The Type III Secretion System-Related CPn0809 from Chlamydia pneumoniae
Astrid C Engel1, Frauke Herbst1, Anne Kerres1
1Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, Düsseldorf, Germany.
Plos One
|February 20, 2016
Summary
Chlamydia pneumoniae uses a type III secretion system (T3SS) to infect host cells. This study identifies CPn0809 as a likely translocon protein crucial for T3SS function during infection.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Chlamydia pneumoniae is an intracellular bacterium employing a type III secretion system (T3SS) for host cell invasion.
- The T3SS translocon complex is vital for delivering effector proteins into host cells, but chlamydial translocons remain poorly understood.
- C. pneumoniae uniquely possesses two putative translocon operons, LcrH_1 and LcrH_2.
Purpose of the Study:
- To characterize CPn0809, a putative translocator protein encoded by the LcrH_1 operon in C. pneumoniae.
- To elucidate the role of CPn0809 in the T3SS machinery and its association with the infection cycle.
Main Methods:
- Bioinformatic analysis to identify functional domains within CPn0809.
- Microscopy techniques (bright-field and confocal) to visualize CPn0809 localization during infection.
- Biochemical assays to study protein oligomerization and interactions with T3SS components.
- Heterologous expression in E. coli to assess cytotoxic effects.
Main Results:
- CPn0809 contains an 'SseC-like family' domain, characteristic of T3S translocators.
- CPn0809 localizes with elementary bodies (EBs) during early and late stages of C. pneumoniae infection.
- CPn0809 forms oligomers and interacts with the T3SS chaperone LcrH_1.
- Expression of CPn0809 in E. coli induces significant cytotoxicity, leading to cell death.
Conclusions:
- CPn0809 is identified as a likely translocon protein component of the C. pneumoniae T3SS.
- CPn0809 may play a critical role in effector protein translocation during the early phases of infection.
- Further investigation into CPn0809 function can provide insights into chlamydial pathogenesis and T3SS mechanisms.
More Related Videos
09:12Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System
Published on: March 10, 2020
7.8K
07:18Application of Biolayer Interferometry BLI for Studying Protein-Protein Interactions in Transcription
Published on: July 26, 2019
14.8K
Related Concept Videos
01:17Gram-negative Bacterial Protein Secretion Systems
1.4K
Gram-negative bacteria utilize sophisticated protein secretion systems to transport proteins across their double-membrane envelope into the extracellular environment or host cells. Based on their mechanism of action, these systems are classified into one-step and two-step pathways.One-Step Secretion Systems (Types I, III, IV, and VI)One-step secretion systems bypass the periplasm entirely, forming a continuous channel that spans both the inner and outer membranes:Type I Secretion System (T1SS):...
1.4K
01:29Bacterial Phylum Chlamydiae
698
The phylum Chlamydiae or Chlamydiota is composed of a single order, Chlamydiales. This phylum consists entirely of obligate intracellular parasites that infect eukaryotic hosts. While human pathogens within this group have been studied extensively, the phylum encompasses many species capable of interacting with various eukaryotic organisms. Members of Chlamydiae are typically small cocci, approximately 0.5 μm in diameter, and exhibit a distinctive developmental cycle. As is characteristic...
698
01:14Atypical Pneumonia
33
Atypical pneumonia, often caused by Mycoplasma pneumoniae, is a form of pulmonary infection that differs from the classical presentation of bacterial pneumonia in both its cause and clinical symptoms. Mycoplasma pneumoniae is a pleomorphic bacterium notable for its lack of a rigid cell wall. This structural characteristic imparts resistance to beta-lactam antibiotics and significantly influences the bacterium’s behavior within the human host.Other pathogens responsible for the disease...
33
01:26Bacterial Translocation and Protein Secretion
980
Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...
980
01:19Mechanism of Conjugation
1.4K
Bacterial conjugation is a mechanism of horizontal gene transfer that enables the exchange of genetic material between bacterial cells through direct contact. This process is facilitated by a donor cell carrying a conjugative plasmid, which encodes genes necessary for pilus formation, DNA replication, and transfer. The conjugative plasmid plays a central role in initiating and executing the transfer of genetic material.The tra region of the conjugative plasmid encodes proteins responsible for...
1.4K
01:28Regulation of Bacterial Virulence
14
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
14