The Actin-Polymerizing Activity of SipA Is Not Essential for Salmonella enterica Serovar Typhimurium-Induced Mucosal Inflammation

Li, Dongju; Wang, Xueqin; Wang, Lu; Zhou, Daoguo

doi:10.1128/iai.00337-12

Cited by 11 publications

(18 citation statements)

References 71 publications

(110 reference statements)

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“…The S. Typhimurium effector protein SipA has an actin binding domain to induce actin rearrangement that facilitates the invasion of S. Typhimurium [55]. However, the actin binding domain was shown not to be essential for the induction of NF-κB activation and intestinal inflammation [31, 56]. This finding suggests that SipA activates the NOD1/2 signaling pathway independently of actin rearrangement [31].…”

Section: Sensing Of Rho Gtpase Activation State By Nod1 and Nod2mentioning

confidence: 99%

NOD1 and NOD2: Beyond Peptidoglycan Sensing

Keestra-Gounder

Tsolis²

2017

Trends in Immunology

108

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NOD1 and NOD2 are pattern recognition receptors of the innate immune system with well-established roles in sensing fragments of bacterial peptidoglycan. In addition to their role as microbial sensors, recent evidence indicates that NODs can also recognize a broader array of danger signals. Indeed, recent work has expanded the roles of NOD1 and NOD2 to encompass not only sensing of infections with viruses and parasites but also perceiving perturbations of cellular processes such as regulation of the actin cytoskeleton and maintenance of endoplasmic reticulum homeostasis. This review will comment on recent progress and point out emerging questions in these areas.

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Section: Sensing Of Rho Gtpase Activation State By Nod1 and Nod2mentioning

confidence: 99%

NOD1 and NOD2: Beyond Peptidoglycan Sensing

Keestra-Gounder

Tsolis²

2017

Trends in Immunology

108

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“…The ability of bacteria to invade host cells was also evaluated with the inside/outside differential staining assay, as described previously (24). Briefly, HeLa cells were infected for 15 min with Salmonella at an MOI of 5.…”

Section: Methodsmentioning

confidence: 99%

“…To differentiate these two possibilities, we constructed plasmids encoding the full-length small protein (pyshB), the full yshB gene without the start codon (pyshBnoATG), the full yshB gene with a frameshift mutation from deletion of the first nucleotide (pyshBfs), and the full yshB gene with a degenerate nucleotide sequence encoding the same 36 amino acids of YshB (pyshBdg). These plasmids were then introduced into wild-type Salmonella, and their invasion efficiency was evaluated using both the gentamicin protection assay and the inside/outside differential fluorescence staining assay (24). The reduced invasion phenotype was conspicuously absent when no ATG or frameshift mutations were present ( Fig.…”

mentioning

confidence: 99%

YshB Promotes Intracellular Replication and Is Required for Salmonella Virulence

2019

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Salmonella virulence requires the initial invasion of host cells, followed by modulation of the intracellular environment for survival and replication. In an effort to characterize the role of small RNAs in Salmonella pathogenesis, we inadvertently identified a 5-kDa protein named YshB that is involved in the intracellular survival of Salmonella. We show here that yshB expression is upregulated upon entry into macrophages. When yshB expression is upregulated before bacterial entry, invasion efficiency is inhibited. Lack of YshB resulted in reduced bacterial survival within the macrophages and led to reduced virulence in a mouse model of infection.IMPORTANCE Salmonella gastroenteritis is one of the most common causes of foodborne disease, possibly affecting millions of people globally each year. Here we characterize the role of a novel small protein, YshB, in mediating Salmonella intracellular survival. This elucidation adds to the body of knowledge regarding how this bacterium achieves intracellular survival.

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“…Salmonella infections of HeLa cells were carried out as previously described (34). Briefly, Salmonella were cultured to an optical density of 1.0 (600 nm) in LB broth supplemented with 0.3 M NaCl at 37°C.…”

Section: Methodsmentioning

confidence: 99%

YggG is a Novel SPI-1 Effector Essential for Salmonella Virulence

Bomjan

Chitale

et al. 2018

Preprint

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22Salmonella is a leading cause of food borne illness and poses a major public health 23 problem worldwide. Two type III secretion systems (TTSSs) are responsible for the 24 delivery of a series of bacterial effectors into the infected cells to reprogram host cell 25 functions to promote bacterial invasion and intracellular survival/replication. Nearly half 26of Salmonella genes encode proteins that are annotated as "hypothetical". We 27 hypothesize that some of these hypothetical proteins might be TTSS effectors and 28 participate in Salmonella virulence. In this study, we employed an in silico screen to 29 identify putative TTSS effector proteins and performed a large scale screening of 30Salmonella effectors using a β-lactamase protein translocation reporter assay. We 31 identified 22 novel effectors that have not been previously reported. One of the effector 32 -YggG, is found to be cytotoxic to mammalian cells when overexpressed suggesting 33 interference with mammalian cell functions and survival. Importantly, Salmonella strains 34 lacking YggG has reduced virulence in the mouse infection model. Our study 35 demonstrated that YggG and its protease activity are required for Salmonella virulence 36in the mouse infection model. Surprisingly, no detectable roles in invasion into epithelial 37 cells and no effect on the survival and replication inside cultured macrophages. We 38 speculate that YggG may be involved in altering some aspects of the host immune 39 system to promote infection. Our finding significantly expands the number of known 40Salmonella effectors, and laid a solid foundation in further understanding Salmonella 41 pathogenesis. 42 43 3 Abstract Importance 44Salmonellosis continues to be public health concern in the USA and the world. 45Salmonella delivers a set of bacterial proteins (effectors) into the host cells to invade 46 non-phagocytic cells and to replicate inside the infected cells. Identification and 47 characterization of these effectors are pivotal to the understanding of how Salmonella 48 causes diseases. In addition, Nearly half of Salmonella genes encode proteins that are 49 annotated as "hypothetical". We have identified 22 novel effectors that have not been 50 previously reported. Our finding significantly expands the number of known Salmonella 51 effectors, and laid a solid foundation in further understanding Salmonella pathogenesis. 52 53

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The Actin-Polymerizing Activity of SipA Is Not Essential for Salmonella enterica Serovar Typhimurium-Induced Mucosal Inflammation

Cited by 11 publications

References 71 publications

NOD1 and NOD2: Beyond Peptidoglycan Sensing

NOD1 and NOD2: Beyond Peptidoglycan Sensing

YshB Promotes Intracellular Replication and Is Required for Salmonella Virulence

YggG is a Novel SPI-1 Effector Essential for Salmonella Virulence

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