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Title: Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants

Abstract

The intracellular pathogen Salmonella enterica serovar Typhimurium is a leading cause of acute gastroenteritis in the world. This pathogen has two type-III secretion systems (TTSS) necessary for virulence that are encoded in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) and are expressed during extracellular or intracellular infectious states, respectively, to deliver virulence factors (effectors) to the host cell cytoplasm. While many have been identified and at least partially characterized, the full repertoire of effectors has not been catalogued. In this mass spectrometry-based proteomics study, we identified effector proteins secreted under minimal acidic medium growth conditions that induced the SPI-2 TTSS and its effectors, and compared the secretome from the parent strain to the secretome from strains missing either essential (SsaK) or regulatory components (SsaL) of the SPI-2 secretion apparatus. We identified 75% of the known TTSS effector repertoire. Excluding translocon components, 95% of the known effectors were biased for identification in the ssaL mutant background, which demonstrated that SsaL regulates SPI-2 type III secretion. To confirm secretion to animal cells, we made translational fusions of several of the best candidates to the calmodulin-dependent adenylate cyclase of Bordetella pertussis and assayed cAMP levels of infected J774 macrophage-like cells. Frommore » these infected cells we identified six new TTSS effectors and two others that are secreted independent of TTSS. Our results substantiate reports of additional secretion systems encoded by Salmonella other than TTSS.« less

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1004798
Report Number(s):
PNNL-SA-71385
Journal ID: ISSN 0019-9567; INFIBR; 33210; 400412000; TRN: US201104%%1106
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Infection and Immunity, 79(1):33-43
Additional Journal Information:
Journal Volume: 79; Journal Issue: 1; Journal ID: ISSN 0019-9567
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ANIMAL CELLS; CYCLASES; CYTOPLASM; MUTANTS; PATHOGENS; PROTEINS; SALMONELLA; SECRETION; STRAINS; VIRULENCE; PATHOGENICITY ISLAND 2; ESCHERICHIA-COLI; III SECRETION; MEMBRANE-VESICLES; MASS-SPECTROMETRY; CONTAINING VACUOLES; YEAST PROTEOME; TYPHOID-FEVER; ACCURATE MASS; IDENTIFICATION; Environmental Molecular Sciences Laboratory

Citation Formats

Niemann, George, Brown, Roslyn N., Gustin, Jean K., Stufkens, Afke, Shaikh-Kidwai, Afshan S., Li, Jie, McDermott, Jason E., Brewer, Heather M., Schepmoes, Athena A., Smith, Richard D., Adkins, Joshua N., and Heffron, Fred. Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants. United States: N. p., 2011. Web. doi:10.1128/IAI.00771-10.
Niemann, George, Brown, Roslyn N., Gustin, Jean K., Stufkens, Afke, Shaikh-Kidwai, Afshan S., Li, Jie, McDermott, Jason E., Brewer, Heather M., Schepmoes, Athena A., Smith, Richard D., Adkins, Joshua N., & Heffron, Fred. Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants. United States. https://doi.org/10.1128/IAI.00771-10
Niemann, George, Brown, Roslyn N., Gustin, Jean K., Stufkens, Afke, Shaikh-Kidwai, Afshan S., Li, Jie, McDermott, Jason E., Brewer, Heather M., Schepmoes, Athena A., Smith, Richard D., Adkins, Joshua N., and Heffron, Fred. 2011. "Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants". United States. https://doi.org/10.1128/IAI.00771-10.
@article{osti_1004798,
title = {Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants},
author = {Niemann, George and Brown, Roslyn N. and Gustin, Jean K. and Stufkens, Afke and Shaikh-Kidwai, Afshan S. and Li, Jie and McDermott, Jason E. and Brewer, Heather M. and Schepmoes, Athena A. and Smith, Richard D. and Adkins, Joshua N. and Heffron, Fred},
abstractNote = {The intracellular pathogen Salmonella enterica serovar Typhimurium is a leading cause of acute gastroenteritis in the world. This pathogen has two type-III secretion systems (TTSS) necessary for virulence that are encoded in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) and are expressed during extracellular or intracellular infectious states, respectively, to deliver virulence factors (effectors) to the host cell cytoplasm. While many have been identified and at least partially characterized, the full repertoire of effectors has not been catalogued. In this mass spectrometry-based proteomics study, we identified effector proteins secreted under minimal acidic medium growth conditions that induced the SPI-2 TTSS and its effectors, and compared the secretome from the parent strain to the secretome from strains missing either essential (SsaK) or regulatory components (SsaL) of the SPI-2 secretion apparatus. We identified 75% of the known TTSS effector repertoire. Excluding translocon components, 95% of the known effectors were biased for identification in the ssaL mutant background, which demonstrated that SsaL regulates SPI-2 type III secretion. To confirm secretion to animal cells, we made translational fusions of several of the best candidates to the calmodulin-dependent adenylate cyclase of Bordetella pertussis and assayed cAMP levels of infected J774 macrophage-like cells. From these infected cells we identified six new TTSS effectors and two others that are secreted independent of TTSS. Our results substantiate reports of additional secretion systems encoded by Salmonella other than TTSS.},
doi = {10.1128/IAI.00771-10},
url = {https://www.osti.gov/biblio/1004798}, journal = {Infection and Immunity, 79(1):33-43},
issn = {0019-9567},
number = 1,
volume = 79,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 2011},
month = {Sat Jan 01 00:00:00 EST 2011}
}