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The ESX system in Bacillus subtilis mediates protein secretion
Laura A Huppert1, Talia L Ramsdell2, Michael R Chase2
1Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America.
Plos One
|May 7, 2014
Summary
Bacillus subtilis utilizes a novel Esat-6 protein secretion system (ESX) for virulence factor YukE export. This system, encoded by the yuk/yue locus, highlights a unique substrate secretion mechanism in bacteria.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Esat-6 protein secretion systems (ESX) are crucial for the virulence of human pathogens like Mycobacterium tuberculosis and Staphylococcus aureus.
- ESX systems are characterized by an FtsK/SpoIIIE family ATPase and WXG100 family secreted substrates.
- ESX gene clusters are found in various organisms, including the model bacterium Bacillus subtilis.
Purpose of the Study:
- To investigate the yuk/yue locus in Bacillus subtilis as a potential ESX secretion system.
- To confirm the role of the yuk/yue gene products in the secretion of the WXG100 homolog, YukE.
- To identify additional secreted substrates dependent on this ESX system.
Main Methods:
- Development of a functional secretion assay to assess gene product requirements.
- Quantitative profiling of culture supernatants to identify secreted proteins.
- Genetic analysis of the B. subtilis yuk/yue locus.
Main Results:
- The B. subtilis yuk/yue locus encodes a nonessential ESX secretion system.
- All gene products within the yuk/yue locus are specifically required for YukE secretion.
- YukE appears to be the sole substrate dependent on the FtsK/SpoIIIE family ATPase for secretion by this system.
Conclusions:
- The yuk/yue locus represents a distinct ESX secretion system in Bacillus subtilis.
- This system uniquely secretes a single substrate, YukE, highlighting functional diversity in ESX mechanisms.
- Further research is needed to elucidate the functional implications of this unique secretion strategy.
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