Host manipulation by bacterial type III and type IV secretion system effector proteases

SummaryThe bacterial type IV secretion system (T4SS) is a versatile nanomachine that translocates diverse effector molecules between microbes and into eukaryotic cells. Using electron cryotomography, here we reveal the molecular architecture of the cancer-associatedHelicobacter pylori cagT4SS. Although most components are unique toH. pylori, thecagT4SS exhibits remarkable architectural similarity to previously studied T4SSs. WhenH. pyloriencounters host cells, however, the bacterium elaborates rigid, membranous tubes perforated by lateral ports. Dense, pilus-like rod structures extending from the inner membrane were also observed. We propose that the membrane tubes assemble out of the T4SS and are the delivery system forcagT4SS cargo. These studies reveal the architecture of a dynamic molecular machine that evolved to function in the human gastric niche.

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traG Gene Is Conserved across Mesorhizobium spp. Able to Nodulate the Same Host Plant and Expressed in Response to Root Exudates

BioMed Research International ◽

10.1155/2019/3715271 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13

Author(s):

A. Paço ◽

J. R. da-Silva ◽

F. Eliziário ◽

C. Brígido ◽

S. Oliveira ◽

...

Keyword(s):

Root Exudates ◽

Structural Organization ◽

Functional Organization ◽

Secretion System ◽

Type Iv Secretion ◽

Type Iv Secretion System ◽

Symbiotic Relationship ◽

Genomic Context ◽

Type Iv ◽

Bacterial Type

Evidences for an involvement of the bacterial type IV secretion system (T4SS) in the symbiotic relationship between rhizobia and legumes have been pointed out by several recent studies. However, information regarding this secretion system in Mesorhizobium is still very scarce. The aim of the present study was to investigate the phylogeny and expression of the traG gene, which encodes a substrate receptor of the T4SS. In addition, the occurrence and genomic context of this and other T4SS genes, namely, genes from tra/trb and virB/virD4 complexes, were also analyzed in order to unveil the structural and functional organization of T4SS in mesorhizobia. The location of the T4SS genes in the symbiotic region of the analyzed rhizobial genomes, along with the traG phylogeny, suggests that T4SS genes could be horizontally transferred together with the symbiosis genes. Regarding the T4SS structural organization in Mesorhizobium, the virB/virD4 genes were absent in all chickpea (Cicer arietinum L.) microsymbionts and in the Lotus symbiont Mesorhizobium japonicum MAFF303099T. Interestingly, the presence of genes belonging to another secretion system (T3SS) was restricted to these strains lacking the virB/virD4 genes. The traG gene expression was detected in M. mediterraneum Ca36T and M. ciceri LMS-1 strains when exposed to chickpea root exudates and also in the early nodules formed by M. mediterraneum Ca36T, but not in older nodules. This study contributes to a better understanding of the importance of T4SS in mutualistic symbiotic bacteria.

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Exploring Directionality and Kinetics of a Bacterial Type IV Secretion System

The FASEB Journal ◽

10.1096/fasebj.2021.35.s1.03474 ◽

2021 ◽

Vol 35 (S1) ◽

Author(s):

Olukemi Akinleye ◽

Betelhem Gemechu ◽

Sabrina Ali ◽

Melanie Berkmen

Keyword(s):

Secretion System ◽

Type Iv Secretion ◽

Type Iv Secretion System ◽

Type Iv ◽

Kinetics Of ◽

Bacterial Type

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Faculty Opinions recommendation of Structures of two core subunits of the bacterial type IV secretion system, VirB8 from Brucella suis and ComB10 from Helicobacter pylori.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1024939.293763 ◽

2005 ◽

Author(s):

Murray Stewart

Keyword(s):

Helicobacter Pylori ◽

Secretion System ◽

Type Iv Secretion ◽

Type Iv Secretion System ◽

Type Iv ◽

Brucella Suis ◽

Bacterial Type

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SecReT4: a web-based bacterial type IV secretion system resource

Nucleic Acids Research ◽

10.1093/nar/gks1248 ◽

2012 ◽

Vol 41 (D1) ◽

pp. D660-D665 ◽

Cited By ~ 46

Author(s):

Dexi Bi ◽

Linmeng Liu ◽

Cui Tai ◽

Zixin Deng ◽

Kumar Rajakumar ◽

...

Keyword(s):

Secretion System ◽

Type Iv Secretion ◽

Type Iv Secretion System ◽

Web Based ◽

Type Iv ◽

System Resource ◽

Bacterial Type

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Structures of two core subunits of the bacterial type IV secretion system, VirB8 from Brucella suis and ComB10 from Helicobacter pylori

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0408927102 ◽

2005 ◽

Vol 102 (12) ◽

pp. 4596-4601 ◽

Cited By ~ 88

Author(s):

L. Terradot ◽

R. Bayliss ◽

C. Oomen ◽

G. A. Leonard ◽

C. Baron ◽

...

Keyword(s):

Helicobacter Pylori ◽

Secretion System ◽

Type Iv Secretion ◽

Type Iv Secretion System ◽

Type Iv ◽

Brucella Suis ◽

Bacterial Type

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Peptidoglycan degradation by specialized lytic transglycosylases associated with type III and type IV secretion systems

Microbiology ◽

10.1099/mic.0.28141-0 ◽

2005 ◽

Vol 151 (11) ◽

pp. 3455-3467 ◽

Cited By ~ 83

Author(s):

Doris Zahrl ◽

Maria Wagner ◽

Karin Bischof ◽

Michaela Bayer ◽

Barbara Zavecz ◽

...

Keyword(s):

Secretion System ◽

Type Iv Secretion ◽

Conjugative Plasmid ◽

Type Iv Secretion System ◽

Secretion Systems ◽

Lytic Transglycosylases ◽

Type Iii ◽

Type Iv ◽

Lytic Transglycosylase ◽

Type Iv Secretion Systems

Specialized lytic transglycosylases are muramidases capable of locally degrading the peptidoglycan meshwork of Gram-negative bacteria. Specialized lytic transglycosylase genes are present in clusters encoding diverse macromolecular transport systems. This paper reports the analysis of selected members of the specialized lytic transglycosylase family from type III and type IV secretion systems. These proteins were analysed in vivo by assaying their ability to complement the DNA transfer defect of the conjugative F-like plasmid R1-16 lacking a functional P19 protein, the specialized lytic transglycosylase of this type IV secretion system. Heterologous complementation was accomplished using IpgF from the plasmid-encoded type III secretion system of Shigella sonnei and TrbN from the type IV secretion system of the conjugative plasmid RP4. In contrast, neither VirB1 proteins (Agrobacterium tumefaciens, Brucella suis) nor IagB (Salmonella enterica) could functionally replace P19. In vitro, IpgF, IagB, both VirB1 proteins, HP0523 (Helicobacter pylori) and P19 displayed peptidoglycanase activity in zymogram analyses. Using an established test system and a newly developed assay it was shown that IpgF degraded peptidoglycan in solution. IpgF was active only after removal of the chaperonin GroEL, which co-purified with IpgF and inhibited its enzymic activity. A mutant IpgF protein in which the predicted catalytic amino acid, Glu42, was replaced by Gln, was completely inactive. IpgF-catalysed peptidoglycan degradation was optimal at pH 6 and was inhibited by the lytic transglycosylase inhibitors hexa-N-acetylchitohexaose and bulgecin A.

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