Despite Chlamydia trachomatis being the leading cause of reportable bacterial sexually transmitted infections (STIs) in the U.S. and worldwide, a significant knowledge gap exists regarding how Chlamydia regulates and executes its essential developmental cycle. Disruption of development through novel inhibitors or creation of mutants using state-of-the-art genetic approaches will facilitate advancement of antimicrobials or production of live-attenuated vaccine strains. Improved methods for treating and preventing chlamydial STIs will positively impact human health and the world economy by reducing rates of infertility, pelvic inflammatory disease, ectopic pregnancies, HIV transmission, and HPV-associated cervical cancer. Ser/Thr/Tyr protein phosphorylation is a dynamic and reversible mechanism for controlling protein function that has been increasingly recognized as a widely-employed method for regulating bacterial growth and survival and therefore pathogenesis. The overall objective of our R15 renewal application is to determine how phosphorylation modulates chlamydial growth and development. We hypothesize that the chlamydial kinases and phosphatases, including a phospho-regulated partner switching mechanism (PSM), orchestrate essential changes in development and growth by converting signals into alterations in physiology by modification of substrate function through reversible phosphorylation. Our premise is supported by the: 1) presence of global protein phosphorylation in Chlamydia that is enriched in the elementary body (EB) form compared to the reticulate body (RB) form, 2) conservation of the kinases and kinase substrates, a phosphatase, and the PSM proteins across Chlamydia, 3) inhibition of growth when PknD (kinase) or Cpp1 (phosphatase) are inhibited, and 4) alteration in growth due to genetic modulation of PSM components. Consequently, we predict that disruption of protein phosphorylation will inhibit bacterial growth. We will address our hypothesis in three Aims:
Aim 1. Defining how the pseudokinase Pkn5 impacts chlamydial metabolism and growth, Aim 2. Delineating the role of Cpp1, a PP2C class phosphatase, in bacterial development, and Aim 3. Elucidating the contribution of the PSM to growth rate. In addition, consistent with the mission of AREA grants, the project will involve undergraduate and graduate students in research. Collectively, our studies will: 1) address gaps in the understanding of chlamydial development, 2) identify novel targets for drugs and potential inhibitors, and 3) further illuminate the importance of protein phosphorylation to bacterial physiology and pathogenesis.

Public Health Relevance

The Chlamydia are a group of bacterial pathogens responsible for a variety of infections in humans including pneumonia, trachoma, and the leading cause of reportable, bacterial sexually transmitted infections (over 1.59 million cases were reported in 2016 in the United States). Understanding how these important pathogens control their developmental cycle and growth is critical for the expansion of strategies to prevent and treat infections. Our proposal will specifically study the role that protein phosphorylation (a modification used to alter protein function) plays in the physiology and virulence of Chlamydia trachomatis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Academic Research Enhancement Awards (AREA) (R15)
Project #
2R15AI109566-02
Application #
9597808
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Vincent, Leah Rebecca
Project Start
2018-06-01
Project End
2021-05-31
Budget Start
2018-06-01
Budget End
2021-05-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Southern Illinois University Carbondale
Department
Microbiology/Immun/Virology
Type
Schools of Arts and Sciences
DUNS #
939007555
City
Carbondale
State
IL
Country
United States
Zip Code
62901
Claywell, Ja E; Matschke, Lea M; Plunkett, Kyle N et al. (2018) Inhibition of the Protein Phosphatase CppA Alters Development of Chlamydia trachomatis. J Bacteriol 200:
Key, Charlotte E; Fisher, Derek J (2017) Use of Group II Intron Technology for Targeted Mutagenesis in Chlamydia trachomatis. Methods Mol Biol 1498:163-177
Claywell, Ja E; Fisher, Derek J (2016) CTL0511 from Chlamydia trachomatis Is a Type 2C Protein Phosphatase with Broad Substrate Specificity. J Bacteriol 198:1827-1836
Claywell, Ja E; Matschke, Lea M; Fisher, Derek J (2016) The Impact of Protein Phosphorylation on Chlamydial Physiology. Front Cell Infect Microbiol 6:197
Hooppaw, Anna J; Fisher, Derek J (2015) A Coming of Age Story: Chlamydia in the Post-Genetic Era. Infect Immun 84:612-21
Thompson, Christopher C; Griffiths, Cherry; Nicod, Sophie S et al. (2015) The Rsb Phosphoregulatory Network Controls Availability of the Primary Sigma Factor in Chlamydia trachomatis and Influences the Kinetics of Growth and Development. PLoS Pathog 11:e1005125
Fisher, Derek J; Adams, Nancy E; Maurelli, Anthony T (2015) Phosphoproteomic analysis of the Chlamydia caviae elementary body and reticulate body forms. Microbiology 161:1648-58
Lowden, Nicole M; Yeruva, Laxmi; Johnson, Cayla M et al. (2015) Use of aminoglycoside 3' adenyltransferase as a selection marker for Chlamydia trachomatis intron-mutagenesis and in vivo intron stability. BMC Res Notes 8:570