1
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Xu F, Chen H, Zhou C, Zang T, Wang R, Shen S, Li C, Yu Y, Pei Z, Shen L, Qian J, Ge J. Targeting deubiquitinase OTUB1 protects vascular smooth muscle cells in atherosclerosis by modulating PDGFRβ. Front Med 2024; 18:465-483. [PMID: 38644399 DOI: 10.1007/s11684-024-1056-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 12/04/2023] [Indexed: 04/23/2024]
Abstract
Atherosclerosis is a chronic artery disease that causes various types of cardiovascular dysfunction. Vascular smooth muscle cells (VSMCs), the main components of atherosclerotic plaque, switch from contractile to synthetic phenotypes during atherogenesis. Ubiquitylation is crucial in regulating VSMC phenotypes in atherosclerosis, and it can be reversely regulated by deubiquitinases. However, the specific effects of deubiquitinases on atherosclerosis have not been thoroughly elucidated. In this study, RNAi screening in human aortic smooth muscle cells was performed to explore the effects of OTU family deubiquitinases, which revealed that silencing OTUB1 inhibited PDGF-BB-stimulated VSMC phenotype switch. Further in vivo studies using Apoe-/- mice revealed that knockdown of OTUB1 in VSMCs alleviated atherosclerosis plaque burden in the advanced stage and led to a stable plaque phenotype. Moreover, VSMC proliferation and migration upon PDGF-BB stimulation could be inhibited by silencing OTUB1 in vitro. Unbiased RNA-sequencing data indicated that knocking down OTUB1 influenced VSMC differentiation, adhesion, and proliferation. Mass spectrometry of ubiquitinated protein confirmed that proteins related to cell growth and migration were differentially ubiquitylated. Mechanistically, we found that OTUB1 recognized the K707 residue ubiquitylation of PDGFRβ with its catalytic triad, thereby reducing the K48-linked ubiquitylation of PDGFRβ. Inhibiting OTUB1 in VSMCs could promote PDGFRβ degradation via the ubiquitin-proteasome pathway, so it was beneficial in preventing VSMCs' phenotype switch. These findings revealed that knocking down OTUB1 ameliorated VSMCs' phenotype switch and atherosclerosis progression, indicating that OTUB1 could be a valuable translational therapeutic target in the future.
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Affiliation(s)
- Fei Xu
- Department of Cardiology and Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, Chengdu, 610041, China
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Han Chen
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Changyi Zhou
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Tongtong Zang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Rui Wang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Shutong Shen
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Chaofu Li
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Yue Yu
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Zhiqiang Pei
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China
| | - Li Shen
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China.
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China.
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China.
| | - Juying Qian
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China.
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China.
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China.
| | - Junbo Ge
- Department of Cardiology, Zhongshan Hospital, Fudan University, Research Unit of Cardiovascular Techniques and Devices, Chinese Academy of Medical Sciences, Shanghai, 200032, China.
- Shanghai Institute of Cardiovascular Diseases, Shanghai, 200032, China.
- National Clinical Research Center for Interventional Medicine & Shanghai Clinical Research Center for Interventional Medicine (19MC1910300), Shanghai, 200032, China.
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2
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Zhang Z, Fu J, Rack JGM, Li C, Voorneveld J, Filippov DV, Ahel I, Luo ZQ, Das C. Legionella metaeffector MavL reverses ubiquitin ADP-ribosylation via a conserved arginine-specific macrodomain. Nat Commun 2024; 15:2452. [PMID: 38503748 PMCID: PMC10951314 DOI: 10.1038/s41467-024-46649-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 02/26/2024] [Indexed: 03/21/2024] Open
Abstract
ADP-ribosylation is a reversible post-translational modification involved in various cellular activities. Removal of ADP-ribosylation requires (ADP-ribosyl)hydrolases, with macrodomain enzymes being a major family in this category. The pathogen Legionella pneumophila mediates atypical ubiquitination of host targets using the SidE effector family in a process that involves ubiquitin ADP-ribosylation on arginine 42 as an obligatory step. Here, we show that the Legionella macrodomain effector MavL regulates this pathway by reversing the arginine ADP-ribosylation, likely to minimize potential detrimental effects caused by the modified ubiquitin. We determine the crystal structure of ADP-ribose-bound MavL, providing structural insights into recognition of the ADP-ribosyl group and catalytic mechanism of its removal. Further analyses reveal DUF4804 as a class of MavL-like macrodomain enzymes whose representative members show unique selectivity for mono-ADP-ribosylated arginine residue in synthetic substrates. We find such enzymes are also present in eukaryotes, as exemplified by two previously uncharacterized (ADP-ribosyl)hydrolases in Drosophila melanogaster. Crystal structures of several proteins in this class provide insights into arginine specificity and a shared mode of ADP-ribose interaction distinct from previously characterized macrodomains. Collectively, our study reveals a new regulatory layer of SidE-catalyzed ubiquitination and expands the current understanding of macrodomain enzymes.
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Affiliation(s)
- Zhengrui Zhang
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Jiaqi Fu
- Department of Biological Sciences, Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, 47907, USA
| | - Johannes Gregor Matthias Rack
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, Oxford, UK
- MRC Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, EX4 4QD, Exeter, UK
| | - Chuang Li
- Department of Biological Sciences, Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, 47907, USA
| | - Jim Voorneveld
- Bio-Organic Synthesis, Leiden Institute of Chemistry, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Dmitri V Filippov
- Bio-Organic Synthesis, Leiden Institute of Chemistry, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, Oxford, UK
| | - Zhao-Qing Luo
- Department of Biological Sciences, Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, 47907, USA
| | - Chittaranjan Das
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
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3
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Hermanns T, Uthoff M, Baumann U, Hofmann K. The structural basis for deubiquitination by the fingerless USP-type effector TssM. Life Sci Alliance 2024; 7:e202302422. [PMID: 38170641 PMCID: PMC10719079 DOI: 10.26508/lsa.202302422] [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: 10/06/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 01/05/2024] Open
Abstract
Intracellular bacteria are threatened by ubiquitin-mediated autophagy, whenever the bacterial surface or enclosing membrane structures become targets of host ubiquitin ligases. As a countermeasure, many intracellular pathogens encode deubiquitinase (DUB) effectors to keep their surfaces free of ubiquitin. Most bacterial DUBs belong to the OTU or CE-clan families. The betaproteobacteria Burkholderia pseudomallei and Burkholderia mallei, causative agents of melioidosis and glanders, respectively, encode the TssM effector, the only known bacterial DUB belonging to the USP class. TssM is much shorter than typical eukaryotic USP enzymes and lacks the canonical ubiquitin-recognition region. By solving the crystal structures of isolated TssM and its complex with ubiquitin, we found that TssM lacks the entire "Fingers" subdomain of the USP fold. Instead, the TssM family has evolved the functionally analog "Littlefinger" loop, which is located towards the end of the USP domain and recognizes different ubiquitin interfaces than those used by USPs. The structures revealed the presence of an N-terminal immunoglobulin-fold domain, which is able to form a strand-exchange dimer and might mediate TssM localization to the bacterial surface.
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Affiliation(s)
- Thomas Hermanns
- https://ror.org/00rcxh774 Institute for Genetics, University of Cologne, Cologne, Germany
| | - Matthias Uthoff
- https://ror.org/00rcxh774 Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Ulrich Baumann
- https://ror.org/00rcxh774 Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Kay Hofmann
- https://ror.org/00rcxh774 Institute for Genetics, University of Cologne, Cologne, Germany
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4
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Yang Y, Mei L, Chen J, Chen X, Wang Z, Liu L, Yang A. Legionella pneumophila-mediated host posttranslational modifications. J Mol Cell Biol 2023; 15:mjad032. [PMID: 37156500 PMCID: PMC10720952 DOI: 10.1093/jmcb/mjad032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/17/2023] [Accepted: 05/06/2023] [Indexed: 05/10/2023] Open
Abstract
Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires' disease. During infections, L. pneumophila releases over 300 effector proteins into host cells through an Icm/Dot type IV secretion system to manipulate the host defense system for survival within the host. Notably, certain effector proteins mediate posttranslational modifications (PTMs), serving as useful approaches exploited by L. pneumophila to modify host proteins. Some effectors catalyze the addition of host protein PTMs, while others mediate the removal of PTMs from host proteins. In this review, we summarize L. pneumophila effector-mediated PTMs of host proteins, including phosphorylation, ubiquitination, glycosylation, AMPylation, phosphocholination, methylation, and ADP-ribosylation, as well as dephosphorylation, deubiquitination, deAMPylation, deADP-ribosylation, dephosphocholination, and delipidation. We describe their molecular mechanisms and biological functions in the regulation of bacterial growth and Legionella-containing vacuole biosynthesis and in the disruption of host immune and defense machinery.
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Affiliation(s)
- Yi Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Ligang Mei
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Jing Chen
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaorong Chen
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Zhuolin Wang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Lu Liu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
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5
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Harumoto T. Self-stabilization mechanism encoded by a bacterial toxin facilitates reproductive parasitism. Curr Biol 2023; 33:4021-4029.e6. [PMID: 37673069 DOI: 10.1016/j.cub.2023.08.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/30/2023] [Accepted: 08/10/2023] [Indexed: 09/08/2023]
Abstract
A wide variety of maternally transmitted endosymbionts in insects are associated with reproductive parasitism, whereby they interfere with host reproduction to increase the ratio of infected females and spread within populations.1,2 Recent successes in identifying bacterial factors responsible for reproductive parasitism3,4,5,6,7 as well as further omics approaches8,9,10,11,12 have highlighted the common appearance of deubiquitinase domains, although their biological roles-in particular, how they link to distinct manipulative phenotypes-remain poorly defined. Spiroplasma poulsonii is a helical and motile bacterial endosymbiont of Drosophila,13,14 which selectively kills male progeny with a male-killing toxin Spaid (S. poulsonii androcidin), which encodes an ovarian tumor (OTU) deubiquitinase domain.6 Artificial expression of Spaid in flies reproduces male-killing-associated pathologies that include abnormal apoptosis and neural defects during embryogenesis6,15,16,17,18,19; moreover, it highly accumulates on the dosage-compensated male X chromosome,20 congruent with cellular defects such as the DNA damage/chromatin bridge breakage specifically induced upon that chromosome.6,21,22,23 Here, I show that without the function of OTU, Spaid is polyubiquitinated and degraded through the host ubiquitin-proteasome pathway, leading to the attenuation of male-killing activity as shown previously.6 Furthermore, I find that Spaid utilizes its OTU domain to deubiquitinate itself in an intermolecular manner. Collectively, the deubiquitinase domain of Spaid serves as a self-stabilization mechanism to facilitate male killing in flies, optimizing a molecular strategy of endosymbionts that enables the efficient manipulation of the host at a low energetic cost.
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Affiliation(s)
- Toshiyuki Harumoto
- Hakubi Center for Advanced Research, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan; Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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6
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Roberts CG, Franklin TG, Pruneda JN. Ubiquitin-targeted bacterial effectors: rule breakers of the ubiquitin system. EMBO J 2023; 42:e114318. [PMID: 37555693 PMCID: PMC10505922 DOI: 10.15252/embj.2023114318] [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: 04/19/2023] [Revised: 07/10/2023] [Accepted: 07/18/2023] [Indexed: 08/10/2023] Open
Abstract
Regulation through post-translational ubiquitin signaling underlies a large portion of eukaryotic biology. This has not gone unnoticed by invading pathogens, many of which have evolved mechanisms to manipulate or subvert the host ubiquitin system. Bacteria are particularly adept at this and rely heavily upon ubiquitin-targeted virulence factors for invasion and replication. Despite lacking a conventional ubiquitin system of their own, many bacterial ubiquitin regulators loosely follow the structural and mechanistic rules established by eukaryotic ubiquitin machinery. Others completely break these rules and have evolved novel structural folds, exhibit distinct mechanisms of regulation, or catalyze foreign ubiquitin modifications. Studying these interactions can not only reveal important aspects of bacterial pathogenesis but also shed light on unexplored areas of ubiquitin signaling and regulation. In this review, we discuss the methods by which bacteria manipulate host ubiquitin and highlight aspects that follow or break the rules of ubiquitination.
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Affiliation(s)
- Cameron G Roberts
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
| | - Tyler G Franklin
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
| | - Jonathan N Pruneda
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
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7
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Kang S, Kim G, Choi M, Jeong M, van der Heden van Noort GJ, Roh SH, Shin D. Structural insights into ubiquitin chain cleavage by Legionella ovarian tumor deubiquitinases. Life Sci Alliance 2023; 6:e202201876. [PMID: 37100438 PMCID: PMC10133868 DOI: 10.26508/lsa.202201876] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 04/17/2023] [Accepted: 04/17/2023] [Indexed: 04/28/2023] Open
Abstract
Although ubiquitin is found only in eukaryotes, several pathogenic bacteria and viruses possess proteins that hinder the host ubiquitin system. Legionella, a gram-negative intracellular bacterium, possesses an ovarian tumor (OTU) family of deubiquitinases (Lot DUBs). Herein, we describe the molecular characteristics of Lot DUBs. We elucidated the structure of the LotA OTU1 domain and revealed that entire Lot DUBs possess a characteristic extended helical lobe that is not found in other OTU-DUBs. The structural topology of an extended helical lobe is the same throughout the Lot family, and it provides an S1' ubiquitin-binding site. Moreover, the catalytic triads of Lot DUBs resemble those of the A20-type OTU-DUBs. Furthermore, we revealed a unique mechanism by which LotA OTU domains cooperate together to distinguish the length of the chain and preferentially cleave longer K48-linked polyubiquitin chains. The LotA OTU1 domain itself cleaves K6-linked ubiquitin chains, whereas it is also essential for assisting the cleavage of longer K48-linked polyubiquitin chains by the OTU2 domain. Thus, this study provides novel insights into the structure and mechanism of action of Lot DUBs.
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Affiliation(s)
- Sangwoo Kang
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Gyuhee Kim
- School of Biological Science, Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
| | - Minhyeong Choi
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Minwoo Jeong
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | | | - Soung-Hun Roh
- School of Biological Science, Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
| | - Donghyuk Shin
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
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8
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Shi Y, Liu H, Ma K, Luo ZQ, Qiu J. Legionella longbeachae Regulates the Association of Polyubiquitinated Proteins on Bacterial Phagosome with Multiple Deubiquitinases. Microbiol Spectr 2023; 11:e0417922. [PMID: 36790208 PMCID: PMC10100730 DOI: 10.1128/spectrum.04179-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/16/2023] [Indexed: 02/16/2023] Open
Abstract
Legionella spp. are the causative agents of a severe pneumonia known as Legionnaires' disease. Upon being engulfed by host cells, these environmental bacteria replicate intracellularly in a plasma membrane-derived niche termed Legionella-containing vacuole (LCV) in a way that requires the defective in organelle trafficking/intracellular multiplication (Dot/Icm) protein transporter. Our understanding of interactions between Legionella and its hosts was mostly based on studies of Legionella pneumophila. In this study, we found that the LCVs created by virulent Legionella longbeachae are similarly decorated by polyubiquitinated proteins to those formed by L. pneumophila and that the ubiquitin-proteasome system (UPS) is required for optimal intracellular growth of L. longbeachae. Furthermore, we utilized bioinformatics methods and the ubiquitin-vinylmethyl ester probe to obtain potential deubiquitinases (DUBs) encoded by L. longbeachae. These efforts led to the identification of 9 L. longbeachae DUBs that displayed distinct specificity toward ubiquitin chain types. Among these, LLO_1014 and LLO_2238 are associated with the LCVs and impact the accumulation of polyubiquitinated species on the bacterial phagosome. Moreover, LLO_1014 and LLO_2238 could fully restore the phenotypes associated with Δceg23 (lotB) and Δlem27 (lotC) mutants of L. pneumophila, indicating that these DUBs have similar functions. Together, these results reveal that L. longbeachae uses multiple DUBs to construct an intracellular niche for its replication. IMPORTANCE Legionella spp. are opportunistic intracellular bacterial pathogens that cause Legionnaires' disease. Legionella utilizes the Dot/Icm type IV secretion system to deliver effector protein into host cells to modulate various cellular functions. At least 26 L. pneumophila effectors are known to hijack the host ubiquitin system via diverse mechanisms. L. longbeachae is the second leading cause of Legionnaires' disease worldwide. However, our knowledge about the interactions between L. longbeachae and its hosts is very limited. Here, we found that, similar to L. pneumophila infection, the host ubiquitin proteasome system is also important for the intracellular replication of L. longbeachae. In addition, the bacterial phagosomes harboring L. longbeachae are enriched with polyubiquitinated proteins in a Dot/Icm system-dependent manner. We further identified 9 L. longbeachae proteins that function as DUBs with distinct ubiquitin chain specificity. Of note, several of the phagosome-associated L. longbeachae DUBs regulate the recruitment of polyubiquitinated proteins to the LCV.
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Affiliation(s)
- Yunjia Shi
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Center for Pathogen Biology and Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Hongtao Liu
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Center for Pathogen Biology and Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Kelong Ma
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Center for Pathogen Biology and Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Zhao-Qing Luo
- Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Jiazhang Qiu
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Center for Pathogen Biology and Infectious Diseases, The First Hospital of Jilin University, Changchun, China
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9
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Pruneda JN, Nguyen JV, Nagai H, Kubori T. Bacterial usurpation of the OTU deubiquitinase fold. FEBS J 2023:10.1111/febs.16725. [PMID: 36636866 PMCID: PMC10338644 DOI: 10.1111/febs.16725] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/10/2022] [Accepted: 01/10/2023] [Indexed: 01/14/2023]
Abstract
The extensive cellular signalling events controlled by posttranslational ubiquitination are tightly regulated through the action of specialized proteases termed deubiquitinases. Among them, the OTU family of deubiquitinases can play very specialized roles in the regulation of discrete subtypes of ubiquitin signals that control specific cellular functions. To exert control over host cellular functions, some pathogenic bacteria have usurped the OTU deubiquitinase fold as a secreted virulence factor that interferes with ubiquitination inside infected cells. Herein, we provide a review of the function of bacterial OTU deubiquitinases during infection, the structural basis for their deubiquitinase activities and the bioinformatic approaches leading to their identification. Understanding bacterial OTU deubiquitinases holds the potential for discoveries not only in bacterial pathogenesis but in eukaryotic biology as well.
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Affiliation(s)
- Jonathan N. Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Justine V. Nguyen
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Hiroki Nagai
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan
- Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Gifu, Gifu 501-1194, Japan
| | - Tomoko Kubori
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan
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10
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Warren GD, Kitao T, Franklin TG, Nguyen JV, Geurink PP, Kubori T, Nagai H, Pruneda JN. Mechanism of Lys6 poly-ubiquitin specificity by the L. pneumophila deubiquitinase LotA. Mol Cell 2023; 83:105-120.e5. [PMID: 36538933 PMCID: PMC9825671 DOI: 10.1016/j.molcel.2022.11.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/13/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Abstract
The versatility of ubiquitination to control vast domains of eukaryotic biology is due, in part, to diversification through differently linked poly-ubiquitin chains. Deciphering signaling roles for some chain types, including those linked via K6, has been stymied by a lack of specificity among the implicated regulatory proteins. Forged through strong evolutionary pressures, pathogenic bacteria have evolved intricate mechanisms to regulate host ubiquitin during infection. Herein, we identify and characterize a deubiquitinase domain of the secreted effector LotA from Legionella pneumophila that specifically regulates K6-linked poly-ubiquitin. We demonstrate the utility of LotA for studying K6 poly-ubiquitin signals. We identify the structural basis of LotA activation and poly-ubiquitin specificity and describe an essential "adaptive" ubiquitin-binding domain. Without LotA activity during infection, the Legionella-containing vacuole becomes decorated with K6 poly-ubiquitin as well as the AAA ATPase VCP/p97/Cdc48. We propose that LotA's deubiquitinase activity guards Legionella-containing vacuole components from ubiquitin-dependent extraction.
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Affiliation(s)
- Gus D Warren
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Tomoe Kitao
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan
| | - Tyler G Franklin
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Justine V Nguyen
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Paul P Geurink
- Oncode Institute, Department of Cell and Chemical Biology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Tomoko Kubori
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan; G-CHAIN, Gifu University, Gifu, Gifu 501-1194, Japan
| | - Hiroki Nagai
- Department of Microbiology, Graduate School of Medicine, Gifu University, Gifu, Gifu 501-1194, Japan; G-CHAIN, Gifu University, Gifu, Gifu 501-1194, Japan
| | - Jonathan N Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA.
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11
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Abstract
Ubiquitination is a posttranslational modification that regulates a multitude of cellular functions. Pathogens, such as bacteria and viruses, have evolved sophisticated mechanisms that evade or counteract ubiquitin-dependent host responses, or even exploit the ubiquitin system to their own advantage. This is largely done by numerous pathogen virulence factors that encode E3 ligases and deubiquitinases, which are often used as weapons in pathogen-host cell interactions. Moreover, upon pathogen attack, host cellular signaling networks undergo major ubiquitin-dependent changes to protect the host cell, including coordination of innate immunity, remodeling of cellular organelles, reorganization of the cytoskeleton, and reprogramming of metabolic pathways to restrict growth of the pathogen. Here we provide mechanistic insights into ubiquitin regulation of host-pathogen interactions and how it affects bacterial and viral pathogenesis and the organization and response of the host cell.
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Affiliation(s)
- Rukmini Mukherjee
- Institute of Biochemistry II, Faculty of Medicine, Goethe University, Frankfurt, Germany; .,Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Ivan Dikic
- Institute of Biochemistry II, Faculty of Medicine, Goethe University, Frankfurt, Germany; .,Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt, Germany.,Max Planck Institute of Biophysics, Frankfurt, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch Translational Medicine and Pharmacology, Frankfurt, Germany
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12
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Luo J, Ruan X, Huang Z, Li Z, Ye L, Wu Y, Zhen X, Ouyang S. Structural basis for the dual catalytic activity of the Legionella pneumophila ovarian-tumor (OTU) domain deubiquitinase LotA. J Biol Chem 2022; 298:102414. [PMID: 36007613 PMCID: PMC9486567 DOI: 10.1016/j.jbc.2022.102414] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/26/2022] Open
Abstract
Legionella pneumophila, a bacterial pathogen that causes a severe pneumonia known as Legionnaires’ disease, extensively exploits the ubiquitin (Ub) pathway in the infected host cells through certain virulence effectors excreted by the Dot/Icm system. To date, several Dot/Icm effectors have been found to act as Ub ligases, and four effectors, including LotA, LotB, LotC, and Ceg7, have been identified as deubiquitinases (DUBs) from the ovarian tumor (OTU) domain family. LotA is unique among other OTU DUBs because it possesses two distinct DUB domains and exclusively exhibits catalytic activity against K6-linked diUb and polyUb chains. However, the structure of LotA and the molecular mechanism for the dual DUB activity remains elusive. In this study, we solved the structure of LotA in complex with proximally bound Ub and distal covalently bound Ub. Both Ub molecules are bound to the DUB1 domain and mimic a K6-linked diUb. Structural analysis reveals that the DUB1 domain utilizes a distinct mechanism for recognition of the K6-linked diUb within a large S1′ binding site that is uncommon to OTU DUBs. Structural fold of the LotA DUB2 domain closely resembles LotB and LotC, similarly containing an extra α-helix lobe that has been demonstrated to play an important role in Ub binding. Collectively, our study uncovers the structural basis for the dual catalytic activity of the unique OTU family DUB LotA.
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Affiliation(s)
- Jiwei Luo
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, the Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Xinglin Ruan
- Department of Neurology, Fujian Medical University Union Hospital, 29 Xinquan Road Gulou District, Fuzhou 350001, China
| | - Zhijie Huang
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, the Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Zekai Li
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, the Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Le Ye
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, the Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Yongyu Wu
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, the Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Xiangkai Zhen
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, the Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China.
| | - Songying Ouyang
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, the Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China.
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13
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Jeong M, Jeon H, Shin D. Ubiquitin-regulating effector proteins from Legionella. BMB Rep 2022. [PMID: 35651329 PMCID: PMC9340081 DOI: 10.5483/bmbrep.2022.55.7.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Ubiquitin is relatively modest in size but involves almost entire cellular signaling pathways. The primary role of ubiquitin is maintaining cellular protein homeostasis. Ubiquitination regulates the fate of target proteins using the proteasome- or autophagy-mediated degradation of ubiquitinated substrates, which can be either intracellular or foreign proteins from invading pathogens. Legionella, a gram-negative intracellular pathogen, hinders the host-ubiquitin system by translocating hundreds of effector proteins into the host cell’s cytoplasm. In this review, we describe the current understanding of ubiquitin machinery from Legionella. We summarize structural and biochemical differences between the host-ubiquitin system and ubiquitin-related effectors of Legionella. Some of these effectors act much like canonical host-ubiquitin machinery, whereas others have distinctive structures and accomplish non-canonical ubiquitination via novel biochemical mechanisms.
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Affiliation(s)
- Minwoo Jeong
- Department of System Biology, College of Life Sciences and Biotechnology, Yonsei University, Seoul 03722, Korea
| | - Hayoung Jeon
- Department of System Biology, College of Life Sciences and Biotechnology, Yonsei University, Seoul 03722, Korea
| | - Donghyuk Shin
- Department of System Biology, College of Life Sciences and Biotechnology, Yonsei University, Seoul 03722, Korea
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14
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Estavoyer B, Messmer C, Echbicheb M, Rudd CE, Milot E, Affar EB. Mechanisms orchestrating the enzymatic activity and cellular functions of deubiquitinases. J Biol Chem 2022; 298:102198. [PMID: 35764170 PMCID: PMC9356280 DOI: 10.1016/j.jbc.2022.102198] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 06/13/2022] [Accepted: 06/22/2022] [Indexed: 11/30/2022] Open
Abstract
Deubiquitinases (DUBs) are required for the reverse reaction of ubiquitination and act as major regulators of ubiquitin signaling processes. Emerging evidence suggests that these enzymes are regulated at multiple levels in order to ensure proper and timely substrate targeting and to prevent the adverse consequences of promiscuous deubiquitination. The importance of DUB regulation is highlighted by disease-associated mutations that inhibit or activate DUBs, deregulating their ability to coordinate cellular processes. Here, we describe the diverse mechanisms governing protein stability, enzymatic activity, and function of DUBs. In particular, we outline how DUBs are regulated by their protein domains and interacting partners. Intramolecular interactions can promote protein stability of DUBs, influence their subcellular localization, and/or modulate their enzymatic activity. Remarkably, these intramolecular interactions can induce self-deubiquitination to counteract DUB ubiquitination by cognate E3 ubiquitin ligases. In addition to intramolecular interactions, DUBs can also oligomerize and interact with a wide variety of cellular proteins, thereby forming obligate or facultative complexes that regulate their enzymatic activity and function. The importance of signaling and post-translational modifications in the integrated control of DUB function will also be discussed. While several DUBs are described with respect to the multiple layers of their regulation, the tumor suppressor BAP1 will be outlined as a model enzyme whose localization, stability, enzymatic activity, and substrate recognition are highly orchestrated by interacting partners and post-translational modifications.
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Affiliation(s)
- Benjamin Estavoyer
- Laboratory for Cell Signaling and Cancer, Maisonneuve-Rosemont Hospital Research Center, H1T 2M4, Montréal, Québec, Canada
| | - Clémence Messmer
- Laboratory for Cell Signaling and Cancer, Maisonneuve-Rosemont Hospital Research Center, H1T 2M4, Montréal, Québec, Canada
| | - Mohamed Echbicheb
- Laboratory for Cell Signaling and Cancer, Maisonneuve-Rosemont Hospital Research Center, H1T 2M4, Montréal, Québec, Canada
| | - Christopher E Rudd
- Laboratory for Cell Signaling in Immunotherapy, Maisonneuve-Rosemont Hospital Research Center, H1T 2M4, Montréal, Québec, Canada; Department of Medicine, University of Montréal, Montréal H3C 3J7, Québec, Canada
| | - Eric Milot
- Laboratory for Malignant Hematopoiesis and Epigenetic Regulation of Gene Expression, Maisonneuve-Rosemont Hospital Research Center, H1T 2M4, Montréal, Québec, Canada; Department of Medicine, University of Montréal, Montréal H3C 3J7, Québec, Canada
| | - El Bachir Affar
- Laboratory for Cell Signaling and Cancer, Maisonneuve-Rosemont Hospital Research Center, H1T 2M4, Montréal, Québec, Canada; Department of Medicine, University of Montréal, Montréal H3C 3J7, Québec, Canada.
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15
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Lockwood DC, Amin H, Costa TRD, Schroeder GN. The Legionella pneumophila Dot/Icm type IV secretion system and its effectors. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35639581 DOI: 10.1099/mic.0.001187] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To prevail in the interaction with eukaryotic hosts, many bacterial pathogens use protein secretion systems to release virulence factors at the host–pathogen interface and/or deliver them directly into host cells. An outstanding example of the complexity and sophistication of secretion systems and the diversity of their protein substrates, effectors, is the Defective in organelle trafficking/Intracellular multiplication (Dot/Icm) Type IVB secretion system (T4BSS) of
Legionella pneumophila
and related species.
Legionella
species are facultative intracellular pathogens of environmental protozoa and opportunistic human respiratory pathogens. The Dot/Icm T4BSS translocates an exceptionally large number of effectors, more than 300 per
L. pneumophila
strain, and is essential for evasion of phagolysosomal degradation and exploitation of protozoa and human macrophages as replicative niches. Recent technological advancements in the imaging of large protein complexes have provided new insight into the architecture of the T4BSS and allowed us to propose models for the transport mechanism. At the same time, significant progress has been made in assigning functions to about a third of
L. pneumophila
effectors, discovering unprecedented new enzymatic activities and concepts of host subversion. In this review, we describe the current knowledge of the workings of the Dot/Icm T4BSS machinery and provide an overview of the activities and functions of the to-date characterized effectors in the interaction of
L. pneumophila
with host cells.
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Affiliation(s)
- Daniel C Lockwood
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
| | - Himani Amin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
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16
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Luo J, Wang L, Song L, Luo ZQ. Exploitation of the Host Ubiquitin System: Means by Legionella pneumophila. Front Microbiol 2022; 12:790442. [PMID: 35003021 PMCID: PMC8727461 DOI: 10.3389/fmicb.2021.790442] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/30/2021] [Indexed: 01/12/2023] Open
Abstract
Ubiquitination is a commonly used post-translational modification (PTM) in eukaryotic cells, which regulates a wide variety of cellular processes, such as differentiation, apoptosis, cell cycle, and immunity. Because of its essential role in immunity, the ubiquitin network is a common target of infectious agents, which have evolved various effective strategies to hijack and co-opt ubiquitin signaling for their benefit. The intracellular pathogen Legionella pneumophila represents one such example; it utilizes a large cohort of virulence factors called effectors to modulate diverse cellular processes, resulting in the formation a compartment called the Legionella-containing vacuole (LCV) that supports its replication. Many of these effectors function to re-orchestrate ubiquitin signaling with distinct biochemical activities. In this review, we highlight recent progress in the mechanism of action of L. pneumophila effectors involved in ubiquitination and discuss their roles in bacterial virulence and host cell biology.
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Affiliation(s)
- Jingjing Luo
- Department of Respiratory Medicine, Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Lidong Wang
- Department of Respiratory Medicine, Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Lei Song
- Department of Respiratory Medicine, Center for Pathogen Biology and Infectious Diseases, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Zhao-Qing Luo
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
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17
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Structural basis of ubiquitin recognition by a bacterial OTU deubiquitinase LotA. J Bacteriol 2021; 204:e0037621. [PMID: 34633867 DOI: 10.1128/jb.00376-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pathogenic bacteria have acquired a vast array of eukaryotic-like proteins via intimate interaction with host cells. Bacterial effector proteins that function as ubiquitin ligases and deubiquitinases (DUBs) are remarkable examples of such molecular mimicry. LotA, a Legionella pneumophila effector, belongs to the ovarian tumor (OTU) superfamily, which regulates diverse ubiquitin signals by their DUB activities. LotA harbors two OTU domains that have distinct reactivities; the first one is responsible for the cleavage of the K6-linked ubiquitin chain, and the second one shows an uncommon preference for long chains of ubiquitin. Here, we report the crystal structure of a middle domain of LotA (LotAM), which contains the second OTU domain. LotAM consists of two distinct subdomains, a catalytic domain having high structural similarity with human OTU DUBs and an extended helical lobe (EHL) domain, which is characteristically conserved only in Legionella OTU DUBs. The docking simulation of LotAM with ubiquitin suggested that hydrophobic and electrostatic interactions between the EHL of LotAM and the C-terminal region of ubiquitin are crucial for the binding of ubiquitin to LotAM. The structure-based mutagenesis demonstrated that the acidic residue in the characteristic short helical segment termed the 'helical arm' is essential for the enzymatic activity of LotAM. The EHL domain of the three Legionella OTU DUBs, LotA, LotB, and LotC, share the 'helical arm' structure, suggesting that the EHL domain defines the Lot-OTUs as a unique class of DUBs. Importance To successfully colonize, some pathogenic bacteria hijack the host ubiquitin system. Legionella OTU-like-DUBs (Lot-DUBs) are novel bacterial deubiquitinases found in effector proteins of L. pneumophila. LotA is a member of Lot-DUBs and has two OTU domains (OTU1 and OTU2). We determined the structure of a middle fragment of LotA (LotAM), which includes OTU2. LotAM consists of the conserved catalytic domain and the Legionella OTUs-specific EHL domain. The docking simulation with ubiquitin and the mutational analysis suggested that the acidic surface in the EHL is essential for enzymatic activity. The structure of the EHL differs from those of other Lot-DUBs, suggesting that the variation of the EHL is related to the variable cleaving specificity of each DUB.
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18
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Schlüter D, Schulze-Niemand E, Stein M, Naumann M. Ovarian tumor domain proteases in pathogen infection. Trends Microbiol 2021; 30:22-33. [PMID: 34016513 DOI: 10.1016/j.tim.2021.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 01/06/2023]
Abstract
With the aim of overcoming host immune responses, and to permit persistence, numerous bacterial and viral pathogens have evolved effective strategies to control the activity of ovarian tumor domain proteases (OTUs), a group of deubiquitinylases crucial for regulating ubiquitin-modified proteins. Due to the important role of eukaryotic OTUs in cellular physiology, it is not surprising that pathogens have evolutionarily developed effector proteins which mimic host OTUs. Here, we focus on recent findings that illustrate how pathogen-encoded OTUs modulate eukaryotic host proteins and how they are implicated in cellular dysregulation. Further, we discuss the biological effects of OTUs in the context of structural features and pharmacological targeting. We point out the potentiality of selective OTU inhibitors, which shield ubiquitin-binding sites, as pharmacologic targets to treat harmful infections.
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Affiliation(s)
- Dirk Schlüter
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, 30625 Hannover, Germany; Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, 30625 Hannover, Germany
| | - Eric Schulze-Niemand
- Institute of Experimental Internal Medicine, Otto von Guericke University Magdeburg, 39120 Magdeburg, Germany; Molecular Simulations and Design Group, Max Planck Institute of Dynamic of Complex Technical Systems, 39106 Magdeburg, Germany
| | - Matthias Stein
- Molecular Simulations and Design Group, Max Planck Institute of Dynamic of Complex Technical Systems, 39106 Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Otto von Guericke University Magdeburg, 39120 Magdeburg, Germany.
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