Legionella pneumophila and Coxiella burnetii are intracellular bacterial pathogens capable of causing human disease. A notable feature of these two pathogens is that they retain a common virulence determinant that is essential for their ability to replicate intracellularly, which is the specialized type IV secretion system (T4SS) called Dot/Icm. The Dot/Icm is an incredibly versatile secretion apparatus that has the capacity to translocate into host cells a repertoire of over 300 different proteins with different biochemical functions and diverse structural properties. The goal of this project is to determine the structure and assembly of the Dot/Icm machine and elucidate how the individual Dot and Icm proteins contribute to machine function at the molecular level. We will combine advanced cryo-electron tomography (cryo-ET) with genetic and biochemical approaches to determine the pathway of Dot/Icm machine assembly (Aim 1) and to determine the mechanism by which cytosolic ATPases recruit effectors and mediate changes in the Dot/Icm structure (Aim 2). Furthermore, we aim to characterize the translocation pore in the host cell membrane that serves as the protein-conducting channel for Dot/Icm effectors (Aim 3).

Public Health Relevance

/Relevance The Dot/Icm type IV secretion system is a versatile virulence nanomachine that has the amazing capacity to translocate into host cells a repertoire of over 300 different bacterial proteins during infection. The proposed work promises to provide mechanistic insights into structure and function of this fascinating nanomachine in intracellular bacterial pathogens: Legionella pneumophila and Coxiella burnetii.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI152421-01A1
Application #
10142816
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Ernst, Nancy L
Project Start
2020-09-16
Project End
2025-08-31
Budget Start
2020-09-16
Budget End
2021-08-31
Support Year
1
Fiscal Year
2020
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
06520