Legionella pneumophila, the etiological agent of Legionnaires'disease is an intracellular pathogen. Essential to its pathogenicity is the Dot/Icm type IV secretion system that translocates a large number of bacterial effectors into host cell. These effectors modulate multiple host cell processes to create an endoplasmic reticulum (ER) derived organelle permissive for Legionella intracellular growth. We recently found that one of such effectors called SidJ plays an important role in the biogenesis of replicative Legionella-containing vacuoles (LCVs) and loss of SidJ results in a temporal delay in the recruitment of ER proteins to the LCVs. Further studies indicate that SidJ is a protein phosphatase that interacts with and dephosphorylates Sec31, the major subunit of the outer shell complexes of the COPII-coated vesicles. Our working hypothesis is that SidJ, by coordinating with other effectors, redirects the trafficking of COPII-coated vesicles to the bacterial phagosomes. The goal of this project is to characterize SidJ and its protein phosphatase activity in Legionella infection using genetic, biochemical and cell biological approaches. We propose to: 1) Analyzing the interactions between SidJ and Sec31 and the effect of SidJ on host secretory pathways. 2) Studying the functional consequence of SidJ-Sec31 interaction on COPII coated vesicle formation. 3) Identification and characterization of effectors that function synergistically with SidJ. Results from this study will contribute to the emerging field of cellular microbiology and to the field of cell biology, particularly the roles of protein phosphorylation of COPII components in the regulation of vesicle trafficking. These studies will also expand our research capacity, thus allowing us to establish a research program with a broader spectrum of projects. A K02 award would allow me to invest more effort to develop my research career by exploring and acquiring background knowledge and new techniques necessary for future success in this multidisciplinary field. Relevance: Because of its potential fatality, infection by Legionella pneumophila is a concern of public health. Our study can provide novel strategies for its prevention and/or treatment. Furthermore, understanding of mammalian cell processes affected by this bacterium could lead to clues in our study of other diseases associated with abnormality of these processes. Project Narrative: Infection by Legionella pneumophila often leads to the development of a fatal form of pneumonia. In addition, study on this bacterium could share light on our understanding of other intracellular pathogens because L. pneumophila and these infectious agents share many pathogenic mechanisms.

Public Health Relevance

Infection by Legionella pneumophila often leads to the development of a fatal form of pneumonia. In addition, study on this bacterium could share light on our understanding of other intracellular pathogens because L. pneumophila and these infectious agents share many pathogenic mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Scientist Development Award - Research (K02)
Project #
5K02AI085403-05
Application #
8617206
Study Section
Microbiology and Infectious Diseases B Subcommittee (MID)
Program Officer
Perdue, Samuel S
Project Start
2010-03-15
Project End
2015-02-28
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
5
Fiscal Year
2014
Total Cost
$111,201
Indirect Cost
$8,237
Name
Purdue University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907
Weber, Mary M; Faris, Robert; van Schaik, Erin J et al. (2016) The Type IV Secretion System Effector Protein CirA Stimulates the GTPase Activity of RhoA and Is Required for Virulence in a Mouse Model of Coxiella burnetii Infection. Infect Immun 84:2524-33
Zhu, Wenhan; Luo, Zhao-Qing (2016) Cell biology and immunology lessons taught by Legionella pneumophila. Sci China Life Sci 59:3-10
Lu, Canhua; Nakayasu, Ernesto S; Zhang, Li-Qun et al. (2016) Identification of Fic-1 as an enzyme that inhibits bacterial DNA replication by AMPylating GyrB, promoting filament formation. Sci Signal 9:ra11
Qiu, Jiazhang; Sheedlo, Michael J; Yu, Kaiwen et al. (2016) Ubiquitination independent of E1 and E2 enzymes by bacterial effectors. Nature 533:120-4
Wang, Tietao; Si, Meiru; Song, Yunhong et al. (2015) Type VI Secretion System Transports Zn2+ to Combat Multiple Stresses and Host Immunity. PLoS Pathog 11:e1005020
Sheedlo, Michael J; Qiu, Jiazhang; Tan, Yunhao et al. (2015) Structural basis of substrate recognition by a bacterial deubiquitinase important for dynamics of phagosome ubiquitination. Proc Natl Acad Sci U S A 112:15090-5
Zhu, Wenhan; Luo, Zhao-Qing (2015) A new way to detect the danger: Lysosomal cell death induced by a bacterial ribosomal protein. J Nat Sci 1:
Luo, Xi; Wasilko, David J; Liu, Yao et al. (2015) Structure of the Legionella Virulence Factor, SidC Reveals a Unique PI(4)P-Specific Binding Domain Essential for Its Targeting to the Bacterial Phagosome. PLoS Pathog 11:e1004965
Zhu, Wenhan; Tao, Lili; Quick, Marsha L et al. (2015) Sensing cytosolic RpsL by macrophages induces lysosomal cell death and termination of bacterial infection. PLoS Pathog 11:e1004704
Cui, Boyu; Wang, Yao; Song, Yunhong et al. (2014) Bioluminescence resonance energy transfer system for measuring dynamic protein-protein interactions in bacteria. MBio 5:e01050-14

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