scholarly journals Gliding Motility and Por Secretion System Genes Are Widespread among Members of the Phylum Bacteroidetes

2012 ◽  
Vol 195 (2) ◽  
pp. 270-278 ◽  
Author(s):  
Mark J. McBride ◽  
Yongtao Zhu

ABSTRACTThe phylumBacteroidetesis large and diverse, with rapid gliding motility and the ability to digest macromolecules associated with many genera and species. Recently, a novel protein secretion system, the Por secretion system (PorSS), was identified in two members of the phylum, the gliding bacteriumFlavobacterium johnsoniaeand the nonmotile oral pathogenPorphyromonas gingivalis. The components of the PorSS are not similar in sequence to those of other well-studied bacterial secretion systems. TheF. johnsoniaePorSS genes are a subset of the gliding motility genes, suggesting a role for the secretion system in motility. TheF. johnsoniaePorSS is needed for assembly of the gliding motility apparatus and for secretion of a chitinase, and theP. gingivalisPorSS is involved in secretion of gingipain protease virulence factors. Comparative analysis of 37 genomes of members of the phylumBacteroidetesrevealed the widespread occurrence of gliding motility genes and PorSS genes. Genes associated with other bacterial protein secretion systems were less common. The results suggest that gliding motility is more common than previously reported. Microscopic observations confirmed that organisms previously described as nonmotile, includingCroceibacter atlanticus, “Gramella forsetii,”Paludibacter propionicigenes,Riemerella anatipestifer, andRobiginitalea biformata, exhibit gliding motility. Three genes (gldA,gldF, andgldG) that encode an apparent ATP-binding cassette transporter required forF. johnsoniaegliding were absent from two related gliding bacteria, suggesting that the transporter may not be central to gliding motility.

2017 ◽  
Vol 200 (2) ◽  
Author(s):  
Joseph J. Johnston ◽  
Abhishek Shrivastava ◽  
Mark J. McBride

ABSTRACTFlavobacterium johnsoniaeexhibits rapid gliding motility over surfaces. At least 20 genes are involved in this process. Seven of these,gldK,gldL,gldM,gldN,sprA,sprE, andsprT, encode proteins of the type IX protein secretion system (T9SS). The T9SS is required for surface localization of the motility adhesins SprB and RemA, and for secretion of the soluble chitinase ChiA. Here, we demonstrate that the gliding motility proteins GldA, GldB, GldD, GldF, GldH, GldI, and GldJ are also essential for secretion. Cells with mutations in the genes encoding any of these seven proteins had normal levels ofgldKmRNA but dramatically reduced levels of the GldK protein, which may explain the secretion defects of the motility mutants. GldJ is necessary for stable accumulation of GldK, and each mutant lacked the GldJ protein.F. johnsoniaecells that produced truncated GldJ, lacking eight to 13 amino acids from the C terminus, accumulated GldK but were deficient in gliding motility. SprB was secreted by these cells but was not propelled along their surfaces. This C-terminal region of GldJ is thus required for gliding motility but not for secretion. The identification of mutants that are defective for motility but competent for secretion begins to untangle theF. johnsoniaegliding motility machinery from the T9SS.IMPORTANCEMany members of the phylumBacteroidetessecrete proteins using T9SSs. T9SSs appear to be confined to members of this phylum. Many of these bacteria also glide rapidly over surfaces using a motility machine that is also confined to theBacteroidetesand appears to be intertwined with the T9SS. This study identifiesF. johnsoniaeproteins that are required for both T9SS function and gliding motility. It also provides an explanation for the link between secretion and gliding and identifies mutants with defects in motility but not secretion.


2014 ◽  
Vol 197 (1) ◽  
pp. 147-158 ◽  
Author(s):  
Sampada S. Kharade ◽  
Mark J. McBride

Flavobacterium johnsoniaeexhibits gliding motility and digests many polysaccharides, including chitin. A novel protein secretion system, the type IX secretion system (T9SS), is required for gliding and chitin utilization. The T9SS secretes the cell surface motility adhesins SprB and RemA and the chitinase ChiA. Proteins involved in secretion by the T9SS include GldK, GldL, GldM, GldN, SprA, SprE, and SprT.Porphyromonas gingivalishas orthologs for each of these that are required for secretion of gingipain protease virulence factors by its T9SS.P. gingivalisporUandporVhave also been linked to T9SS-mediated secretion, andF. johnsoniaehas orthologs of these. Mutations inF. johnsoniaeporUandporVwere constructed to determine if they function in secretion. Cells of aporVdeletion mutant were deficient in chitin utilization and failed to secrete ChiA. They were also deficient in secretion of the motility adhesin RemA but retained the ability to secrete SprB. SprB is involved in gliding motility and is needed for formation of spreading colonies on agar, and theporVmutant exhibited gliding motility and formed spreading colonies. However, theporVmutant was partially deficient in attachment to glass, apparently because of the absence of RemA and other adhesins on the cell surface. TheporVmutant also appeared to be deficient in secretion of numerous other proteins that have carboxy-terminal domains associated with targeting to the T9SS. PorU was not required for secretion of ChiA, RemA, or SprB, indicating that it does not play an essential role in theF. johnsoniaeT9SS.


2020 ◽  
Vol 9 (7) ◽  
Author(s):  
Shicheng Chen ◽  
Edward D. Walker

The bacterium Flavobacteriaceae strain W22 was isolated from the water column of a tree hole larval habitat of the mosquito Aedes triseriatus. The draft genome contained 3,796,379 bp, a G+C content of 35.4%, and several genes encoding enzymes functioning in polysaccharide degradation, gliding motility, and the type IX protein secretion system (T9SS).


2017 ◽  
Vol 83 (23) ◽  
Author(s):  
Nan Li ◽  
Yongtao Zhu ◽  
Benjamin R. LaFrentz ◽  
Jason P. Evenhuis ◽  
David W. Hunnicutt ◽  
...  

ABSTRACT Flavobacterium columnare, a member of the phylum Bacteroidetes, causes columnaris disease in wild and aquaculture-reared freshwater fish. The mechanisms responsible for columnaris disease are not known. Many members of the phylum Bacteroidetes use type IX secretion systems (T9SSs) to secrete enzymes, adhesins, and proteins involved in gliding motility. The F. columnare genome has all of the genes needed to encode a T9SS. gldN, which encodes a core component of the T9SS, was deleted in wild-type strains of F. columnare. The F. columnare ΔgldN mutants were deficient in the secretion of several extracellular proteins and lacked gliding motility. The ΔgldN mutants exhibited reduced virulence in zebrafish, channel catfish, and rainbow trout, and complementation restored virulence. PorV is required for the secretion of a subset of proteins targeted to the T9SS. An F. columnare ΔporV mutant retained gliding motility but exhibited reduced virulence. Cell-free spent media from exponentially growing cultures of wild-type and complemented strains caused rapid mortality, but spent media from ΔgldN and ΔporV mutants did not, suggesting that soluble toxins are secreted by the T9SS. IMPORTANCE Columnaris disease, caused by F. columnare, is a major problem for freshwater aquaculture. Little is known regarding the virulence factors produced by F. columnare, and control measures are limited. Analysis of targeted gene deletion mutants revealed the importance of the type IX protein secretion system (T9SS) and of secreted toxins in F. columnare virulence. T9SSs are common in members of the phylum Bacteroidetes and likely contribute to the virulence of other animal and human pathogens.


2009 ◽  
Vol 192 (5) ◽  
pp. 1201-1211 ◽  
Author(s):  
Ryan G. Rhodes ◽  
Mudiarasan Napoleon Samarasam ◽  
Abhishek Shrivastava ◽  
Jessica M. van Baaren ◽  
Soumya Pochiraju ◽  
...  

ABSTRACT Cells of the gliding bacterium Flavobacterium johnsoniae move rapidly over surfaces. Mutations in gldN cause a partial defect in gliding. A novel bacteriophage selection strategy was used to aid construction of a strain with a deletion spanning gldN and the closely related gene gldO in an otherwise wild-type F. johnsoniae UW101 background. Bacteriophage transduction was used to move a gldN mutation into F. johnsoniae UW101 to allow phenotypic comparison with the gldNO deletion mutant. Cells of the gldN mutant formed nonspreading colonies on agar but retained some ability to glide in wet mounts. In contrast, cells of the gldNO deletion mutant were completely nonmotile, indicating that cells require GldN, or the GldN-like protein GldO, to glide. Recent results suggest that Porphyromonas gingivalis PorN, which is similar in sequence to GldN, has a role in protein secretion across the outer membrane. Cells of the F. johnsoniae gldNO deletion mutant were defective in localization of the motility protein SprB to the cell surface, suggesting that GldN may be involved in secretion of components of the motility machinery. Cells of the gldNO deletion mutant were also deficient in chitin utilization and were resistant to infection by bacteriophages, phenotypes that may also be related to defects in protein secretion.


2015 ◽  
Vol 197 (7) ◽  
pp. 1263-1275 ◽  
Author(s):  
Wanyin Deng ◽  
Hong B. Yu ◽  
Yuling Li ◽  
B. Brett Finlay

ABSTRACTThe type III protein secretion system (T3SS) encoded by the locus of enterocyte effacement (LEE) is essential for the pathogenesis of attaching/effacing bacterial pathogens, including enteropathogenicEscherichia coli(EPEC), enterohemorrhagicE. coli(EHEC), andCitrobacter rodentium. These pathogens use the T3SS to sequentially secrete three categories of proteins: the T3SS needle and inner rod protein components; the EspA, EspB, and EspD translocators; and many LEE- and non-LEE-encoded effectors. SepD and SepL are essential for translocator secretion, and mutations in either lead to hypersecretion of effectors. However, how SepD and SepL control translocator secretion and secretion hierarchy between translocators and effectors is poorly understood. In this report, we show that the secreted T3SS components, the translocators, and both LEE- and non-LEE-encoded effectors all carry N-terminal type III secretion and translocation signals. These signals all behave like those of the effectors and are sufficient for mediating type III secretion and translocation by wild-type EPEC and hypersecretion by thesepDandsepLmutants. Our results extended previous observations and suggest that the secretion hierarchy of the different substrates is determined by a signal other than the N-terminal secretion signal. We identified a domain located immediately downstream of the N-terminal secretion signal in the translocator EspB that is required for SepD/SepL-dependent secretion. We further demonstrated that this EspB domain confers SepD/SepL- and CesAB-dependent secretion on the secretion signal of effector EspZ. Our results thus suggest that SepD and SepL control and regulate secretion hierarchy between translocators and effectors by recognizing translocator-specific export signals.IMPORTANCEMany bacterial pathogens use a syringe-like protein secretion apparatus, termed the type III protein secretion system (T3SS), to secrete and inject numerous proteins directly into the host cells to cause disease. The secreted proteins perform different functions at various stages during infection and are classified into three substrate categories (T3SS components, translocators, and effectors). They all contain secretion signals at their N termini, but how their secretion hierarchy is determined is poorly understood. Here, we show that the N-terminal secretion signals from different substrate categories all behave the same and do not confer substrate specificity. We further characterize the secretion signals of the translocators and identify a translocator-specific signal, demonstrating that substrate-specific secretion signals are required in regulating T3SS substrate hierarchy.


mBio ◽  
2021 ◽  
Author(s):  
Steven J. Hersch ◽  
Linh Lam ◽  
Tao G. Dong

Delivery of protein-based drugs, antigens, and gene-editing agents has broad applications. The type VI protein secretion system (T6SS) can target both bacteria and eukaryotic cells and deliver proteins of diverse size and function.


2009 ◽  
Vol 107 (1) ◽  
pp. 276-281 ◽  
Author(s):  
K. Sato ◽  
M. Naito ◽  
H. Yukitake ◽  
H. Hirakawa ◽  
M. Shoji ◽  
...  

2012 ◽  
Vol 78 (20) ◽  
pp. 7476-7479 ◽  
Author(s):  
Maged M. Saad ◽  
Michèle Crèvecoeur ◽  
Catherine Masson-Boivin ◽  
Xavier Perret

ABSTRACTCupriavidus taiwanensisforms proficient symbioses with a fewMimosaspecies. Inactivation of a type III protein secretion system (T3SS) had no effect onMimosa pudicabut allowedC. taiwanensisto establish chronic infections and fix nitrogen inLeucaena leucocephala. Unlike what was observed for other rhizobia, glutamate rather than plant flavonoids mediated transcriptional activation of this atypical T3SS.


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