Ubiquitination of USP5 by a bacterial ubiquitin ligase inhibits NLRP3 inflammasome activation
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo Sapiens
SUBMITTER: 
Jiaqi Fu
PROVIDER: PXD076728 | iProX | Wed Apr 08 00:00:00 BST 2026
REPOSITORIES: iProX
Similar Datasets
Project description:Legionella pneumophila utilises a type IVB secretion system (T4SS) to translocate over 300 effectors into host cells, hijacking cellular processes, including those within the mitochondrion. Currently, no Legionella effectors have been identified at the mitochondrial outer membrane, a critical interface between the organelle and rest of the cell. We screened the Legionella effector repertoire for features of mitochondrial tail-anchored (TA) proteins and identified four putative TA effectors. Among them, Lpg1625 was confirmed to localize to the mitochondrial outer membrane and shown to interact with all three isoforms of protein phosphatase 1 (PP1) through an RVxF motif. Importantly, PP1 remains catalytically active upon interaction with Lpg1625, leading to dephosphorylation of specific mitochondrial outer membrane proteins. Altering the TA signature to direct Lpg1625 to the ER led to ER-recruitment of PP1 and subsequent dephosphorylation of ER resident proteins indicating that Lpg1625 controls PP1 localisation and not substrate specificity. This study uncovers a novel pathogen-mediated strategy to modulate PP1 and manipulate the host phosphoproteome.
2025-06-03 | PXD057005 | Pride
Project description:This SuperSeries is composed of the following subset Series: GSE26473: Secreted bacterial effectors that inhibit host protein synthesis are critical for induction of the innate immune response to virulent Legionella pneumophila [exp1] GSE26490: Secreted bacterial effectors that inhibit host protein synthesis are critical for induction of the innate immune response to virulent Legionella pneumophila [exp2] Refer to individual Series
2011-01-08 | E-GEOD-26491 | biostudies-arrayexpress
Project description:Purpose: The interaction between Legionella pneumophila and its host cell is not completly understood. The aim of this study was to identify eukaryotic-like bacterial factors which manipulate the host cell. Method: A stable overexpression of LPC_1677 was performed in THP-1 cells. The LPC_1677 overexpressing cells were infected with L.p. and RNA sequencing was performed. Key pro-inflammatory markers were validated via qPCR and ELISA. Results: Bioinformatic screening for eukaryotic-like motives in L.p. took us to LPC_1677 which deacetylates host histones and thereby attenuating gene transcription. Conclusion: This study demonstrated that the eukaryotic-like bacterial factor LPC_1677 de-acetylates Histones in the host cell.
2023-01-01 | GSE185936 | GEO
Project description:The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires’ Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis. Three-condition experiment: macrophages left uninfected (negative control), or infected with wildtype Legionella pneumophila, or the mutant Δ5, which lacks five bacterial effectors involved in inhibition of host protein synthesis (lgt1, lgt2, lgt3, sidI, sidL) (two experimental conditions). Biological replicates: two, independently infected, harvested, and hybridized to arrays. One technical replicate per array.
2011-01-08 | E-GEOD-26490 | biostudies-arrayexpress
Project description:The innate defense mechanisms that control infections with intracellular bacteria are still incompletely understood. Here we show that type I and II IFNs are key regulators of the early gene expression and the host-protective immune response during Legionella pneumophila-induced pneumonia. Using mixed bone marrow-chimeric mice and isolated cells we indicate that both IFNs protect against L. pneumophila by activating an alveolar macrophage-intrinsic antibacterial defense pathway. Quantitative mass spectrometry analysis reveals that both IFNs markedly alter the protein composition of purified Legionella-containing vacuoles, and integrated network analysis defines distinct subsets of IFN-regulated proteins. Subsequent experiments uncover Immunoresponsive gene 1 (Irg1) as a central effector that restricts the bacteria through production of itaconic acid. Collectively, we provide a comprehensive analysis of IFN-mediated effects on gene expression and the bacterial vacuole proteome, and show that L. pneumophila is restricted by an Irg1-dependent production of a bactericidal metabolite.
2015-01-01 | GSE60085 | GEO
Project description:The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires’ Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis. Four-condition experiment: macrophages left uninfected (negative control), or infected with wildtype Legionella pneumophila, the flagellin-deficient mutant ΔflaA, or the secretion-deficient mutant ΔdotA (three experimental conditions). Biological replicates: two, independently infected, harvested, and hybridized to arrays. One to two technical replicates per array, as indicated in file titles.
2011-01-08 | E-GEOD-26473 | biostudies-arrayexpress
Project description:The innate defense mechanisms that control infections with intracellular bacteria are still incompletely understood. Here we show that type I and II IFNs are key regulators of the early gene expression and the host-protective immune response during Legionella pneumophila-induced pneumonia. Using mixed bone marrow-chimeric mice and isolated cells we indicate that both IFNs protect against L. pneumophila by activating an alveolar macrophage-intrinsic antibacterial defense pathway. Quantitative mass spectrometry analysis reveals that both IFNs markedly alter the protein composition of purified Legionella-containing vacuoles, and integrated network analysis defines distinct subsets of IFN-regulated proteins. Subsequent experiments uncover Immunoresponsive gene 1 (Irg1) as a central effector that restricts the bacteria through production of itaconic acid. Collectively, we provide a comprehensive analysis of IFN-mediated effects on gene expression and the bacterial vacuole proteome, and show that L. pneumophila is restricted by an Irg1-dependent production of a bactericidal metabolite. Microarray experiments were performed as dual-color hybridizations on Agilent mouse whole genome catalog 44K arrays. To compensate for dye-specific effects, a dye-reversal color-swap was applied.
2015-01-01 | E-GEOD-60085 | biostudies-arrayexpress
Project description:Differential gene expression of Dictyostelium discoideum after infection with Legionella pneumophila was investigated using DNA microarrays. A detailed analysis of the 24 h time point post infection was performed in comparison to three controls, uninfected cells and co-incubation with Legionella hackeliae and L. pneumophila DeltadotA. One hundred and thirty-one differentially expressed D. discoideum genes were identified as common to all three experiments and are thought to be involved in the pathogenic response. Functional annotation of the differentially regulated genes revealed that apart from triggering a stress response, Legionella apparently not only interferes with intracellular vesicle fusion and destination but also profoundly influences and exploits the metabolism of its host. The results provide the basis for a better understanding of the complex host-pathogen interactions and for further studies on the Dictyostelium response to Legionella infection.
2013-09-11 | GSE50696 | GEO
Project description:Differential gene expression of Dictyostelium discoideum after infection with Legionella pneumophila was investigated using DNA microarrays. A detailed analysis of the 24 h time point post infection was performed in comparison to three controls, uninfected cells and co-incubation with Legionella hackeliae and L. pneumophila DeltadotA. One hundred and thirty-one differentially expressed D. discoideum genes were identified as common to all three experiments and are thought to be involved in the pathogenic response. Functional annotation of the differentially regulated genes revealed that apart from triggering a stress response Legionella apparently not only interferes with intracellular vesicle fusion and destination but also profoundly influences and exploits the metabolism of its host. The results provide the basis for a better understanding of the complex host-pathogen interactions and for further studies on the Dictyostelium response to Legionella infection.
2013-09-07 | GSE50651 | GEO
Project description:Differential gene expression of Dictyostelium discoideum after infection with Legionella pneumophila was investigated using DNA microarrays. A detailed analysis of the 24 h time point post infection was performed in comparison to three controls, uninfected cells and co-incubation with Legionella hackeliae and L. pneumophila DeltadotA. One hundred and thirty-one differentially expressed D. discoideum genes were identified as common to all three experiments and are thought to be involved in the pathogenic response. Functional annotation of the differentially regulated genes revealed that apart from triggering a stress response Legionella apparently not only interferes with intracellular vesicle fusion and destination but also profoundly influences and exploits the metabolism of its host. The results provide the basis for a better understanding of the complex host-pathogen interactions and for further studies on the Dictyostelium response to Legionella infection.
2013-09-07 | GSE50536 | GEO