scholarly journals Protein Interactome Analysis of the Type IX Secretion System Identifies PorW as the Missing Link between the PorK/N Ring Complex and the Sov Translocon

2022 ◽  
Author(s):  
Dhana G. Gorasia ◽  
Ignacio Lunar Silva ◽  
Catherine A. Butler ◽  
Maïalène Chabalier ◽  
Thierry Doan ◽  
...  
Keyword(s):  
Cell Surface ◽  
Virulence Factors ◽  
Protein Secretion ◽  
Secretion System ◽  
Surface Attachment ◽  
Protein Interactome ◽  
Core Module ◽  
Ring Complex ◽  
Protein Secretion System ◽  
Type Ix Secretion System

The T9SS is a newly identified protein secretion system of the Fibrobacteres - Chlorobi - Bacteroidetes superphylum used by pathogens associated with diseases of humans, fish, and poultry for the secretion and cell surface attachment of virulence factors. The T9SS comprises three known modules: (i) the trans-envelope core module comprising the PorL/M motor and the PorK/N ring, (ii) the outer membrane Sov translocon, and (iii) the cell surface attachment complex.

scholarly journals Flavobacterium johnsoniae PorV Is Required for Secretion of a Subset of Proteins Targeted to the Type IX Secretion System

2014 ◽  
Vol 197 (1) ◽  
pp. 147-158 ◽  
Author(s):  
Sampada S. Kharade ◽  
Mark J. McBride
Keyword(s):  
Cell Surface ◽  
Secretion System ◽  
Gliding Motility ◽  
Content Type ◽  
Flavobacterium Johnsoniae ◽  
Protein Secretion System ◽  
Surface Motility ◽  
Type Ix Secretion System ◽  
Carboxy Terminal ◽  
Novel Protein

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.

scholarly journals Antieukaryotic Type Six Secretion System Virulence Factors of Bacteria

2020 ◽  
Author(s):  
Silindile Maphosa ◽  
Lucy Moleleki ◽  
Thabiso Motaung
Keyword(s):  
Virulence Factors ◽  
Protein Secretion ◽  
Physiological Responses ◽  
Secretion System ◽  
Special Focus ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Gram Negative ◽  
Bacterial Interactions ◽  
Protein Secretion System

The type 6 protein secretion system (T6SS) is prevalently utilized by Gram-negative bacteria to compete for resources and space. Upon activation, toxic effectors from this secretion system are translocated into the competitor prokaryote or eukaryote in a contact-dependent manner. While much has been reported on T6SS-mediated prokaryotic competition, very little is understood about the mechanisms of bacterial interactions with eukaryotic hosts. Likewise, many virulent T6SS effectors are known to be antibacterial. In recent years, however, evidence has emerged on numerous T6SS effectors that interact with related immunity proteins in a range of eukaryotic hosts. Insights into how this effector-immunity pairing alters the physiological responses of the recipient organism might provide opportunities relating to the T6SS agricultural and biotherapeutic applications. We, therefore, summarize the impacts of the T6SS effectors with a special focus on bacterial interactions with animals, plants, and fungi. We further briefly discuss pipelines that are currently used to characterize antieukaryotic T6SS effectors.

scholarly journals Antieukaryotic Type Six Secretion System Virulence Factors of Bacteria

2020 ◽  
Author(s):  
Silindile Maphosa ◽  
Thabiso Motaung ◽  
Lucy Moleleki
Keyword(s):  
Virulence Factors ◽  
Protein Secretion ◽  
Physiological Responses ◽  
Secretion System ◽  
Special Focus ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Gram Negative ◽  
Bacterial Interactions ◽  
Protein Secretion System

The type 6 protein secretion system (T6SS) is prevalently utilized by Gram-negative bacteria to compete for resources and space. Upon activation, toxic effectors from this secretion system are translocated into the competitor prokaryote or eukaryote in a contact-dependent manner. While much has been reported on T6SS-mediated prokaryotic competition, very little is understood about the mechanisms of bacterial interactions with eukaryotic hosts. Likewise, many virulent T6SS effectors are known to be antibacterial. In recent years, however, evidence has emerged on numerous T6SS effectors that interact with related immunity proteins in a range of eukaryotic hosts. Insights into how this effector-immunity pairing alters the physiological responses of the recipient organism might provide opportunities relating to the T6SS agricultural and biotherapeutic applications. We, therefore, summarize the impacts of the T6SS effectors with a special focus on bacterial interactions with animals, plants, and fungi. We further briefly discuss pipelines that are currently used to characterize antieukaryotic T6SS effectors.

scholarly journals Cytophaga hutchinsonii SprA and SprT Are Essential Components of the Type IX Secretion System Required for Ca2+ Acquisition, Cellulose Degradation, and Cell Motility

2021 ◽  
Vol 12 ◽  
Author(s):  
Lijuan Gao ◽  
Yahong Tan ◽  
Weican Zhang ◽  
Qingsheng Qi ◽  
Xuemei Lu
Keyword(s):  
Cell Surface ◽  
Protein Secretion ◽  
Cellulose Degradation ◽  
Secretion System ◽  
Gliding Motility ◽  
Uptake System ◽  
Cytophaga Hutchinsonii ◽  
Essential Components ◽  
Single Deletion ◽  
Type Ix Secretion System

The type IX secretion system (T9SS) is a novel protein secretion system, which is found in and confined to the phylum Bacteroidetes. T9SS is involved in the secretion of virulence factors, cell surface adhesins, and complex biopolymer degrading enzymes to the cell surface or extracellular medium. Cytophaga hutchinsonii is a widely distributed bacterium, which is able to efficiently digest cellulose and rapidly glide along the solid surfaces. C. hutchinsonii has a full set of orthologs of T9SS components. However, the functions of most homologous proteins have not been verified. In C. hutchinsonii, CHU_0029 and CHU_2709 are similar in sequence to Flavobacterium johnsoniae T9SS components SprA and SprT, respectively. In this study, the single deletion mutants of chu_0029 (sprA) and chu_2709 (sprT) were obtained using a complex medium with the addition of Ca2+ and Mg2+. Single deletion of sprA or sprT resulted in defects in cellulose utilization and gliding motility. Moreover, the ΔsprA and ΔsprT mutants showed growth defects in Ca2+- and Mg2+-deficient media. The results of ICP-MS test showed that both the whole cell and intracellular concentrations of Ca2+ were dramatically reduced in the ΔsprA and ΔsprT mutants, indicating that SprA and SprT are both important for the assimilation of trace amount of Ca2+. While the assimilation of Mg2+ was not obviously influenced in the ΔsprA and ΔsprT mutants. Through proteomics analysis of the cell surface proteins of the wild type and mutants, we found that the ΔsprA and ΔsprT mutants were defective in secretion of the majority of T9SS substrates. Together, these results indicate that SprA and SprT are both essential components of C. hutchinsonii T9SS, which is required for protein secretion, Ca2+ acquisition, cellulose degradation, and gliding motility in C. hutchinsonii. Our study shed more light on the functions of SprA and SprT in T9SS, and further proved the link between the T9SS and Ca2+ uptake system.

The Type IX Secretion System and Its Role in Bacterial Function and Pathogenesis

2021 ◽  
pp. 002203452110515
Author(s):  
P.D. Veith ◽  
M.D. Glew ◽  
D.G. Gorasia ◽  
E. Cascales ◽  
E.C. Reynolds
Keyword(s):  
Cell Surface ◽  
Outer Membrane ◽  
Virulence Factors ◽  
Secretion System ◽  
Outer Membrane Vesicles ◽  
Molecular Structures ◽  
Molecular Architecture ◽  
Cargo Proteins ◽  
Type Ix Secretion System ◽  
Insight Into

Porphyromonas, Tannerella, and Prevotella species found in severe periodontitis use the Type IX Secretion System (T9SS) to load their outer membrane surface with an array of virulence factors. These virulence factors are then released on outer membrane vesicles (OMVs), which penetrate the host to dysregulate the immune response to establish a positive feedback loop of chronic, inflammatory destruction of the tooth’s supporting tissues. In this review, we present the latest information on the molecular architecture of the T9SS and provide mechanistic insight into its role in secretion and attachment of cargo proteins to produce a virulence coat on cells and OMVs. The recent molecular structures of the T9SS motor comprising PorL and PorM as well as the secretion pore Sov, together with advances in the overall interactome, have provided insight into the possible mechanisms of secretion. We propose the presence of PorL/M motors arranged in a circle at the inner membrane with bent periplasmic rotors interacting with the PorN protein. At the outer membrane, we envisage a slide carousel model where the PorN protein is driven around a circular track composed of PorK. Cargo proteins are transported by PorN to PorW and the Sov translocon just as slides are rotated to the projection window. Secreted proteins are proposed to then be shuttled along highways consisting of the PorV shuttle protein to an array of attachment complexes distributed around the cell. The cell surface attachment of cargo is a hallmark of the T9SS, and in Porphyromonas gingivalis and Tannerella forsythia, this attachment is achieved via covalent bonding to a linking sugar synthesized by the Wbp/Vim pathway. The cell-surface attached cargo are enriched on OMVs, which are then released from the cell.

scholarly journals In situ structure and organisation of the type IX secretion system

2020 ◽  
Author(s):  
DG Gorasia ◽  
G Chreifi ◽  
CA Seers ◽  
CA Butler ◽  
JE Heath ◽  
...  
Keyword(s):  
Cell Surface ◽  
Outer Membrane ◽  
Electron Tomography ◽  
Secretion System ◽  
Gliding Motility ◽  
Type B ◽  
Surface Attachment ◽  
Flavobacterium Johnsoniae ◽  
Close Proximity ◽  
Type Ix Secretion System

AbstractThe Bacteroidetes type IX secretion system (T9SS) consists of at least 19 components that translocate proteins with a type A or type B C-terminal domain (CTD) signal across the outer membrane. The overall organisation and architecture of this system including how the secretion pore (Sov) interacts with the other components is unknown. We used cryo-electron tomography to obtain the first images of the T9SS including PorK/N rings inside intact Porphyromonas gingivalis cells. Using proteomics, we identified a novel complex between Sov, PorV and PorA and showed that Sov interacts with the PorK/N rings via PorW and a new component PGN_1783. A separate complex comprising the outer membrane β-barrel protein PorP, PorE, and the type B CTD protein PG1035 was also identified. Similarly, the Flavobacterium johnsoniae PorP-like protein, SprF was found bound to the major gliding motility adhesin, SprB. Based on these data, we propose cell surface anchorage for type B CTD proteins to PorP-like proteins and a unique model where the PorK/N rings function as an outer membrane barrier to maintain the close proximity of the translocon to the shuttle and attachment complexes inside the rings, ensuring the harmonized secretion and cell surface attachment of the T9SS substrates.

scholarly journals The Carboxy-Terminal Region ofFlavobacterium johnsoniaeSprB Facilitates Its Secretion by the Type IX Secretion System and Propulsion by the Gliding Motility Machinery

2019 ◽  
Vol 201 (19) ◽  
Author(s):  
Surashree S. Kulkarni ◽  
Joseph J. Johnston ◽  
Yongtao Zhu ◽  
Zachary T. Hying ◽  
Mark J. McBride
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cell Surface ◽  
Type A ◽  
Secretion System ◽  
Gliding Motility ◽  
Foreign Protein ◽  
Type B ◽  
Content Type ◽  
Type Ix Secretion System

ABSTRACTFlavobacterium johnsoniaeSprB moves rapidly along the cell surface, resulting in gliding motility. SprB secretion requires the type IX secretion system (T9SS). Proteins secreted by the T9SS typically have conserved C-terminal domains (CTDs) belonging to the type A CTD or type B CTD family. Attachment of 70- to 100-amino-acid type A CTDs to a foreign protein allows its secretion. Type B CTDs are common but have received little attention. Secretion of the foreign protein superfolder green fluorescent protein (sfGFP) fused to regions spanning the SprB type B CTD (sfGFP-CTDSprB) was analyzed. CTDs of 218 amino acids or longer resulted in secretion of sfGFP, whereas a 149-amino-acid region did not. Some sfGFP was secreted in soluble form, whereas the rest was attached on the cell surface. Surface-attached sfGFP was rapidly propelled along the cell, suggesting productive interaction with the motility machinery. This did not result in rapid cell movement, which apparently requires additional regions of SprB. Secretion of sfGFP-CTDSprBrequired coexpression withsprF, which lies downstream ofsprB. SprF is similar in sequence toPorphyromonas gingivalisPorP. MostF. johnsoniaegenes encoding proteins with type B CTDs lie immediately upstream ofporP/sprF-like genes. sfGFP was fused to the type B CTD from one such protein (Fjoh_3952). This resulted in secretion of sfGFP only when it was coexpressed with its cognate PorP/SprF-like protein. These results highlight the need for extended regions of type B CTDs and for coexpression with the appropriate PorP/SprF-like protein for efficient secretion and cell surface localization of cargo proteins.IMPORTANCETheF. johnsoniaegliding motility adhesin SprB is delivered to the cell surface by the type IX secretion system (T9SS) and is rapidly propelled along the cell by the motility machinery. How this 6,497-amino-acid protein interacts with the secretion and motility machines is not known. Fusion of the C-terminal 218 amino acids of SprB to a foreign cargo protein resulted in its secretion, attachment to the cell surface, and rapid movement by the motility machinery. Efficient secretion of SprB required coexpression with the outer membrane protein SprF. Secreted proteins that have sequence similarity to SprB in their C-terminal regions are common in the phylumBacteroidetesand may have roles in adhesion, motility, and virulence.

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