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Untangling Flavobacterium johnsoniae Gliding Motility and Protein Secretion
Joseph J Johnston1, Abhishek Shrivastava1, Mark J McBride2
1Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA.
Journal of Bacteriology
|November 8, 2017
Summary
Flavobacterium johnsoniae gliding motility requires specific proteins for both surface movement and the type IX protein secretion system (T9SS). This study untangles these processes, identifying motility mutants that still secrete proteins.
Area of Science:
- Microbiology
- Bacterial Motility
- Protein Secretion
Background:
- Flavobacterium johnsoniae uses gliding motility, a process involving over 20 genes.
- Seven genes encode proteins for the type IX protein secretion system (T9SS), crucial for motility adhesin localization and enzyme secretion.
Purpose of the Study:
- To investigate the role of gliding motility proteins in secretion.
- To differentiate the mechanisms of gliding motility from the T9SS in F. johnsoniae.
Main Methods:
- Mutagenesis of gliding motility genes (gldA, gldB, gldD, gldF, gldH, gldI, gldJ).
- Analysis of protein levels (GldK, GldJ) and mRNA (gldK).
- Assessment of SprB secretion and surface translocation.
Main Results:
- Mutations in seven gld genes caused reduced GldK protein levels, impacting secretion.
- GldJ is essential for GldK stability; its absence prevents GldK accumulation.
- Truncated GldJ allowed GldK accumulation and SprB secretion but impaired motility, indicating a motility-specific function for GldJ's C-terminus.
Conclusions:
- Certain gliding motility proteins are essential for T9SS function in F. johnsoniae.
- The C-terminal region of GldJ is critical for motility but not secretion.
- This research distinguishes motility from secretion pathways in F. johnsoniae, offering insights into Bacteroidetes biology.
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