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Gao S, Gao L, Yuan D, Lin X, van der Veen S. Gonococcal OMV-delivered PorB induces epithelial cell mitophagy. Nat Commun 2024; 15:1669. [PMID: 38396029 PMCID: PMC10891091 DOI: 10.1038/s41467-024-45961-1] [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: 10/17/2023] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
The bacterial pathogen Neisseria gonorrhoeae is able to invade epithelial cells and survive intracellularly. During this process, it secretes outer membrane vesicles (OMVs), however, the mechanistic details for interactions between gonococcal OMVs and epithelial cells and their impact on intracellular survival are currently not established. Here, we show that gonococcal OMVs induce epithelial cell mitophagy to reduce mitochondrial secretion of reactive oxygen species (ROS) and enhance intracellular survival. We demonstrate that OMVs deliver PorB to mitochondria to dissipate the mitochondrial membrane potential, resulting in mitophagy induction through a conventional PINK1 and OPTN/NDP52 mechanism. Furthermore, PorB directly recruits the E3 ubiquitin ligase RNF213, which decorates PorB lysine residue 171 with K63-linked polyubiquitin to induce mitophagy in a p62-dependent manner. These results demonstrate a mechanism in which polyubiquitination of a bacterial virulence factor that targets mitochondria directs mitophagy processes to this organelle to prevent its secretion of deleterious ROS.
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Affiliation(s)
- Shuai Gao
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
| | - Lingyu Gao
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
| | - Dailin Yuan
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, PR China
| | - Xu'ai Lin
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
| | - Stijn van der Veen
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China.
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China.
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, PR China.
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2
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Verma P, Chauhan A, Thakur R, Lata K, Sharma A, Chattopadhyay K, Mukhopadhaya A. Vibrio parahaemolyticus thermostable direct haemolysin induces non-classical programmed cell death despite caspase activation. Mol Microbiol 2023; 120:845-873. [PMID: 37818865 DOI: 10.1111/mmi.15180] [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: 02/07/2023] [Revised: 09/02/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
Thermostable direct haemolysin (TDH) is the key virulence factor secreted by the human gastroenteric bacterial pathogen Vibrio parahaemolyticus. TDH is a membrane-damaging pore-forming toxin. It evokes potent cytotoxicity, the mechanism of which still remains under-explored. Here, we have elucidated the mechanistic details of cell death response elicited by TDH. Employing Caco-2 intestinal epithelial cells and THP-1 monocytic cells, we show that TDH induces some of the hallmark features of apoptosis-like programmed cell death. TDH triggers caspase-3 and 7 activations in the THP-1 cells, while caspase-7 activation is observed in the Caco-2 cells. Interestingly, TDH appears to induce caspase-independent cell death. Higher XIAP level and lower Smac/Diablo level upon TDH intoxication provide plausible explanation for the functional inability of caspases in the THP-1 cells, in particular. Further exploration reveals that mitochondria play a central role in the TDH-induced cell death. TDH triggers mitochondrial damage, resulting in the release of AIF and endonuclease G, responsible for the execution of caspase-independent cell death. Among the other critical mediators of cell death, ROS is found to play an important role in the THP-1 cells, while PARP-1 appears to play a critical role in the Caco-2 cells. Altogether, our work provides critical new insights into the mechanism of cell death induction by TDH, showing a common central theme of non-classical programmed cell death. Our study also unravels the interplay of crucial molecules in the underlying signalling processes. Our findings add valuable insights into the role of TDH in the context of the host-pathogen interaction processes.
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Affiliation(s)
- Pratima Verma
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Aakanksha Chauhan
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Reena Thakur
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Kusum Lata
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Arpita Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Kausik Chattopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Arunika Mukhopadhaya
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
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3
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Waguia Kontchou C, Häcker G. Role of mitochondrial outer membrane permeabilization during bacterial infection. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2023; 374:83-127. [PMID: 36858657 DOI: 10.1016/bs.ircmb.2022.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Beyond the initial 'powerhouse' view, mitochondria have numerous functions in their mammalian cell and contribute to many physiological processes, and many of these we understand only partially. The control of apoptosis by mitochondria is firmly established. Many questions remain however how this function is embedded into physiology, and how other signaling pathways regulate mitochondrial apoptosis; the interplay of bacteria with the mitochondrial apoptosis pathway is one such example. The outer mitochondrial membrane regulates both import into mitochondria and the release of intermembrane, and in some situations also matrix components from mitochondria, and these mitochondrial components can have signaling function in the cytosol. One function is the induction of apoptotic cell death. An exciting, more recently discovered function is the regulation of inflammation. Mitochondrial molecules, both proteins and nucleic acids, have inflammatory activity when released from mitochondria, an activity whose regulation is intertwined with the activation of apoptotic caspases. Bacterial infection can have more general effects on mitochondrial apoptosis-regulation, through effects on host transcription and other pathways, such as signals controlled by pattern recognition. Some specialized bacteria have products that more specifically regulate signaling to the outer mitochondrial membrane, and to apoptosis; both pro- and anti-apoptotic mechanisms have been reported. Among the intriguing recent findings in this area are signaling contributions of porins and the sub-lethal release of intermembrane constituents. We will here review the literature and place the new developments into the established context of mitochondrial signaling during the contact of bacterial pathogens with human cells.
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Affiliation(s)
- Collins Waguia Kontchou
- Institute of Medical Microbiology and Hygiene, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Georg Häcker
- Institute of Medical Microbiology and Hygiene, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
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4
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Walker E, van Niekerk S, Hanning K, Kelton W, Hicks J. Mechanisms of host manipulation by Neisseria gonorrhoeae. Front Microbiol 2023; 14:1119834. [PMID: 36819065 PMCID: PMC9935845 DOI: 10.3389/fmicb.2023.1119834] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
Neisseria gonorrhoeae (also known as gonococcus) has been causing gonorrhoea in humans since ancient Egyptian times. Today, global gonorrhoea infections are rising at an alarming rate, in concert with an increasing number of antimicrobial-resistant strains. The gonococcus has concurrently evolved several intricate mechanisms that promote pathogenesis by evading both host immunity and defeating common therapeutic interventions. Central to these adaptations is the ability of the gonococcus to manipulate various host microenvironments upon infection. For example, the gonococcus can survive within neutrophils through direct regulation of both the oxidative burst response and maturation of the phagosome; a concerning trait given the important role neutrophils have in defending against invading pathogens. Hence, a detailed understanding of how N. gonorrhoeae exploits the human host to establish and maintain infection is crucial for combating this pathogen. This review summarizes the mechanisms behind host manipulation, with a central focus on the exploitation of host epithelial cell signaling to promote colonization and invasion of the epithelial lining, the modulation of the host immune response to evade both innate and adaptive defenses, and the manipulation of host cell death pathways to both assist colonization and combat antimicrobial activities of innate immune cells. Collectively, these pathways act in concert to enable N. gonorrhoeae to colonize and invade a wide array of host tissues, both establishing and disseminating gonococcal infection.
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Affiliation(s)
- Emma Walker
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand
| | - Stacy van Niekerk
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand
| | - Kyrin Hanning
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand
| | - William Kelton
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand,Te Aka Mātuatua School of Science, University of Waikato, Hamilton, New Zealand
| | - Joanna Hicks
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand,*Correspondence: Joanna Hicks,
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Mahmud SA, Qureshi MA, Pellegrino MW. On the offense and defense: mitochondrial recovery programs amidst targeted pathogenic assault. FEBS J 2022; 289:7014-7037. [PMID: 34270874 PMCID: PMC9192128 DOI: 10.1111/febs.16126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/24/2021] [Accepted: 07/15/2021] [Indexed: 01/13/2023]
Abstract
Bacterial pathogens employ a variety of tactics to persist in their host and promote infection. Pathogens often target host organelles in order to benefit their survival, either through manipulation or subversion of their function. Mitochondria are regularly targeted by bacterial pathogens owing to their diverse cellular roles, including energy production and regulation of programmed cell death. However, disruption of normal mitochondrial function during infection can be detrimental to cell viability because of their essential nature. In response, cells use multiple quality control programs to mitigate mitochondrial dysfunction and promote recovery. In this review, we will provide an overview of mitochondrial recovery programs including mitochondrial dynamics, the mitochondrial unfolded protein response (UPRmt ), and mitophagy. We will then discuss the various approaches used by bacterial pathogens to target mitochondria, which result in mitochondrial dysfunction. Lastly, we will discuss how cells leverage mitochondrial recovery programs beyond their role in organelle repair, to promote host defense against pathogen infection.
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Affiliation(s)
- Siraje A Mahmud
- Department of Biology, University of Texas Arlington, TX, USA
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6
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Kaur D, Verma P, Singh M, Sharma A, Lata K, Mukhopadhaya A, Chattopadhyay K. Pore formation-independent cell death induced by a β-barrel pore-forming toxin. FASEB J 2022; 36:e22557. [PMID: 36125006 DOI: 10.1096/fj.202200788r] [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: 05/21/2022] [Revised: 08/16/2022] [Accepted: 09/06/2022] [Indexed: 11/11/2022]
Abstract
Vibrio cholerae cytolysin (VCC) is a β-barrel pore-forming toxin (β-PFT). It exhibits potent hemolytic activity against erythrocytes that appears to be a direct outcome of its pore-forming functionality. However, VCC-mediated cell-killing mechanism is more complicated in the case of nucleated mammalian cells. It induces apoptosis in the target nucleated cells, mechanistic details of which are still unclear. Furthermore, it has never been explored whether the ability of VCC to trigger programmed cell death is stringently dependent on its pore-forming activity. Here, we show that VCC can evoke hallmark features of the caspase-dependent apoptotic cell death even in the absence of the pore-forming ability. Our study demonstrates that VCC mutants with abortive pore-forming hemolytic activity can trigger apoptotic cell death responses and cytotoxicity, similar to those elicited by the wild-type toxin. VCC as well as its pore formation-deficient mutants display prominent propensity to translocate to the target cell mitochondria and cause mitochondrial membrane damage. Therefore, our results for the first time reveal that VCC, despite being an archetypical β-PFT, can kill target nucleated cells independent of its pore-forming functionality. These findings are intriguing for a β-PFT, whose destination is generally expected to remain limited on the target cell membranes, and whose mode of action is commonly attributed to the membrane-damaging pore-forming ability. Taken together, our study provides critical new insights regarding distinct implications of the two important virulence functionalities of VCC for the V. cholerae pathogenesis process: hemolytic activity for iron acquisition and cytotoxicity for tissue damage by the bacteria.
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Affiliation(s)
- Deepinder Kaur
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India.,Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Pratima Verma
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Mahendra Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Arpita Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Kusum Lata
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Arunika Mukhopadhaya
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
| | - Kausik Chattopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, India
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7
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Abstract
Neisseria gonorrhoeae is an obligate human pathogen that is the cause of the sexually transmitted disease gonorrhoea. Recently, there has been a surge in gonorrhoea cases that has been exacerbated by the rapid rise in gonococcal multidrug resistance to all useful antimicrobials resulting in this organism becoming a significant public health burden. Therefore, there is a clear and present need to understand the organism's biology through its physiology and pathogenesis to help develop new intervention strategies. The gonococcus initially colonises and adheres to host mucosal surfaces utilising a type IV pilus that helps with microcolony formation. Other adhesion strategies include the porin, PorB, and the phase variable outer membrane protein Opa. The gonococcus is able to subvert complement mediated killing and opsonisation by sialylation of its lipooligosaccharide and deploys a series of anti-phagocytic mechanisms. N. gonorrhoeae is a fastidious organism that is able to grow on a limited number of primary carbon sources such as glucose and lactate. The utilization of lactate by the gonococcus has been implicated in a number of pathogenicity mechanisms. The bacterium lives mainly in microaerobic environments and can grow both aerobically and anaerobically with the aid of nitrite. The gonococcus does not produce siderophores for scavenging iron but can utilize some produced by other bacteria, and it is able to successful chelate iron from host haem, transferrin and lactoferrin. The gonococcus is an incredibly versatile human pathogen; in the following chapter, we detail the intricate mechanisms used by the bacterium to invade and survive within the host.
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Affiliation(s)
- Luke R Green
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Joby Cole
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Ernesto Feliz Diaz Parga
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Jonathan G Shaw
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom.
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Sharma A, Yadav SP, Sarma D, Mukhopadhaya A. Modulation of host cellular responses by gram-negative bacterial porins. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 128:35-77. [PMID: 35034723 DOI: 10.1016/bs.apcsb.2021.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The outer membrane of a gram-negative bacteria encapsulates the plasma membrane thereby protecting it from the harsh external environment. This membrane acts as a sieving barrier due to the presence of special membrane-spanning proteins called "porins." These porins are β-barrel channel proteins that allow the passive transport of hydrophilic molecules and are impermeable to large and charged molecules. Many porins form trimers in the outer membrane. They are abundantly present on the bacterial surface and therefore play various significant roles in the host-bacteria interactions. These include the roles of porins in the adhesion and virulence mechanisms necessary for the pathogenesis, along with providing resistance to the bacteria against the antimicrobial substances. They also act as the receptors for phage and complement proteins and are involved in modulating the host cellular responses. In addition, the potential use of porins as adjuvants, vaccine candidates, therapeutic targets, and biomarkers is now being exploited. In this review, we focus briefly on the structure of the porins along with their important functions and roles in the host-bacteria interactions.
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Affiliation(s)
- Arpita Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Shashi Prakash Yadav
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Dwipjyoti Sarma
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Arunika Mukhopadhaya
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India.
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Quarleri J, Cevallos C, Delpino MV. Apoptosis in infectious diseases as a mechanism of immune evasion and survival. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 125:1-24. [PMID: 33931136 DOI: 10.1016/bs.apcsb.2021.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In pluricellular organisms, apoptosis is indispensable for the development and homeostasis. During infection, apoptosis plays the main role in the elimination of infected cells. Infectious diseases control apoptosis, and this contributes to disease pathogenesis. Increased apoptosis may participate in two different ways. It can assist the dissemination of intracellular pathogens or induce immunosuppression to favor pathogen dissemination. In other conditions, apoptosis can benefit eradicate infectious agents from the host. Accordingly, bacteria, viruses, fungi, and parasites have developed strategies to inhibit host cell death by apoptosis to allow intracellular survival and persistence of the pathogen. The clarification of the intracellular signaling pathways, the receptors involved and the pathogen factors that interfere with apoptosis could disclose new therapeutic targets for blocking microbial actions on apoptotic pathways. In this review, we summarize the current knowledge on pathogen anti-apoptotic and apoptotic approaches and the mechanisms involving in disease.
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Affiliation(s)
- Jorge Quarleri
- Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Cintia Cevallos
- Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - María Victoria Delpino
- Instituto de Inmunología, Genética y Metabolismo (INIGEM), Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina.
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Yang T, Heydarian M, Kozjak-Pavlovic V, Urban M, Harbottle RP, Rudel T. Folliculin Controls the Intracellular Survival and Trans-Epithelial Passage of Neisseria gonorrhoeae. Front Cell Infect Microbiol 2020; 10:422. [PMID: 33014885 PMCID: PMC7499807 DOI: 10.3389/fcimb.2020.00422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/08/2020] [Indexed: 12/18/2022] Open
Abstract
Neisseria gonorrhoeae, a Gram-negative obligate human pathogenic bacterium, infects human epithelial cells and causes sexually transmitted diseases. Emerging multi-antibiotic resistant gonococci and increasing numbers of infections complicate the treatment of infected patients. Here, we used an shRNA library screen and next-generation sequencing to identify factors involved in epithelial cell infection. Folliculin (FLCN), a 64 kDa protein with a tumor repressor function was identified as a novel host factor important for N. gonorrhoeae survival after uptake. We further determined that FLCN did not affect N. gonorrhoeae adherence and invasion but was essential for its survival in the cells by modulating autophagy. In addition, FLCN was also required to maintain cell to cell contacts in the epithelial layer. In an infection model with polarized cells, FLCN inhibited the polarized localization of E-cadherin and the transcytosis of gonococci across polarized epithelial cells. In conclusion, we demonstrate here the connection between FLCN and bacterial infection and in particular the role of FLCN in the intracellular survival and transcytosis of gonococci across polarized epithelial cell layers.
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Affiliation(s)
- Tao Yang
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | | | | | - Manuela Urban
- DNA Vector Lab, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | | | - Thomas Rudel
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
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11
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Chen J, Xia L, Wang W, Wang Z, Hou S, Xie C, Cai J, Lu Y. Identification of a mitochondrial-targeting secretory protein from Nocardia seriolae which induces apoptosis in fathead minnow cells. JOURNAL OF FISH DISEASES 2019; 42:1493-1507. [PMID: 31482589 DOI: 10.1111/jfd.13062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 06/10/2023]
Abstract
Nocardia seriolae is the main pathogen responsible for fish nocardiosis. A mitochondrial-targeting secretory protein (MTSP) 3141 with an N-terminal transit peptide (TP) from N. seriolae was predicted by bioinformatic analysis based on the genomic sequence of the N. seriolae strain ZJ0503. However, the function of the MTSP3141 and its homologs remains totally unknown. In this study, mass spectrometry analysis of the extracellular products from N. seriolae proved that MTSP3141 was a secretory protein, subcellular localization research showed the MTSP3141-GFP fusion protein co-localized with mitochondria in fathead minnow (FHM) cells, the TP played an important role in mitochondria targeting, and only the TP located at N-terminus but not C-terminus can lead to mitochondria directing. Moreover, quantitative assays of mitochondrial membrane potential (ΔΨm) value, caspase-3 activity and apoptosis-related gene (Bcl-2, Bax, Bad, Bid and p53) mRNA expression suggested that cell apoptosis was induced in FHM cells by the overexpression of both MTSP3141 and MTSP3141ΔTP (with the N-terminal TP deleted) proteins. Taken together, the results of this study indicated that the MTSP3141 of N. seriolae was a secretory protein, might target mitochondria, induce apoptosis in host cells and function as a virulence factor.
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Affiliation(s)
- Jianlin Chen
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
| | - Liqun Xia
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
| | - Wenji Wang
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
| | - Zhiwen Wang
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
| | - Suying Hou
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
| | - Caixia Xie
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
| | - Jia Cai
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
| | - Yishan Lu
- Shenzhen Institute of Guangdong Ocean University, Shenzhen City, China
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fishery College of Guangdong Ocean University, Zhanjiang City, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen City, China
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12
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Naderer T, Fulcher MC. Targeting apoptosis pathways in infections. J Leukoc Biol 2019; 103:275-285. [PMID: 29372933 DOI: 10.1189/jlb.4mr0717-286r] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/29/2017] [Accepted: 09/13/2017] [Indexed: 11/24/2022] Open
Abstract
The programmed cell death pathway of apoptosis is essential for mammalian development and immunity as it eliminates unwanted and dangerous cells. As part of the cellular immune response, apoptosis removes the replicative niche of intracellular pathogens and enables the resolution of infections. To subvert apoptosis, pathogens have evolved a diverse range of mechanisms. In some circumstances, however, pathogens express effector molecules that induce apoptotic cell death. In this review, we focus on selected host-pathogen interactions that affect apoptotic pathways. We discuss how pathogens control the fate of host cells and how this determines the outcome of infections. Finally, small molecule inhibitors that activate apoptosis in cancer cells can also induce apoptotic cell death of infected cells. This suggests that targeting host death factors to kill infected cells is a potential therapeutic option to treat infectious diseases.
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Affiliation(s)
- Thomas Naderer
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Australia
| | - Maria Cecilia Fulcher
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Australia
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13
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14
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Younas F, Soltanmohammadi N, Knapp O, Benz R. The major outer membrane protein of Legionella pneumophila Lpg1974 shows pore-forming characteristics similar to the human mitochondrial outer membrane pore, hVDAC1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1544-1553. [PMID: 29787733 DOI: 10.1016/j.bbamem.2018.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 10/16/2022]
Abstract
Legionella pneumophila is an aerobic and nonspore-forming pathogenic Gram-negative bacterium of the genus Legionella. It is the causative agent of Legionnaires' disease, also known as Legionellosis. The hosts of this organism are diverse, ranging from simple water borne protozoans such as amoebae to more complex hosts such as macrophages in humans. Genome analyses have shown the presence of genes coding for eukaryotic like proteins in several Legionella species. The presence of these proteins may assist L. pneumophila in its adaptation to the eukaryotic host. We studied the characteristics of a protein (Lpg1974) of L. pneumophila that shows remarkable homologies in length of the primary sequence and for the identity/homology of many amino acids to the voltage dependent anion channel (human VDAC1, Porin 31HL) of human mitochondria. Two different forms of Lpg1974 were overexpressed in Escherichia coli and purified to homogeneity: the one containing a putative N-terminal signal sequence and one without it. Reconstituted protein containing the signal sequence formed ion-permeable pores in lipid bilayer membranes with a conductance of approximately 5.4 nS in 1 M KCl. When the predicted N-terminal signal peptide of Lpg1974 comprising an α-helical structure similar to that at the N-terminus of hVDAC1 was removed, the channels formed in reconstitution experiments had a conductance of 7.6 nS in 1 M KCl. Both Lpg1974 proteins formed pores that were voltage-dependent and anion-selective similar to the pores formed by hVDAC1. These results suggest that Lpg1974 of L. pneumophila is indeed a structural and functional homologue to hVDAC1.
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Affiliation(s)
- Farhan Younas
- Department of Life Sciences and Chemistry, Jacobs University, Campusring 1, 28759 Bremen, Germany
| | - Nafiseh Soltanmohammadi
- Department of Life Sciences and Chemistry, Jacobs University, Campusring 1, 28759 Bremen, Germany
| | - Oliver Knapp
- Department of Life Sciences and Chemistry, Jacobs University, Campusring 1, 28759 Bremen, Germany
| | - Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University, Campusring 1, 28759 Bremen, Germany.
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15
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Deo P, Chow SH, Hay ID, Kleifeld O, Costin A, Elgass KD, Jiang JH, Ramm G, Gabriel K, Dougan G, Lithgow T, Heinz E, Naderer T. Outer membrane vesicles from Neisseria gonorrhoeae target PorB to mitochondria and induce apoptosis. PLoS Pathog 2018; 14:e1006945. [PMID: 29601598 PMCID: PMC5877877 DOI: 10.1371/journal.ppat.1006945] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 02/21/2018] [Indexed: 01/31/2023] Open
Abstract
Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhoea by evading innate immunity. Colonizing the mucosa of the reproductive tract depends on the bacterial outer membrane porin, PorB, which is essential for ion and nutrient uptake. PorB is also targeted to host mitochondria and regulates apoptosis pathways to promote infections. How PorB traffics from the outer membrane of N. gonorrhoeae to mitochondria and whether it modulates innate immune cells, such as macrophages, remains unclear. Here, we show that N. gonorrhoeae secretes PorB via outer membrane vesicles (OMVs). Purified OMVs contained primarily outer membrane proteins including oligomeric PorB. The porin was targeted to mitochondria of macrophages after exposure to purified OMVs and wild type N. gonorrhoeae. This was associated with loss of mitochondrial membrane potential, release of cytochrome c, activation of apoptotic caspases and cell death in a time-dependent manner. Consistent with this, OMV-induced macrophage death was prevented with the pan-caspase inhibitor, Q-VD-PH. This shows that N. gonorrhoeae utilizes OMVs to target PorB to mitochondria and to induce apoptosis in macrophages, thus affecting innate immunity. Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhoea in more than 100 million people worldwide every year. The bacteria replicate in the reproductive tract by evading innate and adaptive immunity. In the absence of effective vaccines and the rise of antibiotic resistance, understanding the molecular interactions between innate immune cells and N. gonorrhoeae may lead to new strategies to combat bacterial growth and the symptoms of gonorrhoea. It has long been known that the N. gonorrhoeae porin, PorB, promotes bacterial survival but also targets host mitochondria in infections. The mechanism by which PorB traffics form the bacterial outer membrane to host mitochondria remains unclear. Here, we utilized proteomics and super-resolution microscopy to show that N. gonorrhoeae secretes PorB via outer membrane vesicles. These vesicles are taken up by macrophages and deliver PorB to mitochondria. Macrophages treated with N. gonorrhoeae vesicles contained damaged mitochondria and active caspase-3. A caspase inhibitor prevented apoptosis of macrophages treated with N. gonorrhoeae vesicles. This suggests that N. gonorrhoeae secretes membrane vesicles, which are readily detectable in gonorrhoea patients, to target macrophages and to promote infections.
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Affiliation(s)
- Pankaj Deo
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Seong H Chow
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Iain D Hay
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Oded Kleifeld
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Adam Costin
- Monash Ramaciotti Centre for Cryo Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Kirstin D Elgass
- Monash Micro Imaging, Monash University, Clayton, Victoria, Australia
| | - Jhih-Hang Jiang
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Georg Ramm
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia.,Monash Ramaciotti Centre for Cryo Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Kipros Gabriel
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Gordon Dougan
- Infection Genomics Program, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Trevor Lithgow
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Eva Heinz
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia.,Infection Genomics Program, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Thomas Naderer
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
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16
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Chaturvedi D, Mahalakshmi R. Transmembrane β-barrels: Evolution, folding and energetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2467-2482. [PMID: 28943271 DOI: 10.1016/j.bbamem.2017.09.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/23/2022]
Abstract
The biogenesis of transmembrane β-barrels (outer membrane proteins, or OMPs) is an elaborate multistep orchestration of the nascent polypeptide with translocases, barrel assembly machinery, and helper chaperone proteins. Several theories exist that describe the mechanism of chaperone-assisted OMP assembly in vivo and unassisted (spontaneous) folding in vitro. Structurally, OMPs of bacterial origin possess even-numbered strands, while mitochondrial β-barrels are even- and odd-stranded. Several underlying similarities between prokaryotic and eukaryotic β-barrels and their folding machinery are known; yet, the link in their evolutionary origin is unclear. While OMPs exhibit diversity in sequence and function, they share similar biophysical attributes and structure. Similarly, it is important to understand the intricate OMP assembly mechanism, particularly in eukaryotic β-barrels that have evolved to perform more complex functions. Here, we deliberate known facets of β-barrel evolution, folding, and stability, and attempt to highlight outstanding questions in β-barrel biogenesis and proteostasis.
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Affiliation(s)
- Deepti Chaturvedi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
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17
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Affiliation(s)
- Tobias Jores
- Interfaculty Institute of Biochemistry; University of Tuebingen; Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry; University of Tuebingen; Germany
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18
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Hill SA, Masters TL, Wachter J. Gonorrhea - an evolving disease of the new millennium. MICROBIAL CELL (GRAZ, AUSTRIA) 2016; 3:371-389. [PMID: 28357376 PMCID: PMC5354566 DOI: 10.15698/mic2016.09.524] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/30/2016] [Indexed: 12/21/2022]
Abstract
Etiology, transmission and protection: Neisseria gonorrhoeae (the gonococcus) is the etiological agent for the strictly human sexually transmitted disease gonorrhea. Infections lead to limited immunity, therefore individuals can become repeatedly infected. Pathology/symptomatology: Gonorrhea is generally a non-complicated mucosal infection with a pustular discharge. More severe sequellae include salpingitis and pelvic inflammatory disease which may lead to sterility and/or ectopic pregnancy. Occasionally, the organism can disseminate as a bloodstream infection. Epidemiology, incidence and prevalence: Gonorrhea is a global disease infecting approximately 60 million people annually. In the United States there are approximately 300, 000 cases each year, with an incidence of approximately 100 cases per 100,000 population. Treatment and curability: Gonorrhea is susceptible to an array of antibiotics. Antibiotic resistance is becoming a major problem and there are fears that the gonococcus will become the next "superbug" as the antibiotic arsenal diminishes. Currently, third generation extended-spectrum cephalosporins are being prescribed. Molecular mechanisms of infection: Gonococci elaborate numerous strategies to thwart the immune system. The organism engages in extensive phase (on/off switching) and antigenic variation of several surface antigens. The organism expresses IgA protease which cleaves mucosal antibody. The organism can become serum resistant due to its ability to sialylate lipooligosaccharide in conjunction with its ability to subvert complement activation. The gonococcus can survive within neutrophils as well as in several other lymphocytic cells. The organism manipulates the immune response such that no immune memory is generated which leads to a lack of protective immunity.
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Affiliation(s)
- Stuart A. Hill
- Department of Epidemiology, Gillings School of Global Public Health,
University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435
| | - Thao L. Masters
- Department of Epidemiology, Gillings School of Global Public Health,
University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435
| | - Jenny Wachter
- Department of Epidemiology, Gillings School of Global Public Health,
University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435
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19
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Fielden LF, Kang Y, Newton HJ, Stojanovski D. Targeting mitochondria: how intravacuolar bacterial pathogens manipulate mitochondria. Cell Tissue Res 2016; 367:141-154. [PMID: 27515462 DOI: 10.1007/s00441-016-2475-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 07/07/2016] [Indexed: 02/07/2023]
Abstract
Manipulation of host cell function by bacterial pathogens is paramount for successful invasion and creation of a niche conducive to bacterial replication. Mitochondria play a role in many important cellular processes including energy production, cellular calcium homeostasis, lipid metabolism, haeme biosynthesis, immune signalling and apoptosis. The sophisticated integration of host cell processes by the mitochondrion have seen it emerge as a key target during bacterial infection of human host cells. This review highlights the targeting and interaction of this dynamic organelle by intravacuolar bacterial pathogens and the way that the modulation of mitochondrial function might contribute to pathogenesis.
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Affiliation(s)
- Laura F Fielden
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Yilin Kang
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, 3000, Australia.
| | - Diana Stojanovski
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia.
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20
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Peak IR, Chen A, Jen FEC, Jennings C, Schulz BL, Saunders NJ, Khan A, Seifert HS, Jennings MP. Neisseria meningitidis Lacking the Major Porins PorA and PorB Is Viable and Modulates Apoptosis and the Oxidative Burst of Neutrophils. J Proteome Res 2016; 15:2356-65. [PMID: 26562068 DOI: 10.1021/acs.jproteome.5b00938] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The bacterial pathogen Neisseria meningitidis expresses two major outer-membrane porins. PorA expression is subject to phase-variation (high frequency, random, on-off switching), and both PorA and PorB are antigenically variable between strains. PorA expression is variable and not correlated with meningococcal colonisation or invasive disease, whereas all naturally-occurring strains express PorB suggesting strong selection for expression. We have generated N. meningitidis strains lacking expression of both major porins, demonstrating that they are dispensable for bacterial growth in vitro. The porAB mutant strain has an exponential growth rate similar to the parental strain, as do the single porA or porB mutants, but the porAB mutant strain does not reach the same cell density in stationary phase. Proteomic analysis suggests that the double mutant strain exhibits compensatory expression changes in proteins associated with cellular redox state, energy/nutrient metabolism, and membrane stability. On solid media, there is obvious growth impairment that is rescued by addition of blood or serum from mammalian species, particularly heme. These porin mutants are not impaired in their capacity to inhibit both staurosporine-induced apoptosis and a phorbol 12-myristate 13-acetate-induced oxidative burst in human neutrophils suggesting that the porins are not the only bacterial factors that can modulate these processes in host cells.
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Affiliation(s)
- Ian R Peak
- School of Medical Science, Gold Coast Campus, Griffith University , Southport, QLD 4222, Australia.,Institute for Glycomics, Gold Coast Campus, Griffith University , Southport, QLD 4222, Australia
| | - Adrienne Chen
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University , 303 East Chicago Avenue, Chicago, Illinois 60611, United States
| | - Freda E-C Jen
- Institute for Glycomics, Gold Coast Campus, Griffith University , Southport, QLD 4222, Australia
| | - Courtney Jennings
- Institute for Glycomics, Gold Coast Campus, Griffith University , Southport, QLD 4222, Australia
| | - Benjamin L Schulz
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland , St. Lucia, Brisbane, QLD 4072, Australia
| | - Nigel J Saunders
- Centre for Systems and Synthetic Biology, Brunel University , Uxbridge, Middlesex UB8 3PH, U.K
| | - Arshad Khan
- Centre for Systems and Synthetic Biology, Brunel University , Uxbridge, Middlesex UB8 3PH, U.K
| | - H Steven Seifert
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University , 303 East Chicago Avenue, Chicago, Illinois 60611, United States
| | - Michael P Jennings
- Institute for Glycomics, Gold Coast Campus, Griffith University , Southport, QLD 4222, Australia
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21
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Kummer A, Nishanth G, Koschel J, Klawonn F, Schlüter D, Jänsch L. Listeriosis downregulates hepatic cytochrome P450 enzymes in sublethal murine infection. Proteomics Clin Appl 2016; 10:1025-1035. [PMID: 27273978 DOI: 10.1002/prca.201600030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/11/2016] [Accepted: 06/01/2016] [Indexed: 11/08/2022]
Abstract
PURPOSE Listeria monocytogenes (Lm) can cross the intestinal barrier in humans and then disseminates into different organs. Invasion of the liver occurs even in sublethal infections, however, knowledge of affected physiological processes is scarce. This study employed a sublethal murine infection model to investigate liver responses systematically by proteomics. EXPERIMENTAL DESIGN Liver samples from three stages of the sublethal infection covering the initial invasion, the peak of infection, and the clearance phase (1, 3, 9 days postinoculation) were analyzed in comparison to samples from noninfected mice. Apart from flow cytometry and RT-PCRs for immune status control, liver responses were analyzed by quantitative peptide sequencing (HPLC-Orbitrap Fusion) using 4-plex iTRAQ-labeling. RESULTS Accurate MS characterized about 3600 proteins and statistics revealed 15% of the hepatic proteome as regulated. Immunological data as well as protein regulation dynamics strongly indicate stage-specific hepatic responses in sublethal infections. Most notably, this study detected a comprehensive deregulation of drug metabolizing enzymes at all stages, including 25 components of the cytochrome P450 system. CONCLUSIONS AND CLINICAL RELEVANCE Sublethal Lm infection deregulates hepatic drug metabolizing pathways. This finding indicates the need to monitor drug administration along Lm infections, especially in all patients needing constant medication.
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Affiliation(s)
- Anne Kummer
- Cellular Proteomics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Gopala Nishanth
- Otto-von-Guericke University, Magdeburg, Germany.,Organ-specific Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Frank Klawonn
- Cellular Proteomics, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Department of Computer Science, Ostfalia University of Applied Sciences, Wolfenbüttel, Germany
| | - Dirk Schlüter
- Otto-von-Guericke University, Magdeburg, Germany.,Organ-specific Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Lothar Jänsch
- Cellular Proteomics, Helmholtz Centre for Infection Research, Braunschweig, Germany.
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22
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Rana A, Kumar D, Rub A, Akhter Y. Proteome-scale identification and characterization of mitochondria targeting proteins of Mycobacterium avium subspecies paratuberculosis: Potential virulence factors modulating host mitochondrial function. Mitochondrion 2015; 23:42-54. [PMID: 26048556 DOI: 10.1016/j.mito.2015.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/21/2015] [Accepted: 05/04/2015] [Indexed: 02/03/2023]
Abstract
Mycobacterium avium subsp. paratuberculosis is the etiological agent of Johne's Disease among ruminants. During the course of infection, it expresses a number of proteins for its successful persistence inside the host that cause variety of physiological abnormalities in the host. Mitochondrion is one of the attractive targets for pathogenic bacteria. Employing a proteome-wide sequence and structural signature based approach we have identified 46 M. avium subsp. paratuberculosis proteins as potential targets for the host mitochondrial targeting. These may act as virulence factors modulating mitochondrial physiology for bacterial survival and immune evasion inside the host cells.
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Affiliation(s)
- Aarti Rana
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, 176206 Himachal Pradesh, India
| | - Devender Kumar
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, 176206 Himachal Pradesh, India
| | - Abdur Rub
- Infection and Immunity Lab, Department of Biotechnology, Jamia Millia Islamia (A Central University), New Delhi 110025, India
| | - Yusuf Akhter
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, 176206 Himachal Pradesh, India.
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23
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Höhr AIC, Straub SP, Warscheid B, Becker T, Wiedemann N. Assembly of β-barrel proteins in the mitochondrial outer membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:74-88. [PMID: 25305573 DOI: 10.1016/j.bbamcr.2014.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 09/25/2014] [Accepted: 10/01/2014] [Indexed: 12/15/2022]
Abstract
Mitochondria evolved through endosymbiosis of a Gram-negative progenitor with a host cell to generate eukaryotes. Therefore, the outer membrane of mitochondria and Gram-negative bacteria contain pore proteins with β-barrel topology. After synthesis in the cytosol, β-barrel precursor proteins are first transported into the mitochondrial intermembrane space. Folding and membrane integration of β-barrel proteins depend on the mitochondrial sorting and assembly machinery (SAM) located in the outer membrane, which is related to the β-barrel assembly machinery (BAM) in bacteria. The SAM complex recognizes β-barrel proteins by a β-signal in the C-terminal β-strand that is required to initiate β-barrel protein insertion into the outer membrane. In addition, the SAM complex is crucial to form membrane contacts with the inner mitochondrial membrane by interacting with the mitochondrial contact site and cristae organizing system (MICOS) and shares a subunit with the endoplasmic reticulum-mitochondria encounter structure (ERMES) that links the outer mitochondrial membrane to the endoplasmic reticulum (ER).
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Affiliation(s)
- Alexandra I C Höhr
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany
| | - Sebastian P Straub
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany
| | - Bettina Warscheid
- BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany; Abteilung Biochemie und Funktionelle Proteomik, Institut für Biologie II, Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany
| | - Thomas Becker
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany
| | - Nils Wiedemann
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany.
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24
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Ulrich T, Oberhettinger P, Schütz M, Holzer K, Ramms AS, Linke D, Autenrieth IB, Rapaport D. Evolutionary conservation in biogenesis of β-barrel proteins allows mitochondria to assemble a functional bacterial trimeric autotransporter protein. J Biol Chem 2014; 289:29457-70. [PMID: 25190806 DOI: 10.1074/jbc.m114.565655] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Yersinia adhesin A (YadA) belongs to a class of bacterial adhesins that form trimeric structures. Their mature form contains a passenger domain and a C-terminal β-domain that anchors the protein in the outer membrane (OM). Little is known about how precursors of such proteins cross the periplasm and assemble into the OM. In the present study we took advantage of the evolutionary conservation in the biogenesis of β-barrel proteins between bacteria and mitochondria. We previously observed that upon expression in yeast cells, bacterial β-barrel proteins including the transmembrane domain of YadA assemble into the mitochondrial OM. In the current study we found that when expressed in yeast cells both the monomeric and trimeric forms of full-length YadA were detected in mitochondria but only the trimeric species was fully integrated into the OM. The oligomeric form was exposed on the surface of the organelle in its native conformation and maintained its capacity to adhere to host cells. The co-expression of YadA with a mitochondria-targeted form of the bacterial periplasmic chaperone Skp, but not with SurA or SecB, resulted in enhanced levels of both forms of YadA. Taken together, these results indicate that the proper assembly of trimeric autotransporter can occur also in a system lacking the lipoproteins of the BAM machinery and is specifically enhanced by the chaperone Skp.
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Affiliation(s)
- Thomas Ulrich
- From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Philipp Oberhettinger
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany, and
| | - Monika Schütz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany, and
| | - Katharina Holzer
- From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Anne S Ramms
- From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Dirk Linke
- Department of Protein Evolution, Max-Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Ingo B Autenrieth
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany, and
| | - Doron Rapaport
- From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany,
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25
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Saturating mutagenesis of an essential gene: a majority of the Neisseria gonorrhoeae major outer membrane porin (PorB) is mutable. J Bacteriol 2013; 196:540-7. [PMID: 24244002 DOI: 10.1128/jb.01073-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The major outer membrane porin (PorB) of Neisseria gonorrhoeae is an essential protein that mediates ion exchange between the organism and its environment and also plays multiple roles in human host pathogenesis. To facilitate structure-function studies of porin's multiple roles, we performed saturating mutagenesis at the porB locus and used deep sequencing to identify essential versus mutable residues. Random mutations in porB were generated in a plasmid vector, and mutant gene pools were transformed into N. gonorrhoeae to select for alleles that maintained bacterial viability. Deep sequencing of the input plasmid pools and the output N. gonorrhoeae genomic DNA pools identified mutations present in each, and the mutations in both pools were compared to determine which changes could be tolerated by the organism. We examined the mutability of 328 amino acids in the mature PorB protein and found that 308 of them were likely to be mutable and that 20 amino acids were likely to be nonmutable. A subset of these predictions was validated experimentally. This approach to identifying essential amino acids in a protein of interest introduces an additional application for next-generation sequencing technology and provides a template for future studies of both porin and other essential bacterial genes.
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26
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Structure-function studies of the Neisseria gonorrhoeae major outer membrane porin. Infect Immun 2013; 81:4383-91. [PMID: 24042111 DOI: 10.1128/iai.00367-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The major outer membrane porin (PorB) expressed by Neisseria gonorrhoeae plays multiple roles during infection, in addition to its function as an outer membrane pore. We have generated a panel of mutants of N. gonorrhoeae strain FA1090 expressing a variety of mutant porB genes that all function as porins. We identified multiple regions of porin that are involved in its binding to the complement regulatory factors C4b-binding protein and factor H and confirmed that the ability to bind at least one factor is required for FA1090 to survive the bactericidal effects of human serum. We tested the ability of these mutants to inhibit both apoptosis and the oxidative burst in polymorphonuclear leukocytes but were unable to identify the porin domains required for either function. This study has identified nonessential porin domains and some potentially essential portions of the protein and has further expanded our understanding of the contribution of the porin domains required for complement regulation.
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27
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Abstract
The outer membrane of Gram-negative bacteria contains a large number of channel-forming proteins, porins, for the uptake of small nutrient molecules. Neisseria gonorrhoeae PorBIA (PorB of serotype A) are associated with disseminating diseases and mediate a rapid bacterial invasion into host cells in a phosphate-sensitive manner. To gain insights into this structure-function relationship we analysed PorBIA by X-ray crystallography in the presence of phosphate and ATP. The structure of PorBIA in the complex solved at a resolution of 3.3 Å (1 Å=0.1 nm) displays a surplus of positive charges inside the channel. ATP ligand-binding in the channel is co-ordinated by the positively charged residues of the channel interior. These residues ligate the aromatic, sugar and pyrophosphate moieties of the ligand. Two phosphate ions were observed in the structure, one of which clamped by two arginine residues (Arg92 and Arg124) localized at the extraplasmic channel exit. A short β-bulge in β2-strand together with the long L3 loop narrow the barrel diameter significantly and further support substrate specificity through hydrogen bond interactions. Interestingly the structure also comprised a small peptide as a remnant of a periplasmic protein which physically links porin molecules to the peptidoglycan network. To test the importance of Arg92 on bacterial invasion the residue was mutated. In vivo assays of bacteria carrying a R92S mutation confirmed the importance of this residue for host-cell invasion. Furthermore systematic sequence and structure comparisons of PorBIA from Neisseriaceae indicated Arg92 to be unique in disseminating N. gonorrhoeae thereby possibly distinguishing invasion-promoting porins from other neisserial porins.
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Kattner C, Zaucha J, Jaenecke F, Zachariae U, Tanabe M. Identification of a cation transport pathway in Neisseria meningitidis PorB. Proteins 2013; 81:830-40. [PMID: 23255122 DOI: 10.1002/prot.24241] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/06/2012] [Accepted: 12/08/2012] [Indexed: 11/10/2022]
Abstract
Neisseria meningitidis is the main causative agent of bacterial meningitis. In its outer membrane, the trimeric Neisserial porin PorB is responsible for the diffusive transport of essential hydrophilic solutes across the bilayer. Previous molecular dynamics simulations based on the recent crystal structure of PorB have suggested the presence of distinct solute translocation pathways through this channel. Although PorB has been electrophysiologically characterized as anion-selective, cation translocation through nucleotide-bound PorB during pathogenesis is thought to be instrumental for host cell death. As a result, we were particularly interested in further characterizing cation transport through the pore. We combined a structural approach with additional computational analysis. Here, we present two crystal structures of PorB at 2.1 and 2.65 Å resolution. The new structures display additional electron densities around the protruding loop 3 (L3) inside the pore. We show that these electron densities can be identified as monovalent cations, in our case Cs(+), which are tightly bound to the inner channel. Molecular dynamics simulations reveal further ion interactions and the free energy landscape for ions inside PorB. Our results suggest that the crystallographically identified locations of Cs(+) form a cation transport pathway inside the pore. This finding suggests how positively charged ions are translocated through PorB when the channel is inserted into mitochondrial membranes during Neisserial infection, a process which is considered to dissipate the mitochondrial transmembrane potential gradient and thereby induce apoptosis.
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Affiliation(s)
- Christof Kattner
- HALOmem, Institut für Biochemie und Biotechnologie, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
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Ulrich T, Gross LE, Sommer MS, Schleiff E, Rapaport D. Chloroplast β-barrel proteins are assembled into the mitochondrial outer membrane in a process that depends on the TOM and TOB complexes. J Biol Chem 2012; 287:27467-79. [PMID: 22745120 PMCID: PMC3431683 DOI: 10.1074/jbc.m112.382093] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/27/2012] [Indexed: 11/06/2022] Open
Abstract
Membrane-embedded β-barrel proteins are found in the outer membranes (OM) of Gram-negative bacteria, mitochondria and chloroplasts. In eukaryotic cells, precursors of these proteins are synthesized in the cytosol and have to be sorted to their corresponding organelle. Currently, the signal that ensures their specific targeting to either mitochondria or chloroplasts is ill-defined. To address this issue, we studied targeting of the chloroplast β-barrel proteins Oep37 and Oep24. We found that both proteins can be integrated in vitro into isolated plant mitochondria. Furthermore, upon their expression in yeast cells Oep37 and Oep24 were exclusively located in the mitochondrial OM. Oep37 partially complemented the growth phenotype of yeast cells lacking Porin, the general metabolite transporter of this membrane. Similarly to mitochondrial β-barrel proteins, Oep37 and Oep24 expressed in yeast cells were assembled into the mitochondrial OM in a pathway dependent on the TOM and TOB complexes. Taken together, this study demonstrates that the central mitochondrial components that mediate the import of yeast β-barrel proteins can deal with precursors of chloroplast β-barrel proteins. This implies that the mitochondrial import machinery does not recognize signals that are unique to mitochondrial β-barrel proteins. Our results further suggest that dedicated targeting factors had to evolve in plant cells to prevent mis-sorting of chloroplast β-barrel proteins to mitochondria.
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Affiliation(s)
- Thomas Ulrich
- From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen and
| | - Lucia E. Gross
- the Centre of Membrane Proteomics and Cluster of Excellence Frankfurt, Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, D-60438 Frankfurt, Germany
| | - Maik S. Sommer
- the Centre of Membrane Proteomics and Cluster of Excellence Frankfurt, Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, D-60438 Frankfurt, Germany
| | - Enrico Schleiff
- the Centre of Membrane Proteomics and Cluster of Excellence Frankfurt, Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, D-60438 Frankfurt, Germany
| | - Doron Rapaport
- From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen and
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From evolution to pathogenesis: the link between β-barrel assembly machineries in the outer membrane of mitochondria and gram-negative bacteria. Int J Mol Sci 2012; 13:8038-8050. [PMID: 22942688 PMCID: PMC3430219 DOI: 10.3390/ijms13078038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/21/2012] [Accepted: 06/21/2012] [Indexed: 01/29/2023] Open
Abstract
β-barrel proteins are the highly abundant in the outer membranes of Gram-negative bacteria and the mitochondria in eukaryotes. The assembly of β-barrels is mediated by two evolutionary conserved machineries; the β-barrel Assembly Machinery (BAM) in Gram-negative bacteria; and the Sorting and Assembly Machinery (SAM) in mitochondria. Although the BAM and SAM have functionally conserved roles in the membrane integration and folding of β-barrel proteins, apart from the central BamA and Sam50 proteins, the remaining components of each of the complexes have diverged remarkably. For example all of the accessory components of the BAM complex characterized to date are located in the bacterial periplasm, on the same side as the N-terminal domain of BamA. This is the same side of the membrane as the substrates that are delivered to the BAM. On the other hand, all of the accessory components of the SAM complex are located on the cytosolic side of the membrane, the opposite side of the membrane to the N-terminus of Sam50 and the substrate receiving side of the membrane. Despite the accessory subunits being located on opposite sides of the membrane in each system, it is clear that each system is functionally equivalent with bacterial proteins having the ability to use the eukaryotic SAM and vice versa. In this review, we summarize the similarities and differences between the BAM and SAM complexes, highlighting the possible selecting pressures on bacteria and eukaryotes during evolution. It is also now emerging that bacterial pathogens utilize the SAM to target toxins and effector proteins to host mitochondria and this will also be discussed from an evolutionary perspective.
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Jiang JH, Tong J, Gabriel K. Hijacking Mitochondria: Bacterial Toxins that Modulate Mitochondrial Function. IUBMB Life 2012; 64:397-401. [DOI: 10.1002/iub.1021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Massari P, Wetzler LM. Analysis of parameters associated with prevention of cellular apoptosis by pathogenic Neisseriae and purified porins. Methods Mol Biol 2012; 799:319-41. [PMID: 21993654 DOI: 10.1007/978-1-61779-346-2_19] [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] [Indexed: 06/19/2024]
Abstract
The process of cellular apoptosis is mediated by a number of microbial pathogens to modulate host defense mechanisms. Inhibition of apoptosis is thought to favor microbial survival, replication or immune evasion, while induction of apoptosis is likely to promote escape of the organisms from host cells. Several studies have reported that infection with Neisseria spp. can inhibit or reduce apoptotic cell death, thus allowing adaptation, intracellular replication, and immune evasion, events that are likely to spread infection. In this chapter, various techniques are described for direct measurement of host cell responses to infection with Neisseria meningitidis and to treatment with pure Neisseria porins, the major proteins found in the outer membrane of the pathogen.
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Affiliation(s)
- Paola Massari
- Department of Medicine, Evans BioMedical Research Center, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, USA.
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Jiang JH, Davies JK, Lithgow T, Strugnell RA, Gabriel K. Targeting of Neisserial PorB to the mitochondrial outer membrane: an insight on the evolution of β-barrel protein assembly machines. Mol Microbiol 2011; 82:976-87. [DOI: 10.1111/j.1365-2958.2011.07880.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Neisseria gonorrhoeae-mediated inhibition of apoptotic signalling in polymorphonuclear leukocytes. Infect Immun 2011; 79:4447-58. [PMID: 21844239 DOI: 10.1128/iai.01267-10] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The human pathogen Neisseria gonorrhoeae recruits and interacts extensively with polymorphonuclear leukocytes (PMNs) during infection. N. gonorrhoeae is able to survive the bactericidal activity of these innate immune cells and can actively modulate PMN functions in vitro. PMNs are short-lived cells which readily undergo apoptosis, and thus the effect of N. gonorrhoeae infection on PMN survival has implications for whether PMNs might serve as an important site of bacterial replication during infection. We developed and validated an HL-60 myeloid leukemia cell culture model for PMN infection and used both these cells and primary PMNs to show that N. gonorrhoeae infection alone does not induce apoptosis and furthermore that N. gonorrhoeae can inhibit both spontaneous apoptosis and apoptosis induced by the intrinsic and extrinsic apoptosis inducers staurosporine (STS) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), respectively. N. gonorrhoeae infection also results in the activation of NF-κB signaling in neutrophils and induces secretion of an identical profile of proinflammatory cytokines and chemokines in both HL-60 cells and primary PMNs. Our data show that the HL-60 cell line can be used to effectively model N. gonorrhoeae-PMN interactions and that N. gonorrhoeae actively inhibits apoptosis induced by multiple stimuli to prolong PMN survival and potentially facilitate bacterial survival, replication, and transmission.
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Kozjak-Pavlovic V, Ott C, Götz M, Rudel T. Neisserial Omp85 protein is selectively recognized and assembled into functional complexes in the outer membrane of human mitochondria. J Biol Chem 2011; 286:27019-26. [PMID: 21652692 DOI: 10.1074/jbc.m111.232249] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
As a consequence of their bacterial origin, mitochondria contain β-barrel proteins in their outer membrane (OMM). These proteins require the translocase of the outer membrane (TOM) complex and the conserved sorting and assembly machinery (SAM) complex for transport and integration into the OMM. The SAM complex and the β-barrel assembly machinery (BAM) required for biogenesis of β-barrel proteins in bacteria are evolutionarily related. Despite this homology, we show that bacterial β-barrel proteins are not universally recognized and integrated into the OMM of human mitochondria. Selectivity exists both at the level of the TOM and the SAM complex. Of all of the proteins we tested, human mitochondria imported only β-barrel proteins originating from Neisseria sp., and only Omp85, the central component of the neisserial BAM complex, integrated into the OMM. PorB proteins from different Neisseria, although imported by the TOM, were not recognized by the SAM complex and formed membrane complexes only when functional Omp85 was present at the same time in mitochondria. Omp85 alone was capable of integrating other bacterial β-barrel proteins in human mitochondria, but could not substitute for the function of its mitochondrial homolog Sam50. Thus, signals and machineries for transport and assembly of β-barrel proteins in bacteria and human mitochondria differ enough to allow only a certain type of β-barrel proteins to be targeted and integrated in mitochondrial membranes in human cells.
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Affiliation(s)
- Vera Kozjak-Pavlovic
- Biozentrum, Department of Microbiology, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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Cadieux N, Parra M, Cohen H, Maric D, Morris SL, Brennan MJ. Induction of cell death after localization to the host cell mitochondria by the Mycobacterium tuberculosis PE_PGRS33 protein. MICROBIOLOGY-SGM 2010; 157:793-804. [PMID: 21081760 DOI: 10.1099/mic.0.041996-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PE_PGRS33 is the most studied member of the unique PE family of mycobacterial proteins. These proteins are composed of a PE domain (Pro-Glu motif), a linker region and a PGRS domain (polymorphic GC-rich-repetitive sequence). Previous studies have shown that PE_PGRS33 is surface-exposed, constitutively expressed during growth and infection, involved in creating antigenic diversity, and able to induce death in transfected or infected eukaryotic cells. In this study, we showed that PE_PGRS33 co-localizes to the mitochondria of transfected cells, a phenomenon dependent on the linker region and the PGRS domain, but not the PE domain. Using different genetic fusions and chimeras, we also demonstrated a direct correlation between localization to the host mitochondria and the induction of cell death. Finally, although all constructs localizing to the mitochondria did induce apoptosis, only the wild-type PE_PGRS33 with its own PE domain also induced primary necrosis, indicating a potentially important role for the PE domain. Considering the importance of primary necrosis in Mycobacterium tuberculosis dissemination during natural infection, the PE_PGRS33 protein may play a crucial role in the pathogenesis of tuberculosis.
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Affiliation(s)
- Nathalie Cadieux
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA
| | - Marcela Parra
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA
| | - Hannah Cohen
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA
| | - Dragan Maric
- National Institute of Neurological Disorders and Stroke, Flow Cytometry Core Facility, NIH, Bethesda, MD, USA
| | - Sheldon L Morris
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA
| | - Michael J Brennan
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA
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Abstract
Gram-negative bacteria and mitochondria are both covered by two distinct biological membranes. These membrane systems have been maintained during the course of evolution from an early evolutionary precursor. Both outer membranes accommodate channels of the porin family, which are designed for the uptake and exchange of metabolites, including ions and small molecules, such as nucleosides or sugars. In bacteria, the structure of the outer membrane porin protein family of β-barrels is generally characterized by an even number of β-strands; usually 14, 16 or 18 strands are observed forming the bacterial porin barrel wall. In contrast, the recent structures of the mitochondrial porin, also known as VDAC (voltage-dependent anion channel), show an uneven number of 19 β-strands, but a similar molecular architecture. Despite the lack of a clear evolutionary link between these protein families, their common principles and differences in assembly, architecture and function are summarized in the present review.
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Structural basis for solute transport, nucleotide regulation, and immunological recognition of Neisseria meningitidis PorB. Proc Natl Acad Sci U S A 2010; 107:6811-6. [PMID: 20351243 DOI: 10.1073/pnas.0912115107] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PorB is the second most prevalent outer membrane protein in Neisseria meningitidis. PorB is required for neisserial pathogenesis and can elicit a Toll-like receptor mediated host immune response. Here, the x-ray crystal structure of PorB has been determined to 2.3 A resolution. Structural analysis and cocrystallization studies identify three putative solute translocation pathways through the channel pore: One pathway transports anions nonselectively, one transports cations nonselectively, and one facilitates the specific uptake of sugars. During infection, PorB likely binds host mitochondrial ATP, and cocrystallization with the ATP analog AMP-PNP suggests that binding of nucleotides regulates these translocation pathways both by partial occlusion of the pore and by restricting the motion of a putative voltage gating loop. PorB is located on the surface of N. meningitidis and can be recognized by receptors of the host innate immune system. Features of PorB suggest that Toll-like receptor mediated recognition outer membrane proteins may be initiated with a nonspecific electrostatic attraction.
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Sukumaran SK, Fu NY, Tin CB, Wan KF, Lee SS, Yu VC. A Soluble Form of the Pilus Protein FimA Targets the VDAC-Hexokinase Complex at Mitochondria to Suppress Host Cell Apoptosis. Mol Cell 2010; 37:768-83. [DOI: 10.1016/j.molcel.2010.02.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 10/28/2009] [Accepted: 12/24/2009] [Indexed: 11/16/2022]
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Niu H, Kozjak-Pavlovic V, Rudel T, Rikihisa Y. Anaplasma phagocytophilum Ats-1 is imported into host cell mitochondria and interferes with apoptosis induction. PLoS Pathog 2010; 6:e1000774. [PMID: 20174550 PMCID: PMC2824752 DOI: 10.1371/journal.ppat.1000774] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 01/15/2010] [Indexed: 12/14/2022] Open
Abstract
Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis, infects human neutrophils and inhibits mitochondria-mediated apoptosis. Bacterial factors involved in this process are unknown. In the present study, we screened a genomic DNA library of A. phagocytophilum for effectors of the type IV secretion system by a bacterial two-hybrid system, using A. phagocytophilum VirD4 as bait. A hypothetical protein was identified as a putative effector, hereby named Anaplasmatranslocated substrate 1 (Ats-1). Using triple immunofluorescence labeling and Western blot analysis of infected cells, including human neutrophils, we determined that Ats-1 is abundantly expressed by A. phagocytophilum, translocated across the inclusion membrane, localized in the host cell mitochondria, and cleaved. Ectopically expressed Ats-1 targeted mitochondria in an N-terminal 17 residue-dependent manner, localized in matrix or at the inner membrane, and was cleaved as native protein, which required residues 55–57. In vitro-translated Ats-1 was imported in a receptor-dependent manner into isolated mitochondria. Ats-1 inhibited etoposide-induced cytochrome c release from mitochondria, PARP cleavage, and apoptosis in mammalian cells, as well as Bax-induced yeast apoptosis. Ats-1(55–57) had significantly reduced anti-apoptotic activity. Bax redistribution was inhibited in both etoposide-induced and Bax-induced apoptosis by Ats-1. Taken together, Ats-1 is the first example of a bacterial protein that traverses five membranes and prevents apoptosis at the mitochondria. Anaplasma phagocytophilum is the pathogen that causes human granulocytic anaplasmosis, an emerging infectious disease. As an obligate intracellular organism, this bacterium cannot reproduce outside of eukaryotic cells due to the loss of many genes that are present in free-living bacteria. Paradoxically, it specifically infects short-lived white blood cells that play critical roles in anti-microbial defense, by subverting a number of host innate immune responses including programmed cell death (apoptosis). A. phagocytophilum factors that are involved in this process are largely unknown. In this study, we first searched A. phagocytophilum proteins that are secreted by its specialized secretion system into eukaryotic cells. We found a protein of unknown function, here named Ats-1, which is abundantly produced by A. phagocytophilum and traverses five membranes to enter the mitochondria of human cells. Our further study showed that Ats-1 reduces the sensitivity of mitochondria to respond to apoptosis-inducing factors, leading to the inhibition of host cell apoptosis. Thus, present findings identified a bacterial protein that allows infected white blood cells to live longer to support bacterial growth. The absence of similarity of the sequence or the mode of action to any other known cell death suppressor suggests that Ats-1 defines a previously undescribed class of anti-apoptotic protein. This protein and the mechanism thereof may provide insight regarding a new therapeutic target for treatment of human granulocytic anaplasmosis.
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Affiliation(s)
- Hua Niu
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
| | - Vera Kozjak-Pavlovic
- Biocenter, Department of Microbiology, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Thomas Rudel
- Biocenter, Department of Microbiology, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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Kozjak-Pavlovic V, Ross K, Götz M, Goosmann C, Rudel T. A tag at the carboxy terminus prevents membrane integration of VDAC1 in mammalian mitochondria. J Mol Biol 2010; 397:219-32. [PMID: 20117113 DOI: 10.1016/j.jmb.2010.01.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 01/21/2010] [Accepted: 01/22/2010] [Indexed: 11/26/2022]
Abstract
beta-Barrel proteins are found in the outer membranes of bacteria, chloroplasts and mitochondria. The evolutionary conserved sorting and assembly machinery (SAM complex) assembles mitochondrial beta-barrel proteins, such as voltage-dependent anion-selective channel 1 (VDAC1), into complexes in the outer membrane by recognizing a sorting beta-signal in the carboxy-terminal part of the protein. Here we show that in mammalian mitochondria, masking of the C-terminus of beta-barrel proteins by a tag leads to accumulation of soluble misassembled protein in the intermembrane space, which causes mitochondrial fragmentation and loss of membrane potential. A similar phenotype is observed if the beta-signal is shortened, removed or when the conserved hydrophobic residues in the beta-signal are mutated. The length of the tag at the C-terminus is critical for the assembly of VDAC1, as well as the amino acid residues at positions 130, 222, 225 and 251 of the protein. We propose that if the recognition of the beta-signal or the folding of the beta-barrel proteins is inhibited, the nonassembled protein will accumulate in the intermembrane space, aggregate and damage mitochondria. This effect offers easy tools for studying the requirements for the membrane assembly of beta-barrel proteins, but also advises caution when interpreting the outcome of the beta-barrel protein overexpression experiments.
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Affiliation(s)
- Vera Kozjak-Pavlovic
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
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Kozjak-Pavlovic V, Dian-Lothrop EA, Meinecke M, Kepp O, Ross K, Rajalingam K, Harsman A, Hauf E, Brinkmann V, Günther D, Herrmann I, Hurwitz R, Rassow J, Wagner R, Rudel T. Bacterial porin disrupts mitochondrial membrane potential and sensitizes host cells to apoptosis. PLoS Pathog 2009; 5:e1000629. [PMID: 19851451 PMCID: PMC2759283 DOI: 10.1371/journal.ppat.1000629] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 09/24/2009] [Indexed: 11/28/2022] Open
Abstract
The bacterial PorB porin, an ATP-binding β-barrel protein of pathogenic Neisseria gonorrhoeae, triggers host cell apoptosis by an unknown mechanism. PorB is targeted to and imported by host cell mitochondria, causing the breakdown of the mitochondrial membrane potential (ΔΨm). Here, we show that PorB induces the condensation of the mitochondrial matrix and the loss of cristae structures, sensitizing cells to the induction of apoptosis via signaling pathways activated by BH3-only proteins. PorB is imported into mitochondria through the general translocase TOM but, unexpectedly, is not recognized by the SAM sorting machinery, usually required for the assembly of β-barrel proteins in the mitochondrial outer membrane. PorB integrates into the mitochondrial inner membrane, leading to the breakdown of ΔΨm. The PorB channel is regulated by nucleotides and an isogenic PorB mutant defective in ATP-binding failed to induce ΔΨm loss and apoptosis, demonstrating that dissipation of ΔΨm is a requirement for cell death caused by neisserial infection. PorB is a bacterial porin that plays an important role in the pathogenicity of Neisseria gonorrhoeae. Upon infection with these bacteria, PorB is transported into mitochondria of infected cells, causing the loss of mitochondrial membrane potential and eventually leading to apoptotic cell death. Here, we show that PorB enters mitochondria through the TOM complex, similar to other mitochondria-targeted proteins, but then bypasses the SAM complex machinery that assembles all other porin-like proteins into the outer mitochondrial membrane. This leads to the accumulation of PorB in the intermembrane space and the integration of a fraction of PorB into the inner mitochondrial membrane (IMM). In the IMM, ATP-regulated pores are formed, leading to dissipation of membrane potential and the loss of cristae structure in affected mitochondria, the necessary first steps in induction of apoptosis. Our work offers, for the first time, a detailed analysis of the mechanism by which PorB targets and damages host cell mitochondria.
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Affiliation(s)
- Vera Kozjak-Pavlovic
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | | | - Michael Meinecke
- Department of Biology/Chemistry, Division of Biophysics, University of Osnabrück, Osnabrück, Germany
| | - Oliver Kepp
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Katharina Ross
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Krishnaraj Rajalingam
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Anke Harsman
- Protein Purification Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Eva Hauf
- Microscopy Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Volker Brinkmann
- Microscopy Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Dirk Günther
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Ines Herrmann
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Robert Hurwitz
- Protein Purification Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Joachim Rassow
- Institute for Physiological Chemistry, Ruhr-University Bochum, Bochum, Germany
| | - Richard Wagner
- Department of Biology/Chemistry, Division of Biophysics, University of Osnabrück, Osnabrück, Germany
| | - Thomas Rudel
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
- * E-mail:
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43
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Tanabe M, Iverson TM. Expression, purification and preliminary X-ray analysis of the Neisseria meningitidis outer membrane protein PorB. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:996-1000. [PMID: 19851005 PMCID: PMC2765884 DOI: 10.1107/s1744309109032333] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 08/14/2009] [Indexed: 11/10/2022]
Abstract
The Neisseria meningitidis outer membrane protein PorB was expressed in Escherichia coli and purified from inclusion bodies by denaturation in urea followed by refolding in buffered LDAO on a size-exclusion column. PorB has been crystallized in three different crystal forms: C222, R32 and P6(3). The C222 crystal form may contain either one or two PorB monomers in the asymmetric unit, while both the R32 and P6(3) crystal forms contained one PorB monomer in the asymmetric unit. Of the three, the P6(3) crystal form had the best diffraction quality, yielding data extending to 2.3 A resolution.
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Affiliation(s)
- Mikio Tanabe
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232-6600, USA
| | - Tina M. Iverson
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232-6600, USA
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37232-6600, USA
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Walther DM, Rapaport D, Tommassen J. Biogenesis of beta-barrel membrane proteins in bacteria and eukaryotes: evolutionary conservation and divergence. Cell Mol Life Sci 2009; 66:2789-804. [PMID: 19399587 PMCID: PMC2724633 DOI: 10.1007/s00018-009-0029-z] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 03/26/2009] [Accepted: 04/01/2009] [Indexed: 01/01/2023]
Abstract
Membrane-embedded beta-barrel proteins span the membrane via multiple amphipathic beta-strands arranged in a cylindrical shape. These proteins are found in the outer membranes of Gram-negative bacteria, mitochondria and chloroplasts. This situation is thought to reflect the evolutionary origin of mitochondria and chloroplasts from Gram-negative bacterial endosymbionts. beta-barrel proteins fulfil a variety of functions; among them are pore-forming proteins that allow the flux of metabolites across the membrane by passive diffusion, active transporters of siderophores, enzymes, structural proteins, and proteins that mediate protein translocation across or insertion into membranes. The biogenesis process of these proteins combines evolutionary conservation of the central elements with some noticeable differences in signals and machineries. This review summarizes our current knowledge of the functions and biogenesis of this special family of proteins.
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Affiliation(s)
- Dirk M. Walther
- Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany
| | - Doron Rapaport
- Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
| | - Jan Tommassen
- Department of Molecular Microbiology, Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands
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45
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The role of mitochondria in cellular defense against microbial infection. Semin Immunol 2009; 21:223-32. [PMID: 19535268 DOI: 10.1016/j.smim.2009.05.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 05/07/2009] [Indexed: 12/31/2022]
Abstract
Mitochondria have been long recognized for their key role in the modulation of cell death pathways. Thus, it is therefore not surprising that this organelle represents a recurrent target for pathogenic microbes, aiming to manipulate the fate of the infected host cell. More recently, mitochondria have been shown to serve as a crucial platform for innate immune signaling, as illustrated by the identification of MAVS (also known as IPS-1, VISA and Cardif), NLRX1 and STING as mitochondrial proteins. This review discusses the tight interplay between microbial infection, innate immune signaling and mitochondria.
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Signals in bacterial beta-barrel proteins are functional in eukaryotic cells for targeting to and assembly in mitochondria. Proc Natl Acad Sci U S A 2009; 106:2531-6. [PMID: 19181862 DOI: 10.1073/pnas.0807830106] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The outer membranes of Gram-negative bacteria, mitochondria, and chloroplasts harbor beta-barrel proteins. The signals that allow precursors of such proteins to be targeted to mitochondria were not characterized so far. To better understand the mechanism by which beta-barrel precursor proteins are recognized and sorted within eukaryotic cells, we expressed the bacterial beta-barrel proteins PhoE, OmpA, Omp85, and OmpC in Saccharomyces cerevisiae and demonstrated that they were imported into mitochondria. A detailed investigation of the import pathway of PhoE revealed that it is shared with mitochondrial beta-barrel proteins. PhoE interacts initially with surface import receptors, and its further sorting depends on components of the TOB/SAM complex. The bacterial Omp85 and PhoE integrated into the mitochondrial outer membrane as native-like oligomers. For the latter protein this assembly depended on the C-terminal Phe residue, which is important also for the correct assembly of PhoE into the bacterial outer membrane. Collectively, it appears that mitochondrial beta-barrel proteins have not evolved eukaryotic-specific signals to ensure their import into mitochondria. Furthermore, the signal for assembly of beta-barrel proteins into the bacterial outer membrane is functional in mitochondria.
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Feng P, Liang C, Shin YC, E X, Zhang W, Gravel R, Wu TT, Sun R, Usherwood E, Jung JU. A novel inhibitory mechanism of mitochondrion-dependent apoptosis by a herpesviral protein. PLoS Pathog 2008; 3:e174. [PMID: 18069888 PMCID: PMC2134948 DOI: 10.1371/journal.ppat.0030174] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 10/02/2007] [Indexed: 11/19/2022] Open
Abstract
Upon viral infection, cells undergo apoptosis as a defense against viral replication. Viruses, in turn, have evolved elaborate mechanisms to subvert apoptotic processes. Here, we report that a novel viral mitochondrial anti-apoptotic protein (vMAP) of murine γ-herpesvirus 68 (γHV-68) interacts with Bcl-2 and voltage-dependent anion channel 1 (VDAC1) in a genetically separable manner. The N-terminal region of vMAP interacted with Bcl-2, and this interaction markedly increased not only Bcl-2 recruitment to mitochondria but also its avidity for BH3-only pro-apoptotic proteins, thereby suppressing Bax mitochondrial translocation and activation. In addition, the central and C-terminal hydrophobic regions of vMAP interacted with VDAC1. Consequently, these interactions resulted in the effective inhibition of cytochrome c release, leading to the comprehensive inhibition of mitochondrion-mediated apoptosis. Finally, vMAP gene was required for efficient γHV-68 lytic replication in normal cells, but not in mitochondrial apoptosis-deficient cells. These results demonstrate that γHV-68 vMAP independently targets two important regulators of mitochondrial apoptosis-mediated intracellular innate immunity, allowing efficient viral lytic replication. Apoptosis is a conserved cell death program that contributes to restriction of viral replication and elimination of infected cells. Whether triggered via internal inducers such as DNA damage or via external stimuli such as engagement of the death receptor, apoptosis takes place through a cascade of regulated internal proteolytic digestion, resulting in a collapse of cellular infrastructure, mitochondrial potential, genomic fidelity, and cell membrane integrity. Indeed, apoptosis represents a predominant form of virally infected cell demise. In response, viruses have evolved numerous ways of circumventing this host-cell apoptosis. Most of the DNA viruses including murine γ-herpesvirus 68 (γHV-68) are genetically equipped with anti-apoptotic ability to ensure viral replication and propagation. The authors have identified a new viral mitochondrial protein (vMAP) of γHV-68 that interacts with Bcl-2 and voltage-dependent anion channel 1 (VDAC1) in a genetically separable manner. These interactions markedly suppress Bax mitochondrial translocation and activation and inhibit cytochrome c release, leading to the comprehensive inhibition of mitochondrion-mediated apoptosis. The authors also demonstrate that vMAP gene is required for efficient γHV-68 lytic replication in normal cells, but not in mitochondrial apoptosis-deficient cells. These findings are entirely novel and significantly advance our understanding of how virus escapes host intracellular apoptosis-mediated innate immunity.
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Affiliation(s)
- Pinghui Feng
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * To whom correspondence should be addressed. E-mail: (PF); (JUJ)
| | - Chengyu Liang
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
| | - Young C Shin
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
| | - Xiaofei E
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
| | - Weijun Zhang
- Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire, United States of America
| | - Robyn Gravel
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
| | - Ting-ting Wu
- Department of Molecular and Medical Pharmacology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Ren Sun
- Department of Molecular and Medical Pharmacology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Edward Usherwood
- Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire, United States of America
| | - Jae U Jung
- Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail: (PF); (JUJ)
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Tsugawa H, Ogawa A, Takehara S, Kimura M, Okawa Y. Primary structure and function of a cytotoxic outer-membrane protein (ComP) of Plesiomonas shigelloides. FEMS Microbiol Lett 2008; 281:10-6. [DOI: 10.1111/j.1574-6968.2007.01041.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Kozjak-Pavlovic V, Ross K, Rudel T. Import of bacterial pathogenicity factors into mitochondria. Curr Opin Microbiol 2008; 11:9-14. [PMID: 18280201 DOI: 10.1016/j.mib.2007.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 12/18/2007] [Accepted: 12/19/2007] [Indexed: 12/22/2022]
Abstract
Recent research on the mechanism underlying the interaction of bacterial pathogens with their host has shifted the focus to secreted microbial proteins affecting the physiology and innate immune response of the target cell. These proteins either traverse the plasma membrane via specific entry pathways involving host cell receptors or are directly injected via bacterial secretion systems into the host cell, where they frequently target mitochondria. The import routes of bacterial proteins are mostly unknown, whereas the effect of mitochondrial targeting by these proteins has been investigated in detail. For a number of them, classical leader sequences recognized by the mitochondrial protein import machinery have been identified. Bacterial outer membrane beta-barrel proteins can also be recognized and imported by mitochondrial transporters. Besides an obvious importance in pathogenicity, understanding import of bacterial proteins into mitochondria has a highly relevant evolutionary aspect, considering the endosymbiotic, proteobacterial origin of mitochondria. The review covers the current knowledge on the mitochondrial targeting and import of bacterial pathogenicity factors.
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Affiliation(s)
- Vera Kozjak-Pavlovic
- Max Planck Institute for Infection Biology, Department of Molecular Biology, Research Group for Molecular Infection and Cancer Biology, Charitéplatz 1, Berlin, Germany.
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Bose M, Adams BP, Whittal RM, Bose HS. Identification of unknown protein complex members by radiolocalization and analysis of low-abundance complexes resolved using native polyacrylamide gel electrophoresis. Electrophoresis 2008; 29:753-60. [DOI: 10.1002/elps.200700782] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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