1
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Adolf F, Du J, Goodall EA, Walsh RM, Rawson S, von Gronau S, Harper JW, Hanna J, Schulman BA. Visualizing chaperone-mediated multistep assembly of the human 20S proteasome. Nat Struct Mol Biol 2024:10.1038/s41594-024-01268-9. [PMID: 38600324 DOI: 10.1038/s41594-024-01268-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
Dedicated assembly factors orchestrate the stepwise production of many molecular machines, including the 28-subunit proteasome core particle (CP) that mediates protein degradation. Here we report cryo-electron microscopy reconstructions of seven recombinant human subcomplexes that visualize all five chaperones and the three active site propeptides across a wide swath of the assembly pathway. Comparison of these chaperone-bound intermediates and a matching mature CP reveals molecular mechanisms determining the order of successive subunit additions, as well as how proteasome subcomplexes and assembly factors structurally adapt upon progressive subunit incorporation to stabilize intermediates, facilitate the formation of subsequent intermediates and ultimately rearrange to coordinate proteolytic activation with gated access to active sites. This work establishes a methodologic approach for structural analysis of multiprotein complex assembly intermediates, illuminates specific functions of assembly factors and reveals conceptual principles underlying human proteasome biogenesis, thus providing an explanation for many previous biochemical and genetic observations.
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Affiliation(s)
- Frank Adolf
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
| | - Jiale Du
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Ellen A Goodall
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Richard M Walsh
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Shaun Rawson
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Susanne von Gronau
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - J Wade Harper
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - John Hanna
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA.
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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2
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Poli MC. Proteasome disorders and inborn errors of immunity. Immunol Rev 2024; 322:283-299. [PMID: 38071420 DOI: 10.1111/imr.13299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/27/2023] [Accepted: 11/30/2023] [Indexed: 03/20/2024]
Abstract
Inborn errors of immunity (IEI) or primary immune deficiencies (PIDD) are caused by variants in genes encoding for molecules that are relevant to the innate or adaptive immune response. To date, defects in more than 450 different genes have been identified as causes of IEI, causing a constellation of heterogeneous clinical manifestations ranging from increased susceptibility to infection, to autoimmunity or autoinflammation. IEI that are mainly characterized by autoinflammation are broadly classified according to the inflammatory pathway that they predominantly perturb. Among autoinflammatory IEI are those characterized by the transcriptional upregulation of type I interferon genes and are referred to as interferonopathies. Within the spectrum of interferonopathies, genetic defects that affect the proteasome have been described to cause autoinflammatory disease and represent a growing area of investigation. This review is focused on describing the clinical, genetic, and molecular aspects of IEI associated with mutations that affect the proteasome and how the study of these diseases has contributed to delineate therapeutic interventions.
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Affiliation(s)
- M Cecilia Poli
- Faculty of Medicine, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
- Unit of Immunology and Rheumatology Hospital Roberto del Río, Santiago, Chile
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3
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Bhattarai D, Lee SO, MacMillan-Crow LA, Parajuli N. Normal Proteasome Function Is Needed to Prevent Kidney Graft Injury during Cold Storage Followed by Transplantation. Int J Mol Sci 2024; 25:2147. [PMID: 38396827 PMCID: PMC10888692 DOI: 10.3390/ijms25042147] [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: 01/08/2024] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
Kidney transplantation is the preferred treatment for end-stage kidney disease (ESKD). However, there is a shortage of transplantable kidneys, and donor organs can be damaged by necessary cold storage (CS). Although CS improves the viability of kidneys from deceased donors, prolonged CS negatively affects transplantation outcomes. Previously, we reported that renal proteasome function decreased after rat kidneys underwent CS followed by transplantation (CS + Tx). Here, we investigated the mechanism underlying proteasome dysfunction and the role of the proteasome in kidney graft outcome using a rat model of CS + Tx. We found that the key proteasome subunits β5, α3, and Rpt6 are modified, and proteasome assembly is impaired. Specifically, we detected the modification and aggregation of Rpt6 after CS + Tx, and Rpt6 modification was reversed when renal extracts were treated with protein phosphatases. CS + Tx kidneys also displayed increased levels of nitrotyrosine, an indicator of peroxynitrite (a reactive oxygen species, ROS), compared to sham. Because the Rpt6 subunit appeared to aggregate, we investigated the effect of CS + Tx-mediated ROS (peroxynitrite) generation on renal proteasome assembly and function. We treated NRK cells with exogenous peroxynitrite and evaluated PAC1 (proteasome assembly chaperone), Rpt6, and β5. Peroxynitrite induced a dose-dependent decrease in PAC1 and β5, but Rpt6 was not affected (protein level or modification). Finally, serum creatinine increased when we inhibited the proteasome in transplanted donor rat kidneys (without CS), recapitulating the effects of CS + Tx. These findings underscore the effects of CS + Tx on renal proteasome subunit dysregulation and also highlight the significance of proteasome activity in maintaining graft function following CS + Tx.
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Affiliation(s)
- Dinesh Bhattarai
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Seong-Ok Lee
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Lee Ann MacMillan-Crow
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Nirmala Parajuli
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
- Division of Nephrology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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4
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Adolf F, Du J, Goodall EA, Walsh RM, Rawson S, von Gronau S, Harper JW, Hanna J, Schulman BA. Visualizing chaperone-mediated multistep assembly of the human 20S proteasome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.27.577538. [PMID: 38328185 PMCID: PMC10849659 DOI: 10.1101/2024.01.27.577538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Dedicated assembly factors orchestrate stepwise production of many molecular machines, including the 28-subunit proteasome core particle (CP) that mediates protein degradation. Here, we report cryo-EM reconstructions of seven recombinant human subcomplexes that visualize all five chaperones and the three active site propeptides across a wide swath of the assembly pathway. Comparison of these chaperone-bound intermediates and a matching mature CP reveals molecular mechanisms determining the order of successive subunit additions, and how proteasome subcomplexes and assembly factors structurally adapt upon progressive subunit incorporation to stabilize intermediates, facilitate the formation of subsequent intermediates, and ultimately rearrange to coordinate proteolytic activation with gated access to active sites. The structural findings reported here explain many previous biochemical and genetic observations. This work establishes a methodologic approach for structural analysis of multiprotein complex assembly intermediates, illuminates specific functions of assembly factors, and reveals conceptual principles underlying human proteasome biogenesis.
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Affiliation(s)
- Frank Adolf
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Jiale Du
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Ellen A. Goodall
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Richard M. Walsh
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Shaun Rawson
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Susanne von Gronau
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - J. Wade Harper
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - John Hanna
- Department of Pathology, Harvard Medical School and Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Brenda A. Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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5
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Walsh RM, Rawson S, Schnell HM, Velez B, Rajakumar T, Hanna J. Structure of the preholoproteasome reveals late steps in proteasome core particle biogenesis. Nat Struct Mol Biol 2023; 30:1516-1524. [PMID: 37653242 PMCID: PMC10879985 DOI: 10.1038/s41594-023-01081-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 07/26/2023] [Indexed: 09/02/2023]
Abstract
Assembly of the proteasome's core particle (CP), a barrel-shaped chamber of four stacked rings, requires five chaperones and five subunit propeptides. Fusion of two half-CP precursors yields a complete structure but remains immature until active site maturation. Here, using Saccharomyces cerevisiae, we report a high-resolution cryogenic electron microscopy structure of preholoproteasome, a post-fusion assembly intermediate. Our data reveal how CP midline-spanning interactions induce local changes in structure, facilitating maturation. Unexpectedly, we find that cleavage may not be sufficient for propeptide release, as residual interactions with chaperones such as Ump1 hold them in place. We evaluated previous models proposing that dynamic conformational changes in chaperones drive CP fusion and autocatalytic activation by comparing preholoproteasome to pre-fusion intermediates. Instead, the data suggest a scaffolding role for the chaperones Ump1 and Pba1/Pba2. Our data clarify key aspects of CP assembly, suggest that undiscovered mechanisms exist to explain CP fusion/activation, and have relevance for diseases of defective CP biogenesis.
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Affiliation(s)
- Richard M Walsh
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Shaun Rawson
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Helena M Schnell
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Benjamin Velez
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Tamayanthi Rajakumar
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - John Hanna
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA.
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6
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Silhan J, Fajtova P, Bartosova J, Hurysz BM, Almaliti J, Miyamoto Y, Eckmann L, Gerwick WH, O’Donoghue AJ, Boura E. Structural elucidation of recombinant Trichomonas vaginalis 20S proteasome bound to covalent inhibitors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.17.553660. [PMID: 37645851 PMCID: PMC10462138 DOI: 10.1101/2023.08.17.553660] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Proteasomes are essential for protein homeostasis in mammalian cells1-4 and in protozoan parasites such as Trichomonas vaginalis (Tv).5 Tv and other protozoan 20S proteasomes have been validated as druggable targets.6-8 However, in the case of Tv 20S proteasome (Tv20S), biochemical and structural studies were impeded by low yields and purity of the native proteasome. We successfully made recombinant Tv20S by expressing all seven α and seven β subunits together with the Ump-1 chaperone in insect cells. We isolated recombinant proteasome and showed that it was biochemically indistinguishable from the native enzyme. We confirmed that the recombinant Tv20S is inhibited by the natural product marizomib (MZB)9 and the recently developed peptide inhibitor carmaphycin-17 (CP-17)8,10. Specifically, MZB binds to the β1, β2 and β5 subunits, while CP-17 binds the β2 and β5 subunits. Next, we obtained cryo-EM structures of Tv20S in complex with these covalent inhibitors at 2.8Å resolution. The structures revealed the overall fold of the Tv20S and the binding mode of MZB and CP-17. Our work explains the low specificity of MZB and higher specificity of CP-17 towards Tv20S as compared to human proteasome and provides the platform for the development of Tv20S inhibitors for treatment of trichomoniasis.
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Affiliation(s)
- Jan Silhan
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
| | - Pavla Fajtova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92037, USA
| | - Jitka Bartosova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
| | - Brianna M. Hurysz
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92037, USA
| | - Jehad Almaliti
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92037, USA
| | - Yukiko Miyamoto
- Division of Gastroenterology, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Lars Eckmann
- Division of Gastroenterology, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - William H. Gerwick
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92037, USA
| | - Anthony J. O’Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92037, USA
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague 6, Czech Republic
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7
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Betancourt D, Lawal T, Tomko RJ. Wiggle and Shake: Managing and Exploiting Conformational Dynamics during Proteasome Biogenesis. Biomolecules 2023; 13:1223. [PMID: 37627288 PMCID: PMC10452565 DOI: 10.3390/biom13081223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023] Open
Abstract
The 26S proteasome is the largest and most complicated protease known, and changes to proteasome assembly or function contribute to numerous human diseases. Assembly of the 26S proteasome from its ~66 individual polypeptide subunits is a highly orchestrated process requiring the concerted actions of both intrinsic elements of proteasome subunits, as well as assistance by extrinsic, dedicated proteasome assembly chaperones. With the advent of near-atomic resolution cryo-electron microscopy, it has become evident that the proteasome is a highly dynamic machine, undergoing numerous conformational changes in response to ligand binding and during the proteolytic cycle. In contrast, an appreciation of the role of conformational dynamics during the biogenesis of the proteasome has only recently begun to emerge. Herein, we review our current knowledge of proteasome assembly, with a particular focus on how conformational dynamics guide particular proteasome biogenesis events. Furthermore, we highlight key emerging questions in this rapidly expanding area.
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Affiliation(s)
| | | | - Robert J. Tomko
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA; (D.B.); (T.L.)
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8
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Groh C, Haberkant P, Stein F, Filbeck S, Pfeffer S, Savitski MM, Boos F, Herrmann JM. Mitochondrial dysfunction rapidly modulates the abundance and thermal stability of cellular proteins. Life Sci Alliance 2023; 6:e202201805. [PMID: 36941057 PMCID: PMC10027898 DOI: 10.26508/lsa.202201805] [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: 11/04/2022] [Revised: 03/03/2023] [Accepted: 03/03/2023] [Indexed: 03/23/2023] Open
Abstract
Cellular functionality relies on a well-balanced, but highly dynamic proteome. Dysfunction of mitochondrial protein import leads to the cytosolic accumulation of mitochondrial precursor proteins which compromise cellular proteostasis and trigger a mitoprotein-induced stress response. To dissect the effects of mitochondrial dysfunction on the cellular proteome as a whole, we developed pre-post thermal proteome profiling. This multiplexed time-resolved proteome-wide thermal stability profiling approach with isobaric peptide tags in combination with a pulsed SILAC labelling elucidated dynamic proteostasis changes in several dimensions: In addition to adaptations in protein abundance, we observed rapid modulations of the thermal stability of individual cellular proteins. Different functional groups of proteins showed characteristic response patterns and reacted with group-specific kinetics, allowing the identification of functional modules that are relevant for mitoprotein-induced stress. Thus, our new pre-post thermal proteome profiling approach uncovered a complex response network that orchestrates proteome homeostasis in eukaryotic cells by time-controlled adaptations of the abundance and the conformation of proteins.
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Affiliation(s)
- Carina Groh
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Per Haberkant
- Proteomics Core Facility, EMBL Heidelberg, Heidelberg, Germany
| | - Frank Stein
- Proteomics Core Facility, EMBL Heidelberg, Heidelberg, Germany
| | | | | | | | - Felix Boos
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany;
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9
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Abdullah M, Greco BM, Laurent JM, Garge RK, Boutz DR, Vandeloo M, Marcotte EM, Kachroo AH. Rapid, scalable, combinatorial genome engineering by marker-less enrichment and recombination of genetically engineered loci in yeast. CELL REPORTS METHODS 2023; 3:100464. [PMID: 37323580 PMCID: PMC10261898 DOI: 10.1016/j.crmeth.2023.100464] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 01/30/2023] [Accepted: 04/12/2023] [Indexed: 06/17/2023]
Abstract
A major challenge to rationally building multi-gene processes in yeast arises due to the combinatorics of combining all of the individual edits into the same strain. Here, we present a precise and multi-site genome editing approach that combines all edits without selection markers using CRISPR-Cas9. We demonstrate a highly efficient gene drive that selectively eliminates specific loci by integrating CRISPR-Cas9-mediated double-strand break (DSB) generation and homology-directed recombination with yeast sexual assortment. The method enables marker-less enrichment and recombination of genetically engineered loci (MERGE). We show that MERGE converts single heterologous loci to homozygous loci at ∼100% efficiency, independent of chromosomal location. Furthermore, MERGE is equally efficient at converting and combining multiple loci, thus identifying compatible genotypes. Finally, we establish MERGE proficiency by engineering a fungal carotenoid biosynthesis pathway and most of the human α-proteasome core into yeast. Therefore, MERGE lays the foundation for scalable, combinatorial genome editing in yeast.
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Affiliation(s)
- Mudabir Abdullah
- Centre for Applied Synthetic Biology, Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, QC, Canada
| | - Brittany M. Greco
- Centre for Applied Synthetic Biology, Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, QC, Canada
| | - Jon M. Laurent
- Institute of Systems Genetics, NYU Langone Health, New York, NY, USA
| | - Riddhiman K. Garge
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Daniel R. Boutz
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Michelle Vandeloo
- Centre for Applied Synthetic Biology, Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, QC, Canada
| | - Edward M. Marcotte
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Aashiq H. Kachroo
- Centre for Applied Synthetic Biology, Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, QC, Canada
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10
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Matias AC, Matos J, Dohmen RJ, Ramos PC. Hsp70 and Hsp110 Chaperones Promote Early Steps of Proteasome Assembly. Biomolecules 2022; 13:biom13010011. [PMID: 36671396 PMCID: PMC9855889 DOI: 10.3390/biom13010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Whereas assembly of the 20S proteasome core particle (CP) in prokaryotes apparently occurs spontaneously, the efficiency of this process in eukaryotes relies on the dedicated assembly chaperones Ump1, Pba1-Pba2, and Pba3-Pba4. For mammals, it was reported that CP assembly initiates with formation of a complete α-ring that functions as a template for β subunit incorporation. By contrast, we were not able to detect a ring composed only of a complete set of α subunits in S. cerevisiae. Instead, we found that the CP subunits α1, α2, and α4 each form independent small complexes. Purification of such complexes containing α4 revealed the presence of chaperones of the Hsp70/Ssa and Hsp110/Sse families. Consistently, certain small complexes containing α1, α2, and α4 were not formed in strains lacking these chaperones. Deletion of the SSE1 gene in combination with deletions of PRE9 (α3), PBA3, or UMP1 genes resulted in severe synthetic growth defects, high levels of ubiquitin-conjugates, and an accumulation of distinct small complexes with α subunits. Our study shows that Hsp70 and Hsp110 chaperones cooperate to promote the folding of individual α subunits and/or their assembly with other CP subunits, Ump1, and Pba1-Pba4 in subsequent steps.
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Affiliation(s)
- Ana C. Matias
- Center of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, Germany
- Departamento de Química e Bioquímica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 8000-117 Faro, Portugal
| | - Joao Matos
- Departamento de Química e Bioquímica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 8000-117 Faro, Portugal
| | - R. Jürgen Dohmen
- Center of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, Germany
- Correspondence: (R.J.D.); (P.C.R.)
| | - Paula C. Ramos
- Center of Molecular Biosciences, Institute for Genetics, Department of Biology, Faculty of Natural Sciences and Mathematics, University of Cologne, 50674 Cologne, Germany
- Departamento de Química e Bioquímica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 8000-117 Faro, Portugal
- Correspondence: (R.J.D.); (P.C.R.)
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11
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Kim WD, Huber RJ. An altered transcriptome underlies cln5-deficiency phenotypes in Dictyostelium discoideum. Front Genet 2022; 13:1045738. [DOI: 10.3389/fgene.2022.1045738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/27/2022] [Indexed: 11/11/2022] Open
Abstract
Mutations in CLN5 cause a subtype of neuronal ceroid lipofuscinosis (NCL) called CLN5 disease. The NCLs, commonly referred to as Batten disease, are a family of neurodegenerative lysosomal storage diseases that affect all ages and ethnicities globally. Previous research showed that CLN5 participates in a variety of cellular processes. However, the precise function of CLN5 in the cell and the pathway(s) regulating its function are not well understood. In the model organism Dictyostelium discoideum, loss of the CLN5 homolog, cln5, impacts various cellular and developmental processes including cell proliferation, cytokinesis, aggregation, cell adhesion, and terminal differentiation. In this study, we used comparative transcriptomics to identify differentially expressed genes underlying cln5-deficiency phenotypes during growth and the early stages of multicellular development. During growth, genes associated with protein ubiquitination/deubiquitination, cell cycle progression, and proteasomal degradation were affected, while genes linked to protein and carbohydrate catabolism were affected during early development. We followed up this analysis by showing that loss of cln5 alters the intracellular and extracellular amounts of proliferation repressors during growth and increases the extracellular amount of conditioned medium factor, which regulates cAMP signalling during the early stages of development. Additionally, cln5- cells displayed increased intracellular and extracellular amounts of discoidin, which is involved in cell-substrate adhesion and migration. Previous work in mammalian models reported altered lysosomal enzyme activity due to mutation or loss of CLN5. Here, we detected altered intracellular activities of various carbohydrate enzymes and cathepsins during cln5- growth and starvation. Notably, cln5- cells displayed reduced β-hexosaminidase activity, which aligns with previous work showing that D. discoideum Cln5 and human CLN5 can cleave the substrate acted upon by β-hexosaminidase. Finally, consistent with the differential expression of genes associated with proteasomal degradation in cln5- cells, we also observed elevated amounts of a proteasome subunit and reduced proteasome 20S activity during cln5- growth and starvation. Overall, this study reveals the impact of cln5-deficiency on gene expression in D. discoideum, provides insight on the genes and proteins that play a role in regulating Cln5-dependent processes, and sheds light on the molecular mechanisms underlying CLN5 disease.
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12
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Monzon V, Paysan-Lafosse T, Wood V, Bateman A. Reciprocal best structure hits: using AlphaFold models to discover distant homologues. BIOINFORMATICS ADVANCES 2022; 2:vbac072. [PMID: 36408459 PMCID: PMC9666668 DOI: 10.1093/bioadv/vbac072] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/16/2022] [Accepted: 10/05/2022] [Indexed: 11/17/2022]
Abstract
Motivation The conventional methods to detect homologous protein pairs use the comparison of protein sequences. But the sequences of two homologous proteins may diverge significantly and consequently may be undetectable by standard approaches. The release of the AlphaFold 2.0 software enables the prediction of highly accurate protein structures and opens many opportunities to advance our understanding of protein functions, including the detection of homologous protein structure pairs. Results In this proof-of-concept work, we search for the closest homologous protein pairs using the structure models of five model organisms from the AlphaFold database. We compare the results with homologous protein pairs detected by their sequence similarity and show that the structural matching approach finds a similar set of results. In addition, we detect potential novel homologs solely with the structural matching approach, which can help to understand the function of uncharacterized proteins and make previously overlooked connections between well-characterized proteins. We also observe limitations of our implementation of the structure-based approach, particularly when handling highly disordered proteins or short protein structures. Our work shows that high accuracy protein structure models can be used to discover homologous protein pairs, and we expose areas for improvement of this structural matching approach. Availability and Implementation Information to the discovered homologous protein pairs can be found at the following URL: https://doi.org/10.17863/CAM.87873. The code can be accessed here: https://github.com/VivianMonzon/Reciprocal_Best_Structure_Hits. Supplementary information Supplementary data are available at Bioinformatics Advances online.
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Affiliation(s)
- Vivian Monzon
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton CB21 4HH, UK
| | - Typhaine Paysan-Lafosse
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton CB21 4HH, UK
| | - Valerie Wood
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Alex Bateman
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton CB21 4HH, UK
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13
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Watanabe A, Yashiroda H, Ishihara S, Lo M, Murata S. The Molecular Mechanisms Governing the Assembly of the Immuno- and Thymoproteasomes in the Presence of Constitutive Proteasomes. Cells 2022; 11:cells11091580. [PMID: 35563886 PMCID: PMC9105311 DOI: 10.3390/cells11091580] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 02/06/2023] Open
Abstract
The proteasome is a large protein complex responsible for proteolysis in cells. Though the proteasome is widely conserved in all eukaryotes, vertebrates additionally possess tissue-specific proteasomes, termed immunoproteasomes and thymoproteasomes. These specialized proteasomes diverge from constitutive proteasomes in the makeup of their catalytic 20S core particle (CP), whereby the constitutive β1, β2, and β5 catalytic subunits are replaced by β1i, β2i, and β5i in immunoproteasomes, or β1i, β2i, and β5t in thymoproteasomes. However, as constitutive β1, β2, and β5 are also present in tissues and cells expressing immuno- and thymoproteasomes, the specialized proteasomes must be able to selectively incorporate their specific subunits. Here, we review the mechanisms governing the assembly of constitutive and specialized proteasomes elucidated thus far. Studies have revealed that β1i and β2i are added onto the α-ring of the CP prior to the other β subunits. Furthermore, β5i and β5t can be incorporated independent of β4, whereas constitutive β5 incorporation is dependent on β4. These mechanisms allow the immuno- and thymoproteasomes to integrate tissue-specific β-subunits without contamination from constitutive β1, β2, and β5. We end the review with a brief discussion on the diseases caused by mutations to the immunoproteasome and the proteins involved with its assembly.
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14
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Schnell HM, Walsh RM, Rawson S, Hanna J. Chaperone-mediated assembly of the proteasome core particle - recent developments and structural insights. J Cell Sci 2022; 135:275096. [PMID: 35451017 PMCID: PMC9080555 DOI: 10.1242/jcs.259622] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Much of cellular activity is mediated by large multisubunit complexes. However, many of these complexes are too complicated to assemble spontaneously. Instead, their biogenesis is facilitated by dedicated chaperone proteins, which are themselves excluded from the final product. This is the case for the proteasome, a ubiquitous and highly conserved cellular regulator that mediates most selective intracellular protein degradation in eukaryotes. The proteasome consists of two subcomplexes: the core particle (CP), where proteolysis occurs, and the regulatory particle (RP), which controls substrate access to the CP. Ten chaperones function in proteasome biogenesis. Here, we review the pathway of CP biogenesis, which requires five of these chaperones and proceeds through a highly ordered multistep pathway. We focus on recent advances in our understanding of CP assembly, with an emphasis on structural insights. This pathway of CP biogenesis represents one of the most dramatic examples of chaperone-mediated assembly and provides a paradigm for understanding how large multisubunit complexes can be produced.
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Affiliation(s)
- Helena M Schnell
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
| | - Richard M Walsh
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.,Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Shaun Rawson
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - John Hanna
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
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15
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Schnell HM, Ang J, Rawson S, Walsh RM, Micoogullari Y, Hanna J. Mechanism of Proteasome Gate Modulation by Assembly Chaperones Pba1 and Pba2. J Biol Chem 2022; 298:101906. [PMID: 35398095 PMCID: PMC9065996 DOI: 10.1016/j.jbc.2022.101906] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/22/2022] [Accepted: 03/28/2022] [Indexed: 11/04/2022] Open
Abstract
The active sites of the proteasome are housed within its central core particle (CP), a barrel-shaped chamber of four stacked heptameric rings, and access of substrates to the CP interior is mediated by gates at either axial end. These gates are constitutively closed and may be opened by the regulatory particle (RP), which binds the CP and facilitates substrate degradation. We recently showed that the heterodimeric CP assembly chaperones Pba1/2 also mediate gate opening through an unexpected structural arrangement that facilitates the insertion of the N terminus of Pba1 into the CP interior; however, the full mechanism of Pba1/2-mediated gate opening is unclear. Here, we report a detailed analysis of CP gate modulation by Pba1/2. The clustering of key residues at the interface between neighboring α-subunits is a critical feature of RP-mediated gate opening, and we find that Pba1/2 recapitulate this strategy. Unlike RP, which inserts at six α-subunit interfaces, Pba1/2 insert at only two α-subunit interfaces. Nevertheless, Pba1/2 are able to regulate six of the seven interfacial clusters, largely through direct interactions. The N terminus of Pba1 also physically interacts with the center of the gate, disrupting the intersubunit contacts that maintain the closed state. This novel mechanism of gate modulation appears to be unique to Pba1/2 and therefore likely occurs only during proteasome assembly. Our data suggest that release of Pba1/2 at the conclusion of assembly is what allows the nascent CP to assume its mature gate conformation, which is primarily closed, until activated by RP.
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16
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Gao F, Wang Z, Gu J, Zhang X, Wang H. A Hypoxia-Associated Prognostic Gene Signature Risk Model and Prognosis Predictors in Gliomas. Front Oncol 2021; 11:726794. [PMID: 34868920 PMCID: PMC8632947 DOI: 10.3389/fonc.2021.726794] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 09/27/2021] [Indexed: 01/15/2023] Open
Abstract
Most solid tumours are hypoxic. Tumour cell proliferation and metabolism accelerate oxygen consumption. The low oxygen supply due to vascular abnormalisation and the high oxygen demand of tumour cells give rise to an imbalance, resulting in tumour hypoxia. Hypoxia alters cellular behaviour and is associated with extracellular matrix remodelling, enhanced tumour migration, and metastatic behaviour. In light of the foregoing, more research on the progressive and prognostic impacts of hypoxia on gliomas are crucial. In this study, we analysed the expression levels of 75 hypoxia-related genes in gliomas and found that a total of 26 genes were differentially expressed in The Cancer Genome Atlas (TCGA) database samples. We also constructed protein–protein interaction networks using the STRING database and Cytoscape. We obtained a total of 10 Hub genes using the MCC algorithm screening in the cytoHubba plugin. A prognostic risk model with seven gene signatures (PSMB6, PSMD9, UBB, PSMD12, PSMB10, PSMA5, and PSMD14) was constructed based on the 10 Hub genes using LASSO–Cox regression analysis. The model was verified to be highly accurate using subject work characteristic curves. The seven-gene signatures were then analysed by univariate and multivariate Cox. Notably, PSMB10, PSMD12, UBB, PSMA5, and PSMB6 were found to be independent prognostic predictive markers for glioma. In addition, PSMB6, PSMA5, UBB, and PSMD12 were lowly expressed, while PSMB10 was highly expressed, in the TCGA and GTEx integrated glioma samples and normal samples, which were verified through protein expression levels in the Human Protein Atlas database. This study found the prognostic predictive values of the hypoxia-related genes PSMB10, PSMD12, UBB, PSMA5, and PSMB6 for glioma and provided ideas and entry points for the progress of hypoxia-related glioma.
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Affiliation(s)
- Feng Gao
- Department of Neurosurgery, The Affiliated People's Hospital of Ningbo University, Ningbo City, China
| | - Zhengzheng Wang
- Department of Neurosurgery, The Affiliated People's Hospital of Ningbo University, Ningbo City, China
| | - Jiajie Gu
- Department of Neurosurgery, The Affiliated People's Hospital of Ningbo University, Ningbo City, China
| | - Xiaojia Zhang
- Department of Neurosurgery, The Affiliated People's Hospital of Ningbo University, Ningbo City, China
| | - Huixiao Wang
- Department of Neurosurgery, The Affiliated People's Hospital of Ningbo University, Ningbo City, China
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17
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Henneberg F, Chari A. Chromatography-Free Purification Strategies for Large Biological Macromolecular Complexes Involving Fractionated PEG Precipitation and Density Gradients. Life (Basel) 2021; 11:1289. [PMID: 34947821 PMCID: PMC8707722 DOI: 10.3390/life11121289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/10/2021] [Accepted: 11/22/2021] [Indexed: 12/25/2022] Open
Abstract
A complex interplay between several biological macromolecules maintains cellular homeostasis. Generally, the demanding chemical reactions which sustain life are not performed by individual macromolecules, but rather by several proteins that together form a macromolecular complex. Understanding the functional interactions amongst subunits of these macromolecular machines is fundamental to elucidate mechanisms by which they maintain homeostasis. As the faithful function of macromolecular complexes is essential for cell survival, their mis-function leads to the development of human diseases. Furthermore, detailed mechanistic interrogation of the function of macromolecular machines can be exploited to develop and optimize biotechnological processes. The purification of intact macromolecular complexes is an essential prerequisite for this; however, chromatographic purification schemes can induce the dissociation of subunits or the disintegration of the whole complex. Here, we discuss the development and application of chromatography-free purification strategies based on fractionated PEG precipitation and orthogonal density gradient centrifugation that overcomes existing limitations of established chromatographic purification protocols. The presented case studies illustrate the capabilities of these procedures for the purification of macromolecular complexes.
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Affiliation(s)
- Fabian Henneberg
- Department of Structural Dynamics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany;
| | - Ashwin Chari
- Department of Structural Dynamics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany;
- Research Group for Structural Biochemistry and Mechanisms, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
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18
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Andreev DE, Smirnova VV, Shatsky IN. Modifications of Ribosome Profiling that Provide New Data on the Translation Regulation. BIOCHEMISTRY (MOSCOW) 2021; 86:1095-1106. [PMID: 34565313 DOI: 10.1134/s0006297921090054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ribosome profiling (riboseq) has opened the possibilities for the genome-wide studies of translation in all living organisms. This method is based on deep sequencing of mRNA fragments protected by the ribosomes from hydrolysis by ribonucleases, the so-called ribosomal footprints (RFPs). Ribosomal profiling together with RNA sequencing allows not only to identify with a reasonable accuracy translated reading frames in the transcriptome, but also to track changes in gene expression in response to various stimuli. Notably, ribosomal profiling in its classical version has certain limitations. The size of the selected mRNA fragments is 25-35 nts, while RFPs of other sizes are usually omitted from analysis. Also, ribosomal profiling "averages" the data from all ribosomes and does not allow to study specific ribosomal complexes associated with particular translation factors. However, recently developed modifications of ribosomal profiling provide answers to a number of questions. Thus, it has become possible to analyze not only elongating, but also scanning and reinitiating ribosomes, to study events associated with the collision of ribosomes during mRNA translation, to discover new ways of cotranslational assembly of multisubunit protein complexes during translation, and to selectively isolate ribosomal complexes associated with certain protein factors. New data obtained using these modified approaches provide a better understanding of the mechanisms of translation regulation and the functional roles of translational apparatus components.
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Affiliation(s)
- Dmitry E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997, Russia
| | - Viktoriya V Smirnova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
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19
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Ma Z, Li R, Hu R, Zheng W, Yu S, Cheng K, Zhang H, Xiao Y, Yi J, Wang Z, Wang Y, Chen C. Anaplasma phagocytophilum AptA enhances the UPS, autophagy, and anti-apoptosis of host cells by PSMG3. Int J Biol Macromol 2021; 184:497-508. [PMID: 34126152 DOI: 10.1016/j.ijbiomac.2021.06.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/03/2021] [Accepted: 06/06/2021] [Indexed: 12/12/2022]
Abstract
Anaplasma phagocytophilum is an obligate intracellular bacterium and a common tick-borne infectious pathogen that can cause human granulocytic anaplasmosis (HGA). Effector proteins play an important role in the pathogenic mechanism of A. phagocytophilum, but the specifics of the disease mechanism are unclear. We studied the effector protein AptA (A. phagocytophilum toxin A) using yeast two hybrid assays to screen its interacting protein proteasome assembly chaperone 3 (PSMG3, PAC3), and identified new mechanisms for the pathogenicity of A. phagocytophilum in HEK293T cells. After AptA enters the host cell, it interacts with PSMG3 to enhance the activity of the proteasome, causing ubiquitination and autophagy in the host cell and thereby increasing cross-talk between the ubiquitination-proteasome system (UPS) and autophagy. AptA also reduces the apoptotic efficiency of the host cells. These results offer new clues as to the pathogenic mechanism of A. phagocytophilum and support the hypothesis that AptA interacts with host PSMG3.
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Affiliation(s)
- Zhongchen Ma
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Ruirui Li
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Ruirui Hu
- College of Life Sciences, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Wei Zheng
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Shuifa Yu
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Kejian Cheng
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Huan Zhang
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Yangyang Xiao
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Jihai Yi
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Zhen Wang
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China
| | - Yong Wang
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China.
| | - Chuangfu Chen
- International Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China; Collaborative Innovation Center for prevention and control of high incidence zoonotic infectious diseases in Western China, College of Animal Science and Technology, Shihezi University, 832003 Shihezi, Xinjiang, China.
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20
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Pleiner T, Hazu M, Tomaleri GP, Januszyk K, Oania RS, Sweredoski MJ, Moradian A, Guna A, Voorhees RM. WNK1 is an assembly factor for the human ER membrane protein complex. Mol Cell 2021; 81:2693-2704.e12. [PMID: 33964204 DOI: 10.1016/j.molcel.2021.04.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 03/02/2021] [Accepted: 04/14/2021] [Indexed: 12/13/2022]
Abstract
The assembly of nascent proteins into multi-subunit complexes is a tightly regulated process that must occur at high fidelity to maintain cellular homeostasis. The ER membrane protein complex (EMC) is an essential insertase that requires seven membrane-spanning and two soluble cytosolic subunits to function. Here, we show that the kinase with no lysine 1 (WNK1), known for its role in hypertension and neuropathy, functions as an assembly factor for the human EMC. WNK1 uses a conserved amphipathic helix to stabilize the soluble subunit, EMC2, by binding to the EMC2-8 interface. Shielding this hydrophobic surface prevents promiscuous interactions of unassembled EMC2 and directly competes for binding of E3 ubiquitin ligases, permitting assembly. Depletion of WNK1 thus destabilizes both the EMC and its membrane protein clients. This work describes an unexpected role for WNK1 in protein biogenesis and defines the general requirements of an assembly factor that will apply across the proteome.
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Affiliation(s)
- Tino Pleiner
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Masami Hazu
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Giovani Pinton Tomaleri
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Kurt Januszyk
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Robert S Oania
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Michael J Sweredoski
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Annie Moradian
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Alina Guna
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Rebecca M Voorhees
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
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21
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Affiliation(s)
- Edward P Morris
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
- Division of Structural Biology, The Institute of Cancer Research, London, UK
| | - Paula C A da Fonseca
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK.
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22
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Schnell HM, Walsh RM, Rawson S, Kaur M, Bhanu MK, Tian G, Prado MA, Guerra-Moreno A, Paulo JA, Gygi SP, Roelofs J, Finley D, Hanna J. Structures of chaperone-associated assembly intermediates reveal coordinated mechanisms of proteasome biogenesis. Nat Struct Mol Biol 2021; 28:418-425. [PMID: 33846632 DOI: 10.1038/s41594-021-00583-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/22/2021] [Indexed: 11/09/2022]
Abstract
The proteasome mediates most selective protein degradation. Proteolysis occurs within the 20S core particle (CP), a barrel-shaped chamber with an α7β7β7α7 configuration. CP biogenesis proceeds through an ordered multistep pathway requiring five chaperones, Pba1-4 and Ump1. Using Saccharomyces cerevisiae, we report high-resolution structures of CP assembly intermediates by cryogenic-electron microscopy. The first structure corresponds to the 13S particle, which consists of a complete α-ring, partial β-ring (β2-4), Ump1 and Pba1/2. The second structure contains two additional subunits (β5-6) and represents a later pre-15S intermediate. These structures reveal the architecture and positions of Ump1 and β2/β5 propeptides, with important implications for their functions. Unexpectedly, Pba1's N terminus extends through an open CP pore, accessing the CP interior to contact Ump1 and the β5 propeptide. These results reveal how the coordinated activity of Ump1, Pba1 and the active site propeptides orchestrate key aspects of CP assembly.
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Affiliation(s)
- Helena M Schnell
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Richard M Walsh
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Shaun Rawson
- Harvard Cryo-Electron Microscopy Center for Structural Biology, Harvard Medical School, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Mandeep Kaur
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Meera K Bhanu
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Geng Tian
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Angel Guerra-Moreno
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Jeroen Roelofs
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - John Hanna
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA.
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23
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Edskes HK, Stroobant EE, DeWilde MP, Bezsonov EE, Wickner RB. Proteasome Control of [URE3] Prion Propagation by Degradation of Anti-Prion Proteins Cur1 and Btn2 in Saccharomyces cerevisiae. Genetics 2021; 218:6179111. [PMID: 33742650 DOI: 10.1093/genetics/iyab037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/27/2021] [Indexed: 01/16/2023] Open
Abstract
[URE3] is a prion of the nitrogen catabolism controller, Ure2p, and [PSI+] is a prion of the translation termination factor Sup35p in S. cerevisiae. Btn2p cures [URE3] by sequestration of Ure2p amyloid filaments. Cur1p, paralogous to Btn2p, also cures [URE3], but by a different (unknown) mechanism. We find that an array of mutations impairing proteasome assembly or MG132 inhibition of proteasome activity result in loss of [URE3]. In proportion to their prion-curing effects, each mutation affecting proteasomes elevates the cellular concentration of the anti-prion proteins Btn2 and Cur1. Of >4,600 proteins detected by SILAC, Btn2p was easily the most overexpressed in a pre9Δ (α3 core subunit) strain. Indeed, deletion of BTN2 and CUR1 prevents the prion-curing effects of proteasome impairment. Surprisingly, the 15 most unstable yeast proteins are not increased in pre9Δ cells suggesting altered proteasome specificity rather than simple inactivation. Hsp42, a chaperone that cooperates with Btn2 and Cur1 in curing [URE3], is also necessary for the curing produced by proteasome defects, although Hsp42p levels are not substantially altered by a proteasome defect. We find that pre9Δ and proteasome chaperone mutants that most efficiently lose [URE3], do not destabilize [PSI+] or alter cellular levels of Sup35p. A tof2 mutation or deletion likewise destabilizes [URE3], and elevates Btn2p, suggesting that Tof2p deficiency inactivates proteasomes. We suggest that when proteasomes are saturated with denatured/misfolded proteins, their reduced degradation of Btn2p and Cur1p automatically upregulates these aggregate-handling systems to assist in the clean-up.
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Affiliation(s)
- Herman K Edskes
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Emily E Stroobant
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Morgan P DeWilde
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Evgeny E Bezsonov
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
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24
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Tang M, Xu C, Cao H, Shi Y, Chen J, Chai Y, Li Z. Tomato calmodulin-like protein SlCML37 is a calcium (Ca 2+) sensor that interacts with proteasome maturation factor SlUMP1 and plays a role in tomato fruit chilling stress tolerance. JOURNAL OF PLANT PHYSIOLOGY 2021; 258-259:153373. [PMID: 33652171 DOI: 10.1016/j.jplph.2021.153373] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 05/25/2023]
Abstract
Calmodulin-like proteins (CMLs), as well as their targets, play significant roles in various key developmental and stress responses in the plant. In tomato (Solanum lycopersicum), there are at least 52 CML genes in its genome. However, most of their functions are not well known, especially in response to cold stress. Here, we investigated SlCML37 biochemical and structural characteristics, including a typical α-helical secondary structure and exposing its hydrophobic regions after binding to Ca2+. Then we certificated that SlCML37 protein could physically interact with SlUMP1 by using yeast two-hybrid, bimolecular florescence complementation (BiFC) and GST pull-down assays. Further analysis showed that SlCML37-transgenic tomato fruit conferred significantly improved tolerance to chilling stress. This study indicates a possible role of calmodulin-like protein-mediated proteasome assemble in the regulation of plant cold response.
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Affiliation(s)
- Mingfeng Tang
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China; Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, 401331, Chongqing, China; Institute of Agricultural Quality Standard and Testing Technology, Chongqing Academy of Agricultural Sciences, 401329, Chongqing, China
| | - Chan Xu
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China; Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, 401331, Chongqing, China
| | - Haohao Cao
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China; Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, 401331, Chongqing, China
| | - Yuan Shi
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China; Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, 401331, Chongqing, China
| | - Jing Chen
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China; Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, 401331, Chongqing, China
| | - Yong Chai
- Institute of Agricultural Quality Standard and Testing Technology, Chongqing Academy of Agricultural Sciences, 401329, Chongqing, China
| | - Zhengguo Li
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China; Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, 401331, Chongqing, China.
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25
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Abstract
The 26S proteasome is the most complex ATP-dependent protease machinery, of ~2.5 MDa mass, ubiquitously found in all eukaryotes. It selectively degrades ubiquitin-conjugated proteins and plays fundamentally indispensable roles in regulating almost all major aspects of cellular activities. To serve as the sole terminal "processor" for myriad ubiquitylation pathways, the proteasome evolved exceptional adaptability in dynamically organizing a large network of proteins, including ubiquitin receptors, shuttle factors, deubiquitinases, AAA-ATPase unfoldases, and ubiquitin ligases, to enable substrate selectivity and processing efficiency and to achieve regulation precision of a vast diversity of substrates. The inner working of the 26S proteasome is among the most sophisticated, enigmatic mechanisms of enzyme machinery in eukaryotic cells. Recent breakthroughs in three-dimensional atomic-level visualization of the 26S proteasome dynamics during polyubiquitylated substrate degradation elucidated an extensively detailed picture of its functional mechanisms, owing to progressive methodological advances associated with cryogenic electron microscopy (cryo-EM). Multiple sites of ubiquitin binding in the proteasome revealed a canonical mode of ubiquitin-dependent substrate engagement. The proteasome conformation in the act of substrate deubiquitylation provided insights into how the deubiquitylating activity of RPN11 is enhanced in the holoenzyme and is coupled to substrate translocation. Intriguingly, three principal modes of coordinated ATP hydrolysis in the heterohexameric AAA-ATPase motor were discovered to regulate intermediate functional steps of the proteasome, including ubiquitin-substrate engagement, deubiquitylation, initiation of substrate translocation and processive substrate degradation. The atomic dissection of the innermost working of the 26S proteasome opens up a new era in our understanding of the ubiquitin-proteasome system and has far-reaching implications in health and disease.
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Affiliation(s)
- Youdong Mao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, 02215, Massachusetts, USA. .,School of Physics, Center for Quantitative Biology, Peking University, Beijing, 100871, China.
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26
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Conformational maps of human 20S proteasomes reveal PA28- and immuno-dependent inter-ring crosstalks. Nat Commun 2020; 11:6140. [PMID: 33262340 PMCID: PMC7708635 DOI: 10.1038/s41467-020-19934-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 11/06/2020] [Indexed: 01/17/2023] Open
Abstract
Hydrogen-Deuterium eXchange coupled to Mass Spectrometry (HDX-MS) is now common practice in structural biology. However, it is most of the time applied to rather small oligomeric complexes. Here, we report on the use of HDX-MS to investigate conformational differences between the human standard 20S (std20S) and immuno 20S (i20s) proteasomes alone or in complex with PA28αβ or PA28γ activators. Their solvent accessibility is analyzed through a dedicated bioinformatic pipeline including stringent statistical analysis and 3D visualization. These data confirm the existence of allosteric differences between the std20S and i20S at the surface of the α-ring triggered from inside the catalytic β-ring. Additionally, binding of the PA28 regulators to the 20S proteasomes modify solvent accessibility due to conformational changes of the β-rings. This work is not only a proof-of-concept that HDX-MS can be used to get structural insights on large multi-protein complexes in solution, it also demonstrates that the binding of the std20S or i20S subtype to any of its PA28 activator triggers allosteric changes that are specific to this 20S/PA28 pair.
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27
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Sun S, Mariappan M. C-terminal tail length guides insertion and assembly of membrane proteins. J Biol Chem 2020; 295:15498-15510. [PMID: 32878985 DOI: 10.1074/jbc.ra120.012992] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 08/27/2020] [Indexed: 11/06/2022] Open
Abstract
A large number of newly synthesized membrane proteins in the endoplasmic reticulum (ER) are assembled into multiprotein complexes, but little is known about the mechanisms required for assembly membrane proteins. It has been suggested that membrane chaperones might exist, akin to the molecular chaperones that stabilize and direct the assembly of soluble protein complexes, but the mechanisms by which these proteins would bring together membrane protein components is unclear. Here, we have identified that the tail length of the C-terminal transmembrane domains (C-TMDs) determines efficient insertion and assembly of membrane proteins in the ER. We found that membrane proteins with C-TMD tails shorter than ∼60 amino acids are poorly inserted into the ER membrane, which suggests that translation is terminated before they are recognized by the Sec61 translocon for insertion. These C-TMDs with insufficient hydrophobicity are post-translationally recognized and retained by the Sec61 translocon complex, providing a time window for efficient assembly with TMDs from partner proteins. Retained TMDs that fail to assemble with their cognate TMDs are slowly translocated into the ER lumen and are recognized by the ER-associated degradation (ERAD) pathway for removal. In contrast, C-TMDs with sufficient hydrophobicity or tails longer than ∼80 residues are quickly released from the Sec61 translocon into the membrane or the ER lumen, resulting in inefficient assembly with partner TMDs. Thus, our data suggest that C-terminal tails harbor crucial signals for both the insertion and assembly of membrane proteins.
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Affiliation(s)
- Sha Sun
- Frome the Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, Yale West Campus, West Haven, Connecticut, USA
| | - Malaiyalam Mariappan
- Frome the Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, Yale West Campus, West Haven, Connecticut, USA.
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28
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Marshall RS, Gemperline DC, McLoughlin F, Book AJ, Hofmann K, Vierstra RD. An evolutionarily distinct chaperone promotes 20S proteasome α-ring assembly in plants. J Cell Sci 2020; 133:jcs249862. [PMID: 33033180 PMCID: PMC7657472 DOI: 10.1242/jcs.249862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/21/2020] [Indexed: 11/20/2022] Open
Abstract
The core protease (CP) subcomplex of the 26S proteasome houses the proteolytic active sites and assumes a barrel shape comprised of four co-axially stacked heptameric rings formed by structurally related α- and β-subunits. CP biogenesis typically begins with the assembly of the α-ring, which then provides a template for β-subunit integration. In eukaryotes, α-ring assembly is partially mediated by two hetero-dimeric chaperones, termed Pba1-Pba2 (Add66) and Pba3-Pba4 (also known as Irc25-Poc4) in yeast. Pba1-Pba2 initially promotes orderly recruitment of the α-subunits through interactions between their C-terminal HbYX or HbF motifs and pockets at the α5-α6 and α6-α7 interfaces. Here, we identified PBAC5 as a fifth α-ring assembly chaperone in Arabidopsis that directly binds the Pba1 homolog PBAC1 to form a trimeric PBAC5-PBAC1-PBAC2 complex. PBAC5 harbors a HbYX motif that docks with a pocket between the α4 and α5 subunits during α-ring construction. Arabidopsis lacking PBAC5, PBAC1 and/or PBAC2 are hypersensitive to proteotoxic, salt and osmotic stresses, and display proteasome assembly defects. Remarkably, whereas PBAC5 is evolutionarily conserved among plants, sequence relatives are also dispersed within other kingdoms, including a scattered array of fungal, metazoan and oomycete species.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO 63130, USA
- Department of Genetics, University of Wisconsin, 425 Henry Mall, Madison, WI 53706, USA
| | - David C Gemperline
- Department of Genetics, University of Wisconsin, 425 Henry Mall, Madison, WI 53706, USA
| | - Fionn McLoughlin
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Adam J Book
- Department of Genetics, University of Wisconsin, 425 Henry Mall, Madison, WI 53706, USA
| | - Kay Hofmann
- Institute for Genetics, University of Cologne, Zülpicher Straße 47a, 50674 Cologne, Germany
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO 63130, USA
- Department of Genetics, University of Wisconsin, 425 Henry Mall, Madison, WI 53706, USA
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29
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Spasskaya DS, Nadolinskaia NI, Tutyaeva VV, Lysov YP, Karpov VL, Karpov DS. Yeast Rpn4 Links the Proteasome and DNA Repair via RAD52 Regulation. Int J Mol Sci 2020; 21:ijms21218097. [PMID: 33143019 PMCID: PMC7672625 DOI: 10.3390/ijms21218097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/22/2020] [Accepted: 10/29/2020] [Indexed: 12/11/2022] Open
Abstract
Environmental and intracellular factors often damage DNA, but multiple DNA repair pathways maintain genome integrity. In yeast, the 26S proteasome and its transcriptional regulator and substrate Rpn4 are involved in DNA damage resistance. Paradoxically, while proteasome dysfunction may induce hyper-resistance to DNA-damaging agents, Rpn4 malfunction sensitizes yeasts to these agents. Previously, we proposed that proteasome inhibition causes Rpn4 stabilization followed by the upregulation of Rpn4-dependent DNA repair genes and pathways. Here, we aimed to elucidate the key Rpn4 targets responsible for DNA damage hyper-resistance in proteasome mutants. We impaired the Rpn4-mediated regulation of candidate genes using the CRISPR/Cas9 system and tested the sensitivity of mutant strains to 4-NQO, MMS and zeocin. We found that the separate or simultaneous deregulation of 19S or 20S proteasome subcomplexes induced MAG1, DDI1, RAD23 and RAD52 in an Rpn4-dependent manner. Deregulation of RAD23, DDI1 and RAD52 sensitized yeast to DNA damage. Genetic, epigenetic or dihydrocoumarin-mediated RAD52 repression restored the sensitivity of the proteasome mutants to DNA damage. Our results suggest that the Rpn4-mediated overexpression of DNA repair genes, especially RAD52, defines the DNA damage hyper-resistant phenotype of proteasome mutants. The developed yeast model is useful for characterizing drugs that reverse the DNA damage hyper-resistance phenotypes of cancers.
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Affiliation(s)
- Daria S. Spasskaya
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia; (D.S.S.); (V.V.T.)
| | - Nonna I. Nadolinskaia
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (N.I.N.); (Y.P.L.); (V.L.K.)
| | - Vera V. Tutyaeva
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia; (D.S.S.); (V.V.T.)
| | - Yuriy P. Lysov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (N.I.N.); (Y.P.L.); (V.L.K.)
| | - Vadim L. Karpov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (N.I.N.); (Y.P.L.); (V.L.K.)
| | - Dmitry S. Karpov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia; (D.S.S.); (V.V.T.)
- Correspondence: ; Tel.: +7-499-135-98-01
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30
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Woo TT, Chuang CN, Higashide M, Shinohara A, Wang TF. Dual roles of yeast Rad51 N-terminal domain in repairing DNA double-strand breaks. Nucleic Acids Res 2020; 48:8474-8489. [PMID: 32652040 PMCID: PMC7470947 DOI: 10.1093/nar/gkaa587] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 06/24/2020] [Accepted: 07/03/2020] [Indexed: 01/17/2023] Open
Abstract
Highly toxic DNA double-strand breaks (DSBs) readily trigger the DNA damage response (DDR) in cells, which delays cell cycle progression to ensure proper DSB repair. In Saccharomyces cerevisiae, mitotic S phase (20–30 min) is lengthened upon DNA damage. During meiosis, Spo11-induced DSB onset and repair lasts up to 5 h. We report that the NH2-terminal domain (NTD; residues 1–66) of Rad51 has dual functions for repairing DSBs during vegetative growth and meiosis. Firstly, Rad51-NTD exhibits autonomous expression-enhancing activity for high-level production of native Rad51 and when fused to exogenous β-galactosidase in vivo. Secondly, Rad51-NTD is an S/T-Q cluster domain (SCD) harboring three putative Mec1/Tel1 target sites. Mec1/Tel1-dependent phosphorylation antagonizes the proteasomal degradation pathway, increasing the half-life of Rad51 from ∼30 min to ≥180 min. Our results evidence a direct link between homologous recombination and DDR modulated by Rad51 homeostasis.
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Affiliation(s)
- Tai-Ting Woo
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Chi-Ning Chuang
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Mika Higashide
- Laboratory of Genome-Chromosome Functions, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Japan
| | - Akira Shinohara
- Laboratory of Genome-Chromosome Functions, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Japan
| | - Ting-Fang Wang
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
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31
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Tundo GR, Sbardella D, Santoro AM, Coletta A, Oddone F, Grasso G, Milardi D, Lacal PM, Marini S, Purrello R, Graziani G, Coletta M. The proteasome as a druggable target with multiple therapeutic potentialities: Cutting and non-cutting edges. Pharmacol Ther 2020; 213:107579. [PMID: 32442437 PMCID: PMC7236745 DOI: 10.1016/j.pharmthera.2020.107579] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 01/10/2023]
Abstract
Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.
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Affiliation(s)
- G R Tundo
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
| | | | - A M Santoro
- CNR, Institute of Crystallography, Catania, Italy
| | - A Coletta
- Department of Chemistry, University of Aarhus, Aarhus, Denmark
| | - F Oddone
- IRCCS-Fondazione Bietti, Rome, Italy
| | - G Grasso
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - D Milardi
- CNR, Institute of Crystallography, Catania, Italy
| | - P M Lacal
- Laboratory of Molecular Oncology, IDI-IRCCS, Rome, Italy
| | - S Marini
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - R Purrello
- Department of Chemical Sciences, University of Catania, Catania, Italy
| | - G Graziani
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
| | - M Coletta
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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32
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Sbardella D, Tundo GR, Cunsolo V, Grasso G, Cascella R, Caputo V, Santoro AM, Milardi D, Pecorelli A, Ciaccio C, Di Pierro D, Leoncini S, Campagnolo L, Pironi V, Oddone F, Manni P, Foti S, Giardina E, De Felice C, Hayek J, Curatolo P, Galasso C, Valacchi G, Coletta M, Graziani G, Marini S. Defective proteasome biogenesis into skin fibroblasts isolated from Rett syndrome subjects with MeCP2 non-sense mutations. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165793. [PMID: 32275946 DOI: 10.1016/j.bbadis.2020.165793] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 03/06/2020] [Accepted: 04/04/2020] [Indexed: 01/04/2023]
Abstract
Rett Syndrome (RTT) is a rare X-linked neurodevelopmental disorder which affects about 1: 10000 live births. In >95% of subjects RTT is caused by a mutation in Methyl-CpG binding protein-2 (MECP2) gene, which encodes for a transcription regulator with pleiotropic genetic/epigenetic activities. The molecular mechanisms underscoring the phenotypic alteration of RTT are largely unknown and this has impaired the development of therapeutic approaches to alleviate signs and symptoms during disease progression. A defective proteasome biogenesis into two skin primary fibroblasts isolated from RTT subjects harbouring non-sense (early-truncating) MeCP2 mutations (i.e., R190fs and R255X) is herewith reported. Proteasome is the proteolytic machinery of Ubiquitin Proteasome System (UPS), a pathway of overwhelming relevance for post-mitotic cells metabolism. Molecular, transcription and proteomic analyses indicate that MeCP2 mutations down-regulate the expression of one proteasome subunit, α7, and of two chaperones, PAC1 and PAC2, which bind each other in the earliest step of proteasome biogenesis. Furthermore, this molecular alteration recapitulates in neuron-like SH-SY5Y cells upon silencing of MeCP2 expression, envisaging a general significance of this transcription regulator in proteasome biogenesis.
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Affiliation(s)
- Diego Sbardella
- IRCSS-Fondazione GB Bietti, Via Livenza, 3, 00198 Rome, Italy
| | - Grazia Raffaella Tundo
- Dept of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | | | - Giuseppe Grasso
- Department of Chemistry, University of Catania, Catania, Italy
| | - Raffaella Cascella
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy; Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy
| | - Valerio Caputo
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy; Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy
| | | | - Danilo Milardi
- Institute of Crystallography, National Research Council, Catania, Italy
| | - Alessandra Pecorelli
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; Plant for Human Health Institute, North Carolina State University, Kannapolis, NC, USA
| | - Chiara Ciaccio
- Dept of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Donato Di Pierro
- Dept of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Silvia Leoncini
- Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy; Neonatal Intensive Care Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy
| | - Luisa Campagnolo
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy
| | - Virginia Pironi
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy
| | | | - Priscilla Manni
- Ophthalmology Unit, St. Andrea Hospital, Faculty of Medicine and Psychology, NESMOS Department, University of Rome "Sapienza", Rome, Italy
| | - Salvatore Foti
- Department of Chemistry, University of Catania, Catania, Italy
| | - Emiliano Giardina
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy; Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy
| | - Claudio De Felice
- Neonatal Intensive Care Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy
| | - Joussef Hayek
- Neonatal Intensive Care Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy; "Isola di Bau", Multi-Specialist Centre, Certaldo (Florence), Italy
| | - Paolo Curatolo
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy
| | - Cinzia Galasso
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy
| | - Giuseppe Valacchi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; Plant for Human Health Institute, North Carolina State University, Kannapolis, NC, USA
| | - Massimiliano Coletta
- Dept of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Grazia Graziani
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Stefano Marini
- Dept of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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33
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Hammack LJ, Panfair D, Kusmierczyk AR. A novel proteasome assembly intermediate bypasses the need to form α-rings first. Biochem Biophys Res Commun 2020; 525:S0006-291X(20)30312-0. [PMID: 32081431 DOI: 10.1016/j.bbrc.2020.02.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 11/16/2022]
Abstract
Proteasomes provide the main route of intracellular protein degradation. They consist of a central protease, termed the 20S proteasome, or core particle (CP), that partners with one or more regulatory complexes. The quaternary structure of the CP is conserved across all domains of life and is comprised of four coaxially stacked heptameric rings formed by structurally related α and β subunits. In eukaryotes, biogenesis of the CP is generally assumed to involve the obligate formation of α-rings. These serve as templates upon which β subunits assemble to form half-proteasomes which dimerize to give rise to CP. Here, we demonstrate the in vivo existence of an assembly-competent intermediate containing an incomplete set of both α and β subunits. The novel intermediate exhibits a precursor-product relationship with the well characterized CP assembly intermediate, the 13S. This is the first evidence that eukaryotic CP, like its archaeal and bacterial counterparts, can assemble in an α-ring independent manner.
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Affiliation(s)
- Lindsay J Hammack
- Department of Biology, Indiana University-Purdue University Indianapolis, 723 West Michigan Street, Indianapolis, IN, 46202, USA
| | - Dilrajkaur Panfair
- Department of Biology, Indiana University-Purdue University Indianapolis, 723 West Michigan Street, Indianapolis, IN, 46202, USA
| | - Andrew R Kusmierczyk
- Department of Biology, Indiana University-Purdue University Indianapolis, 723 West Michigan Street, Indianapolis, IN, 46202, USA.
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34
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Coux O, Zieba BA, Meiners S. The Proteasome System in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:55-100. [DOI: 10.1007/978-3-030-38266-7_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Gemperline DC, Marshall RS, Lee KH, Zhao Q, Hu W, McLoughlin F, Scalf M, Smith LM, Vierstra RD. Proteomic analysis of affinity-purified 26S proteasomes identifies a suite of assembly chaperones in Arabidopsis. J Biol Chem 2019; 294:17570-17592. [PMID: 31562246 PMCID: PMC6873196 DOI: 10.1074/jbc.ra119.010219] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/17/2019] [Indexed: 01/01/2023] Open
Abstract
The 26S proteasome is an essential protease that selectively eliminates dysfunctional and short-lived regulatory proteins in eukaryotes. To define the composition of this proteolytic machine in plants, we tagged either the core protease (CP) or the regulatory particle (RP) sub-complexes in Arabidopsis to enable rapid affinity purification followed by mass spectrometric analysis. Studies on proteasomes enriched from whole seedlings, with or without ATP needed to maintain the holo-proteasome complex, identified all known proteasome subunits but failed to detect isoform preferences, suggesting that Arabidopsis does not construct distinct proteasome sub-types. We also detected a suite of proteasome-interacting proteins, including likely orthologs of the yeast and mammalian chaperones Pba1, Pba2, Pba3, and Pba4 that assist in CP assembly; Ump1 that helps connect CP half-barrels; Nas2, Nas6, and Hsm3 that assist in RP assembly; and Ecm29 that promotes CP-RP association. Proteasomes from seedlings exposed to the proteasome inhibitor MG132 accumulated assembly intermediates, reflecting partially built proteasome sub-complexes associated with assembly chaperones, and the CP capped with the PA200/Blm10 regulator. Genetic analyses of Arabidopsis UMP1 revealed that, unlike in yeast, this chaperone is essential, with mutants lacking the major UMP1a and UMP1b isoforms displaying a strong gametophytic defect. Single ump1 mutants were hypersensitive to conditions that induce proteotoxic, salt and osmotic stress, and also accumulated several proteasome assembly intermediates, consistent with its importance for CP construction. Insights into the chaperones reported here should enable study of the assembly events that generate the 26S holo-proteasome in Arabidopsis from the collection of 64 or more subunits.
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Affiliation(s)
- David C Gemperline
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Richard S Marshall
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Kwang-Hee Lee
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Qingzhen Zhao
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Weiming Hu
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Fionn McLoughlin
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Mark Scalf
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Richard D Vierstra
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
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Proteasome subunit α1 overexpression preferentially drives canonical proteasome biogenesis and enhances stress tolerance in yeast. Sci Rep 2019; 9:12418. [PMID: 31455793 PMCID: PMC6712033 DOI: 10.1038/s41598-019-48889-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/13/2019] [Indexed: 02/04/2023] Open
Abstract
The 26S proteasome conducts the majority of regulated protein catabolism in eukaryotes. At the heart of the proteasome is the barrel-shaped 20S core particle (CP), which contains two β-rings sandwiched between two α-rings. Whereas canonical CPs contain α-rings with seven subunits arranged α1-α7, a non-canonical CP in which a second copy of the α4 subunit replaces the α3 subunit occurs in both yeast and humans. The mechanisms that control canonical versus non-canonical CP biogenesis remain poorly understood. Here, we have repurposed a split-protein reporter to identify genes that can enhance canonical proteasome assembly in mutant yeast producing non-canonical α4-α4 CPs. We identified the proteasome subunit α1 as an enhancer of α3 incorporation, and find that elevating α1 protein levels preferentially drives canonical CP assembly under conditions that normally favor α4-α4 CP formation. Further, we demonstrate that α1 is stoichiometrically limiting for α-ring assembly, and that enhancing α1 levels is sufficient to increase proteasome abundance and enhance stress tolerance in yeast. Together, our data indicate that the abundance of α1 exerts multiple impacts on proteasome assembly and composition, and we propose that the limited α1 levels observed in yeast may prime cells for alternative proteasome assembly following environmental stimuli.
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Abstract
The proteasome degrades most cellular proteins in a controlled and tightly regulated manner and thereby controls many processes, including cell cycle, transcription, signalling, trafficking and protein quality control. Proteasomal degradation is vital in all cells and organisms, and dysfunction or failure of proteasomal degradation is associated with diverse human diseases, including cancer and neurodegeneration. Target selection is an important and well-established way to control protein degradation. In addition, mounting evidence indicates that cells adjust proteasome-mediated degradation to their needs by regulating proteasome abundance through the coordinated expression of proteasome subunits and assembly chaperones. Central to the regulation of proteasome assembly is TOR complex 1 (TORC1), which is the master regulator of cell growth and stress. This Review discusses how proteasome assembly and the regulation of proteasomal degradation are integrated with cellular physiology, including the interplay between the proteasome and autophagy pathways. Understanding these mechanisms has potential implications for disease therapy, as the misregulation of proteasome function contributes to human diseases such as cancer and neurodegeneration.
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Aristizábal D, Rivas V, Cassab GI, Lledías F. Heat stress reveals high molecular mass proteasomes in Arabidopsis thaliana suspension cells cultures. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 140:78-87. [PMID: 31085449 DOI: 10.1016/j.plaphy.2019.04.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/01/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
Because of their sessile nature, plants have evolved complex and robust mechanisms to respond to adverse environments. Stress conditions trigger an increase in protein turnover and degradation. Proteasomes are essential to the cell for removing, in a highly regulated manner, partially denatured or oxidized proteins thus minimizing their cytotoxicity. We observed that suspension cells of Arabidopsis thaliana treated with high temperature (37 °C) directed the assembly of high molecular mass proteasomes. The removal of a 75% of the original ubiquitin conjugates and the maintenance of protein carbonyls at basal levels correlated with a specific proteasome profiles. The profiles obtained by the separation of different proteasomes populations by Blue-Native Polyacrylamide Gel Electrophoresis and western blot analysis suggest that synthesis, assembly, and heavy ubiquitination of 20S (CP) subunits are promoted by heat stress.
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Affiliation(s)
- Daniel Aristizábal
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico
| | - Viridiana Rivas
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico
| | - Gladys I Cassab
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico
| | - Fernando Lledías
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor, 62250, Mexico.
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Marshall RS, Vierstra RD. Dynamic Regulation of the 26S Proteasome: From Synthesis to Degradation. Front Mol Biosci 2019; 6:40. [PMID: 31231659 PMCID: PMC6568242 DOI: 10.3389/fmolb.2019.00040] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/09/2019] [Indexed: 01/12/2023] Open
Abstract
All eukaryotes rely on selective proteolysis to control the abundance of key regulatory proteins and maintain a healthy and properly functioning proteome. Most of this turnover is catalyzed by the 26S proteasome, an intricate, multi-subunit proteolytic machine. Proteasomes recognize and degrade proteins first marked with one or more chains of poly-ubiquitin, the addition of which is actuated by hundreds of ligases that individually identify appropriate substrates for ubiquitylation. Subsequent proteasomal digestion is essential and influences a myriad of cellular processes in species as diverse as plants, fungi and humans. Importantly, dysfunction of 26S proteasomes is associated with numerous human pathologies and profoundly impacts crop performance, thus making an understanding of proteasome dynamics critically relevant to almost all facets of human health and nutrition. Given this widespread significance, it is not surprising that sophisticated mechanisms have evolved to tightly regulate 26S proteasome assembly, abundance and activity in response to demand, organismal development and stress. These include controls on transcription and chaperone-mediated assembly, influences on proteasome localization and activity by an assortment of binding proteins and post-translational modifications, and ultimately the removal of excess or damaged particles via autophagy. Intriguingly, the autophagic clearance of damaged 26S proteasomes first involves their modification with ubiquitin, thus connecting ubiquitylation and autophagy as key regulatory events in proteasome quality control. This turnover is also influenced by two distinct biomolecular condensates that coalesce in the cytoplasm, one attracting damaged proteasomes for autophagy, and the other reversibly storing proteasomes during carbon starvation to protect them from autophagic clearance. In this review, we describe the current state of knowledge regarding the dynamic regulation of 26S proteasomes at all stages of their life cycle, illustrating how protein degradation through this proteolytic machine is tightly controlled to ensure optimal growth, development and longevity.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
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Bai M, Zhao X, Sahara K, Ohte Y, Hirano Y, Kaneko T, Yashiroda H, Murata S. In-depth Analysis of the Lid Subunits Assembly Mechanism in Mammals. Biomolecules 2019; 9:biom9060213. [PMID: 31159305 PMCID: PMC6627463 DOI: 10.3390/biom9060213] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/21/2019] [Accepted: 05/29/2019] [Indexed: 01/16/2023] Open
Abstract
The 26S proteasome is a key player in the degradation of ubiquitinated proteins, comprising a 20S core particle (CP) and a 19S regulatory particle (RP). The RP is further divided into base and lid subcomplexes, which are assembled independently from each other. We have previously demonstrated the assembly pathway of the CP and the base by observing assembly intermediates resulting from knockdowns of each proteasome subunit and the assembly chaperones. In this study, we examine the assembly pathway of the mammalian lid, which remains to be elucidated. We show that the lid assembly pathway is conserved between humans and yeast. The final step is the incorporation of Rpn12 into the assembly intermediate consisting of two modular complexes, Rpn3-7-15 and Rpn5-6-8-9-11, in both humans and yeast. Furthermore, we dissect the assembly pathways of the two modular complexes by the knockdown of each lid subunit.
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Affiliation(s)
- Minghui Bai
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Xian Zhao
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kazutaka Sahara
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuki Ohte
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuko Hirano
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Takeumi Kaneko
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Hideki Yashiroda
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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41
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Wendler P, Enenkel C. Nuclear Transport of Yeast Proteasomes. Front Mol Biosci 2019; 6:34. [PMID: 31157235 PMCID: PMC6532418 DOI: 10.3389/fmolb.2019.00034] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 04/26/2019] [Indexed: 11/13/2022] Open
Abstract
Proteasomes are key proteases in regulating protein homeostasis. Their holo-enzymes are composed of 40 different subunits which are arranged in a proteolytic core (CP) flanked by one to two regulatory particles (RP). Proteasomal proteolysis is essential for the degradation of proteins which control time-sensitive processes like cell cycle progression and stress response. In dividing yeast and human cells, proteasomes are primarily nuclear suggesting that proteasomal proteolysis is mainly required in the nucleus during cell proliferation. In yeast, which have a closed mitosis, proteasomes are imported into the nucleus as immature precursors via the classical import pathway. During quiescence, the reversible absence of proliferation induced by nutrient depletion or growth factor deprivation, proteasomes move from the nucleus into the cytoplasm. In the cytoplasm of quiescent yeast, proteasomes are dissociated into CP and RP and stored in membrane-less cytoplasmic foci, named proteasome storage granules (PSGs). With the resumption of growth, PSGs clear and mature proteasomes are transported into the nucleus by Blm10, a conserved 240 kDa protein and proteasome-intrinsic import receptor. How proteasomes are exported from the nucleus into the cytoplasm is unknown.
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Affiliation(s)
- Petra Wendler
- Institut für Biochemie und Biologie, Universität Potsdam, Potsdam, Germany
| | - Cordula Enenkel
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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42
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Satoh T, Yagi-Utsumi M, Okamoto K, Kurimoto E, Tanaka K, Kato K. Molecular and Structural Basis of the Proteasome α Subunit Assembly Mechanism Mediated by the Proteasome-Assembling Chaperone PAC3-PAC4 Heterodimer. Int J Mol Sci 2019; 20:ijms20092231. [PMID: 31067643 PMCID: PMC6539346 DOI: 10.3390/ijms20092231] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/26/2019] [Accepted: 05/03/2019] [Indexed: 01/07/2023] Open
Abstract
The 26S proteasome is critical for the selective degradation of proteins in eukaryotic cells. This enzyme complex is composed of approximately 70 subunits, including the structurally homologous proteins α1–α7, which combine to form heptameric rings. The correct arrangement of these α subunits is essential for the function of the proteasome, but their assembly does not occur autonomously. Assembly of the α subunit is assisted by several chaperones, including the PAC3-PAC4 heterodimer. In this study we showed that the PAC3-PAC4 heterodimer functions as a molecular matchmaker, stabilizing the α4-α5-α6 subcomplex during the assembly of the α-ring. We solved a 0.96-Å atomic resolution crystal structure for a PAC3 homodimer which, in conjunction with nuclear magnetic resonance (NMR) data, highlighted the mobility of the loop comprised of residues 51 to 61. Based on these structural and dynamic data, we created a three-dimensional model of the PAC3-4/α4/α5/α6 quintet complex, and used this model to investigate the molecular and structural basis of the mechanism of proteasome α subunit assembly, as mediated by the PAC3-PAC4 heterodimeric chaperone. Our results provide a potential basis for the development of selective inhibitors against proteasome biogenesis.
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Affiliation(s)
- Tadashi Satoh
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
| | - Maho Yagi-Utsumi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
| | - Kenta Okamoto
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
| | - Eiji Kurimoto
- Faculty of Pharmacy, Meijo University, Tempaku-ku, Nagoya 468-8503, Japan.
| | - Keiji Tanaka
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
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Novel proteasome assembly chaperone mutations in PSMG2/PAC2 cause the autoinflammatory interferonopathy CANDLE/PRAAS4. J Allergy Clin Immunol 2019; 143:1939-1943.e8. [PMID: 30664889 DOI: 10.1016/j.jaci.2018.12.1012] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 11/30/2018] [Accepted: 12/07/2018] [Indexed: 12/24/2022]
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Abstract
Proteasomes are a class of protease that carry out the degradation of a specific set of cellular proteins. While essential for eukaryotic life, proteasomes are found only in a small subset of bacterial species. In this chapter, we present the current knowledge of bacterial proteasomes, detailing the structural features and catalytic activities required to achieve proteasomal proteolysis. We describe the known mechanisms by which substrates are doomed for degradation, and highlight potential non-degradative roles for components of bacterial proteasome systems. Additionally, we highlight several pathways of microbial physiology that rely on proteasome activity. Lastly, we explain the various gaps in our understanding of bacterial proteasome function and emphasize several opportunities for further study.
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Affiliation(s)
- Samuel H Becker
- Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, Room 312, New York, NY, 10016, USA
| | - Huilin Li
- Van Andel Research Institute, Cryo-EM Structural Biology Laboratory, 333 Bostwick Ave, NE, Grand Rapids, MI, 4950, USA
| | - K Heran Darwin
- Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, Room 312, New York, NY, 10016, USA.
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45
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Cotranslational assembly of protein complexes in eukaryotes revealed by ribosome profiling. Nature 2018; 561:268-272. [PMID: 30158700 PMCID: PMC6372068 DOI: 10.1038/s41586-018-0462-y] [Citation(s) in RCA: 192] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 08/02/2018] [Indexed: 02/07/2023]
Abstract
The folding of newly synthesized proteins to the native state is a major
challenge within the crowded cellular environment, as non-productive
interactions can lead to misfolding, aggregation and degradation1. Cells cope with this challenge by
coupling synthesis with polypeptide folding and by using molecular chaperones to
safeguard folding cotranslationally2.
However, although most of the cellular proteome forms oligomeric assemblies3, little is known about the final step of
folding: the assembly of polypeptides into complexes. In prokaryotes, a
proof-of-concept study showed that the assembly of heterodimeric luciferase is
an organized cotranslational process that is facilitated by spatially confined
translation of the subunits encoded on a polycistronic mRNA4. In eukaryotes, however, fundamental
differences—such as the rarity of polycistronic mRNAs and different
chaperone constellations—raise the question of whether assembly is also
coordinated with translation. Here we provide a systematic and mechanistic
analysis of the assembly of protein complexes in eukaryotes using ribosome
profiling. We determined the in vivo interactions of the
nascent subunits from twelve hetero-oligomeric protein complexes of
Saccharomyces cerevisiae at near-residue resolution. We
find nine complexes assemble cotranslationally; the three complexes that do not
show cotranslational interactions are regulated by dedicated assembly
chaperones5–7. Cotranslational assembly often occurs
uni-directionally, with one fully synthesized subunit engaging its nascent
partner subunit, thereby counteracting its propensity for aggregation. The onset
of cotranslational subunit association coincides directly with the full exposure
of the nascent interaction domain at the ribosomal tunnel exit. The
ribosome-associated Hsp70 chaperone Ssb8
is coordinated with assembly. Ssb transiently engages partially synthesized
interaction domains and then dissociates before the onset of partner subunit
association, presumably to prevent premature assembly interactions. Our study
shows that cotranslational subunit association is a prevalent mechanism for the
assembly of hetero-oligomers in yeast and indicates that translation, folding
and assembly of protein complexes are integrated processes in eukaryotes.
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Wu W, Sahara K, Hirayama S, Zhao X, Watanabe A, Hamazaki J, Yashiroda H, Murata S. PAC1-PAC2 proteasome assembly chaperone retains the core α4-α7 assembly intermediates in the cytoplasm. Genes Cells 2018; 23:839-848. [PMID: 30133132 DOI: 10.1111/gtc.12631] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 01/10/2023]
Abstract
The proteasome core particle (CP) is a cytoplasmic and nuclear protease complex and is comprised of two α-rings and two β-rings stacked in order of αββα. The assembly of CP proceeds by ordered recruitment of β-subunits on an α-ring with help of assembly chaperones PAC1-PAC2, PAC3-PAC4, and UMP1. However, the mechanism of α-ring formation remains unsolved. Here, we show that α4, α5, α6, and α7 form a core intermediate as the initial process of α-ring assembly, which requires PAC3-PAC4. α1 and α3 can be incorporated independently into the core α4-α7 intermediate, whereas α2 incorporation is dependent on preceding incorporation of α1. Through these processes, PAC1-PAC2 prevents nonproductive dimerization of α-ring assembly intermediates. We also found that PAC1-PAC2 overrides the effect of nuclear localization signals of α-subunits and retains α-ring assembly intermediates in the cytoplasm. Our results first show a detailed assembly pathway of proteasomal α-ring and explain the mechanism by which CP assembly occurs in the cytoplasm.
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Affiliation(s)
- Wei Wu
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazutaka Sahara
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Shoshiro Hirayama
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Xian Zhao
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Ayaka Watanabe
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Jun Hamazaki
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hideki Yashiroda
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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Mishra R, Upadhyay A, Prajapati VK, Mishra A. Proteasome-mediated proteostasis: Novel medicinal and pharmacological strategies for diseases. Med Res Rev 2018; 38:1916-1973. [DOI: 10.1002/med.21502] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/13/2018] [Accepted: 04/04/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Ribhav Mishra
- Cellular and Molecular Neurobiology Unit; Indian Institute of Technology Jodhpur; Rajasthan India
| | - Arun Upadhyay
- Cellular and Molecular Neurobiology Unit; Indian Institute of Technology Jodhpur; Rajasthan India
| | - Vijay Kumar Prajapati
- Department of Biochemistry; School of Life Sciences; Central University of Rajasthan; Rajasthan India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit; Indian Institute of Technology Jodhpur; Rajasthan India
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48
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Structural insights on the dynamics of proteasome formation. Biophys Rev 2017; 10:597-604. [PMID: 29243089 DOI: 10.1007/s12551-017-0381-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/27/2017] [Indexed: 12/28/2022] Open
Abstract
Molecular organization in biological systems comprises elaborately programmed processes involving metastable complex formation of biomolecules. This is exemplified by the formation of the proteasome, which is one of the largest and most complicated biological supramolecular complexes. This biomolecular machinery comprises approximately 70 subunits, including structurally homologous, but functionally distinct, ones, thereby exerting versatile proteolytic functions. In eukaryotes, proteasome formation is non-autonomous and is assisted by assembly chaperones, which transiently associate with assembly intermediates, operating as molecular matchmakers and checkpoints for the correct assembly of proteasome subunits. Accumulated data also suggest that eukaryotic proteasome formation involves scrap-and-build mechanisms. However, unlike the eukaryotic proteasome subunits, the archaeal subunits show little structural divergence and spontaneously assemble into functional machinery. Nevertheless, the archaeal genomes encode homologs of eukaryotic proteasome assembly chaperones. Recent structural and functional studies of these proteins have advanced our understanding of the evolution of molecular mechanisms involved in proteasome biogenesis. This knowledge, in turn, provides a guiding principle in designing molecular machineries using protein engineering approaches and de novo synthesis of artificial molecular systems.
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49
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Rippin M, Becker B, Holzinger A. Enhanced Desiccation Tolerance in Mature Cultures of the Streptophytic Green Alga Zygnema circumcarinatum Revealed by Transcriptomics. PLANT & CELL PHYSIOLOGY 2017; 58:2067-2084. [PMID: 29036673 PMCID: PMC5722205 DOI: 10.1093/pcp/pcx136] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 09/05/2017] [Indexed: 05/20/2023]
Abstract
Desiccation tolerance is commonly regarded as one of the key features for the colonization of terrestrial habitats by green algae and the evolution of land plants. Extensive studies, focused mostly on physiology, have been carried out assessing the desiccation tolerance and resilience of the streptophytic genera Klebsormidium and Zygnema. Here we present transcriptomic analyses of Zygnema circumcarinatum exposed to desiccation stress. Cultures of Z. circumcarinatum grown in liquid medium or on agar plates were desiccated at ∼86% relative air humidity until the effective quantum yield of PSII [Y(II)] ceased. In general, the response to dehydration was much more pronounced in Z. circumcarinatum cultured in liquid medium for 1 month compared with filaments grown on agar plates for 7 and 12 months. Culture on solid medium enables the alga to acclimate to dehydration much better and an increase in desiccation tolerance was clearly correlated to increased culture age. Moreover, gene expression analysis revealed that photosynthesis was strongly repressed upon desiccation treatment in the liquid culture while only minor effects were detected in filaments cultured on agar plates for 7 months. Otherwise, both samples showed induction of stress protection mechanisms such as reactive oxygen species scavenging (early light-induced proteins, glutathione metabolism) and DNA repair as well as the expression of chaperones and aquaporins. Additionally, Z. circumcarinatum cultured in liquid medium upregulated sucrose-synthesizing enzymes and strongly induced membrane modifications in response to desiccation stress. These results corroborate the previously described hardening and associated desiccation tolerance in Zygnema in response to seasonal fluctuations in water availability.
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Affiliation(s)
- Martin Rippin
- University of Cologne, Cologne Biocentre, Botanical Institute, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Burkhard Becker
- University of Cologne, Cologne Biocentre, Botanical Institute, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Andreas Holzinger
- University of Innsbruck, Department of Botany, Functional Plant Biology, Sternwartestrasse 15, 6020 Innsbruck, Austria
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Coyne LP, Chen XJ. mPOS is a novel mitochondrial trigger of cell death - implications for neurodegeneration. FEBS Lett 2017; 592:759-775. [PMID: 29090463 DOI: 10.1002/1873-3468.12894] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/14/2017] [Accepted: 10/26/2017] [Indexed: 12/14/2022]
Abstract
In addition to its central role in energy metabolism, the mitochondrion has many other functions essential for cell survival. When stressed, the multifunctional mitochondria are expected to engender multifaceted cell stress with complex physiological consequences. Potential extra-mitochondrial proteostatic burdens imposed by inefficient protein import have been largely overlooked. Accumulating evidence suggests that a diverse range of pathogenic mitochondrial stressors, which do not directly target the core protein import machinery, can reduce cell fitness by disrupting the proteostatic network in the cytosol. The resulting stress, named mitochondrial precursor overaccumulation stress (mPOS), is characterized by the toxic accumulation of unimported mitochondrial proteins in the cytosol. Here, we review our current understanding of how mitochondrial dysfunction can impact the cytosolic proteome and proteostatic signaling. We also discuss the intriguing possibility that the mPOS model may help untangle the cause-effect relationship between mitochondrial dysfunction and cytosolic protein aggregation, which are probably the two most prominent molecular hallmarks of neurodegenerative disease.
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Affiliation(s)
- Liam P Coyne
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Xin Jie Chen
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA.,Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY, USA
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