Genes encoding putative effector proteins of the type III secretion system of <i>Salmonella</i> pathogenicity island 2 are required for bacterial virulence and proliferation in macrophages

Hensel, Michael; Shea, Jacqueline E.; Waterman, Scott R.; Mundy, Rosanna; Nikolaus, Thomas; Banks, G. T.; Vázquez‐Torres, Andrés; Gleeson, Colin; Fang, Ferric C.; Holden, David W.

doi:10.1046/j.1365-2958.1998.01047.x

Cited by 578 publications

(624 citation statements)

References 51 publications

Supporting

Mentioning

588

Contrasting

Unclassified

Order By: Relevance

“…Interestingly, EseE also shares 10.2% identity with SseE, a protein located within Salmonella pathogenicity island 2. While its function is unknown, SseE was known not to be secreted into culture supernatants (29).…”

Section: Sequence Analysis Of Eseementioning

confidence: 99%

EseE of Edwardsiella tarda Augments Secretion of Translocon Protein EseC and Expression of the escC - eseE Operon

et al. 2016

View full text Add to dashboard Cite

Edwardsiella tarda is an important Gram-negative pathogen that employs a type III secretion system (T3SS) to deliver effectors into host cells to facilitate bacterial survival and replication. These effectors are translocated into host cells through a translocon complex composed of three secreted proteins, namely, EseB, EseC, and EseD. The secretion of EseB and EseD requires a chaperone protein called EscC, whereas the secretion of EseC requires the chaperone EscA. In this study, we identified a novel protein (EseE) that also regulates the secretion of EseC. An eseE deletion mutant secreted much less EseC into supernatants, accompanied by increased EseC levels within bacterial cells. We also demonstrated that EseE interacted directly with EseC in a pulldown assay. Interestingly, EseC, EseE, and EscA were able to form a ternary complex, as revealed by pulldown and gel filtration assays. Of particular importance, the deletion of eseE resulted in decreased levels of EseB and EseD proteins in both the bacterial pellet and supernatant fraction. Furthermore, real-time PCR assays showed that EseE positively regulated the transcription of the translocon operon escC-eseE, comprising escC, eseB, escA, eseC, eseD, and eseE. These effects of EseE on the translocon components/operon appeared to have a functional consequence, since the ⌬eseE strain was outcompeted by wild-type E. tarda in a mixed infection in blue gourami fish. Collectively, our results demonstrate that EseE not only functions as a chaperone for EseC but also acts as a positive regulator controlling the expression of the translocon operon escC-eseE, thus contributing to the pathogenesis of E. tarda in fish.T he type III secretion system (T3SS) is a contact-dependent translocation system. It forms a syringe-like structure spanning the inner and outer membranes of bacteria and induces pore formation on host cells (1). Through these pores, an array of bacterial proteins (effectors) are delivered into host cells, where they manipulate host cell signaling pathways to promote bacterial survival (2).Edwardsiella tarda is a Gram-negative intracellular pathogen that can cause hemorrhagic septicemia in fish (3), as well as gastroand extraintestinal infections in humans (4, 5). The T3SS is well known to be one of the most important virulence factors in E. tarda (6, 7). It facilitates the survival and replication of E. tarda in host cells (6-9). E. tarda T3SS contains 34 open reading frames (ORFs), which encode the apparatus, chaperones, effectors, and regulators (6, 10). The expression of E. tarda T3SS is controlled by many factors, such as the two-component system esrA-esrB (6) and esrC (11) inside the T3SS gene cluster, as well as phoP-phoQ (12) and phoR-phoB (13) located outside the T3SS gene cluster. Intriguingly, our group recently showed that a type III secretion system-secreted protein (EscE) also functions as a regulator controlling the injection of effectors and secretion of translocators (14).EseB, EseC, and EseD, secreted by the E. tarda T3SS, are homologous ...

show abstract

Section: Sequence Analysis Of Eseementioning

confidence: 99%

EseE of Edwardsiella tarda Augments Secretion of Translocon Protein EseC and Expression of the escC - eseE Operon

et al. 2016

View full text Add to dashboard Cite

show abstract

“…It is also possible that factors other than immune attack were at play; however, bacterial cell division per se did not seem to be affected because SPI -2 mutations did not impair growth rates of these strains in LB broth (not shown ). Further, although it has been well established that loss of SPI -2 function impairs Salmonella replication within macrophages, 14,15,17,18,29 we found that sseB À , sseC À , and ssrA À mutants grew intracellularly in both B16F10 and Cloudman S91 melanoma cells at the same rate as the parental YS1646 strain ( not shown ). These experiments employed the gentamycin protection assay 18 ( Materials and methods ), and multiple time points were examined over 24 hours.…”

Section: Discussionmentioning

confidence: 59%

“…In accord with these findings on sseF and sseG, studies of systemic infections in mice revealed that mutations in sseF and sseG (as well as sseE ) did not result in significant attenuation of virulence, indicating that these genes may not be essential for the function of SPI -2, or that they have redundant functions. 14,15 The impaired anticancer capabilities of SPI -2 mutants occurred in both msbB À ( YS1456, YS1646 ) and msbB + (YS7212) strains, indicating that the effects were independent of the msbB À mutation, which is characterized by altered lipid A. 7 Because delayed amplification of SPI-2 À salmonellae was observed even after direct i.t.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Salmonella pathogenicity island-2 and anticancer activity in mice

et al. 2002

Self Cite

View full text Add to dashboard Cite

Salmonella enterica servovar Typhimurium is capable of targeting, colonizing, and eliciting growth suppression of tumors in mice. We examined the effects of mutations on this anticancer phenotype in two Salmonella virulence gene clusters. Salmonella pathogenicity island ( SPI ) -1 genes promote systemic invasion from the intestine, whereas SPI -2 genes support systemic survival within macrophages and other cells. Disabling SPI -1 ( prgH À ) strongly reduced invasion in vitro, but had no effect on tumor growth suppression in vivo. However, disabling SPI -2 ( ssaT À ) ablated tumor growth suppression. In addition to ssaT À , mutations in SPI -2 genes sseA, sseB, sseC, sscA, and ssrA also eliminated antitumor activity, whereas mutations in sseF or sseG yielded partial loss of function. Impaired tumor amplification was seen in three SPI -2 mutants tested after intravenous or intratumoral injection. A SPI -2 À strain was unable to suppress tumor growth in CD18 -deficient mice with defective macrophages and neutrophils, suggesting that loss of tumor growth suppression in wild -type mice by SPI -2 mutants was not solely a function of increased susceptibility to immune attack. Thus, SPI -2 is essential for the Salmonella antitumor effects, perhaps by aiding bacterial amplification within tumors, and is the first identified genetic system for this Salmonella phenotype.

show abstract

“…invJ, sipA, sipB, sipC, hilA or invF) are localised to SPI-1 (Darwin and Miller, 1999;Eichelberg and Galan, 1999) while genes essential for the intracellular survival of S. Typhimurium (e.g. ssrA, ssaB or sseA) are clustered in SPI-2 (Cirillo et al, 1998;Hensel et al, 1998). The expression of SPI-1 genes is known to be suppressed by bile salts, acidification or nutrient limitation and S. enterica grown in such an environment exhibits a reduced ability to invade tissue culture cells (Prouty and Gunn, 2000;Boddicker and Jones, 2004).…”

mentioning

confidence: 99%

Comparison of live and inactivated Salmonella Typhimurium vaccines containing different combinations of SPI-1 and SPI-2 antigens in poultry

Papezova¹,

Havlíčková²,

Šišák³

et al. 2008

Vet. Med. - Czech

View full text Add to dashboard Cite

Salmonella enterica subsp. enterica originating from poultry and poultry products is responsible for the vast majority of human gastrointestinal disorders in Europe. For this reason different measures that seek to decrease its incidence in poultry including vaccination with inactivated vaccine continue to be tested. In this study we compared four different inactivated vaccines of S. Typhimurium in chickens which were enriched by SPI-1 or SPI-2 proteins that are central to Salmonella virulence. Six-week-old chickens were intramuscularly vaccinated, revaccinated at 9 weeks and challenged at 12 weeks of age. For two weeks post challenge faecal shedding was monitored. There was no significant difference in the performance of the four compared inactivated vaccines and all of them decreased faecal shedding during the first weeks post infection by 10-1 000× when compared with non-immunized control chickens. However, the level of protection provided by inactivated vaccines was much lower when compared with a live vaccine based on a phoP rpoS double deletion S. Typhimurium mutant which was included as an additional control.

show abstract

Genes encoding putative effector proteins of the type III secretion system of Salmonella pathogenicity island 2 are required for bacterial virulence and proliferation in macrophages

Cited by 578 publications

References 51 publications

EseE of Edwardsiella tarda Augments Secretion of Translocon Protein EseC and Expression of the escC - eseE Operon

EseE of Edwardsiella tarda Augments Secretion of Translocon Protein EseC and Expression of the escC - eseE Operon

Salmonella pathogenicity island-2 and anticancer activity in mice

Comparison of live and inactivated Salmonella Typhimurium vaccines containing different combinations of SPI-1 and SPI-2 antigens in poultry

Contact Info

Product

Resources

About