The human-pathogenic Yersinia spp. (Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are responsible for a range of diseases including diarrhea, mesenteric lymphadenitis, and bubonic plague. These bacteria invade into and colonize the lymphatic organs of humans and a variety of animal hosts. Colonization of a host by Yersinia requires the function of a plasmid-encoded contact-dependent type III secretion system. This type III system translocates a set of toxic proteins known as Yops into host cells. The Yops impair normal host cell signaling functions, resulting in inhibition of phagocytosis, suppression of cytokine synthesis, and induction of apoptosis. The long-term goal of this grant is to understand how Yops modulate host cell signaling functions. The investigators will focus their studies primarily on YopH, a protein tyrosine phosphatase that inhibits phagocytosis, and YopJ, a protein that prevents cytokine synthesis and induces apoptosis. The first specific aim is to carry out a structure/function analysis of an amino-terminal domain in YopH that mediates translocation and substrate recognition. A combination of biophysical and genetic approaches will be used to achieve this goal. The second specific aim is to examine the mechanism of substrate recognition by YopH inside host cells. Animal and cultured cell infection assays will be used to study the behavior of genetically-altered YopH proteins in vivo. The third specific aim is to analyze the interaction of YopJ with host target proteins and to elucidate its mechanism action. Mutant forms of YopJ unable to bind target proteins will be generated and analyzed for biological activity in animal and cultured cell infection assays. The possibility that other Yops modulate the activities of mitogen-activated protein kinases in host cells will also be explored. As type III secretion pathways are important virulence determinants in a large number of bacterial pathogens, and the Yops provide an extremely powerful system to study pathogen interference with host signaling functions, these studies will aid the development of new strategies to combat a variety infectious diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI043389-04
Application #
6627870
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Schmitt, Clare K
Project Start
2000-02-01
Project End
2005-01-31
Budget Start
2003-02-01
Budget End
2004-01-31
Support Year
4
Fiscal Year
2003
Total Cost
$291,416
Indirect Cost
Name
State University New York Stony Brook
Department
Genetics
Type
Schools of Medicine
DUNS #
804878247
City
Stony Brook
State
NY
Country
United States
Zip Code
11794
Zheng, Ying; Lilo, Sarit; Brodsky, Igor E et al. (2011) A Yersinia effector with enhanced inhibitory activity on the NF-?B pathway activates the NLRP3/ASC/caspase-1 inflammasome in macrophages. PLoS Pathog 7:e1002026
Zhang, Yue; Bliska, James B (2011) Mathematical relationship between cytokine concentrations and pathogen levels during infection. Cytokine 53:158-62
Zhang, Yue; Romanov, Galina; Bliska, James B (2011) Type III secretion system-dependent translocation of ectopically expressed Yop effectors into macrophages by intracellular Yersinia pseudotuberculosis. Infect Immun 79:4322-31
Zhang, Yue; Bliska, James B (2010) YopJ-promoted cytotoxicity and systemic colonization are associated with high levels of murine interleukin-18, gamma interferon, and neutrophils in a live vaccine model of Yersinia pseudotuberculosis infection. Infect Immun 78:2329-41
Brodsky, Igor E; Palm, Noah W; Sadanand, Saheli et al. (2010) A Yersinia effector protein promotes virulence by preventing inflammasome recognition of the type III secretion system. Cell Host Microbe 7:376-87
McPhee, Joseph B; Mena, Patricio; Bliska, James B (2010) Delineation of regions of the Yersinia YopM protein required for interaction with the RSK1 and PRK2 host kinases and their requirement for interleukin-10 production and virulence. Infect Immun 78:3529-39
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Noel, Betty L; Lilo, Sarit; Capurso, Daniel et al. (2009) Yersinia pestis can bypass protective antibodies to LcrV and activation with gamma interferon to survive and induce apoptosis in murine macrophages. Clin Vaccine Immunol 16:1457-66
Zhang, Yue; Murtha, James; Roberts, Margaret A et al. (2008) Type III secretion decreases bacterial and host survival following phagocytosis of Yersinia pseudotuberculosis by macrophages. Infect Immun 76:4299-310
Lilo, Sarit; Zheng, Ying; Bliska, James B (2008) Caspase-1 activation in macrophages infected with Yersinia pestis KIM requires the type III secretion system effector YopJ. Infect Immun 76:3911-23

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