Elucidating the functions of bacterial secretion systems is important for a complete understanding of host pathogen interaction processes. Secretion systems are complex machines that inject effectors proteins into the host, and in some cases allow establishment of a replicative niche by promoting biogenesis of a cellular compartment that supports bacterial replication. In this project we will determine how the Legionella pneumophila Type IVB secretion system called Dot/Icm functions at the molecular level. This will be accomplished by studying the spatiotemporal dynamics of fluorescently tagged secretion system components using time-lapse video microscopy. Strains of Legionella that have been genetically modified to eliminate individual Dot and Icm proteins, and strains engineered to produce minicells, will be used to determine the structure of the Dot/Icm system by cryo-electron tomography. The overall goal of the project is to use imaging and molecular approaches to characterize what are the spatiotemporal dynamics processes that control Dot/Icm secretion system activity, and to visualize the Dot/icm system so that we have an understanding of the different subassemblies that comprise a functional Type IVB apparatus.

Public Health Relevance

The proposed work promises to provide important new tools for studying the Type IVB secretion system called Dot/Icm of the respiratory bacterial pathogen Legionella pneumophila yielding clues to the mechanism of function that are essential for its pathogenicity. Live bacterial cell imaging and structural studies are employed to dissect at the molecular level the activity of the Dot/Icm secretion system.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AI130671-01A1
Application #
9471901
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Ernst, Nancy L
Project Start
2017-12-15
Project End
2019-11-30
Budget Start
2017-12-15
Budget End
2018-11-30
Support Year
1
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Yale University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
Chetrit, David; Hu, Bo; Christie, Peter J et al. (2018) A unique cytoplasmic ATPase complex defines the Legionella pneumophila type IV secretion channel. Nat Microbiol 3:678-686