Effector translocation by the Legionella Dot/Icm type IV secretion system.
1Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA.
Current Topics in Microbiology and Immunology
|August 7, 2013
Summary
Legionella pneumophila evades host defenses using the Dot/Icm type IV secretion system. This review details factors influencing the translocation of effector proteins, crucial for bacterial survival and Legionnaires' disease pathogenesis.
Area of Science:
- Microbiology
- Cell Biology
- Pathogen-Host Interactions
Background:
- Legionella pneumophila causes Legionnaires' disease, a severe pneumonia.
- The bacterium survives intracellularly within host phagocytes by evading immune responses.
- This intracellular survival is critically dependent on the Dot/Icm type IV secretion system.
Purpose of the Study:
- To review recent advancements in understanding the Dot/Icm type IV secretion system.
- To elucidate the factors governing the translocation of effector proteins into host cells.
- To highlight mechanisms enabling L. pneumophila's intracellular replication and pathogenesis.
Main Methods:
- Literature review of recent studies on Legionella pneumophila Dot/Icm system.
- Analysis of factors influencing protein translocation: substrate signals, chaperones, transcriptional regulation, and protein stability.
- Synthesis of current knowledge on Dot/Icm substrate delivery and host cell manipulation.
Main Results:
- The Dot/Icm system mediates the injection of numerous effector proteins into host cells.
- Protein translocation is a complex process influenced by substrate-specific signals and host-pathogen interactions.
- Factors like protein folding, stability, and temporal expression are critical for effective effector delivery.
Conclusions:
- Understanding the Dot/Icm translocation mechanism is key to deciphering L. pneumophila pathogenesis.
- Continued research into translocation factors will reveal novel therapeutic targets for Legionnaires' disease.
- The Dot/Icm system represents a sophisticated virulence factor essential for bacterial intracellular survival.
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