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Structures of Type III Secretion System Needle Filaments
Birgit Habenstein1, Nadia El Mammeri2, James Tolchard2
1University of Bordeaux, CNRS, UMR 5248, European Institute of Chemistry and Biology, 2 rue Robert Escarpit, Pessac, 33607, France. b.habenstein@iecb.u-bordeaux.fr.
Current Topics in Microbiology and Immunology
|January 25, 2020
Summary
Type III secretion systems (T3SS) use a needle structure for bacterial protein delivery. Advanced imaging reveals the needle
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Type III secretion systems (T3SS) are crucial virulence factors in Gram-negative bacteria.
- The T3SS needle is a conserved, helical protein filament forming a conduit for effector proteins.
Purpose of the Study:
- To summarize current knowledge on the structure and function of the T3SS needle.
- To highlight the role of the needle in bacterial pathogenesis and protein secretion.
Main Methods:
- Cryo-electron microscopy (cryo-EM) and solid-state NMR (SSNMR) spectroscopy.
- Analysis of high-resolution structures of T3SS needles from Salmonella typhimurium and Shigella flexneri.
Main Results:
- Detailed atomic resolution structures of T3SS needles have been elucidated.
- A common structural fold is conserved across different bacterial species.
- Structural models explain signal transduction and effector protein injection.
Conclusions:
- The T3SS needle is a complex molecular machine essential for bacterial virulence.
- Structural insights are key to understanding T3SS assembly and function.
- Further research can leverage these findings for therapeutic strategies.
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