Related Experiment Videos
Three-dimensional secretion signals in chaperone-effector complexes of bacterial pathogens
Sara C Birtalan1, Rebecca M Phillips, Partho Ghosh
1Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
Molecular Cell
|June 7, 2002
Summary
Gram-negative bacteria use the type III secretion system (TTSS) to inject virulence proteins into host cells. Chaperones, essential for this process, were found to interact with only a small part of the effector protein.
Area of Science:
- Microbiology
- Molecular Biology
- Structural Biology
Background:
- Gram-negative pathogens utilize the type III secretion system (TTSS) to deliver effector proteins into host cells, crucial for virulence.
- The precise mechanism by which cognate chaperones facilitate effector protein delivery via TTSS remains largely unknown.
Purpose of the Study:
- To elucidate the mechanism of chaperone action in the type III secretion system.
- To investigate the structural and functional relationship between the SycE chaperone and its YopE effector in Yersinia.
Main Methods:
- Biochemical assays
- Crystallographic analysis of the SycE-YopE chaperone-effector complex
Main Results:
- The study revealed that chaperone SycE interacts with only a limited region of the effector YopE, challenging prior models.
- Evidence suggests stereochemical conservation in chaperone-effector interactions across different TTSS, despite sequence dissimilarity.
- These conserved interactions may function as general, three-dimensional secretion signals for the TTSS.
Conclusions:
- Chaperone action in TTSS is localized to a specific effector domain, not the entire protein.
- Chaperone-effector complexes may act as conserved, structural signals for type III secretion.
- This mechanism could potentially regulate the temporal order of effector protein secretion.