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Hogrel G, Marino-Puertas L, Laurent S, Ibrahim Z, Covès J, Girard E, Gabel F, Fenel D, Daugeron MC, Clouet-d'Orval B, Basta T, Flament D, Franzetti B. Characterization of a small tRNA-binding protein that interacts with the archaeal proteasome complex. Mol Microbiol 2022; 118:16-29. [PMID: 35615908 PMCID: PMC9540759 DOI: 10.1111/mmi.14948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/15/2022] [Accepted: 05/17/2022] [Indexed: 11/27/2022]
Abstract
The proteasome system allows the elimination of functional or structurally impaired proteins. This includes the degradation of nascent peptides. In Archaea, how the proteasome complex interacts with the translational machinery remains to be described. Here, we characterised a small orphan protein, Q9UZY3 (Uniprot ID) conserved in Thermococcales. The protein was identified in native pull-down experiments using the proteasome regulatory complex (PAN) as bait. X-ray crystallography and SAXS experiments revealed that the protein is monomeric and adopts a β-barrel core structure with an Oligonucleotide/oligosaccharide-Binding (OB) fold, typically found in translation elongation factors. Mobility shift experiment showed that Q9UZY3 displays tRNA binding properties. Pull-downs, co-immunoprecipitation and ITC studies revealed that Q9UZY3 interacts in vitro with PAN. Native pull-downs and proteomic analysis using different versions of Q9UZY3 showed that the protein interacts with the assembled PAN-20S proteasome machinery in Pyrococcus abyssi cellular extracts. The protein was therefore named Pbp11, for Proteasome Binding Protein of 11 kDa. Interestingly, the interaction network of Pbp11 also includes ribosomal proteins, tRNA processing enzymes and exosome subunits dependent on Pbp11's N-terminal domain that was found to be essential for tRNA binding. Together these data suggest that Pbp11 participates in an interface between the proteasome and the translational machinery.
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Affiliation(s)
- Gaëlle Hogrel
- Univ Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.,University of St Andrews, St Andrews, UK
| | | | - Sébastien Laurent
- Univ Brest, Ifremer, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, Plouzané, France
| | - Ziad Ibrahim
- Univ Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.,University of Leicester, Leicester, UK
| | - Jacques Covès
- Univ Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Eric Girard
- Univ Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Frank Gabel
- Univ Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Daphna Fenel
- Univ Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Marie-Claire Daugeron
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Béatrice Clouet-d'Orval
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Tamara Basta
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Didier Flament
- Univ Brest, Ifremer, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, Plouzané, France
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2
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Song C, Satoh T, Sekiguchi T, Kato K, Murata K. Structural Fluctuations of the Human Proteasome α7 Homo-Tetradecamer Double Ring Imply the Proteasomal α-Ring Assembly Mechanism. Int J Mol Sci 2021; 22:ijms22094519. [PMID: 33926037 PMCID: PMC8123668 DOI: 10.3390/ijms22094519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/17/2021] [Accepted: 04/23/2021] [Indexed: 11/16/2022] Open
Abstract
The 20S proteasome, which is composed of layered α and β heptameric rings, is the core complex of the eukaryotic proteasome involved in proteolysis. The α7 subunit is a component of the α ring, and it self-assembles into a homo-tetradecamer consisting of two layers of α7 heptameric rings. However, the structure of the α7 double ring in solution has not been fully elucidated. We applied cryo-electron microscopy to delineate the structure of the α7 double ring in solution, revealing a structure different from the previously reported crystallographic model. The D7-symmetrical double ring was stacked with a 15° clockwise twist and a separation of 3 Å between the two rings. Two more conformations, dislocated and fully open, were also identified. Our observations suggest that the α7 double-ring structure fluctuates considerably in solution, allowing for the insertion of homologous α subunits, finally converting to the hetero-heptameric α rings in the 20S proteasome.
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Affiliation(s)
- Chihong Song
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan; (C.S.); (T.S.)
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan
| | - Tadashi Satoh
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan;
| | - Taichiro Sekiguchi
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan; (C.S.); (T.S.)
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan;
- School of Physical Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan; (C.S.); (T.S.)
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan;
- School of Physical Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Correspondence: (K.K.); (K.M.)
| | - Kazuyoshi Murata
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan; (C.S.); (T.S.)
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan
- Correspondence: (K.K.); (K.M.)
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3
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Medvedev KE, Kinch LN, Dustin Schaeffer R, Pei J, Grishin NV. A Fifth of the Protein World: Rossmann-like Proteins as an Evolutionarily Successful Structural unit. J Mol Biol 2021; 433:166788. [PMID: 33387532 PMCID: PMC7870570 DOI: 10.1016/j.jmb.2020.166788] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/26/2020] [Accepted: 12/18/2020] [Indexed: 10/22/2022]
Abstract
The Rossmann-like fold is the most prevalent and diversified doubly-wound superfold of ancient evolutionary origin. Rossmann-like domains are present in a variety of metabolic enzymes and are capable of binding diverse ligands. Discerning evolutionary relationships among these domains is challenging because of their diverse functions and ancient origin. We defined a minimal Rossmann-like structural motif (RLM), identified RLM-containing domains among known 3D structures (20%) and classified them according to their homologous relationships. New classifications were incorporated into our Evolutionary Classification of protein Domains (ECOD) database. We defined 156 homology groups (H-groups), which were further clustered into 123 possible homology groups (X-groups). Our analysis revealed that RLM-containing proteins constitute approximately 15% of the human proteome. We found that disease-causing mutations are more frequent within RLM domains than within non-RLM domains of these proteins, highlighting the importance of RLM-containing proteins for human health.
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Affiliation(s)
- Kirill E Medvedev
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Lisa N Kinch
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - R Dustin Schaeffer
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Jimin Pei
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Nick V Grishin
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States.
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4
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Majumder P, Baumeister W. Proteasomes: unfoldase-assisted protein degradation machines. Biol Chem 2020; 401:183-199. [PMID: 31665105 DOI: 10.1515/hsz-2019-0344] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 10/02/2019] [Indexed: 01/05/2023]
Abstract
Proteasomes are the principal molecular machines for the regulated degradation of intracellular proteins. These self-compartmentalized macromolecular assemblies selectively degrade misfolded, mistranslated, damaged or otherwise unwanted proteins, and play a pivotal role in the maintenance of cellular proteostasis, in stress response, and numerous other processes of vital importance. Whereas the molecular architecture of the proteasome core particle (CP) is universally conserved, the unfoldase modules vary in overall structure, subunit complexity, and regulatory principles. Proteasomal unfoldases are AAA+ ATPases (ATPases associated with a variety of cellular activities) that unfold protein substrates, and translocate them into the CP for degradation. In this review, we summarize the current state of knowledge about proteasome - unfoldase systems in bacteria, archaea, and eukaryotes, the three domains of life.
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Affiliation(s)
- Parijat Majumder
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
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6
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Supramolecular tholos-like architecture constituted by archaeal proteins without functional annotation. Sci Rep 2020; 10:1540. [PMID: 32001743 PMCID: PMC6992696 DOI: 10.1038/s41598-020-58371-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/14/2020] [Indexed: 11/08/2022] Open
Abstract
Euryarchaeal genomes encode proteasome-assembling chaperone homologs, PbaA and PbaB, although archaeal proteasome formation is a chaperone-independent process. Homotetrameric PbaB functions as a proteasome activator, while PbaA forms a homopentamer that does not interact with the proteasome. Notably, PbaA forms a complex with PF0014, an archaeal protein without functional annotation. In this study, based on our previous research on PbaA crystal structure, we performed an integrative analysis of the supramolecular structure of the PbaA/PF0014 complex using native mass spectrometry, solution scattering, high-speed atomic force microscopy, and electron microscopy. The results indicated that this highly thermostable complex constitutes ten PbaA and ten PF0014 molecules, which are assembled into a dumbbell-shaped structure. Two PbaA homopentameric rings correspond to the dumbbell plates, with their N-termini located outside of the plates and C-terminal segments left mobile. Furthermore, mutant PbaA lacking the mobile C-terminal segment retained the ability to form a complex with PF0014, allowing 3D modeling of the complex. The complex shows a five-column tholos-like architecture, in which each column comprises homodimeric PF0014, harboring a central cavity, which can potentially accommodate biomacromolecules including proteins. Our findings provide insight into the functional roles of Pba family proteins, offering a novel framework for designing functional protein cages.
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7
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Proteolytic systems of archaea: slicing, dicing, and mincing in the extreme. Emerg Top Life Sci 2018; 2:561-580. [PMID: 32953999 DOI: 10.1042/etls20180025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Archaea are phylogenetically distinct from bacteria, and some of their proteolytic systems reflect this distinction. Here, the current knowledge of archaeal proteolysis is reviewed as it relates to protein metabolism, protein homeostasis, and cellular regulation including targeted proteolysis by proteasomes associated with AAA-ATPase networks and ubiquitin-like modification. Proteases and peptidases that facilitate the recycling of peptides to amino acids as well as membrane-associated and integral membrane proteases are also reviewed.
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8
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Baarda RA, Marianchuk TL, Toney MD, Cox DL. In silico stress-strain measurements on self-assembled protein lattices. SOFT MATTER 2018; 14:8095-8104. [PMID: 30159554 DOI: 10.1039/c8sm00412a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Due to their large mechanical strength and potential for functionalization, beta-solenoid proteins show promise as building blocks in biomaterials applications such as two- and three-dimensional scaffolds. We have designed simulation models of two-dimensional square and honeycomb protein lattices by covalently linking a beta-solenoid protein, the spruce budworm antifreeze protein (SBAFP), to symmetric protein multimers. Periodic boundary conditions applied to the simulation cell allow for the simulation of an infinite lattice. We use molecular dynamics to strain the lattice by deforming the simulation cell and measuring the resulting stress tensor. We evaluate the linear portion of stress-strain curves to extract the corresponding bulk and shear elastic moduli. When strained at a rate of 0.3 nm ps-1, the lattices yield a bulk modulus of approximately 3 GPa. This large elastic modulus demonstrates that 2-dimensional structures designed from beta-solenoid proteins can be expected to retain the exceptional material strength of their building blocks.
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Affiliation(s)
- Rachel A Baarda
- Department of Physics, University of California, Davis, California, USA.
| | | | - Michael D Toney
- Department of Chemistry, University of California, Davis, California, USA
| | - Daniel L Cox
- Department of Physics, University of California, Davis, California, USA.
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9
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Yagi-Utsumi M, Sikdar A, Kozai T, Inoue R, Sugiyama M, Uchihashi T, Yagi H, Satoh T, Kato K. Conversion of functionally undefined homopentameric protein PbaA into a proteasome activator by mutational modification of its C-terminal segment conformation. Protein Eng Des Sel 2017; 31:29-36. [DOI: 10.1093/protein/gzx066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/06/2017] [Indexed: 01/10/2023] Open
Affiliation(s)
- Maho Yagi-Utsumi
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Functional Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 465-8603, Japan
| | - Arunima Sikdar
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Functional Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787Japan
| | - Toshiya Kozai
- Graduate School of Natural Science & Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Rintaro Inoue
- Research Reactor Institute, Kyoto University, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - Masaaki Sugiyama
- Research Reactor Institute, Kyoto University, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - Takayuki Uchihashi
- Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Hirokazu Yagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 465-8603, Japan
| | - Tadashi Satoh
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 465-8603, Japan
| | - Koichi Kato
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Functional Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 465-8603, Japan
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10
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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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11
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de la Peña AH, Lander GC. What's the Key to Unlocking the Proteasome's Gate? Structure 2017; 24:2037-2038. [PMID: 27926830 DOI: 10.1016/j.str.2016.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In this issue of Structure, Bolten et al. (2016) describe the organization of the mycobacterial proteasome in complex with the ATP-independent bacterial proteasome activator (Bpa, PafE). They confirm several activation motifs employed by archaea and eukaryotes and highlight differences that pose Bpa as a novel architectural class of proteasome activators.
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Affiliation(s)
- Andres H de la Peña
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037, USA.
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12
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Budenholzer L, Cheng CL, Li Y, Hochstrasser M. Proteasome Structure and Assembly. J Mol Biol 2017; 429:3500-3524. [PMID: 28583440 DOI: 10.1016/j.jmb.2017.05.027] [Citation(s) in RCA: 232] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/22/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
The eukaryotic 26S proteasome is a large multisubunit complex that degrades the majority of proteins in the cell under normal conditions. The 26S proteasome can be divided into two subcomplexes: the 19S regulatory particle and the 20S core particle. Most substrates are first covalently modified by ubiquitin, which then directs them to the proteasome. The function of the regulatory particle is to recognize, unfold, deubiquitylate, and translocate substrates into the core particle, which contains the proteolytic sites of the proteasome. Given the abundance and subunit complexity of the proteasome, the assembly of this ~2.5MDa complex must be carefully orchestrated to ensure its correct formation. In recent years, significant progress has been made in the understanding of proteasome assembly, structure, and function. Technical advances in cryo-electron microscopy have resulted in a series of atomic cryo-electron microscopy structures of both human and yeast 26S proteasomes. These structures have illuminated new intricacies and dynamics of the proteasome. In this review, we focus on the mechanisms of proteasome assembly, particularly in light of recent structural information.
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Affiliation(s)
- Lauren Budenholzer
- Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - Chin Leng Cheng
- Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - Yanjie Li
- Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - Mark Hochstrasser
- Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA.
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Structural Analysis of Mycobacterium tuberculosis Homologues of the Eukaryotic Proteasome Assembly Chaperone 2 (PAC2). J Bacteriol 2017; 199:JB.00846-16. [PMID: 28193903 DOI: 10.1128/jb.00846-16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/06/2017] [Indexed: 12/20/2022] Open
Abstract
A previous bioinformatics analysis identified the Mycobacterium tuberculosis proteins Rv2125 and Rv2714 as orthologs of the eukaryotic proteasome assembly chaperone 2 (PAC2). We set out to investigate whether Rv2125 or Rv2714 can function in proteasome assembly. We solved the crystal structure of Rv2125 at a resolution of 3.0 Å, which showed an overall fold similar to that of the PAC2 family proteins that include the archaeal PbaB and the yeast Pba1. However, Rv2125 and Rv2714 formed trimers, whereas PbaB forms tetramers and Pba1 dimerizes with Pba2. We also found that purified Rv2125 and Rv2714 could not bind to M. tuberculosis 20S core particles. Finally, proteomic analysis showed that the levels of known proteasome components and substrate proteins were not affected by disruption of Rv2125 in M. tuberculosis Our work suggests that Rv2125 does not participate in bacterial proteasome assembly or function.IMPORTANCE Although many bacteria do not encode proteasomes, M. tuberculosis not only uses proteasomes but also has evolved a posttranslational modification system called pupylation to deliver proteins to the proteasome. Proteasomes are essential for M. tuberculosis to cause lethal infections in animals; thus, determining how proteasomes are assembled may help identify new ways to combat tuberculosis. We solved the structure of a predicted proteasome assembly factor, Rv2125, and isolated a genetic Rv2125 mutant of M. tuberculosis Our structural, biochemical, and genetic studies indicate that Rv2125 and Rv2714 do not function as proteasome assembly chaperones and are unlikely to have roles in proteasome biology in mycobacteria.
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14
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Structural analysis of the dodecameric proteasome activator PafE in Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2016; 113:E1983-92. [PMID: 27001842 DOI: 10.1073/pnas.1512094113] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The human pathogen Mycobacterium tuberculosis (Mtb) requires a proteasome system to cause lethal infections in mice. We recently found that proteasome accessory factor E (PafE, Rv3780) activates proteolysis by the Mtb proteasome independently of adenosine triphosphate (ATP). Moreover, PafE contributes to the heat-shock response and virulence of Mtb Here, we show that PafE subunits formed four-helix bundles similar to those of the eukaryotic ATP-independent proteasome activator subunits of PA26 and PA28. However, unlike any other known proteasome activator, PafE formed dodecamers with 12-fold symmetry, which required a glycine-XXX-glycine-XXX-glycine motif that is not found in previously described activators. Intriguingly, the truncation of the PafE carboxyl-terminus resulted in the robust binding of PafE rings to native proteasome core particles and substantially increased proteasomal activity, suggesting that the extended carboxyl-terminus of this cofactor confers suboptimal binding to the proteasome core particle. Collectively, our data show that proteasomal activation is not limited to hexameric ATPases in bacteria.
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15
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Jastrab JB, Wang T, Murphy JP, Bai L, Hu K, Merkx R, Huang J, Chatterjee C, Ovaa H, Gygi SP, Li H, Darwin KH. An adenosine triphosphate-independent proteasome activator contributes to the virulence of Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2015; 112:E1763-72. [PMID: 25831519 PMCID: PMC4394314 DOI: 10.1073/pnas.1423319112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mycobacterium tuberculosis encodes a proteasome that is highly similar to eukaryotic proteasomes and is required to cause lethal infections in animals. The only pathway known to target proteins for proteasomal degradation in bacteria is pupylation, which is functionally analogous to eukaryotic ubiquitylation. However, evidence suggests that the M. tuberculosis proteasome contributes to pupylation-independent pathways as well. To identify new proteasome cofactors that might contribute to such pathways, we isolated proteins that bound to proteasomes overproduced in M. tuberculosis and found a previously uncharacterized protein, Rv3780, which formed rings and capped M. tuberculosis proteasome core particles. Rv3780 enhanced peptide and protein degradation by proteasomes in an adenosine triphosphate (ATP)-independent manner. We identified putative Rv3780-dependent proteasome substrates and found that Rv3780 promoted robust degradation of the heat shock protein repressor, HspR. Importantly, an M. tuberculosis Rv3780 mutant had a general growth defect, was sensitive to heat stress, and was attenuated for growth in mice. Collectively, these data demonstrate that ATP-independent proteasome activators are not confined to eukaryotes and can contribute to the virulence of one the world's most devastating pathogens.
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Affiliation(s)
- Jordan B Jastrab
- Department of Microbiology, New York University School of Medicine, New York, NY 10016
| | - Tong Wang
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973
| | - J Patrick Murphy
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Lin Bai
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973
| | - Kuan Hu
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794
| | - Remco Merkx
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; and
| | - Jessica Huang
- Department of Chemistry, University of Washington, Seattle, WA 98195
| | | | - Huib Ovaa
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; and
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Huilin Li
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794
| | - K Heran Darwin
- Department of Microbiology, New York University School of Medicine, New York, NY 10016;
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Gu ZC, Enenkel C. Proteasome assembly. Cell Mol Life Sci 2014; 71:4729-45. [PMID: 25107634 PMCID: PMC11113775 DOI: 10.1007/s00018-014-1699-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/30/2014] [Accepted: 07/31/2014] [Indexed: 10/24/2022]
Abstract
In eukaryotic cells, proteasomes are highly conserved protease complexes and eliminate unwanted proteins which are marked by poly-ubiquitin chains for degradation. The 26S proteasome consists of the proteolytic core particle, the 20S proteasome, and the 19S regulatory particle, which are composed of 14 and 19 different subunits, respectively. Proteasomes are the second-most abundant protein complexes and are continuously assembled from inactive precursor complexes in proliferating cells. The modular concept of proteasome assembly was recognized in prokaryotic ancestors and applies to eukaryotic successors. The efficiency and fidelity of eukaryotic proteasome assembly is achieved by several proteasome-dedicated chaperones that initiate subunit incorporation and control the quality of proteasome assemblies by transiently interacting with proteasome precursors. It is important to understand the mechanism of proteasome assembly as the proteasome has key functions in the turnover of short-lived proteins regulating diverse biological processes.
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Affiliation(s)
- Zhu Chao Gu
- Department of Biochemistry, University of Toronto, Medical Sciences Building, 1 King’s College Circle, Toronto, ON M5S 1A8 Canada
| | - Cordula Enenkel
- Department of Biochemistry, University of Toronto, Medical Sciences Building, 1 King’s College Circle, Toronto, ON M5S 1A8 Canada
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Crystal structure of archaeal homolog of proteasome-assembly chaperone PbaA. Biochem Biophys Res Commun 2014; 453:493-7. [PMID: 25285636 DOI: 10.1016/j.bbrc.2014.09.114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 09/25/2014] [Indexed: 11/23/2022]
Abstract
Formation of the eukaryotic proteasome is not a spontaneous process but a highly ordered process assisted by several assembly chaperones. In contrast, archaeal proteasome subunits can spontaneously assemble into an active form. Recent bioinformatic analysis identified the proteasome-assembly chaperone-like proteins, PbaA and PbaB, in archaea. Our previous study showed that the PbaB homotetramer functions as a proteasome activator through its tentacle-like C-terminal segments. However, a functional role of the other homolog PbaA has remained elusive. Here we determined the 2.25-Å resolution structure of PbaA, illustrating its disparate tertiary and quaternary structures compared with PbaB. PbaA forms a homopentamer in which the C-terminal segments, with a putative proteasome-activating motif, are packed against the core. These findings offer deeper insights into the molecular evolution relationships between the proteasome-assembly chaperones and the proteasome activators.
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Uekusa Y, Okawa K, Yagi-Utsumi M, Serve O, Nakagawa Y, Mizushima T, Yagi H, Saeki Y, Tanaka K, Kato K. Backbone ¹H, ¹³C and ¹⁵N assignments of yeast Ump1, an intrinsically disordered protein that functions as a proteasome assembly chaperone. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:383-386. [PMID: 24065419 DOI: 10.1007/s12104-013-9523-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 09/06/2013] [Indexed: 06/02/2023]
Abstract
Eukaryotic proteasome assembly is a highly organized process mediated by several proteasome-specific chaperones, which interact with proteasome assembly intermediates. In yeast, Ump1 and Pba1-4 have been identified as assembly chaperones that are dedicated to the formation of the proteasome 20S catalytic core complex. The crystal structures of Pba chaperones have been reported previously, but no detailed information has been provided for the structure of Ump1. Thus, to better understand the mechanisms underlying Ump1-mediated proteasome assembly, we characterized the conformation of Ump1 in solution using NMR. Backbone chemical shift data indicated that Ump1 is an intrinsically unstructured protein and largely devoid of secondary structural elements.
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Affiliation(s)
- Yoshinori Uekusa
- Graduate School and Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
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