1
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von Rosen T, Pepelnjak M, Quast JP, Picotti P, Weber-Ban E. ATP-independent substrate recruitment to proteasomal degradation in mycobacteria. Life Sci Alliance 2023; 6:e202301923. [PMID: 37562848 PMCID: PMC10415612 DOI: 10.26508/lsa.202301923] [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: 01/13/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023] Open
Abstract
Mycobacteria and other actinobacteria possess proteasomal degradation pathways in addition to the common bacterial compartmentalizing protease systems. Proteasomal degradation plays a crucial role in the survival of these bacteria in adverse environments. The mycobacterial proteasome interacts with several ring-shaped activators, including the bacterial proteasome activator (Bpa), which enables energy-independent degradation of heat shock repressor HspR. However, the mechanism of substrate selection and processing by the Bpa-proteasome complex remains unclear. In this study, we present evidence that disorder in substrates is required but not sufficient for recruitment to Bpa-mediated proteasomal degradation. We demonstrate that Bpa binds to the folded N-terminal helix-turn-helix domain of HspR, whereas the unstructured C-terminal tail of the substrate acts as a sequence-specific threading handle to promote efficient proteasomal degradation. In addition, we establish that the heat shock chaperone DnaK, which interacts with and co-regulates HspR, stabilizes HspR against Bpa-mediated proteasomal degradation. By phenotypical characterization of Mycobacterium smegmatis parent and bpa deletion mutant strains, we show that Bpa-dependent proteasomal degradation supports the survival of the bacterium under stress conditions by degrading HspR that regulates vital chaperones.
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Affiliation(s)
- Tatjana von Rosen
- ETH Zurich, Institute of Molecular Biology and Biophysics, Zurich, Switzerland
| | - Monika Pepelnjak
- ETH Zurich, Institute of Molecular Systems Biology, Zurich Switzerland
| | - Jan-Philipp Quast
- ETH Zurich, Institute of Molecular Systems Biology, Zurich Switzerland
| | - Paola Picotti
- ETH Zurich, Institute of Molecular Systems Biology, Zurich Switzerland
| | - Eilika Weber-Ban
- ETH Zurich, Institute of Molecular Biology and Biophysics, Zurich, Switzerland
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2
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The β-Grasp Domain of Proteasomal ATPase Mpa Makes Critical Contacts with the Mycobacterium tuberculosis 20S Core Particle to Facilitate Degradation. mSphere 2022; 7:e0027422. [PMID: 35993699 PMCID: PMC9599533 DOI: 10.1128/msphere.00274-22] [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] [Indexed: 01/12/2023] Open
Abstract
Mycobacterium tuberculosis possesses a Pup-proteasome system analogous to the eukaryotic ubiquitin-proteasome pathway. We have previously shown that the hexameric mycobacterial proteasome ATPase (Mpa) recruits pupylated protein substrates via interactions between amino-terminal coiled-coils in Mpa monomers and the degradation tag Pup. However, it is unclear how Mpa rings interact with a proteasome due to the presence of a carboxyl-terminal β-grasp domain unique to Mpa homologues that makes the interaction highly unstable. Here, we describe newly identified critical interactions between Mpa and 20S core proteasomes. Interestingly, the Mpa C-terminal GQYL motif binds the 20S core particle activation pocket differently than the same motif of the ATP-independent proteasome accessory factor PafE. We further found that the β-hairpin of the Mpa β-grasp domain interacts variably with the H0 helix on top of the 20S core particle via a series of ionic and hydrogen-bond interactions. Individually mutating several involved residues reduced Mpa-mediated protein degradation both in vitro and in vivo. IMPORTANCE The Pup-proteasome system in Mycobacterium tuberculosis is critical for this species to cause lethal infections in mice. Investigating the molecular mechanism of how the Mpa ATPase recruits and unfolds pupylated substrates to the 20S proteasomal core particle for degradation will be essential to fully understand how degradation is regulated, and the structural information we report may be useful for the development of new tuberculosis chemotherapies.
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3
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Abstract
Proteasomes are compartmentalized, ATP-dependent, N-terminal nucleophile hydrolases that play essentials roles in intracellular protein turnover. They are present in all 3 kingdoms. Pharmacological inhibition of proteasomes is detrimental to cell viability. Proteasome inhibitor rugs revolutionize the treatment of multiple myeloma. Proteasomes in pathogenic microbes such as Mycobacterium tuberculosis (Mtb), Plasmodium falciparum (Pf), and other parasites and worms have been validated as therapeutic targets. Starting with Mtb proteasome, efforts in developing inhibitors selective for microbial proteasomes have made great progress lately. In this review, we describe the strategies and pharmacophores that have been used in developing proteasome inhibitors with potency and selectivity that spare human proteasomes and highlight the development of clinical proteasome inhibitor candidates for treatment of leishmaniasis and Chagas disease. Finally, we discuss the future challenges and therapeutical potentials of the microbial proteasome inhibitors.
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Affiliation(s)
- Hao Zhang
- Department of Microbiology & Immunology, Weill Cornell Medicine, New York, New York, United States of America
| | - Gang Lin
- Department of Microbiology & Immunology, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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4
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Zhang H, Hsu HC, Kahne SC, Hara R, Zhan W, Jiang X, Burns-Huang K, Ouellette T, Imaeda T, Okamoto R, Kawasaki M, Michino M, Wong TT, Toita A, Yukawa T, Moraca F, Vendome J, Saha P, Sato K, Aso K, Ginn J, Meinke PT, Foley M, Nathan CF, Darwin KH, Li H, Lin G. Macrocyclic Peptides that Selectively Inhibit the Mycobacterium tuberculosis Proteasome. J Med Chem 2021; 64:6262-6272. [PMID: 33949190 PMCID: PMC8194371 DOI: 10.1021/acs.jmedchem.1c00296] [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] [Indexed: 11/28/2022]
Abstract
Treatment of tuberculosis (TB) currently takes at least 6 months. Latent Mycobacterium tuberculosis (Mtb) is phenotypically tolerant to most anti-TB drugs. A key hypothesis is that drugs that kill nonreplicating (NR) Mtb may shorten treatment when used in combination with conventional drugs. The Mtb proteasome (Mtb20S) could be such a target because its pharmacological inhibition kills NR Mtb and its genetic deletion renders Mtb unable to persist in mice. Here, we report a series of macrocyclic peptides that potently and selectively target the Mtb20S over human proteasomes, including macrocycle 6. The cocrystal structure of macrocycle 6 with Mtb20S revealed structural bases for the species selectivity. Inhibition of 20S within Mtb by 6 dose dependently led to the accumulation of Pup-tagged GFP that is degradable but resistant to depupylation and death of nonreplicating Mtb under nitrosative stress. These results suggest that compounds of this class have the potential to develop as anti-TB therapeutics.
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Affiliation(s)
- Hao Zhang
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
| | - Hao-Chi Hsu
- Department of Structural Biology, Van Andel Institute, 333 Bostwick Ave. NE, Grand Rapids, MI 49503
| | - Shoshanna C. Kahne
- Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, New York, NY 10016
| | - Ryoma Hara
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Wenhu Zhan
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
| | - Xiuju Jiang
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
| | - Kristin Burns-Huang
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
| | - Tierra Ouellette
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
| | - Toshihiro Imaeda
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Rei Okamoto
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Masanori Kawasaki
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Mayako Michino
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Tzu-Tshin Wong
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Akinori Toita
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Takafumi Yukawa
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | | | | | - Priya Saha
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
| | - Kenjiro Sato
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Kazuyoshi Aso
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - John Ginn
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Peter T. Meinke
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Michael Foley
- Tri-Institutional Therapeutics Discovery Institute, 413 E. 69th St, New York, NY 10065
| | - Carl F Nathan
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
| | - K. Heran Darwin
- Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, New York, NY 10016
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, 333 Bostwick Ave. NE, Grand Rapids, MI 49503
| | - Gang Lin
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065
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5
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Yin Y, Kovach A, Hsu HC, Darwin KH, Li H. The mycobacterial proteasomal ATPase Mpa forms a gapped ring to engage the 20S proteasome. J Biol Chem 2021; 296:100713. [PMID: 33930464 PMCID: PMC8142254 DOI: 10.1016/j.jbc.2021.100713] [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: 02/04/2021] [Revised: 04/17/2021] [Accepted: 04/26/2021] [Indexed: 11/25/2022] Open
Abstract
Although many bacterial species do not possess proteasome systems, the actinobacteria, including the human pathogen Mycobacterium tuberculosis, use proteasome systems for targeted protein removal. Previous structural analyses of the mycobacterial proteasome ATPase Mpa revealed a general structural conservation with the archaeal proteasome-activating nucleotidase and eukaryotic proteasomal Rpt1–6 ATPases, such as the N-terminal coiled-coil domain, oligosaccharide-/oligonucleotide-binding domain, and ATPase domain. However, Mpa has a unique β-grasp domain that in the ADP-bound crystal structure appears to interfere with the docking to the 20S proteasome core particle (CP). Thus, it is unclear how Mpa binds to proteasome CPs. In this report, we show by cryo-EM that the Mpa hexamer in the presence of a degradation substrate and ATP forms a gapped ring, with two of its six ATPase domains being highly flexible. We found that the linkers between the oligonucleotide-binding and ATPase domains undergo conformational changes that are important for function, revealing a previously unappreciated role of the linker region in ATP hydrolysis–driven protein unfolding. We propose that this gapped ring configuration is an intermediate state that helps rearrange its β-grasp domains and activating C termini to facilitate engagement with proteasome CPs. This work provides new insights into the crucial process of how an ATPase interacts with a bacterial proteasome protease.
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Affiliation(s)
- Yanting Yin
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA
| | - Amanda Kovach
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA
| | - Hao-Chi Hsu
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA
| | - K Heran Darwin
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA.
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6
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Allosteric coupling between α-rings of the 20S proteasome. Nat Commun 2020; 11:4580. [PMID: 32917864 PMCID: PMC7486400 DOI: 10.1038/s41467-020-18415-7] [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] [Accepted: 08/21/2020] [Indexed: 11/21/2022] Open
Abstract
Proteasomal machinery performs essential regulated protein degradation in eukaryotes. Classic proteasomes are symmetric, with a regulatory ATPase docked at each end of the cylindrical 20S. Asymmetric complexes are also present in cells, either with a single ATPase or with an ATPase and non-ATPase at two opposite ends. The mechanism that populates these different proteasomal complexes is unknown. Using archaea homologs, we construct asymmetric forms of proteasomes. We demonstrate that the gate conformation of the two opposite ends of 20S are coupled: binding one ATPase opens a gate locally, and also opens the opposite gate allosterically. Such allosteric coupling leads to cooperative binding of proteasomal ATPases to 20S and promotes formation of proteasomes symmetrically configured with two identical ATPases. It may also promote formation of asymmetric complexes with an ATPase and a non-ATPase at opposite ends. We propose that in eukaryotes a similar mechanism regulates the composition of the proteasomal population. The 26S proteasome is a protein degradation machine composed of a 20S core particle (CP) flanked at one or both ends by a 19S ATPase regulatory particle (RP). Here the authors reconstitute asymmetric archaeal proteasomes and reveal allosteric coupling between the conformations of gates in the α-rings positioned at opposite ends of the CP, which modulates RP assembly and substrate entry.
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7
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Nagpal J, Paxman JJ, Zammit JE, Thomas AA, Truscott KN, Heras B, Dougan DA. Molecular and structural insights into an asymmetric proteolytic complex (ClpP1P2) from Mycobacterium smegmatis. Sci Rep 2019; 9:18019. [PMID: 31792243 PMCID: PMC6889138 DOI: 10.1038/s41598-019-53736-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/25/2019] [Indexed: 11/09/2022] Open
Abstract
The ClpP protease is found in all kingdoms of life, from bacteria to humans. In general, this protease forms a homo-oligomeric complex composed of 14 identical subunits, which associates with its cognate ATPase in a symmetrical manner. Here we show that, in contrast to this general architecture, the Clp protease from Mycobacterium smegmatis (Msm) forms an asymmetric hetero-oligomeric complex ClpP1P2, which only associates with its cognate ATPase through the ClpP2 ring. Our structural and functional characterisation of this complex demonstrates that asymmetric docking of the ATPase component is controlled by both the composition of the ClpP1 hydrophobic pocket (Hp) and the presence of a unique C-terminal extension in ClpP1 that guards this Hp. Our structural analysis of MsmClpP1 also revealed openings in the side-walls of the inactive tetradecamer, which may represent sites for product egress.
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Affiliation(s)
- Jyotsna Nagpal
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Jason J Paxman
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Jessica E Zammit
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Adam A. Thomas
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Kaye N Truscott
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Begoña Heras
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia.
| | - David A Dougan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia.
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8
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Zhan W, Hsu HC, Morgan T, Ouellette T, Burns-Huang K, Hara R, Wright AG, Imaeda T, Okamoto R, Sato K, Michino M, Ramjee M, Aso K, Meinke PT, Foley M, Nathan CF, Li H, Lin G. Selective Phenylimidazole-Based Inhibitors of the Mycobacterium tuberculosis Proteasome. J Med Chem 2019; 62:9246-9253. [PMID: 31560200 DOI: 10.1021/acs.jmedchem.9b01187] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Proteasomes of pathogenic microbes have become attractive targets for anti-infectives. Coevolving with its human host, Mycobacterium tuberculosis (Mtb) has developed mechanisms to resist host-imposed nitrosative and oxidative stresses. Genetic deletion or pharmacological inhibition of the Mtb proteasome (Mtb20S) renders nonreplicating Mtb susceptible to reactive nitrogen species in vitro and unable to survive in the lungs of mice, validating the Mtb proteasome as a promising target for anti-Mtb agents. Using a structure-guided and flow chemistry-enabled study of structure-activity relationships, we developed phenylimidazole-based peptidomimetics that are highly potent for Mtb20S. X-ray structures of selected compounds with Mtb20S shed light on their selectivity for mycobacterial over human proteasomes.
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Affiliation(s)
- Wenhu Zhan
- Department of Microbiology & Immunology , Weill Cornell Medicine , 1300 York Avenue , New York , New York 10065 , United States
| | - Hao-Chi Hsu
- Structural Biology Program , Van Andel Institute , 333 Bostwick Avenue Northeast , Grand Rapids , Michigan 49503 , United States
| | - Trevor Morgan
- Cyclofluidic Limited , Biopark Broadwater Road , Welwyn Garden City AL7 3AX , U.K
| | - Tierra Ouellette
- Department of Microbiology & Immunology , Weill Cornell Medicine , 1300 York Avenue , New York , New York 10065 , United States
| | - Kristin Burns-Huang
- Department of Microbiology & Immunology , Weill Cornell Medicine , 1300 York Avenue , New York , New York 10065 , United States
| | - Ryoma Hara
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Adrian G Wright
- Cyclofluidic Limited , Biopark Broadwater Road , Welwyn Garden City AL7 3AX , U.K
| | - Toshihiro Imaeda
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Rei Okamoto
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Kenjiro Sato
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Mayako Michino
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Manoj Ramjee
- Cyclofluidic Limited , Biopark Broadwater Road , Welwyn Garden City AL7 3AX , U.K
| | - Kazuyoshi Aso
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Peter T Meinke
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Michael Foley
- Tri-Institutional Therapeutics Discovery Institute , 413 East 69th Street , New York , New York 10065 , United States
| | - Carl F Nathan
- Department of Microbiology & Immunology , Weill Cornell Medicine , 1300 York Avenue , New York , New York 10065 , United States
| | - Huilin Li
- Structural Biology Program , Van Andel Institute , 333 Bostwick Avenue Northeast , Grand Rapids , Michigan 49503 , United States
| | - Gang Lin
- Department of Microbiology & Immunology , Weill Cornell Medicine , 1300 York Avenue , New York , New York 10065 , United States
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9
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Müller AU, Weber-Ban E. The Bacterial Proteasome at the Core of Diverse Degradation Pathways. Front Mol Biosci 2019; 6:23. [PMID: 31024929 PMCID: PMC6466877 DOI: 10.3389/fmolb.2019.00023] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/18/2019] [Indexed: 12/02/2022] Open
Abstract
Proteasomal protein degradation exists in mycobacteria and other actinobacteria, and expands their repertoire of compartmentalizing protein degradation pathways beyond the usual bacterial types. A product of horizontal gene transfer, bacterial proteasomes have evolved to support the organism's survival under challenging environmental conditions like nutrient starvation and physical or chemical stresses. Like the eukaryotic 20S proteasome, the bacterial core particle is gated and must associate with a regulator complex to form a fully active protease capable of recruiting and internalizing substrate proteins. By association with diverse regulator complexes that employ different recruitment strategies, the bacterial 20S core particle is able to act in different cellular degradation pathways. In association with the mycobacterial proteasomal ATPase Mpa, the proteasome degrades substrates post-translationally modified with prokaryotic, ubiquitin-like protein Pup in a process called pupylation. Upon interaction with the ATP-independent bacterial proteasome activator Bpa, poorly structured substrates are recruited for proteasomal degradation. A potential third degradation route might employ a Cdc48-like protein of actinobacteria (Cpa), for which interaction with the 20S core was recently demonstrated but no degradation substrates have been identified yet. The alternative interaction partners and wide range of substrate proteins suggest that the bacterial proteasome is a modular, functionally flexible and conditionally regulated degradation machine in bacteria that encounter rapidly changing and challenging conditions.
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Affiliation(s)
- Andreas U Müller
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Eilika Weber-Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
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10
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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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11
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Hu K, Jastrab JB, Zhang S, Kovach A, Zhao G, Darwin KH, Li H. Proteasome substrate capture and gate opening by the accessory factor PafE from Mycobacterium tuberculosis. J Biol Chem 2018; 293:4713-4723. [PMID: 29414791 DOI: 10.1074/jbc.ra117.001471] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/31/2018] [Indexed: 11/06/2022] Open
Abstract
In all domains of life, proteasomes are gated, chambered proteases that require opening by activators to facilitate protein degradation. Twelve proteasome accessory factor E (PafE) monomers assemble into a single dodecameric ring that promotes proteolysis required for the full virulence of the human bacterial pathogen Mycobacterium tuberculosis Whereas the best characterized proteasome activators use ATP to deliver proteins into a proteasome, PafE does not require ATP. Here, to unravel the mechanism of PafE-mediated protein targeting and proteasome activation, we studied the interactions of PafE with native substrates, including a newly identified proteasome substrate, the ParA-like protein, Rv3213c, and with proteasome core particles. We characterized the function of a highly conserved feature in bacterial proteasome activator proteins: a glycine-glutamine-tyrosine-leucine (GQYL) motif at their C termini that is essential for stimulating proteolysis. Using cryo-electron microscopy (cryo-EM), we found that the GQYL motif of PafE interacts with specific residues in the α subunits of the proteasome core particle to trigger gate opening and degradation. Finally, we also found that PafE rings have 40-Å openings lined with hydrophobic residues that form a chamber for capturing substrates before they are degraded, suggesting PafE has a previously unrecognized chaperone activity. In summary, we have identified the interactions between PafE and the proteasome core particle that cause conformational changes leading to the opening of the proteasome gate and have uncovered a mechanism of PafE-mediated substrate degradation. Collectively, our results provide detailed insights into the mechanism of ATP-independent proteasome degradation in bacteria.
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Affiliation(s)
- Kuan Hu
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Jordan B Jastrab
- Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Susan Zhang
- Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Amanda Kovach
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Gongpu Zhao
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - K Heran Darwin
- Department of Microbiology, New York University School of Medicine, New York, New York 10016.
| | - Huilin Li
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, Michigan 49503.
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12
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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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13
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Alhuwaider AAH, Dougan DA. AAA+ Machines of Protein Destruction in Mycobacteria. Front Mol Biosci 2017; 4:49. [PMID: 28770209 PMCID: PMC5515868 DOI: 10.3389/fmolb.2017.00049] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 06/27/2017] [Indexed: 01/05/2023] Open
Abstract
The bacterial cytosol is a complex mixture of macromolecules (proteins, DNA, and RNA), which collectively are responsible for an enormous array of cellular tasks. Proteins are central to most, if not all, of these tasks and as such their maintenance (commonly referred to as protein homeostasis or proteostasis) is vital for cell survival during normal and stressful conditions. The two key aspects of protein homeostasis are, (i) the correct folding and assembly of proteins (coupled with their delivery to the correct cellular location) and (ii) the timely removal of unwanted or damaged proteins from the cell, which are performed by molecular chaperones and proteases, respectively. A major class of proteins that contribute to both of these tasks are the AAA+ (ATPases associated with a variety of cellular activities) protein superfamily. Although much is known about the structure of these machines and how they function in the model Gram-negative bacterium Escherichia coli, we are only just beginning to discover the molecular details of these machines and how they function in mycobacteria. Here we review the different AAA+ machines, that contribute to proteostasis in mycobacteria. Primarily we will focus on the recent advances in the structure and function of AAA+ proteases, the substrates they recognize and the cellular pathways they control. Finally, we will discuss the recent developments related to these machines as novel drug targets.
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Affiliation(s)
- Adnan Ali H Alhuwaider
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe UniversityMelbourne, VIC, Australia
| | - David A Dougan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe UniversityMelbourne, VIC, Australia
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Wu Y, Hu K, Li D, Bai L, Yang S, Jastrab JB, Xiao S, Hu Y, Zhang S, Darwin KH, Wang T, Li H. Mycobacterium tuberculosis proteasomal ATPase Mpa has a β-grasp domain that hinders docking with the proteasome core protease. Mol Microbiol 2017; 105:227-241. [PMID: 28419599 DOI: 10.1111/mmi.13695] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2017] [Indexed: 12/21/2022]
Abstract
Mycobacterium tuberculosis (Mtb) has a proteasome system that is essential for its ability to cause lethal infections in mice. A key component of the system is the proteasomal adenosine triphosphatase (ATPase) Mpa, which captures, unfolds, and translocates protein substrates into the Mtb proteasome core particle for degradation. Here, we report the crystal structures of near full-length hexameric Mtb Mpa in apo and ADP-bound forms. Surprisingly, the structures revealed a ubiquitin-like β-grasp domain that precedes the proteasome-activating carboxyl terminus. This domain, which was only found in bacterial proteasomal ATPases, buries the carboxyl terminus of each protomer in the central channel of the hexamer and hinders the interaction of Mpa with the proteasome core protease. Thus, our work reveals the structure of a bacterial proteasomal ATPase in the hexameric form, and the structure finally explains why Mpa is unable to stimulate robust protein degradation in vitro in the absence of other, yet-to-be-identified co-factors.
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Affiliation(s)
- Yujie Wu
- Department of Biology, Southern University of Science and Technology, 1088 Xueyuan Road, Nanshan District, Shenzhen, 518055, China
| | - Kuan Hu
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA.,Biochemistry and Structural Biology Graduate Program, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Defeng Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
| | - Lin Bai
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Shaoqing Yang
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
| | - Jordan B Jastrab
- Department of Microbiology, New York University School of Medicine, 450 East 29th Street, New York, NY, 10016, USA
| | - Shuhao Xiao
- Department of Biology, Southern University of Science and Technology, 1088 Xueyuan Road, Nanshan District, Shenzhen, 518055, China
| | - Yonglin Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China
| | - Susan Zhang
- Department of Microbiology, New York University School of Medicine, 450 East 29th Street, New York, NY, 10016, USA
| | - K Heran Darwin
- Department of Microbiology, New York University School of Medicine, 450 East 29th Street, New York, NY, 10016, USA
| | - Tao Wang
- Department of Biology, Southern University of Science and Technology, 1088 Xueyuan Road, Nanshan District, Shenzhen, 518055, China.,SZCDC-SUSTech Joint Key Laboratory for Tropical Diseases, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China
| | - Huilin Li
- Cryo-EM Structural Biology Laboratory, Van Andel Research Institute, Grand Rapids, MI, 49503, USA
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15
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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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16
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Loss-of-Function Mutations in HspR Rescue the Growth Defect of a Mycobacterium tuberculosis Proteasome Accessory Factor E ( pafE) Mutant. J Bacteriol 2017; 199:JB.00850-16. [PMID: 28096448 DOI: 10.1128/jb.00850-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 01/12/2017] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium tuberculosis uses a proteasome to degrade proteins by both ATP-dependent and -independent pathways. While much has been learned about ATP-dependent degradation, relatively little is understood about the ATP-independent pathway, which is controlled by Mycobacterium tuberculosisproteasome accessory factor E (PafE). Recently, we found that a Mycobacterium tuberculosispafE mutant has slowed growth in vitro and is sensitive to killing by heat stress. However, we did not know if these phenotypes were caused by an inability to degrade the PafE-proteasome substrate HspR (heat shock protein repressor), an inability to degrade any damaged or misfolded proteins, or a defect in another protein quality control pathway. To address this question, we characterized pafE suppressor mutants that grew similarly to pafE+ bacteria under normal culture conditions. All but one suppressor mutant analyzed contained mutations that inactivated HspR function, demonstrating that the slowed growth and heat shock sensitivity of a pafE mutant were caused primarily by the inability of the proteasome to degrade HspR.IMPORTANCEMycobacterium tuberculosis encodes a proteasome that is highly similar to eukaryotic proteasomes and is required for virulence. We recently discovered a proteasome cofactor, PafE, which is required for the normal growth, heat shock resistance, and full virulence of M. tuberculosis In this study, we demonstrate that PafE influences this phenotype primarily by promoting the expression of protein chaperone genes that are necessary for surviving proteotoxic stress.
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17
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Hsu HC, Singh PK, Fan H, Wang R, Sukenick G, Nathan C, Lin G, Li H. Structural Basis for the Species-Selective Binding of N,C-Capped Dipeptides to the Mycobacterium tuberculosis Proteasome. Biochemistry 2016; 56:324-333. [PMID: 27976853 DOI: 10.1021/acs.biochem.6b01107] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Mycobacterium tuberculosis (Mtb) 20S proteasome is vital for the pathogen to survive under nitrosative stress in vitro and to persist in mice. To qualify for drug development, inhibitors targeting Mtb 20S must spare both the human constitutive proteasome (c-20S) and immunoproteasome (i-20S). We recently reported members of a family of noncovalently binding dipeptide proteasome inhibitors that are highly potent and selective for Mtb 20S over human c-20S and i-20S. To understand the structural basis of their potency and selectivity, we have studied the structure-activity relationship of six derivatives and solved their cocrystal structures with Mtb 20S. The dipeptide inhibitors form an antiparallel β-strand with the active site β-strands. Selectivity is conferred by several features of Mtb 20S relative to its mouse counterparts, including a larger S1 pocket, additional hydrogen bonds in the S3 pocket, and hydrophobic interactions in the S4 pocket. Serine-20 and glutamine-22 of Mtb 20S interact with the dipeptides and confer Mtb-specific inhibition over c-20S and i-20S. The Mtb 20S and mammalian i-20S have a serine-27 that interacts strongly with the dipeptides, potentially explaining the higher inhibitory activity of the dipeptides toward i-20S over c-20S. This detailed structural knowledge will aid in optimizing the dipeptides as anti-tuberculosis drugs.
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Affiliation(s)
- Hao-Chi Hsu
- Van Andel Research Institute , Grand Rapids, Michigan 49503, United States
| | | | | | - Rong Wang
- NMR Analytical Core Facility, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | - George Sukenick
- NMR Analytical Core Facility, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | | | | | - Huilin Li
- Van Andel Research Institute , Grand Rapids, Michigan 49503, United States
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18
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Bacterial Proteasomes: Mechanistic and Functional Insights. Microbiol Mol Biol Rev 2016; 81:81/1/e00036-16. [PMID: 27974513 DOI: 10.1128/mmbr.00036-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Regulated proteolysis is essential for the normal physiology of all organisms. While all eukaryotes and archaea use proteasomes for protein degradation, only certain orders of bacteria have proteasomes, whose functions are likely as diverse as the species that use them. In this review, we discuss the most recent developments in the understanding of how proteins are targeted to proteasomes for degradation, including ATP-dependent and -independent mechanisms, and the roles of proteasome-dependent degradation in protein quality control and the regulation of cellular physiology. Furthermore, we explore newly established functions of proteasome system accessory factors that function independently of proteolysis.
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Bolten M, Delley CL, Leibundgut M, Boehringer D, Ban N, Weber-Ban E. Structural Analysis of the Bacterial Proteasome Activator Bpa in Complex with the 20S Proteasome. Structure 2016; 24:2138-2151. [PMID: 27839949 DOI: 10.1016/j.str.2016.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/04/2016] [Accepted: 10/12/2016] [Indexed: 11/19/2022]
Abstract
Mycobacterium tuberculosis harbors proteasomes that recruit substrates for degradation through an ubiquitin-like modification pathway. Recently, a non-ATPase activator termed Bpa (bacterial proteasome activator) was shown to support an alternate proteasomal degradation pathway. Here, we present the cryo-electron microscopy (cryo-EM) structure of Bpa in complex with the 20S core particle (CP). For docking into the cryo-EM density, we solved the X-ray structure of Bpa, showing that it forms tight four-helix bundles arranged into a 12-membered ring with a 40 Å wide central pore and the C-terminal helix of each protomer protruding from the ring. The Bpa model was fitted into the cryo-EM map of the Bpa-CP complex, revealing its architecture and striking symmetry mismatch. The Bpa-CP interface was resolved to 3.5 Å, showing the interactions between the C-terminal GQYL motif of Bpa and the proteasome α-rings. This docking mode is related to the one observed for eukaryotic activators with features specific to the bacterial complex.
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Affiliation(s)
- Marcel Bolten
- ETH Zurich, Institute of Molecular Biology & Biophysics, 8093 Zurich, Switzerland
| | - Cyrille L Delley
- ETH Zurich, Institute of Molecular Biology & Biophysics, 8093 Zurich, Switzerland
| | - Marc Leibundgut
- ETH Zurich, Institute of Molecular Biology & Biophysics, 8093 Zurich, Switzerland
| | - Daniel Boehringer
- ETH Zurich, Institute of Molecular Biology & Biophysics, 8093 Zurich, Switzerland
| | - Nenad Ban
- ETH Zurich, Institute of Molecular Biology & Biophysics, 8093 Zurich, Switzerland
| | - Eilika Weber-Ban
- ETH Zurich, Institute of Molecular Biology & Biophysics, 8093 Zurich, Switzerland.
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