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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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2
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Auliah FN, Nilamyani AN, Shoombuatong W, Alam MA, Hasan MM, Kurata H. PUP-Fuse: Prediction of Protein Pupylation Sites by Integrating Multiple Sequence Representations. Int J Mol Sci 2021; 22:ijms22042120. [PMID: 33672741 PMCID: PMC7924619 DOI: 10.3390/ijms22042120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/12/2021] [Accepted: 02/18/2021] [Indexed: 12/30/2022] Open
Abstract
Pupylation is a type of reversible post-translational modification of proteins, which plays a key role in the cellular function of microbial organisms. Several proteomics methods have been developed for the prediction and analysis of pupylated proteins and pupylation sites. However, the traditional experimental methods are laborious and time-consuming. Hence, computational algorithms are highly needed that can predict potential pupylation sites using sequence features. In this research, a new prediction model, PUP-Fuse, has been developed for pupylation site prediction by integrating multiple sequence representations. Meanwhile, we explored the five types of feature encoding approaches and three machine learning (ML) algorithms. In the final model, we integrated the successive ML scores using a linear regression model. The PUP-Fuse achieved a Mathew correlation value of 0.768 by a 10-fold cross-validation test. It also outperformed existing predictors in an independent test. The web server of the PUP-Fuse with curated datasets is freely available.
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Affiliation(s)
- Firda Nurul Auliah
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; (F.N.A.); (A.N.N.); (M.M.H.)
| | - Andi Nur Nilamyani
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; (F.N.A.); (A.N.N.); (M.M.H.)
| | - Watshara Shoombuatong
- Center of Data Mining and Biomedical Informatics, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand;
| | - Md Ashad Alam
- Tulane Center for Biomedical Informatics and Genomics, Division of Biomedical Informatics and Genomics, John W. Deming Department of Medicine, School of Medicine, Tulane University, New Orleans, LA 70112, USA;
| | - Md Mehedi Hasan
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; (F.N.A.); (A.N.N.); (M.M.H.)
- Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Hiroyuki Kurata
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; (F.N.A.); (A.N.N.); (M.M.H.)
- Correspondence:
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3
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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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4
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Regev O, Linder H, Gur E. Pup-Click-A New Chemoenzymatic Method for the Generation of Singly Pupylated Targets. Bioconjug Chem 2019; 30:2909-2916. [PMID: 31663726 DOI: 10.1021/acs.bioconjchem.9b00611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Conjugation of the prokaryotic ubiquitin-like protein (Pup) to cellular proteins tags these proteins for degradation by a proteasome in actinobacteria. To study the Pup-proteasome system in in vitro biochemical assays, Pup-tagged (i.e., pupylated) proteins are often used. However, the purification of a homogeneous preparation of pupylated proteins often suffers from poor yields and limitations in terms of selecting the target protein and its site of pupylation. Here, we report on the development of a biochemical methodology we term Pup-Click for the generation of pupylated protein mimics in vitro. Pup-Click relies on a natural pupylation reaction combined with the use of a synthetic peptide and genetic code expansion via the use of unnatural amino acids and Click chemistry. In principle, this approach allows for conjugation of Pup to any selected target at potentially any desired position. Importantly, pupylated protein mimics generated by Pup-Click are recognized and processed by enzymes of the Pup-proteasome system. As such, Pup-Click can serve as a powerful tool for studying this protein degradation pathway.
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5
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Pupylated proteins are subject to broad proteasomal degradation specificity and differential depupylation. PLoS One 2019; 14:e0215439. [PMID: 31009487 PMCID: PMC6476560 DOI: 10.1371/journal.pone.0215439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 04/02/2019] [Indexed: 11/19/2022] Open
Abstract
In actinobacteria, post-translational modification of proteins with prokaryotic ubiquitin-like protein Pup targets them for degradation by a bacterial proteasome assembly consisting of the 20S core particle (CP) and the mycobacterial proteasomal ATPase (Mpa). Modification of hundreds of cellular proteins with Pup at specific surface lysines is carried out by a single Pup-ligase (PafA, proteasome accessory factor A). Pupylated substrates are recruited to the degradative pathway by binding of Pup to the N-terminal coiled-coil domains of Mpa. Alternatively, pupylation can be reversed by the enzyme Dop (deamidase of Pup). Although pupylated substrates outcompete free Pup in proteasomal degradation, potential discrimination of the degradation complex between the various pupylated substrates has not been investigated. Here we show that Mpa binds stably to an open-gate variant of the proteasome (oCP) and associates with bona fide substrates with highly similar affinities. The proteasomal degradation of substrates differing in size, structure and assembly state was recorded in real-time, showing that the pupylated substrates are processed by the Mpa-oCP complex with comparable kinetic parameters. Furthermore, the members of a complex, pupylated proteome (pupylome) purified from Mycobacterium smegmatis are degraded evenly as followed by western blotting. In contrast, analysis of the depupylation behavior of several pupylome members suggests substrate-specific differences in enzymatic turnover, leading to the conclusion that largely indiscriminate degradation competes with differentiated depupylation to control the ultimate fate of pupylated substrates.
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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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7
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Jiang HW, Czajkowsky DM, Wang T, Wang XD, Wang JB, Zhang HN, Liu CX, Wu FL, He X, Xu ZW, Chen H, Guo SJ, Li Y, Bi LJ, Deng JY, Xie J, Pei JF, Zhang XE, Tao SC. Identification of Serine 119 as an Effective Inhibitor Binding Site of M. tuberculosis Ubiquitin-like Protein Ligase PafA Using Purified Proteins and M. smegmatis. EBioMedicine 2018; 30:225-236. [PMID: 29622495 PMCID: PMC5952411 DOI: 10.1016/j.ebiom.2018.03.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/21/2018] [Accepted: 03/21/2018] [Indexed: 12/26/2022] Open
Abstract
Owing to the spread of multidrug resistance (MDR) and extensive drug resistance (XDR), there is a pressing need to identify potential targets for the development of more-effective anti-M. tuberculosis (Mtb) drugs. PafA, as the sole Prokaryotic Ubiquitin-like Protein ligase in the Pup-proteasome System (PPS) of Mtb, is an attractive drug target. Here, we show that the activity of purified Mtb PafA is significantly inhibited upon the association of AEBSF (4-(2-aminoethyl) benzenesulfonyl fluoride) to PafA residue Serine 119 (S119). Mutation of S119 to amino acids that resemble AEBSF has similar inhibitory effects on the activity of purified Mtb PafA. Structural analysis reveals that although S119 is distant from the PafA catalytic site, it is located at a critical position in the groove where PafA binds the C-terminal region of Pup. Phenotypic studies demonstrate that S119 plays critical roles in the function of Mtb PafA when tested in M. smegmatis. Our study suggests that targeting S119 is a promising direction for developing an inhibitor of M. tuberculosis PafA. The pupylation activity of purified M. tuberculosis PafA is almost completely inhibited upon the association of AEBSF. The AEBSF binding site, Ser 119 plays critical roles in both the pupylation and depupylation activity of purified M. tuberculosis PafA. Disruption of purified M. tuberculosis PafA Ser 119 causes a dramatic reduction in Pup binding.
Drug-resistant tuberculosis is a major challenge worldwide, there is an urgent need to identify potential drug targets for developing more effective anti-tubercular drugs. M. tuberculosis ubiquitin-like protein ligase PafA is an attractive drug target, however, effective PafA inhibitors have not yet been identified. Here, we show that interruption of a single amino acid, S119, causes dramatic loss of PafA activity. S119 could thus serve as a promising precise target for developing M. tuberculosis PafA inhibitors.
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Affiliation(s)
- He-Wei Jiang
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Daniel M Czajkowsky
- School of Biomedical Engineering, Bio-ID Center, Shanghai Jiao Tong University, Shanghai 200240, China; School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tao Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China; SZCDC-SUSTech Joint Key Laboratory for Tropical Diseases, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Xu-De Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jia-Bin Wang
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hai-Nan Zhang
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Cheng-Xi Liu
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fan-Lin Wu
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiang He
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhao-Wei Xu
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hong Chen
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shu-Juan Guo
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yang Li
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Li-Jun Bi
- National Key Laboratory of Biomacromolecules, Key Laboratory of Non-Coding RNA and Key Laboratory of Protein and Peptide Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; TB Healthcare Biotechnology Co., Ltd., Foshan, Guangdong 528000, China; School of Stomatology and Medicine, Foshan University, Foshan 528000, Guangdong Province, China
| | - Jiao-Yu Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jin Xie
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Jian-Feng Pei
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xian-En Zhang
- National Key Laboratory of Biomacromolecules, Key Laboratory of Non-Coding RNA and Key Laboratory of Protein and Peptide Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Sheng-Ce Tao
- Shanghai Center for Systems Biomedicine, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China; School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University, Shanghai 200240, China.
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8
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The Effect of Ubiquitin Like Protein-Proteasome System on the Drug Resistance of Isoniazid Mono-Resistant Mycobacterium tuberculosis. Jundishapur J Microbiol 2018. [DOI: 10.5812/jjm.58591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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9
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Alhuwaider AAH, Truscott KN, Dougan DA. Pupylation of PafA or Pup inhibits components of the Pup-Proteasome System. FEBS Lett 2017; 592:15-23. [PMID: 29197082 DOI: 10.1002/1873-3468.12930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/13/2017] [Accepted: 11/26/2017] [Indexed: 11/06/2022]
Abstract
The pupylation of cellular proteins plays a crucial role in the degradation cascade via the Pup-Proteasome system (PPS). It is essential for the survival of Mycobacterium smegmatis under nutrient starvation and, as such, the activity of many components of the pathway is tightly regulated. Here, we show that Pup, like ubiquitin, can form polyPup chains primarily through K61 and that this form of Pup inhibits the ATPase-mediated turnover of pupylated substrates by the 20S proteasome. Similarly, the autopupylation of PafA (the sole Pup ligase found in mycobacteria) inhibits its own enzyme activity; hence, pupylation of PafA may act as a negative feedback mechanism to prevent substrate pupylation under specific cellular conditions.
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Affiliation(s)
- Adnan Ali H Alhuwaider
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Kaye N Truscott
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - David A Dougan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
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10
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Bao W, You ZH, Huang DS. CIPPN: computational identification of protein pupylation sites by using neural network. Oncotarget 2017; 8:108867-108879. [PMID: 29312575 PMCID: PMC5752488 DOI: 10.18632/oncotarget.22335] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/03/2017] [Indexed: 11/25/2022] Open
Abstract
Recently, experiments revealed the pupylation to be a signal for the selective regulation of proteins in several serious human diseases. As one of the most significant post translational modification in the field of biology and disease, pupylation has the ability to playing the key role in the regulation various diseases’ biological processes. Meanwhile, effectively identification such type modification will be helpful for proteins to perform their biological functions and contribute to understanding the molecular mechanism, which is the foundation of drug design. The existing algorithms of identification such types of modified sites often have some defects, such as low accuracy and time-consuming. In this research, the pupylation sites’ identification model, CIPPN, demonstrates better performance than other existing approaches in this field. The proposed predictor achieves Acc value of 89.12 and Mcc value of 0.7949 in 10-fold cross-validation tests in the Pupdb Database (http://cwtung.kmu.edu.tw/pupdb). Significantly, such algorithm not only investigates the sequential, structural and evolutionary hallmarks around pupylation sites but also compares the differences of pupylation from the environmental, conservative and functional characterization of substrates. Therefore, the proposed feature description approach and algorithm results prove to be useful for further experimental investigation of such modification’s identification.
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Affiliation(s)
- Wenzheng Bao
- Institute of Machine Learning and Systems Biology, School of Electronics and Information Engineering, Tongji University, Shanghai, China
| | - Zhu-Hong You
- Xinjiang Technical Institutes of Physics and Chemistry, Chinese Academy of Science, Urumqi 830011, China
| | - De-Shuang Huang
- Institute of Machine Learning and Systems Biology, School of Electronics and Information Engineering, Tongji University, Shanghai, China
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11
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Gur E, Korman M, Hecht N, Regev O, Schlussel S, Silberberg N, Elharar Y. How to control an intracellular proteolytic system: Coordinated regulatory switches in the mycobacterial Pup-proteasome system. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2253-2260. [PMID: 28887055 DOI: 10.1016/j.bbamcr.2017.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/26/2017] [Accepted: 08/31/2017] [Indexed: 10/18/2022]
Abstract
Intracellular proteolysis is critical for the proper functioning of all cells, owing to its involvement in a wide range of processes. Because of the destructive nature of protein degradation, intracellular proteolysis is restricted by control mechanisms at almost every step of the proteolytic process. Understanding the coordination of such mechanisms is a challenging task, especially in systems as complex as the eukaryotic ubiquitin-proteasome system (UPS). In comparison, the bacterial analog of the UPS, the Pup-proteasome system (PPS) is much simpler and, therefore, allows for insight into the control of a proteolytic system. This review integrates available information to present a coherent picture of what is known of PPS regulatory switches and describes how these switches act in concert to enforce regulation at the system level. Finally, open questions regarding PPS regulation are discussed, providing readers with a sense of what lies ahead in the field.
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Affiliation(s)
- 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.
| | - Maayan Korman
- 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
| | - Ofir Regev
- 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
| | - Nimrod Silberberg
- 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
| | - Yifat Elharar
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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12
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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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13
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Akhter Y, Thakur S. Targets of ubiquitin like system in mycobacteria and related actinobacterial species. Microbiol Res 2017; 204:9-29. [PMID: 28870295 DOI: 10.1016/j.micres.2017.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 06/22/2017] [Accepted: 07/05/2017] [Indexed: 12/22/2022]
Abstract
Protein turnover and recycling is a prerequisite in all living organisms to maintain normal cellular physiology. Many bacteria are proteasome deficient but they possess typical protease enzymes for carrying out protein turnover. However, several groups of actinobacteria such as mycobacteria harbor both proteasome and proteases. In these bacteria, for cellular protein turnover the target proteins undergo post-translational modification referred as pupylation in which a small protein Pup (prokaryotic ubiquitin-like protein) is tagged to the specific lysine residues of the target proteins and after that those target proteins undergo proteasomal degradation. Thus, Pup serves as a degradation signal, helps in directing proteins toward the bacterial proteasome for a turnover. Although the Pup-proteasome system has a multifaceted role in environmental stresses, pathogenicity and regulation of cellular signaling, but the fate of all types of pupylation such as mono and polypupylation on the proteins is still not completely understood. In this review, we present the mechanisms involved in the activation and conjugation of Pup to the target proteins, describing the structural sketch of pupylation and fundamental differences between the eukaryotic ubiquitin-proteasome and bacterial Pup-proteasome systems. We are also presenting a concise classification and cataloging of the complete battery of experimentally identified Pup-substrates from various species of actinobacteria.
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Affiliation(s)
- Yusuf Akhter
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, Himachal Pradesh, 176206, India.
| | - Shweta Thakur
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, Himachal Pradesh, 176206, India
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14
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Barandun J, Damberger FF, Delley CL, Laederach J, Allain FHT, Weber-Ban E. Prokaryotic ubiquitin-like protein remains intrinsically disordered when covalently attached to proteasomal target proteins. BMC STRUCTURAL BIOLOGY 2017; 17:1. [PMID: 28143508 PMCID: PMC5286830 DOI: 10.1186/s12900-017-0072-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/24/2017] [Indexed: 11/11/2022]
Abstract
Background The post-translational modification pathway referred to as pupylation marks proteins for proteasomal degradation in Mycobacterium tuberculosis and other actinobacteria by covalently attaching the small protein Pup (prokaryotic ubiquitin-like protein) to target lysine residues. In contrast to the functionally analogous eukaryotic ubiquitin, Pup is intrinsically disordered in its free form. Its unfolded state allows Pup to adopt different structures upon interaction with different binding partners like the Pup ligase PafA and the proteasomal ATPase Mpa. While the disordered behavior of free Pup has been well characterized, it remained unknown whether Pup adopts a distinct structure when attached to a substrate. Results Using a combination of NMR experiments and biochemical analysis we demonstrate that Pup remains unstructured when ligated to two well-established pupylation substrates targeted for proteasomal degradation in Mycobacterium tuberculosis, malonyl transacylase (FabD) and ketopantoyl hydroxylmethyltransferase (PanB). Isotopically labeled Pup was linked to FabD and PanB by in vitro pupylation to generate homogeneously pupylated substrates suitable for NMR analysis. The single target lysine of PanB was identified by a combination of mass spectroscopy and mutational analysis. Chemical shift comparison between Pup in its free form and ligated to substrate reveals intrinsic disorder of Pup in the conjugate. Conclusion When linked to the proteasomal substrates FabD and PanB, Pup is unstructured and retains the ability to interact with its different binding partners. This suggests that it is not the conformation of Pup attached to these two substrates which determines their delivery to the proteasome, but the availability of the degradation complex and the depupylase. Electronic supplementary material The online version of this article (doi:10.1186/s12900-017-0072-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jonas Barandun
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zürich, CH-8093, Switzerland.,Present address: Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY, USA
| | - Fred F Damberger
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zürich, CH-8093, Switzerland
| | - Cyrille L Delley
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zürich, CH-8093, Switzerland
| | - Juerg Laederach
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zürich, CH-8093, Switzerland
| | - Frédéric H T Allain
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zürich, CH-8093, Switzerland
| | - Eilika Weber-Ban
- ETH Zurich, Institute of Molecular Biology & Biophysics, Zürich, CH-8093, Switzerland.
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15
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Bastos PAD, da Costa JP, Vitorino R. A glimpse into the modulation of post-translational modifications of human-colonizing bacteria. J Proteomics 2016; 152:254-275. [PMID: 27888141 DOI: 10.1016/j.jprot.2016.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/22/2016] [Accepted: 11/07/2016] [Indexed: 12/19/2022]
Abstract
Protein post-translational modifications (PTMs) are a key bacterial feature that holds the capability to modulate protein function and responses to environmental cues. Until recently, their role in the regulation of prokaryotic systems has been largely neglected. However, the latest developments in mass spectrometry-based proteomics have allowed an unparalleled identification and quantification of proteins and peptides that undergo PTMs in bacteria, including in species which directly or indirectly affect human health. Herein, we address this issue by carrying out the largest and most comprehensive global pooling and comparison of PTM peptides and proteins from bacterial species performed to date. Data was collected from 91 studies relating to PTM bacterial peptides or proteins identified by mass spectrometry-based methods. The present analysis revealed that there was a considerable overlap between PTMs across species, especially between acetylation and other PTMs, particularly succinylation. Phylogenetically closer species may present more overlapping phosphoproteomes, but environmental triggers also contribute to this proximity. PTMs among bacteria were found to be extremely versatile and diverse, meaning that the same protein may undergo a wide variety of different modifications across several species, but it could also suffer different modifications within the same species.
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Affiliation(s)
- Paulo André Dias Bastos
- Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal; Department of Chemistry, University of Aveiro, Portugal
| | | | - Rui Vitorino
- Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal; Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal.
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16
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The pupylation machinery is involved in iron homeostasis by targeting the iron storage protein ferritin. Proc Natl Acad Sci U S A 2016; 113:4806-11. [PMID: 27078093 DOI: 10.1073/pnas.1514529113] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The balance of sufficient iron supply and avoidance of iron toxicity by iron homeostasis is a prerequisite for cellular metabolism and growth. Here we provide evidence that, in Actinobacteria, pupylation plays a crucial role in this process. Pupylation is a posttranslational modification in which the prokaryotic ubiquitin-like protein Pup is covalently attached to a lysine residue in target proteins, thus resembling ubiquitination in eukaryotes. Pupylated proteins are recognized and unfolded by a dedicated AAA+ ATPase (Mycobacterium proteasomal AAA+ ATPase; ATPase forming ring-shaped complexes). In Mycobacteria, degradation of pupylated proteins by the proteasome serves as a protection mechanism against several stress conditions. Other bacterial genera capable of pupylation such as Corynebacterium lack a proteasome, and the fate of pupylated proteins is unknown. We discovered that Corynebacterium glutamicum mutants lacking components of the pupylation machinery show a strong growth defect under iron limitation, which was caused by the absence of pupylation and unfolding of the iron storage protein ferritin. Genetic and biochemical data support a model in which the pupylation machinery is responsible for iron release from ferritin independent of degradation.
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17
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Chen X, Li C, Wang L, Liu Y, Li C, Zhang J. The Mechanism of Mycobacterium smegmatis PafA Self-Pupylation. PLoS One 2016; 11:e0151021. [PMID: 26953889 PMCID: PMC4783102 DOI: 10.1371/journal.pone.0151021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/23/2016] [Indexed: 11/19/2022] Open
Abstract
PafA, the prokaryotic ubiquitin-like protein (Pup) ligase, catalyzes the Pup modification of bacterial proteins and targets the substrates for proteasomal degradation. It has been reported that that M. smegmatis PafA can be poly-pupylated. In this study, the mechanism of PafA self-pupylation is explored. We found that K320 is the major target residue for the pupylation of PafA. During the self-pupylation of PafA, the attachment of the first Pup to PafA is catalyzed by the other PafA molecule through an intermolecular reaction, while the formation of the polymeric Pup chain is carried out in an intramolecular manner through the internal ligase activity of the already pupylated PafA. Among the three lysine residues, K7, K31 and K61, in M. smegmatis Pup, K7 and K31 are involved in the formation of the poly-Pup chain in PafA poly-pupylation. Poly-pupylation of PafA can be reversibly regulated by depupylase Dop. The polymeric Pup chain formed through K7/K31 linkage is much more sensitive to Dop than the mono-Pup directly attached to PafA. Moreover, self-pupylation of PafA is involved in the regulation of its stability in vivo in a proteasome-dependent manner, suggesting that PafA self-pupylation functions as a mechanism in the auto-regulation of the Pup-proteasome system.
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Affiliation(s)
- Xuejie Chen
- The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Chandan Li
- The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Li Wang
- The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Yi Liu
- The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- Department of Bacteriology and Immunology, Beijing Tuberculosis and Thoracic Tumor Research Institute/Beijing Chest Hospital, Capital Medical University, Tongzhou District, Beijing, China
| | - Chuanyou Li
- Department of Bacteriology and Immunology, Beijing Tuberculosis and Thoracic Tumor Research Institute/Beijing Chest Hospital, Capital Medical University, Tongzhou District, Beijing, China
| | - Junjie Zhang
- The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Institute of Cell Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
- * E-mail:
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18
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Posttranslational regulation of coordinated enzyme activities in the Pup-proteasome system. Proc Natl Acad Sci U S A 2016; 113:E1605-14. [PMID: 26951665 DOI: 10.1073/pnas.1525185113] [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: 11/18/2022] Open
Abstract
The proper functioning of any biological system depends on the coordinated activity of its components. Regulation at the genetic level is, in many cases, effective in determining the cellular levels of system components. However, in cases where regulation at the genetic level is insufficient for attaining harmonic system function, posttranslational regulatory mechanisms are often used. Here, we uncover posttranslational regulatory mechanisms in the prokaryotic ubiquitin-like protein (Pup)-proteasome system (PPS), the bacterial equivalent of the eukaryotic ubiquitin-proteasome system. Pup, a ubiquitin analog, is conjugated to proteins through the activities of two enzymes, Dop (deamidase of Pup) and PafA (proteasome accessory factor A), the Pup ligase. As Dop also catalyzes depupylation, it was unclear how PPS function could be maintained without Dop and PafA canceling the activity of the other, and how the two activities of Dop are balanced. We report that tight Pup binding and the limited degree of Dop interaction with high-molecular-weight pupylated proteins results in preferred Pup deamidation over protein depupylation by this enzyme. Under starvation conditions, when accelerated protein pupylation is required, this bias is intensified by depletion of free Dop molecules, thereby minimizing the chance of depupylation. We also find that, in contrast to Dop, PafA presents a distinct preference for high-molecular-weight protein substrates. As such, PafA and Dop act in concert, rather than canceling each other's activity, to generate a high-molecular-weight pupylome. This bias in pupylome molecular weight distribution is consistent with the proposed nutritional role of the PPS under starvation conditions.
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19
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Abstract
Proteasomes are ATP-dependent, barrel-shaped proteases found in all three domains of life. In eukaryotes, proteins are typically targeted for degradation by posttranslational modification with the small protein ubiquitin. In 2008, the first bacterial protein modifier, Pup (prokaryotic ubiquitin-like protein), was identified in Mycobacterium tuberculosis. Functionally analogous to ubiquitin, conjugation with Pup serves as a signal for degradation by the mycobacterial proteasome. Proteolysis-dependent and -independent functions of the M. tuberculosis proteasome are essential for virulence of this successful pathogen. In this article we describe the discovery of the proteasome as a key player in tuberculosis pathogenesis and the biology and biochemistry of the Pup-proteasome system.
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20
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Samanovic MI, Darwin KH. Game of 'Somes: Protein Destruction for Mycobacterium tuberculosis Pathogenesis. Trends Microbiol 2016; 24:26-34. [PMID: 26526503 PMCID: PMC4698092 DOI: 10.1016/j.tim.2015.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 09/25/2015] [Accepted: 10/05/2015] [Indexed: 01/12/2023]
Abstract
The proteasome system of Mycobacterium tuberculosis is required for causing disease. Proteasomes are multisubunit chambered proteases and, until recently, were only known to participate in adenosine triphosphate (ATP)-dependent proteolysis in bacteria. In this review, we discuss the latest advances in understanding how both ATP-dependent and ATP-independent proteasome-regulated pathways contribute to M. tuberculosis virulence.
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Affiliation(s)
- Marie I Samanovic
- New York University School of Medicine, Department of Microbiology, 550 First Avenue, MSB 236 New York, NY 10016, USA
| | - K Heran Darwin
- New York University School of Medicine, Department of Microbiology, 550 First Avenue, MSB 236 New York, NY 10016, USA.
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21
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Samanovic MI, Tu S, Novák O, Iyer LM, McAllister FE, Aravind L, Gygi SP, Hubbard SR, Strnad M, Darwin KH. Proteasomal control of cytokinin synthesis protects Mycobacterium tuberculosis against nitric oxide. Mol Cell 2015; 57:984-994. [PMID: 25728768 DOI: 10.1016/j.molcel.2015.01.024] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/17/2014] [Accepted: 01/16/2015] [Indexed: 12/19/2022]
Abstract
One of several roles of the Mycobacterium tuberculosis proteasome is to defend against host-produced nitric oxide (NO), a free radical that can damage numerous biological macromolecules. Mutations that inactivate proteasomal degradation in Mycobacterium tuberculosis result in bacteria that are hypersensitive to NO and attenuated for growth in vivo, but it was not known why. To elucidate the link between proteasome function, NO resistance, and pathogenesis, we screened for suppressors of NO hypersensitivity in a mycobacterial proteasome ATPase mutant and identified mutations in Rv1205. We determined that Rv1205 encodes a pupylated proteasome substrate. Rv1205 is a homolog of the plant enzyme LONELY GUY, which catalyzes the production of hormones called cytokinins. Remarkably, we report that an obligate human pathogen secretes several cytokinins. Finally, we determined that the Rv1205-dependent accumulation of cytokinin breakdown products is likely responsible for the sensitization of Mycobacterium tuberculosis proteasome-associated mutants to NO.
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Affiliation(s)
- Marie I Samanovic
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Shengjiang Tu
- Howard Hughes Medical Institute, Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Ondřej Novák
- Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, 78371 Olomouc, Czech Republic; Laboratory of Growth Regulators, Institute of Experimental Botany AS CR, 78371 Olomouc, Czech Republic
| | - Lakshminarayan M Iyer
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA
| | - Fiona E McAllister
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Stevan R Hubbard
- Department of Biochemistry and Molecular Pharmacology, The Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Miroslav Strnad
- Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, 78371 Olomouc, Czech Republic; Laboratory of Growth Regulators, Institute of Experimental Botany AS CR, 78371 Olomouc, Czech Republic
| | - K Heran Darwin
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
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22
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Elharar Y, Roth Z, Hermelin I, Moon A, Peretz G, Shenkerman Y, Vishkautzan M, Khalaila I, Gur E. Survival of mycobacteria depends on proteasome-mediated amino acid recycling under nutrient limitation. EMBO J 2014; 33:1802-14. [PMID: 24986881 DOI: 10.15252/embj.201387076] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Intracellular protein degradation is an essential process in all life domains. While in all eukaryotes regulated protein degradation involves ubiquitin tagging and the 26S-proteasome, bacterial prokaryotic ubiquitin-like protein (Pup) tagging and proteasomes are conserved only in species belonging to the phyla Actinobacteria and Nitrospira. In Mycobacterium tuberculosis, the Pup-proteasome system (PPS) is important for virulence, yet its physiological role in non-pathogenic species has remained an enigma. We now report, using Mycobacterium smegmatis as a model organism, that the PPS is essential for survival under starvation. Upon nitrogen limitation, PPS activity is induced, leading to accelerated tagging and degradation of many cytoplasmic proteins. We suggest a model in which the PPS functions to recycle amino acids under nitrogen starvation, thereby enabling the cell to maintain basal metabolic activities. We also find that the PPS auto-regulates its own activity via pupylation and degradation of its components in a manner that promotes the oscillatory expression of PPS components. As such, the destructive activity of the PPS is carefully balanced to maintain cellular functions during starvation.
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Affiliation(s)
- Yifat Elharar
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ziv Roth
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Inna Hermelin
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Alexandra Moon
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Gabriella Peretz
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yael Shenkerman
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Marina Vishkautzan
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Isam Khalaila
- The Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Eyal Gur
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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23
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Abstract
Prokaryotes form ubiquitin (Ub)-like isopeptide bonds on the lysine residues of proteins by at least two distinct pathways that are reversible and regulated. In mycobacteria, the C-terminal Gln of Pup (prokaryotic ubiquitin-like protein) is deamidated and isopeptide linked to proteins by a mechanism distinct from ubiquitylation in enzymology yet analogous to ubiquitylation in targeting proteins for destruction by proteasomes. Ub-fold proteins of archaea (SAMPs, small archaeal modifier proteins) and Thermus (TtuB, tRNA-two-thiouridine B) that differ from Ub in amino acid sequence, yet share a common β-grasp fold, also form isopeptide bonds by a mechanism that appears streamlined compared with ubiquitylation. SAMPs and TtuB are found to be members of a small group of Ub-fold proteins that function not only in protein modification but also in sulfur-transfer pathways associated with tRNA thiolation and molybdopterin biosynthesis. These multifunctional Ub-fold proteins are thought to be some of the most ancient of Ub-like protein modifiers.
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Affiliation(s)
- Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611;
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24
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Forer N, Korman M, Elharar Y, Vishkautzan M, Gur E. Bacterial proteasome and PafA, the pup ligase, interact to form a modular protein tagging and degradation machine. Biochemistry 2013; 52:9029-35. [PMID: 24228735 DOI: 10.1021/bi401017b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Proteasome-containing bacteria possess a tagging system that directs proteins to proteasomal degradation by conjugating them to a prokaryotic ubiquitin-like protein (Pup). A single ligating enzyme, PafA, is responsible for Pup conjugation to lysine side chains of protein substrates. As Pup is recognized by the regulatory subunit of the proteasome, Pup functions as a degradation tag. Pup presents overlapping regions for binding of the proteasome and PafA. It was, therefore, unclear whether Pup binding by the proteasome regulatory subunit, Mpa, and by PafA are mutually exclusive events. The work presented here provides evidence for the simultaneous interaction of Pup with both Mpa and PafA. Surprisingly, we found that PafA and Mpa can form a complex both in vitro and in vivo. Our results thus suggest that PafA and the proteasome can function as a modular machine for the tagging and degradation of cytoplasmic proteins.
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Affiliation(s)
- Nadav Forer
- Department of Life Sciences and ‡The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev , Beer-Sheva 84105, Israel
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25
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Maldonado AY, Burz DS, Reverdatto S, Shekhtman A. Fate of pup inside the Mycobacterium proteasome studied by in-cell NMR. PLoS One 2013; 8:e74576. [PMID: 24040288 PMCID: PMC3769308 DOI: 10.1371/journal.pone.0074576] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 08/06/2013] [Indexed: 12/18/2022] Open
Abstract
The Mycobacterium tuberculosis proteasome is required for maximum virulence and to resist killing by the host immune system. The prokaryotic ubiquitin-like protein, Pup-GGE, targets proteins for proteasome-mediated degradation. We demonstrate that Pup-GGQ, a precursor of Pup-GGE, is not a substrate for proteasomal degradation. Using STINT-NMR, an in-cell NMR technique, we studied the interactions between Pup-GGQ, mycobacterial proteasomal ATPase, Mpa, and Mtb proteasome core particle (CP) inside a living cell at amino acid residue resolution. We showed that under in-cell conditions, in the absence of the proteasome CP, Pup-GGQ interacts with Mpa only weakly, primarily through its C-terminal region. When Mpa and non-stoichiometric amounts of proteasome CP are present, both the N-terminal and C-terminal regions of Pup-GGQ bind strongly to Mpa. This suggests a mechanism by which transient binding of Mpa to the proteasome CP controls the fate of Pup.
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Affiliation(s)
- Andres Y. Maldonado
- Department of Chemistry, State University of New York at Albany, Albany, New York, United States of America
| | - David S. Burz
- Department of Chemistry, State University of New York at Albany, Albany, New York, United States of America
| | - Sergey Reverdatto
- Department of Chemistry, State University of New York at Albany, Albany, New York, United States of America
| | - Alexander Shekhtman
- Department of Chemistry, State University of New York at Albany, Albany, New York, United States of America
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26
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Cain JA, Solis N, Cordwell SJ. Beyond gene expression: the impact of protein post-translational modifications in bacteria. J Proteomics 2013; 97:265-86. [PMID: 23994099 DOI: 10.1016/j.jprot.2013.08.012] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/08/2013] [Accepted: 08/10/2013] [Indexed: 12/12/2022]
Abstract
The post-translational modification (PTM) of proteins plays a critical role in the regulation of a broad range of cellular processes in eukaryotes. Yet their role in governing similar systems in the conventionally presumed 'simpler' forms of life has been largely neglected and, until recently, was thought to occur only rarely, with some modifications assumed to be limited to higher organisms alone. Recent developments in mass spectrometry-based proteomics have provided an unparalleled power to enrich, identify and quantify peptides with PTMs. Additional modifications to biological molecules such as lipids and carbohydrates that are essential for bacterial pathophysiology have only recently been detected on proteins. Here we review bacterial protein PTMs, focusing on phosphorylation, acetylation, proteolytic degradation, methylation and lipidation and the roles they play in bacterial adaptation - thus highlighting the importance of proteomic techniques in a field that is only just in its infancy. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.
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Affiliation(s)
- Joel A Cain
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia
| | - Nestor Solis
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia
| | - Stuart J Cordwell
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia; Discipline of Pathology, School of Medical Sciences, The University of Sydney, 2006, Australia.
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27
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Humbard MA, Maupin-Furlow JA. Prokaryotic proteasomes: nanocompartments of degradation. J Mol Microbiol Biotechnol 2013; 23:321-34. [PMID: 23920495 DOI: 10.1159/000351348] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Proteasomes are self-compartmentalized energy-dependent proteolytic machines found in Archaea, Actinobacteria species of bacteria and eukaryotes. Proteasomes consist of two separate protein complexes, the core particle that hydrolyzes peptide bonds and an AAA+ ATPase domain responsible for the binding, unfolding and translocation of protein substrates into the core particle for degradation. Similarly to eukaryotes, proteasomes play a central role in protein degradation and can be essential in Archaea. Core particles associate with and utilize a variety of ATPase complexes to carry out protein degradation in Archaea. In actinobacterial species, such as Mycobacterium tuberculosis, proteasome-mediated degradation is associated with pathogenesis and does not appear to be essential. Interestingly, both actinobacterial species and Archaea use small proteins to covalently modify proteins, prokaryotic ubiquitin-like proteins (Pup) in Actinobacteria and ubiquitin-like small archaeal modifier proteins (SAMP) in Archaea. These modifications may play a role in proteasome targeting similar to the ubiquitin-proteasome system in eukaryotes.
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Affiliation(s)
- Matthew A Humbard
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Md., USA
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28
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Striebel F, Imkamp F, Özcelik D, Weber-Ban E. Pupylation as a signal for proteasomal degradation in bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:103-13. [PMID: 23557784 DOI: 10.1016/j.bbamcr.2013.03.022] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/21/2013] [Accepted: 03/12/2013] [Indexed: 12/23/2022]
Abstract
Posttranslational modifications in the form of covalently attached proteins like ubiquitin (Ub), were long considered an exclusive feature of eukaryotic organisms. The discovery of pupylation, the modification of lysine residues with a prokaryotic, ubiquitin-like protein (Pup), demonstrated that certain bacteria use a tagging pathway functionally related to ubiquitination in order to target proteins for proteasomal degradation. However, functional analogies do not translate into structural or mechanistic relatedness. Bacterial Pup, unlike eukaryotic Ub, does not adopt a β-grasp fold, but is intrinsically disordered. Furthermore, isopeptide bond formation in the pupylation process is carried out by enzymes evolutionary descendent from glutamine synthetases. While in eukaryotes, the proteasome is the main energy-dependent protein degradation machine, bacterial proteasomes exist in addition to other architecturally related degradation complexes, and their specific role along with the role of pupylation is still poorly understood. In Mycobacterium tuberculosis (Mtb), the Pup-proteasome system contributes to pathogenicity by supporting the bacterium's persistence within host macrophages. Here, we describe the mechanism and structural framework of pupylation and the targeting of pupylated proteins to the proteasome complex. Particular attention is given to the comparison of the bacterial Pup-proteasome system and the eukaryotic ubiquitin-proteasome system. Furthermore, the involvement of pupylation and proteasomal degradation in Mtb pathogenesis is discussed together with efforts to establish the Pup-proteasome system as a drug target. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- Frank Striebel
- Max Planck Institute of Biochemistry, Department of Molecular Cell Biology, D-82152 Martinsried, Germany
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Smirnov D, Dhall A, Sivanesam K, Sharar RJ, Chatterjee C. Fluorescent probes reveal a minimal ligase recognition motif in the prokaryotic ubiquitin-like protein from Mycobacterium tuberculosis. J Am Chem Soc 2013; 135:2887-90. [PMID: 23402667 DOI: 10.1021/ja311376h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The prokaryotic ubiquitin-like protein (Pup)-based proteasomal system in the pathogen Mycobacterium tuberculosis (Mtb) is essential for its survival in a mammalian host. The Pup ligase enzyme, PafA, conjugates Pup to a suite of proteins targeted for proteasomal degradation and is necessary for persistent infection by Mtb. We report the design and application of fluorescent probes for use in elucidating the mechanisms of Pup and substrate recognition by PafA. Our studies revealed that the C-terminal 26 amino acid sequence of Pup is the minimal ligase recognition motif in Mtb. Specific hydrophobic residues within this sequence that are known to be important for the interactions of Pup with proteasomes are also critical for the activation of Pup by PafA.
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Affiliation(s)
- Denis Smirnov
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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30
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Abstract
Pupylation is a post-translational protein modification occurring in actinobacteria through which the small, intrinsically disordered protein Pup (prokaryotic ubiquitin-like protein) is conjugated to lysine residues of proteins, marking them for proteasomal degradation. Although functionally related to ubiquitination, pupylation is carried out by different enzymes that are evolutionarily linked to bacterial carboxylate-amine ligases. Here, we compare the mechanism of Pup-conjugation to target proteins with ubiquitination, describe the evolutionary emergence of pupylation and discuss the importance of this pathway for survival of Mycobacterium tuberculosis in the host.
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Affiliation(s)
- Jonas Barandun
- ETH Zurich, Institute of Molecular Biology & Biophysics, CH-8093 Zurich, Switzerland
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Burns KE, McAllister FE, Schwerdtfeger C, Mintseris J, Cerda-Maira F, Noens EE, Wilmanns M, Hubbard SR, Melandri F, Ovaa H, Gygi SP, Darwin KH. Mycobacterium tuberculosis prokaryotic ubiquitin-like protein-deconjugating enzyme is an unusual aspartate amidase. J Biol Chem 2012; 287:37522-9. [PMID: 22942282 DOI: 10.1074/jbc.m112.384784] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Deamidase of Pup (Dop), the prokaryotic ubiquitin-like protein (Pup)-deconjugating enzyme, is critical for the full virulence of Mycobacterium tuberculosis and is unique to bacteria, providing an ideal target for the development of selective chemotherapies. We used a combination of genetics and chemical biology to characterize the mechanism of depupylation. We identified an aspartate as a potential nucleophile in the active site of Dop, suggesting a novel protease activity to target for inhibitor development.
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Affiliation(s)
- Kristin E Burns
- Department of Microbiology, New York University, New York, New York 10016, USA
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