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Kahne SC, Yoo JH, Chen J, Nakedi K, Iyer LM, Putzel G, Samhadaneh NM, Pironti A, Aravind L, Ekiert DC, Bhabha G, Rhee KY, Darwin KH. Identification of a proteolysis regulator for an essential enzyme in Mycobacterium tuberculosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.29.587195. [PMID: 38585835 PMCID: PMC10996600 DOI: 10.1101/2024.03.29.587195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
In Mycobacterium tuberculosis proteins that are post-translationally modified with Pup, a prokaryotic ubiquitin-like protein, can be degraded by proteasomes. While pupylation is reversible, mechanisms regulating substrate specificity have not been identified. Here, we identify the first depupylation regulators: CoaX, a pseudokinase, and pantothenate, an essential, central metabolite. In a Δ coaX mutant, pantothenate synthesis enzymes were more abundant, including PanB, a substrate of the Pup-proteasome system. Media supplementation with pantothenate decreased PanB levels in a coaX and Pup-proteasome-dependent manner. In vitro , CoaX accelerated depupylation of Pup∼PanB, while addition of pantothenate inhibited this reaction. Collectively, we propose CoaX contributes to proteasomal degradation of PanB by modulating depupylation of Pup∼PanB in response to pantothenate levels. One Sentence Summary A pseudo-pantothenate kinase regulates proteasomal degradation of a pantothenate synthesis enzyme in M. tuberculosis .
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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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Block MF, Delley CL, Keller LML, Stuehlinger TT, Weber-Ban E. Electrostatic interactions guide substrate recognition of the prokaryotic ubiquitin-like protein ligase PafA. Nat Commun 2023; 14:5266. [PMID: 37644028 PMCID: PMC10465538 DOI: 10.1038/s41467-023-40807-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 08/09/2023] [Indexed: 08/31/2023] Open
Abstract
Pupylation, a post-translational modification found in Mycobacterium tuberculosis and other Actinobacteria, involves the covalent attachment of prokaryotic ubiquitin-like protein (Pup) to lysines on target proteins by the ligase PafA (proteasome accessory factor A). Pupylated proteins, like ubiquitinated proteins in eukaryotes, are recruited for proteasomal degradation. Proteomic studies suggest that hundreds of potential pupylation targets are modified by the sole existing ligase PafA. This raises intriguing questions regarding the selectivity of this enzyme towards a diverse range of substrates. Here, we show that the availability of surface lysines alone is not sufficient for interaction between PafA and target proteins. By identifying the interacting residues at the pupylation site, we demonstrate that PafA recognizes authentic substrates via a structural recognition motif centered around exposed lysines. Through a combination of computational analysis, examination of available structures and pupylated proteomes, and biochemical experiments, we elucidate the mechanism by which PafA achieves recognition of a wide array of substrates while retaining selective protein turnover.
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Affiliation(s)
- Matthias F Block
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zurich, Switzerland
| | - Cyrille L Delley
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zurich, Switzerland
- University of California, San Francisco, USA
| | - Lena M L Keller
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zurich, Switzerland
| | - Timo T Stuehlinger
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zurich, Switzerland
| | - Eilika Weber-Ban
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zurich, Switzerland.
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Li C, Liu S, Dong B, Li C, Jian L, He J, Zeng J, Zhou Q, Jia D, Luo Y, Sun Q. Discovery and Mechanistic Study of Mycobacterium tuberculosis PafA Inhibitors. J Med Chem 2022; 65:11058-11065. [PMID: 35926511 DOI: 10.1021/acs.jmedchem.2c00289] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Tuberculosis is caused by the bacterium Mycobacterium tuberculosis (Mtb) and is ranked as the second killer infectious disease after COVID-19. Proteasome accessory factor A (PafA) is considered an attractive target because of its low sequence conservation in humans and its role in virulence. In this study, we designed a mutant of Mtb PafA that enabled large-scale purification of active PafA. Using a devised high-throughput screening assay, two PafA inhibitors were discovered. ST1926 inhibited Mtb PafA by binding in the Pup binding groove, but it was less active against Corynebacterium glutamicum PafA because the ST1926-binding residues are not conserved. Bithionol bound to the conserved ATP-binding pocket, thereby, inhibits PafA in an ATP-competitive manner. Both ST1926 and bithionol inhibited the growth of an attenuated Mtb strain (H37Ra) at micromolar concentrations. Our work thus provides new tools for tuberculosis research and a foundation for future PafA-targeted drug development for treating tuberculosis.
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Affiliation(s)
- Cong Li
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, P. R. China
| | - Song Liu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Baoyu Dong
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, Sichuan, P. R. China
| | - Chungen Li
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Lunan Jian
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, P. R. China
| | - Juan He
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Jumei Zeng
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, Sichuan, P. R. China
| | - Qiao Zhou
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, P. R. China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, Division of Neurology, West China Second University Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Youfu Luo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P. R. China
| | - Qingxiang Sun
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, P. R. China
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Zerbib E, Schlussel S, Hecht N, Bagdadi N, Eichler J, Gur E. The prokaryotic ubiquitin-like protein presents poor cleavage sites for proteasomal degradation. Cell Rep 2021; 36:109428. [PMID: 34320347 DOI: 10.1016/j.celrep.2021.109428] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 05/09/2021] [Accepted: 06/30/2021] [Indexed: 11/17/2022] Open
Abstract
In an event reminiscent of eukaryotic ubiquitination, the bacterial prokaryotic ubiquitin-like protein (Pup)-proteasome system (PPS) marks target proteins for proteasomal degradation by covalently attaching Pup, the bacterial tagging molecule. Yet, ubiquitin is released from its conjugated target following proteasome binding, whereas Pup enters the proteasome and remains conjugated to the target. Here, we report that although Pup can be degraded by the bacterial proteasome, it lacks favorable 20S core particle (CP) cleavage sites and is thus a very poor 20S CP substrate. Reconstituting the PPS in vitro, we demonstrate that during pupylated protein degradation, Pup can escape unharmed and remain conjugated to a target-derived degradation fragment. Removal of this degradation fragment by Dop, a depupylase, facilitates Pup recycling and re-conjugation to a new target. This study thus offers a mechanistic model for Pup recycling and demonstrates how a lack of protein susceptibility to proteasome-mediated cleavage can play a mechanistic role in a biological system.
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Affiliation(s)
- Erez Zerbib
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Shai Schlussel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Nir Hecht
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Noy Bagdadi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Jerry Eichler
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Eyal Gur
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel; The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
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Breindel L, Burz DS, Shekhtman A. Active metabolism unmasks functional protein-protein interactions in real time in-cell NMR. Commun Biol 2020; 3:249. [PMID: 32439966 PMCID: PMC7242440 DOI: 10.1038/s42003-020-0976-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/29/2020] [Indexed: 01/05/2023] Open
Abstract
Protein–protein interactions, PPIs, underlie most cellular processes, but many PPIs depend on a particular metabolic state that can only be observed in live, actively metabolizing cells. Real time in-cell NMR spectroscopy, RT-NMR, utilizes a bioreactor to maintain cells in an active metabolic state. Improvement in bioreactor technology maintains ATP levels at >95% for up to 24 hours, enabling protein overexpression and a previously undetected interaction between prokaryotic ubiquitin-like protein, Pup, and mycobacterial proteasomal ATPase, Mpa, to be detected. Singular value decomposition, SVD, of the NMR spectra collected over the course of Mpa overexpression easily identified the PPIs despite the large variation in background signals due to the highly active metabolome. Leonard Breindel et al. develop a real time in-cell NMR spectroscopy that utilizes a bioreactor to maintain cells metabolically active. This real time in-cell NMR spectroscopy enables the identification of protein–protein interactions that would not happen when cells don’t produce energy, suggesting the utility of this method.
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Affiliation(s)
- Leonard Breindel
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave, Albany, NY, 12222, USA
| | - David S Burz
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave, Albany, NY, 12222, USA
| | - Alexander Shekhtman
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave, Albany, NY, 12222, USA.
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