microbiology and Immunology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Johanna L Höög
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Claes Andréasson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691, Stockholm, Sweden.
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691, Stockholm, Sweden.
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10
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Li L, Li D, Sun D, Zhang X, Lei W, Wu M, Huang Q, Nian X, Dai W, Lu X, Zhou Z, Zhu Y, Xiao Y, Zhang L, Mo W, Liu Z, Zhang L. Nuclear import carrier Hikeshi cooperates with HSP70 to promote murine oligodendrocyte differentiation and CNS myelination. Dev Cell 2023; 58:2275-2291.e6. [PMID: 37865085 DOI: 10.1016/j.devcel.2023.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/14/2023] [Accepted: 09/18/2023] [Indexed: 10/23/2023]
Abstract
Dysregulation of factors in nucleocytoplasmic transport is closely linked to neural developmental diseases. Mutation in Hikeshi, encoding a nonconventional nuclear import carrier of heat shock protein 70 family (HSP70s), leads to inherited leukodystrophy; however, the pathological mechanisms remain elusive. Here, we showed that Hikeshi is essential for central nervous system (CNS) myelination. Deficiency of Hikeshi, which is observed in inherited leukodystrophy patients, resulted in murine oligodendrocyte maturation arrest. Hikeshi is required for nuclear translocation of HSP70s upon differentiation. Nuclear-localized HSP70 promotes murine oligodendrocyte differentiation and remyelination after white matter injury. Mechanistically, HSP70s interacted with SOX10 in the nucleus and protected it from E3 ligase FBXW7-mediated ubiquitination degradation. Importantly, we discovered that Hikeshi-dependent hyperthermia therapy, which induces nuclear import of HSP70s, promoted oligodendrocyte differentiation and remyelination following in vivo demyelinating injury. Overall, these findings demonstrate that Hikeshi-mediated nuclear translocation of HSP70s is essential for myelinogenesis and provide insights into pathological mechanisms of Hikeshi-related leukodystrophy.
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Affiliation(s)
- Li Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Daopeng Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Di Sun
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Xueqin Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Wanying Lei
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Mei Wu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Qiuying Huang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Ximing Nian
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Wenxiu Dai
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Xiaoyun Lu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Zhihao Zhou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Yanqin Zhu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Yunshan Xiao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Ling Zhang
- Department of Clinic Laboratory, The Affiliated Chenggong Hospital, School of Medicine, Xiamen University, Xiamen 361102, Fujian, China
| | - Wei Mo
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Zhixiong Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China
| | - Liang Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, Fujian, China.
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11
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den Brave F, Schulte U, Fakler B, Pfanner N, Becker T. Mitochondrial complexome and import network. Trends Cell Biol 2023:S0962-8924(23)00208-8. [PMID: 37914576 DOI: 10.1016/j.tcb.2023.10.004] [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: 08/21/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 11/03/2023]
Abstract
Mitochondria perform crucial functions in cellular metabolism, protein and lipid biogenesis, quality control, and signaling. The systematic analysis of protein complexes and interaction networks provided exciting insights into the structural and functional organization of mitochondria. Most mitochondrial proteins do not act as independent units, but are interconnected by stable or dynamic protein-protein interactions. Protein translocases are responsible for importing precursor proteins into mitochondria and form central elements of several protein interaction networks. These networks include molecular chaperones and quality control factors, metabolite channels and respiratory chain complexes, and membrane and organellar contact sites. Protein translocases link the distinct networks into an overarching network, the mitochondrial import network (MitimNet), to coordinate biogenesis, membrane organization and function of mitochondria.
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Affiliation(s)
- Fabian den Brave
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany
| | - Uwe Schulte
- Institute of Physiology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Nikolaus Pfanner
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, 53115 Bonn, Germany.
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12
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Rödl S, Herrmann JM. The role of the proteasome in mitochondrial protein quality control. IUBMB Life 2023; 75:868-879. [PMID: 37178401 DOI: 10.1002/iub.2734] [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: 02/21/2023] [Accepted: 04/15/2023] [Indexed: 05/15/2023]
Abstract
The abundance of each cellular protein is dynamically adjusted to the prevailing metabolic and stress conditions by modulation of their synthesis and degradation rates. The proteasome represents the major machinery for the degradation of proteins in eukaryotic cells. How the ubiquitin-proteasome system (UPS) controls protein levels and removes superfluous and damaged proteins from the cytosol and the nucleus is well characterized. However, recent studies showed that the proteasome also plays a crucial role in mitochondrial protein quality control. This mitochondria-associated degradation (MAD) thereby acts on two layers: first, the proteasome removes mature, functionally compromised or mis-localized proteins from the mitochondrial surface; and second, the proteasome cleanses the mitochondrial import pore of import intermediates of nascent proteins that are stalled during translocation. In this review, we provide an overview about the components and their specific functions that facilitate proteasomal degradation of mitochondrial proteins in the yeast Saccharomyces cerevisiae. Thereby we explain how the proteasome, in conjunction with a set of intramitochondrial proteases, maintains mitochondrial protein homeostasis and dynamically adapts the levels of mitochondrial proteins to specific conditions.
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Affiliation(s)
- Saskia Rödl
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
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13
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Boronat S, Cabrera M, Vega M, Alcalá J, Salas-Pino S, Daga RR, Ayté J, Hidalgo E. Formation of Transient Protein Aggregate-like Centers Is a General Strategy Postponing Degradation of Misfolded Intermediates. Int J Mol Sci 2023; 24:11202. [PMID: 37446379 DOI: 10.3390/ijms241311202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023] Open
Abstract
When misfolded intermediates accumulate during heat shock, the protein quality control system promotes cellular adaptation strategies. In Schizosaccharomyces pombe, thermo-sensitive proteins assemble upon stress into protein aggregate-like centers, PACs, to escape from degradation. The role of this protein deposition strategy has been elusive due to the use of different model systems and reporters, and to the addition of artificial inhibitors, which made interpretation of the results difficult. Here, we compare fission and budding yeast model systems, expressing the same misfolding reporters in experiments lacking proteasome or translation inhibitors. We demonstrate that mild heat shock triggers reversible PAC formation, with the collapse of both reporters and chaperones in a process largely mediated by chaperones. This assembly postpones proteasomal degradation of the misfolding reporters, and their Hsp104-dependent disassembly occurs during stress recovery. Severe heat shock induces formation of cytosolic PACs, but also of nuclear structures resembling nucleolar rings, NuRs, presumably to halt nuclear functions. Our study demonstrates that these distantly related yeasts use very similar strategies to adapt and survive to mild and severe heat shock and that aggregate-like formation is a general cellular scheme to postpone protein degradation and facilitate exit from stress.
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Affiliation(s)
- Susanna Boronat
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Margarita Cabrera
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Doctor Aiguader 88, 08003 Barcelona, Spain
- Centro de Biología Molecular Severo Ochoa and Departamento de Biología Molecular, Universidad Autónoma de Madrid (UAM), 28049 Madrid, Spain
| | - Montserrat Vega
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Jorge Alcalá
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Silvia Salas-Pino
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucía, Carretera de Utrera, km1, 41013 Seville, Spain
| | - Rafael R Daga
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucía, Carretera de Utrera, km1, 41013 Seville, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Doctor Aiguader 88, 08003 Barcelona, Spain
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14
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Cai M, Wu X, Liang X, Hu H, Liu Y, Yong T, Li X, Xiao C, Gao X, Chen S, Xie Y, Wu Q. Comparative proteomic analysis of two divergent strains provides insights into thermotolerance mechanisms of Ganoderma lingzhi. Fungal Genet Biol 2023; 167:103796. [PMID: 37146899 DOI: 10.1016/j.fgb.2023.103796] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 02/18/2023] [Accepted: 04/03/2023] [Indexed: 05/07/2023]
Abstract
Heat stress (HS) is a major abiotic factor influencing fungal growth and metabolism. However, the genetic basis of thermotolerance in Ganoderma lingzhi (G. lingzhi) remains largely unknown. In this study, we investigated the thermotolerance capacities of 21 G. lingzhi strains and screened the thermo-tolerant (S566) and heat-sensitive (Z381) strains. The mycelia of S566 and Z381 were collected and subjected to a tandem mass tag (TMT)-based proteome assay. We identified 1493 differentially expressed proteins (DEPs), with 376 and 395 DEPs specific to the heat-tolerant and heat-susceptible genotypes, respectively. In the heat-tolerant genotype, upregulated proteins were linked to stimulus regulation and response. Proteins related to oxidative phosphorylation, glycosylphosphatidylinositol-anchor biosynthesis, and cell wall macromolecule metabolism were downregulated in susceptible genotypes. After HS, the mycelial growth of the heat-sensitive Z381 strain was inhibited, and mitochondrial cristae and cell wall integrity of this strain were severely impaired, suggesting that HS may inhibit mycelial growth of Z381 by damaging the cell wall and mitochondrial structure. Furthermore, thermotolerance-related regulatory pathways were explored by analyzing the protein-protein interaction network of DEPs considered to participate in the controlling the thermotolerance capacity. This study provides insights into G. lingzhi thermotolerance mechanisms and a basis for breeding a thermotolerant germplasm bank for G. lingzhi and other fungi.
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Affiliation(s)
- Manjun Cai
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xiaoxian Wu
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xiaowei Liang
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Huiping Hu
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yuanchao Liu
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Tianqiao Yong
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xiangmin Li
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Chun Xiao
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xiong Gao
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Shaodan Chen
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yizhen Xie
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; Guangdong Yuewei Edible Fungi Technology Co. Ltd., Guangzhou 510663, China.
| | - Qingping Wu
- Key Laboratory of Agricultural Microbiomics and Precision Application, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
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15
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Suresh HG, Bonneil E, Albert B, Dominique C, Costanzo M, Pons C, David Masinas MP, Shuteriqi E, Shore D, Henras AK, Thibault P, Boone C, Andrews BJ. K29-linked unanchored polyubiquitin chains disrupt ribosome biogenesis and direct ribosomal proteins to the Intranuclear Quality control compartment (INQ). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.03.539259. [PMID: 37205480 PMCID: PMC10187189 DOI: 10.1101/2023.05.03.539259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ribosome assembly requires precise coordination between the production and assembly of ribosomal components. Mutations in ribosomal proteins that inhibit the assembly process or ribosome function are often associated with Ribosomopathies, some of which are linked to defects in proteostasis. In this study, we examine the interplay between several yeast proteostasis enzymes, including deubiquitylases (DUBs), Ubp2 and Ubp14, and E3 ligases, Ufd4 and Hul5, and we explore their roles in the regulation of the cellular levels of K29-linked unanchored polyubiquitin (polyUb) chains. Accumulating K29-linked unanchored polyUb chains associate with maturing ribosomes to disrupt their assembly, activate the Ribosome assembly stress response (RASTR), and lead to the sequestration of ribosomal proteins at the Intranuclear Quality control compartment (INQ). These findings reveal the physiological relevance of INQ and provide insights into mechanisms of cellular toxicity associated with Ribosomopathies.
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16
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Affiliation(s)
- Simon Alberti
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Dresden, Germany
| | - Serena Carra
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Dresden, Germany.
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
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17
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Kohler V, Andréasson C. Reversible protein assemblies in the proteostasis network in health and disease. Front Mol Biosci 2023; 10:1155521. [PMID: 37021114 PMCID: PMC10067754 DOI: 10.3389/fmolb.2023.1155521] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/09/2023] [Indexed: 04/07/2023] Open
Abstract
While proteins populating their native conformations constitute the functional entities of cells, protein aggregates are traditionally associated with cellular dysfunction, stress and disease. During recent years, it has become clear that large aggregate-like protein condensates formed via liquid-liquid phase separation age into more solid aggregate-like particles that harbor misfolded proteins and are decorated by protein quality control factors. The constituent proteins of the condensates/aggregates are disentangled by protein disaggregation systems mainly based on Hsp70 and AAA ATPase Hsp100 chaperones prior to their handover to refolding and degradation systems. Here, we discuss the functional roles that condensate formation/aggregation and disaggregation play in protein quality control to maintain proteostasis and why it matters for understanding health and disease.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Claes Andréasson
- Department of Molecular Biosciences, Stockholm University, Stockholm, Sweden
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18
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Merjane J, Chung R, Patani R, Lisowski L. Molecular mechanisms of amyotrophic lateral sclerosis as broad therapeutic targets for gene therapy applications utilizing adeno-associated viral vectors. Med Res Rev 2023. [PMID: 36786126 DOI: 10.1002/med.21937] [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: 11/13/2021] [Revised: 08/19/2022] [Accepted: 02/02/2023] [Indexed: 02/15/2023]
Abstract
Despite the devastating clinical outcome of the neurodegenerative disease, amyotrophic lateral sclerosis (ALS), its etiology remains mysterious. Approximately 90% of ALS is characterized as sporadic, signifying that the patient has no family history of the disease. The development of an impactful disease modifying therapy across the ALS spectrum has remained out of grasp, largely due to the poorly understood mechanisms of disease onset and progression. Currently, ALS is invariably fatal and rapidly progressive. It is hypothesized that multiple factors can lead to the development of ALS, however, treatments are often focused on targeting specific familial forms of the disease (10% of total cases). There is a strong need to develop disease modifying treatments for ALS that can be effective across the full ALS spectrum of familial and sporadic cases. Although the onset of disease varies significantly between patients, there are general disease mechanisms and progressions that can be seen broadly across ALS patients. Therefore, this review explores the targeting of these widespread disease mechanisms as possible areas for therapeutic intervention to treat ALS broadly. In particular, this review will focus on targeting mechanisms of defective protein homeostasis and RNA processing, which are both increasingly recognized as design principles of ALS pathogenesis. Additionally, this review will explore the benefits of gene therapy as an approach to treating ALS, specifically focusing on the use of adeno-associated virus (AAV) as a vector for gene delivery to the CNS and recent advances in the field.
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Affiliation(s)
- Jessica Merjane
- Translational Vectorology Research Unit, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia
| | - Roger Chung
- Department of Biomedical Sciences, Centre for Motor Neuron Disease Research, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Rickie Patani
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,The Francis Crick Institute, London, UK
| | - Leszek Lisowski
- Translational Vectorology Research Unit, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia.,Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine, Warsaw, Poland
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19
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Jawed A, Ho CT, Grousl T, Shrivastava A, Ruppert T, Bukau B, Mogk A. Balanced activities of Hsp70 and the ubiquitin proteasome system underlie cellular protein homeostasis. Front Mol Biosci 2023; 9:1106477. [PMID: 36660429 PMCID: PMC9845930 DOI: 10.3389/fmolb.2022.1106477] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 12/15/2022] [Indexed: 01/05/2023] Open
Abstract
To counteract proteotoxic stress and cellular aging, protein quality control (PQC) systems rely on the refolding, degradation and sequestration of misfolded proteins. In Saccharomyces cerevisiae the Hsp70 chaperone system plays a central role in protein refolding, while degradation is predominantly executed by the ubiquitin proteasome system (UPS). The sequestrases Hsp42 and Btn2 deposit misfolded proteins in cytosolic and nuclear inclusions, thereby restricting the accessibility of misfolded proteins to Hsp70 and preventing the exhaustion of limited Hsp70 resources. Therefore, in yeast, sequestrase mutants show negative genetic interactions with double mutants lacking the Hsp70 co-chaperone Fes1 and the Hsp104 disaggregase (fes1Δ hsp104Δ, ΔΔ) and suffering from low Hsp70 capacity. Growth of ΔΔbtn2Δ mutants is highly temperature-sensitive and results in proteostasis breakdown at non-permissive temperatures. Here, we probed for the role of the ubiquitin proteasome system in maintaining protein homeostasis in ΔΔbtn2Δ cells, which are affected in two major protein quality control branches. We show that ΔΔbtn2Δ cells induce expression of diverse stress-related pathways including the ubiquitin proteasome system to counteract the proteostasis defects. Ubiquitin proteasome system dependent degradation of the stringent Hsp70 substrate firefly Luciferase in the mutant cells mirrors such compensatory activities of the protein quality control system. Surprisingly however, the enhanced ubiquitin proteasome system activity does not improve but aggravates the growth defects of ΔΔbtn2Δ cells. Reducing ubiquitin proteasome system activity in the mutant by lowering the levels of functional 26S proteasomes improved growth, increased refolding yield of the Luciferase reporter and attenuated global stress responses. Our findings indicate that an imbalance between Hsp70-dependent refolding, sequestration and ubiquitin proteasome system-mediated degradation activities strongly affects protein homeostasis of Hsp70 capacity mutants and contributes to their severe growth phenotypes.
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Affiliation(s)
- Areeb Jawed
- Center for Molecular Biology of Heidelberg University (ZMBH), University of Heidelberg, Heidelberg, Germany,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Chi-Ting Ho
- Center for Molecular Biology of Heidelberg University (ZMBH), University of Heidelberg, Heidelberg, Germany,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Tomas Grousl
- Center for Molecular Biology of Heidelberg University (ZMBH), University of Heidelberg, Heidelberg, Germany,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Aseem Shrivastava
- Center for Molecular Biology of Heidelberg University (ZMBH), University of Heidelberg, Heidelberg, Germany,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Thomas Ruppert
- Center for Molecular Biology of Heidelberg University (ZMBH), University of Heidelberg, Heidelberg, Germany
| | - Bernd Bukau
- Center for Molecular Biology of Heidelberg University (ZMBH), University of Heidelberg, Heidelberg, Germany,German Cancer Research Center (DKFZ), Heidelberg, Germany,*Correspondence: Axel Mogk, ; Bernd Bukau,
| | - Axel Mogk
- Center for Molecular Biology of Heidelberg University (ZMBH), University of Heidelberg, Heidelberg, Germany,German Cancer Research Center (DKFZ), Heidelberg, Germany,*Correspondence: Axel Mogk, ; Bernd Bukau,
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20
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Schulte U, den Brave F, Haupt A, Gupta A, Song J, Müller CS, Engelke J, Mishra S, Mårtensson C, Ellenrieder L, Priesnitz C, Straub SP, Doan KN, Kulawiak B, Bildl W, Rampelt H, Wiedemann N, Pfanner N, Fakler B, Becker T. Mitochondrial complexome reveals quality-control pathways of protein import. Nature 2023; 614:153-159. [PMID: 36697829 PMCID: PMC9892010 DOI: 10.1038/s41586-022-05641-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 12/09/2022] [Indexed: 01/26/2023]
Abstract
Mitochondria have crucial roles in cellular energetics, metabolism, signalling and quality control1-4. They contain around 1,000 different proteins that often assemble into complexes and supercomplexes such as respiratory complexes and preprotein translocases1,3-7. The composition of the mitochondrial proteome has been characterized1,3,5,6; however, the organization of mitochondrial proteins into stable and dynamic assemblies is poorly understood for major parts of the proteome1,4,7. Here we report quantitative mapping of mitochondrial protein assemblies using high-resolution complexome profiling of more than 90% of the yeast mitochondrial proteome, termed MitCOM. An analysis of the MitCOM dataset resolves >5,200 protein peaks with an average of six peaks per protein and demonstrates a notable complexity of mitochondrial protein assemblies with distinct appearance for respiration, metabolism, biogenesis, dynamics, regulation and redox processes. We detect interactors of the mitochondrial receptor for cytosolic ribosomes, of prohibitin scaffolds and of respiratory complexes. The identification of quality-control factors operating at the mitochondrial protein entry gate reveals pathways for preprotein ubiquitylation, deubiquitylation and degradation. Interactions between the peptidyl-tRNA hydrolase Pth2 and the entry gate led to the elucidation of a constitutive pathway for the removal of preproteins. The MitCOM dataset-which is accessible through an interactive profile viewer-is a comprehensive resource for the identification, organization and interaction of mitochondrial machineries and pathways.
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Affiliation(s)
- Uwe Schulte
- grid.5963.9Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany ,grid.5963.9CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Fabian den Brave
- grid.10388.320000 0001 2240 3300Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Alexander Haupt
- grid.5963.9Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Arushi Gupta
- grid.10388.320000 0001 2240 3300Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany ,grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jiyao Song
- grid.10388.320000 0001 2240 3300Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany ,grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Catrin S. Müller
- grid.5963.9Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jeannine Engelke
- grid.10388.320000 0001 2240 3300Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Swadha Mishra
- grid.10388.320000 0001 2240 3300Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Christoph Mårtensson
- grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany ,Present Address: MTIP, Basel, Switzerland
| | - Lars Ellenrieder
- grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany ,grid.419481.10000 0001 1515 9979Present Address: Novartis, Basel, Switzerland
| | - Chantal Priesnitz
- grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sebastian P. Straub
- grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, Freiburg, Germany ,grid.482402.8Present Address: Sanofi-Aventis (Suisse), Vernier, Switzerland
| | - Kim Nguyen Doan
- grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Bogusz Kulawiak
- grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany ,grid.413454.30000 0001 1958 0162Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Wolfgang Bildl
- grid.5963.9Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Heike Rampelt
- grid.5963.9CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany ,grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nils Wiedemann
- grid.5963.9CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany ,grid.5963.9Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany ,grid.5963.9BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Nikolaus Pfanner
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany. .,Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany. .,Center for Basics in NeuroModulation, Freiburg, Germany.
| | - Thomas Becker
- grid.10388.320000 0001 2240 3300Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
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21
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Tseng CS, Chao YW, Liu YH, Huang YS, Chao HW. Dysregulated proteostasis network in neuronal diseases. Front Cell Dev Biol 2023; 11:1075215. [PMID: 36910151 PMCID: PMC9998692 DOI: 10.3389/fcell.2023.1075215] [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: 10/20/2022] [Accepted: 02/15/2023] [Indexed: 03/14/2023] Open
Abstract
Long-term maintenance of synaptic connections is important for brain function, which depends on varying proteostatic regulations to govern the functional integrity of neuronal proteomes. Proteostasis supports an interconnection of pathways that regulates the fate of proteins from synthesis to degradation. Defects in proteostatic signaling are associated with age-related functional decline and neurodegenerative diseases. Recent studies have advanced our knowledge of how cells have evolved distinct mechanisms to safely control protein homeostasis during synthesis, folding and degradation, and in different subcellular organelles and compartments. Neurodegeneration occurs when these protein quality controls are compromised by accumulated pathogenic proteins or aging to an irreversible state. Consequently, several therapeutic strategies, such as targeting the unfolded protein response and autophagy pathways, have been developed to reduce the burden of misfolded proteins and proved useful in animal models. Here, we present a brief overview of the molecular mechanisms involved in maintaining proteostatic networks, along with some examples linking dysregulated proteostasis to neuronal diseases.
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Affiliation(s)
- Ching-San Tseng
- Department of Anatomy, School of Medicine, China Medical University, Taichung, Taiwan
| | - Yu-Wen Chao
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yi-Hsiang Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Shuian Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hsu-Wen Chao
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
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22
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Differential contributions of the proteasome, autophagy, and chaperones to the clearance of arsenite-induced protein aggregates in yeast. J Biol Chem 2022; 298:102680. [PMID: 36356902 PMCID: PMC9723941 DOI: 10.1016/j.jbc.2022.102680] [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: 04/25/2022] [Revised: 10/27/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022] Open
Abstract
The poisonous metalloid arsenite induces widespread misfolding and aggregation of nascent proteins in vivo, and this mode of toxic action might underlie its suspected role in the pathology of certain protein misfolding diseases. Evolutionarily conserved protein quality-control systems protect cells against arsenite-mediated proteotoxicity, and herein, we systematically assessed the contribution of the ubiquitin-proteasome system, the autophagy-vacuole pathway, and chaperone-mediated disaggregation to the clearance of arsenite-induced protein aggregates in Saccharomyces cerevisiae. We show that the ubiquitin-proteasome system is the main pathway that clears aggregates formed during arsenite stress and that cells depend on this pathway for optimal growth. The autophagy-vacuole pathway and chaperone-mediated disaggregation both contribute to clearance, but their roles appear less prominent than the ubiquitin-proteasome system. Our in vitro assays with purified components of the yeast disaggregating machinery demonstrated that chaperone binding to aggregates formed in the presence of arsenite is impaired. Hsp104 and Hsp70 chaperone activity was unaffected by arsenite, suggesting that this metalloid influences aggregate structure, making them less accessible for chaperone-mediated disaggregation. We further show that the defect in chaperone-mediated refolding of a model protein was abrogated in a cysteine-free version of the substrate, suggesting that arsenite directly modifies cysteines in non-native target proteins. In conclusion, our study sheds novel light on the differential contributions of protein quality-control systems to aggregate clearance and cell proliferation and extends our understanding of how these systems operate during arsenite stress.
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23
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Kumar A, Mathew V, Stirling PC. Nuclear protein quality control in yeast: the latest INQuiries. J Biol Chem 2022; 298:102199. [PMID: 35760103 PMCID: PMC9305344 DOI: 10.1016/j.jbc.2022.102199] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 06/07/2022] [Accepted: 06/19/2022] [Indexed: 11/29/2022] Open
Abstract
The nucleus is a highly organized organelle with an intricate substructure of chromatin, RNAs, and proteins. This environment represents a challenge for maintaining protein quality control, since non-native proteins may interact inappropriately with other macromolecules and thus interfere with their function. Maintaining a healthy nuclear proteome becomes imperative during times of stress, such as upon DNA damage, heat shock, or starvation, when the proteome must be remodeled to effect cell survival. This is accomplished with the help of nuclear-specific chaperones, degradation pathways, and specialized structures known as protein quality control (PQC) sites that sequester proteins to help rapidly remodel the nuclear proteome. In this review, we focus on the current knowledge of PQC sites in Saccharomyces cerevisiae, particularly on a specialized nuclear PQC site called the intranuclear quality control site, a poorly understood nuclear inclusion that coordinates dynamic proteome triage decisions in yeast.
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Affiliation(s)
- Arun Kumar
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada; Dept. of Medical Genetics, University of British Columbia, Vancouver Canada
| | - Veena Mathew
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada; Dept. of Medical Genetics, University of British Columbia, Vancouver Canada.
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24
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Eldeeb MA, Thomas RA, Ragheb MA, Fallahi A, Fon EA. Mitochondrial quality control in health and in Parkinson's disease. Physiol Rev 2022; 102:1721-1755. [PMID: 35466694 DOI: 10.1152/physrev.00041.2021] [Citation(s) in RCA: 74] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
As a central hub for cellular metabolism and intracellular signalling, the mitochondrion is a pivotal organelle, dysfunction of which has been linked to several human diseases including neurodegenerative disorders, and in particular Parkinson's disease. An inherent challenge that mitochondria face is the continuous exposure to diverse stresses which increase their likelihood of dysregulation. In response, eukaryotic cells have evolved sophisticated quality control mechanisms to monitor, identify, repair and/or eliminate abnormal or misfolded proteins within the mitochondrion and/or the dysfunctional mitochondrion itself. Chaperones identify unstable or otherwise abnormal conformations in mitochondrial proteins and can promote their refolding to recover their correct conformation and stability. However, if repair is not possible, the abnormal protein is selectively degraded to prevent potentially damaging interactions with other proteins or its oligomerization into toxic multimeric complexes. The autophagic-lysosomal system and the ubiquitin-proteasome system mediate the selective and targeted degradation of such abnormal or misfolded protein species. Mitophagy (a specific kind of autophagy) mediates the selective elimination of dysfunctional mitochondria, in order to prevent the deleterious effects the dysfunctional organelles within the cell. Despite our increasing understanding of the molecular responses toward dysfunctional mitochondria, many key aspects remain relatively poorly understood. Herein, we review the emerging mechanisms of mitochondrial quality control including quality control strategies coupled to mitochondrial import mechanisms. In addition, we review the molecular mechanisms regulating mitophagy with an emphasis on the regulation of PINK1/PARKIN-mediated mitophagy in cellular physiology and in the context of Parkinson's disease cell biology.
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Affiliation(s)
- Mohamed A Eldeeb
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Rhalena A Thomas
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Mohamed A Ragheb
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Armaan Fallahi
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Edward A Fon
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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25
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Song J, Becker T. Fidelity of organellar protein targeting. Curr Opin Cell Biol 2022; 75:102071. [DOI: 10.1016/j.ceb.2022.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 11/26/2022]
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26
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Three Microbial Musketeers of the Seas: Shewanella baltica, Aliivibrio fischeri and Vibrio harveyi, and Their Adaptation to Different Salinity Probed by a Proteomic Approach. Int J Mol Sci 2022; 23:ijms23020619. [PMID: 35054801 PMCID: PMC8775919 DOI: 10.3390/ijms23020619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 11/17/2022] Open
Abstract
Osmotic changes are common challenges for marine microorganisms. Bacteria have developed numerous ways of dealing with this stress, including reprogramming of global cellular processes. However, specific molecular adaptation mechanisms to osmotic stress have mainly been investigated in terrestrial model bacteria. In this work, we aimed to elucidate the basis of adjustment to prolonged salinity challenges at the proteome level in marine bacteria. The objects of our studies were three representatives of bacteria inhabiting various marine environments, Shewanella baltica, Vibrio harveyi and Aliivibrio fischeri. The proteomic studies were performed with bacteria cultivated in increased and decreased salinity, followed by proteolytic digestion of samples which were then subjected to liquid chromatography with tandem mass spectrometry analysis. We show that bacteria adjust at all levels of their biological processes, from DNA topology through gene expression regulation and proteasome assembly, to transport and cellular metabolism. The finding that many similar adaptation strategies were observed for both low- and high-salinity conditions is particularly striking. The results show that adaptation to salinity challenge involves the accumulation of DNA-binding proteins and increased polyamine uptake. We hypothesize that their function is to coat and protect the nucleoid to counteract adverse changes in DNA topology due to ionic shifts.
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27
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Borgert L, Mishra S, den Brave F. Quality control of cytoplasmic proteins inside the nucleus. Comput Struct Biotechnol J 2022; 20:4618-4625. [PMID: 36090811 PMCID: PMC9440239 DOI: 10.1016/j.csbj.2022.08.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 11/03/2022] Open
Abstract
A complex network of molecular chaperones and proteolytic machinery safeguards the proteins which comprise the proteome, from the time they are synthesized on ribosomes to their destruction via proteolysis. Impaired protein quality control results in the accumulation of aberrant proteins, which may undergo unwanted spurious interactions with other proteins, thereby interfering with a broad range of cellular functions. To protect the cellular environment, such proteins are degraded or sequestered into inclusions in different subcellular compartments. Recent findings demonstrate that aberrant or mistargeted proteins from different cytoplasmic compartments are removed from their environment by transporting them into the nucleus. These proteins are degraded by the nuclear ubiquitin–proteasome system or sequestered into intra-nuclear inclusions. Here, we discuss the emerging role of the nucleus as a cellular quality compartment based on recent findings in the yeast Saccharomyces cerevisiae. We describe the current knowledge on cytoplasmic substrates of nuclear protein quality control, the mechanism of nuclear import of such proteins, as well as possible advantages and risks of nuclear sequestration of aberrant proteins.
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28
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den Brave F, Gupta A, Becker T. Protein Quality Control at the Mitochondrial Surface. Front Cell Dev Biol 2021; 9:795685. [PMID: 34926473 PMCID: PMC8678412 DOI: 10.3389/fcell.2021.795685] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/05/2021] [Indexed: 12/14/2022] Open
Abstract
Mitochondria contain two membranes, the outer and inner membrane. The outer membrane fulfills crucial functions for the communication of mitochondria with the cellular environment like exchange of lipids via organelle contact sites, the transport of metabolites and the formation of a signaling platform in apoptosis and innate immunity. The translocase of the outer membrane (TOM complex) forms the entry gate for the vast majority of precursor proteins that are produced on cytosolic ribosomes. Surveillance of the functionality of outer membrane proteins is critical for mitochondrial functions and biogenesis. Quality control mechanisms remove defective and mistargeted proteins from the outer membrane as well as precursor proteins that clog the TOM complex. Selective degradation of single proteins is also an important mode to regulate mitochondrial dynamics and initiation of mitophagy pathways. Whereas inner mitochondrial compartments are equipped with specific proteases, the ubiquitin-proteasome system is a central player in protein surveillance on the mitochondrial surface. In this review, we summarize our current knowledge about the molecular mechanisms that govern quality control of proteins at the outer mitochondrial membrane.
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Affiliation(s)
- Fabian den Brave
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Arushi Gupta
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
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29
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Kumari D, Fisher EA, Brodsky JL. Hsp40s play distinct roles during the initial stages of apolipoprotein B biogenesis. Mol Biol Cell 2021; 33:ar15. [PMID: 34910568 PMCID: PMC9236142 DOI: 10.1091/mbc.e21-09-0436] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Apolipoprotein B (ApoB) is the primary component of atherogenic lipoproteins, which transport serum fats and cholesterol. Therefore, elevated levels of circulating ApoB are a primary risk factor for cardiovascular disease. During ApoB biosynthesis in the liver and small intestine under nutrient-rich conditions, ApoB cotranslationally translocates into the endoplasmic reticulum (ER) and is lipidated and ultimately secreted. Under lipid-poor conditions, ApoB is targeted for ER Associated Degradation (ERAD). Although prior work identified select chaperones that regulate ApoB biogenesis, the contributions of cytoplasmic Hsp40s are undefined. To this end, we screened ApoB-expressing yeast and determined that a class A ER-associated Hsp40, Ydj1, associates with and facilitates the ERAD of ApoB. Consistent with these results, a homologous Hsp40, DNAJA1, functioned similarly in rat hepatoma cells. DNAJA1 deficient cells also secreted hyperlipidated lipoproteins, in accordance with attenuated ERAD. In contrast to the role of DNAJA1 during ERAD, DNAJB1-a class B Hsp40-helped stabilize ApoB. Depletion of DNAJA1 and DNAJB1 also led to opposing effects on ApoB ubiquitination. These data represent the first example in which different Hsp40s exhibit disparate effects during regulated protein biogenesis in the ER, and highlight distinct roles that chaperones can play on a single ERAD substrate.
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Affiliation(s)
- Deepa Kumari
- Department of Biological Sciences, A320 Langley Hall, Fifth & Ruskin Ave, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Edward A Fisher
- Department of Medicine, Leon H. Charney Division of Cardiology, Cardiovascular Research Center, New York University Grossman School of Medicine, New York, United States
| | - Jeffrey L Brodsky
- Department of Biological Sciences, A320 Langley Hall, Fifth & Ruskin Ave, University of Pittsburgh, Pittsburgh, PA 15260 USA
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30
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Ubiquitin Ligase Redundancy and Nuclear-Cytoplasmic Localization in Yeast Protein Quality Control. Biomolecules 2021; 11:biom11121821. [PMID: 34944465 PMCID: PMC8698790 DOI: 10.3390/biom11121821] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 12/12/2022] Open
Abstract
The diverse functions of proteins depend on their proper three-dimensional folding and assembly. Misfolded cellular proteins can potentially harm cells by forming aggregates in their resident compartments that can interfere with vital cellular processes or sequester important factors. Protein quality control (PQC) pathways are responsible for the repair or destruction of these abnormal proteins. Most commonly, the ubiquitin-proteasome system (UPS) is employed to recognize and degrade those proteins that cannot be refolded by molecular chaperones. Misfolded substrates are ubiquitylated by a subset of ubiquitin ligases (also called E3s) that operate in different cellular compartments. Recent research in Saccharomyces cerevisiae has shown that the most prominent ligases mediating cytoplasmic and nuclear PQC have overlapping yet distinct substrate specificities. Many substrates have been characterized that can be targeted by more than one ubiquitin ligase depending on their localization, and cytoplasmic PQC substrates can be directed to the nucleus for ubiquitylation and degradation. Here, we review some of the major yeast PQC ubiquitin ligases operating in the nucleus and cytoplasm, as well as current evidence indicating how these ligases can often function redundantly toward substrates in these compartments.
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31
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Kumar AV, Lapierre LR. Location, location, location: subcellular protein partitioning in proteostasis and aging. Biophys Rev 2021; 13:931-941. [PMID: 35047088 PMCID: PMC8724496 DOI: 10.1007/s12551-021-00890-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/01/2021] [Indexed: 12/25/2022] Open
Abstract
Somatic maintenance and cell survival rely on proper protein homeostasis to ensure reliable functions across the cell and to prevent proteome collapse. Maintaining protein folding and solubility is central to proteostasis and is coordinated by protein synthesis, chaperoning, and degradation capacities. An emerging aspect that influences proteostasis is the dynamic protein partitioning across different subcellular structures and compartments. Here, we review recent literature related to nucleocytoplasmic partitioning of proteins, nuclear and cytoplasmic quality control mechanisms, and their impact on the development of age-related diseases. We also highlight new points of entry to modulate spatially-regulated proteostatic mechanisms to delay aging.
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Affiliation(s)
- Anita V. Kumar
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 USA
| | - Louis R. Lapierre
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 USA
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32
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Blumenstock S, Schulz-Trieglaff EK, Voelkl K, Bolender AL, Lapios P, Lindner J, Hipp MS, Hartl FU, Klein R, Dudanova I. Fluc-EGFP reporter mice reveal differential alterations of neuronal proteostasis in aging and disease. EMBO J 2021; 40:e107260. [PMID: 34410010 PMCID: PMC8488555 DOI: 10.15252/embj.2020107260] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 07/09/2021] [Accepted: 07/19/2021] [Indexed: 12/22/2022] Open
Abstract
The cellular protein quality control machinery is important for preventing protein misfolding and aggregation. Declining protein homeostasis (proteostasis) is believed to play a crucial role in age‐related neurodegenerative disorders. However, how neuronal proteostasis capacity changes in different diseases is not yet sufficiently understood, and progress in this area has been hampered by the lack of tools to monitor proteostasis in mammalian models. Here, we have developed reporter mice for in vivo analysis of neuronal proteostasis. The mice express EGFP‐fused firefly luciferase (Fluc‐EGFP), a conformationally unstable protein that requires chaperones for proper folding, and that reacts to proteotoxic stress by formation of intracellular Fluc‐EGFP foci and by reduced luciferase activity. Using these mice, we provide evidence for proteostasis decline in the aging brain. Moreover, we find a marked reaction of the Fluc‐EGFP sensor in a mouse model of tauopathy, but not in mouse models of Huntington’s disease. Mechanistic investigations in primary neuronal cultures demonstrate that different types of protein aggregates have distinct effects on the cellular protein quality control. Thus, Fluc‐EGFP reporter mice enable new insights into proteostasis alterations in different diseases.
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Affiliation(s)
- Sonja Blumenstock
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Martinsried, Germany.,Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | | | - Kerstin Voelkl
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Martinsried, Germany.,Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Anna-Lena Bolender
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Martinsried, Germany.,Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Paul Lapios
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Martinsried, Germany.,Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Jana Lindner
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Mark S Hipp
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany.,Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Rüdiger Klein
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Irina Dudanova
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Martinsried, Germany.,Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
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33
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Quality control of protein import into mitochondria. Biochem J 2021; 478:3125-3143. [PMID: 34436539 DOI: 10.1042/bcj20190584] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022]
Abstract
Mitochondria import about 1000 proteins that are produced as precursors on cytosolic ribosomes. Defects in mitochondrial protein import result in the accumulation of non-imported precursor proteins and proteotoxic stress. The cell is equipped with different quality control mechanisms to monitor protein transport into mitochondria. First, molecular chaperones guide unfolded proteins to mitochondria and deliver non-imported proteins to proteasomal degradation. Second, quality control factors remove translocation stalled precursor proteins from protein translocases. Third, protein translocases monitor protein sorting to mitochondrial subcompartments. Fourth, AAA proteases of the mitochondrial subcompartments remove mislocalized or unassembled proteins. Finally, impaired efficiency of protein transport is an important sensor for mitochondrial dysfunction and causes the induction of cellular stress responses, which could eventually result in the removal of the defective mitochondria by mitophagy. In this review, we summarize our current understanding of quality control mechanisms that govern mitochondrial protein transport.
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34
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Zhao S, Huang D, Peng J. Nucleolus-localized Def-CAPN3 protein degradation pathway and its role in cell cycle control and ribosome biogenesis. J Genet Genomics 2021; 48:955-960. [PMID: 34452850 DOI: 10.1016/j.jgg.2021.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/16/2021] [Accepted: 06/17/2021] [Indexed: 12/25/2022]
Abstract
The nucleolus, as the 'nucleus of the nucleus', is a prominent subcellular organelle in a eukaryocyte. The nucleolus serves as the centre for ribosome biogenesis, as well as an important site for cell-cycle regulation, cellular senescence, and stress response. The protein composition of the nucleolus changes dynamically through protein turnover to meet the needs of cellular activities or stress responses. Recent studies have identified a nucleolus-localized protein degradation pathway in zebrafish and humans, namely the Def-CAPN3 pathway, which is essential to ribosome production and cell-cycle progression, by controlling the turnover of multiple substrates (e.g., ribosomal small-subunit [SSU] processome component Mpp10, transcription factor p53, check-point proteins Chk1 and Wee1). This pathway relies on the Ca2+-dependent cysteine proteinase CAPN3 and is independent of the ubiquitin-mediated proteasome pathway. CAPN3 is recruited by nucleolar protein Def from cytoplasm to nucleolus, where it proteolyzes its substrates which harbor a CAPN3 recognition-motif. Def depletion leads to the exclusion of CAPN3 and accumulation of p53, Wee1, Chk1, and Mpp10 in the nucleolus that result in cell-cycle arrest and rRNA processing abnormality. Here, we summarize the discovery of the Def-CAPN3 pathway and propose its biological role in cell-cycle control and ribosome biogenesis.
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Affiliation(s)
- Shuyi Zhao
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Delai Huang
- Department of Biology, University of Virginia, Charlottesville, VA 22904, United States
| | - Jinrong Peng
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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35
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Reversible protein aggregation as cytoprotective mechanism against heat stress. Curr Genet 2021; 67:849-855. [PMID: 34091720 PMCID: PMC8592950 DOI: 10.1007/s00294-021-01191-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 01/01/2023]
Abstract
Temperature fluctuation is one of the most frequent threats to which organisms are exposed in nature. The activation of gene expression programs that trigger the transcription of heat stress-protective genes is the main cellular response to resist high temperatures. In addition, reversible accumulation and compartmentalization of thermosensitive proteins in high-order molecular assemblies are emerging as critical mechanisms to ensure cellular protection upon heat stress. Here, we summarize representative examples of membrane-less intracellular bodies formed upon heat stress in yeasts and human cells and highlight how protein aggregation can be turned into a cytoprotective mechanism.
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36
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Lei L, Wu Z, Winklhofer KF. Protein quality control by the proteasome and autophagy: A regulatory role of ubiquitin and liquid-liquid phase separation. Matrix Biol 2021; 100-101:9-22. [DOI: 10.1016/j.matbio.2020.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 12/14/2022]
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37
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Nuclear Ubiquitin-Proteasome Pathways in Proteostasis Maintenance. Biomolecules 2021; 11:biom11010054. [PMID: 33406777 PMCID: PMC7824755 DOI: 10.3390/biom11010054] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/19/2022] Open
Abstract
Protein homeostasis, or proteostasis, is crucial for the functioning of a cell, as proteins that are mislocalized, present in excessive amounts, or aberrant due to misfolding or other type of damage can be harmful. Proteostasis includes attaining the correct protein structure, localization, and the formation of higher order complexes, and well as the appropriate protein concentrations. Consequences of proteostasis imbalance are evident in a range of neurodegenerative diseases characterized by protein misfolding and aggregation, such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis. To protect the cell from the accumulation of aberrant proteins, a network of protein quality control (PQC) pathways identifies the substrates and direct them towards refolding or elimination via regulated protein degradation. The main pathway for degradation of misfolded proteins is the ubiquitin-proteasome system. PQC pathways have been first described in the cytoplasm and the endoplasmic reticulum, however, accumulating evidence indicates that the nucleus is an important PQC compartment for ubiquitination and proteasomal degradation of not only nuclear, but also cytoplasmic proteins. In this review, we summarize the nuclear ubiquitin-proteasome pathways involved in proteostasis maintenance in yeast, focusing on inner nuclear membrane-associated degradation (INMAD) and San1-mediated protein quality control.
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38
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Mathew V, Kumar A, Jiang YK, West K, Tam AS, Stirling PC. Cdc48 regulates intranuclear quality control sequestration of the Hsh155 splicing factor in budding yeast. J Cell Sci 2020; 133:jcs.252551. [PMID: 33172985 DOI: 10.1242/jcs.252551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/30/2020] [Indexed: 11/20/2022] Open
Abstract
Cdc48 (known as VCP in mammals) is a highly conserved ATPase chaperone that plays an essential role in the assembly and disassembly of protein-DNA complexes and in degradation of misfolded proteins. We find that in Saccharomyces cerevisiae budding yeast, Cdc48 accumulates during cellular stress at intranuclear protein quality control sites (INQ). We show that Cdc48 function is required to suppress INQ formation under non-stress conditions and to promote recovery following genotoxic stress. Cdc48 physically associates with the INQ substrate and splicing factor Hsh155, and regulates its assembly with partner proteins. Accordingly, cdc48 mutants have defects in splicing and show spontaneous distribution of Hsh155 to INQ aggregates, where it is stabilized. Overall, this study shows that Cdc48 regulates deposition of proteins at INQ and suggests a previously unknown role for Cdc48 in the regulation or stabilization of splicing subcomplexes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Veena Mathew
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver V5Z 1L3, Canada
| | - Arun Kumar
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver V5Z 1L3, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver V6H 3N1, Canada
| | - Yangyang K Jiang
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver V5Z 1L3, Canada
| | - Kyra West
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver V5Z 1L3, Canada
| | - Annie S Tam
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver V5Z 1L3, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver V6H 3N1, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver V5Z 1L3, Canada .,Department of Medical Genetics, University of British Columbia, Vancouver V6H 3N1, Canada
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Sheng J, Olrichs NK, Gadella BM, Kaloyanova DV, Helms JB. Regulation of Functional Protein Aggregation by Multiple Factors: Implications for the Amyloidogenic Behavior of the CAP Superfamily Proteins. Int J Mol Sci 2020; 21:E6530. [PMID: 32906672 PMCID: PMC7554809 DOI: 10.3390/ijms21186530] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022] Open
Abstract
The idea that amyloid fibrils and other types of protein aggregates are toxic for cells has been challenged by the discovery of a variety of functional aggregates. However, an identification of crucial differences between pathological and functional aggregation remains to be explored. Functional protein aggregation is often reversible by nature in order to respond properly to changing physiological conditions of the cell. In addition, increasing evidence indicates that fast fibril growth is a feature of functional amyloids, providing protection against the long-term existence of potentially toxic oligomeric intermediates. It is becoming clear that functional protein aggregation is a complexly organized process that can be mediated by a multitude of biomolecular factors. In this overview, we discuss the roles of diverse biomolecules, such as lipids/membranes, glycosaminoglycans, nucleic acids and metal ions, in regulating functional protein aggregation. Our studies on the protein GAPR-1 revealed that several of these factors influence the amyloidogenic properties of this protein. These observations suggest that GAPR-1, as well as the cysteine-rich secretory proteins, antigen 5 and pathogenesis-related proteins group 1 (CAP) superfamily of proteins that it belongs to, require the assembly into an amyloid state to exert several of their functions. A better understanding of functional aggregate formation may also help in the prevention and treatment of amyloid-related diseases.
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Affiliation(s)
| | | | | | | | - J. Bernd Helms
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (J.S.); (N.K.O.); (B.M.G.); (D.V.K.)
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Releasing the Lockdown: An Emerging Role for the Ubiquitin-Proteasome System in the Breakdown of Transient Protein Inclusions. Biomolecules 2020; 10:biom10081168. [PMID: 32784966 PMCID: PMC7463783 DOI: 10.3390/biom10081168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/06/2020] [Accepted: 08/08/2020] [Indexed: 12/20/2022] Open
Abstract
Intracellular protein inclusions are diverse cellular entities with distinct biological properties. They vary in their protein content, sequestration sites, physiological function, conditions for their generation, and turnover rates. Major distinctions have been recognized between stationary amyloids and dynamic, misfolded protein deposits. The former being a dead end for irreversibly misfolded proteins, hence, cleared predominantly by autophagy, while the latter consists of a protein-quality control mechanism, important for cell endurance, where proteins are sequestered during proteotoxic stress and resolved upon its relief. Accordingly, the disaggregation of transient inclusions is a regulated process consisting of protein solubilization, followed by a triage step to either refolding or to ubiquitin-mediated degradation. Recent studies have demonstrated an indispensable role in disaggregation for components of the chaperone and the ubiquitin-proteasome systems. These include heat-shock chaperones of the 40/70/100 kDa families, the proteasome, proteasome substrate shuttling factors, and deubiquitylating enzymes. Thus, a functional link has been established between the chaperone machinery that extracts proteins from transient deposits and 26S proteasome-dependent disaggregation, indicative of a coordinated process. In this review, we discuss data emanating from these important studies and subsequently consolidate the information in the form of a working model for the disaggregation mechanism.
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Abildgaard AB, Gersing SK, Larsen-Ledet S, Nielsen SV, Stein A, Lindorff-Larsen K, Hartmann-Petersen R. Co-Chaperones in Targeting and Delivery of Misfolded Proteins to the 26S Proteasome. Biomolecules 2020; 10:biom10081141. [PMID: 32759676 PMCID: PMC7463752 DOI: 10.3390/biom10081141] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis (proteostasis) is essential for the cell and is maintained by a highly conserved protein quality control (PQC) system, which triages newly synthesized, mislocalized and misfolded proteins. The ubiquitin-proteasome system (UPS), molecular chaperones, and co-chaperones are vital PQC elements that work together to facilitate degradation of misfolded and toxic protein species through the 26S proteasome. However, the underlying mechanisms are complex and remain partly unclear. Here, we provide an overview of the current knowledge on the co-chaperones that directly take part in targeting and delivery of PQC substrates for degradation. While J-domain proteins (JDPs) target substrates for the heat shock protein 70 (HSP70) chaperones, nucleotide-exchange factors (NEFs) deliver HSP70-bound substrates to the proteasome. So far, three NEFs have been established in proteasomal delivery: HSP110 and the ubiquitin-like (UBL) domain proteins BAG-1 and BAG-6, the latter acting as a chaperone itself and carrying its substrates directly to the proteasome. A better understanding of the individual delivery pathways will improve our ability to regulate the triage, and thus regulate the fate of aberrant proteins involved in cell stress and disease, examples of which are given throughout the review.
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Affiliation(s)
- Amanda B. Abildgaard
- Department of Biology, The Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; (A.B.A.); (S.K.G.); (S.L.-L.); (K.L.-L.)
| | - Sarah K. Gersing
- Department of Biology, The Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; (A.B.A.); (S.K.G.); (S.L.-L.); (K.L.-L.)
| | - Sven Larsen-Ledet
- Department of Biology, The Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; (A.B.A.); (S.K.G.); (S.L.-L.); (K.L.-L.)
| | - Sofie V. Nielsen
- Department of Biology, Section for Computational and RNA Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; (S.V.N.); (A.S.)
| | - Amelie Stein
- Department of Biology, Section for Computational and RNA Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; (S.V.N.); (A.S.)
| | - Kresten Lindorff-Larsen
- Department of Biology, The Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; (A.B.A.); (S.K.G.); (S.L.-L.); (K.L.-L.)
| | - Rasmus Hartmann-Petersen
- Department of Biology, The Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; (A.B.A.); (S.K.G.); (S.L.-L.); (K.L.-L.)
- Correspondence:
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