The type III secretion system needle, tip, and translocon

Dey, Sumita; Chakravarty, Amritangshu; Biswas, Pallavi Guha; Guzman, Roberto N. De

doi:10.1002/pro.3682

Cited by 47 publications

(40 citation statements)

References 123 publications

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“…Disruption of the FT3SS affects entry and infectivity of the bacteria and is mostly associated with the epiphytic stage of Xanthomonas life cycle [ 1 , 17 ]. Injectisome type 3 secretion system (T3SS) enables the translocation of effector proteins from bacteria to eukaryotic cells which affect host signaling and metabolism [ 18 ]. Many bacteria utilize this system to establish pathogenic or symbiotic interactions with their eukaryotic hosts.…”

Section: Virulence and Occurrence Of Secretion Systems Inmentioning

confidence: 99%

The HrpG/HrpX Regulon of Xanthomonads—An Insight to the Complexity of Regulation of Virulence Traits in Phytopathogenic Bacteria

2021

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Bacteria of the genus Xanthomonas cause a wide variety of economically important diseases in most crops. The virulence of the majority of Xanthomonas spp. is dependent on secretion and translocation of effectors by the type 3 secretion system (T3SS) that is controlled by two master transcriptional regulators HrpG and HrpX. Since their discovery in the 1990s, the two regulators were the focal point of many studies aiming to decipher the regulatory network that controls pathogenicity in Xanthomonas bacteria. HrpG controls the expression of HrpX, which subsequently controls the expression of T3SS apparatus genes and effectors. The HrpG/HrpX regulon is activated in planta and subjected to tight metabolic and genetic regulation. In this review, we cover the advances made in understanding the regulatory networks that control and are controlled by the HrpG/HrpX regulon and their conservation between different Xanthomonas spp.

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Section: Virulence and Occurrence Of Secretion Systems Inmentioning

confidence: 99%

The HrpG/HrpX Regulon of Xanthomonads—An Insight to the Complexity of Regulation of Virulence Traits in Phytopathogenic Bacteria

2021

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“…To optimize the living environment in host cells, gram‐negative bacterial pathogens rely mainly on the type III secretion system (T3SS) to manipulate a variety of essential biological processes (Dodds and Rathjen, ; Dey et al ., ). Characterizing the spatiotemporal expression patterns, the assembled structure, and the secreted/translocated components of the T3SS is therefore critical.…”

Section: Introductionmentioning

confidence: 99%

Analysis of HrpG regulons and HrpG‐interacting proteins by ChIP‐seq and affinity proteomics in Xanthomonas campestris

Zhang

Wei

Qian

et al. 2020

Molecular Plant Pathology

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Gamma‐proteobacteria Xanthomonas spp. cause at least 350 different plant diseases among important agricultural crops, which result in serious yield losses. Xanthomonas spp. rely mainly on the type III secretion system (T3SS) to infect their hosts and induce a hypersensitive response in nonhosts. HrpG, the master regulator of the T3SS, plays the dominant role in bacterial virulence. In this study, we used chromatin immunoprecipitation followed by sequencing (ChIP‐seq) and tandem affinity purification (TAP) to systematically characterize the HrpG regulon and HrpG interacting proteins in vivo. We obtained 186 candidate HrpG downstream genes from the ChIP‐seq analysis, which represented the genomic‐wide regulon spectrum. A consensus HrpG‐binding motif was obtained and three T3SS genes, hpa2, hrcU, and hrpE, were confirmed to be directly transcriptionally activated by HrpG in the inducing medium. A total of 273 putative HrpG interacting proteins were identified from the TAP data and the DNA‐binding histone‐like HU protein of Xanthomonas campestris pv. campestris (HUxcc) was proved to be involved in bacterial virulence by increasing the complexity and intelligence of the bacterial signalling pathways in the T3SS.

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“…Toxins are called 'effectors', and the mechanism used by the toxins to move from the bacterial cytosol to the outside of the bacterial cell membrane is defined as 'secretion' [22][23][24]30]. The bacterium also makes holes in the cell membrane of the target cell to drive toxins into the cytoplasm, a process called 'translocation' [31]. Translocation involves a two-protein structure called the 'translocon', which is described later [31].…”

Section: The Bacterial Type III Secretion System and Its Toxinsmentioning

confidence: 99%

“…The bacterium also makes holes in the cell membrane of the target cell to drive toxins into the cytoplasm, a process called 'translocation' [31]. Translocation involves a two-protein structure called the 'translocon', which is described later [31].…”

Section: The Bacterial Type III Secretion System and Its Toxinsmentioning

confidence: 99%

Immunoglobulin for Treating Bacterial Infections: One More Mechanism of Action

et al. 2019

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The mechanisms underlying the effects of immunoglobulins on bacterial infections are thought to involve bacterial cell lysis via complement activation, phagocytosis via bacterial opsonization, toxin neutralization, and antibody-dependent cell-mediated cytotoxicity. Nevertheless, recent advances in the study of the pathogenicity of Gram-negative bacteria have raised the possibility of an association between immunoglobulin and bacterial toxin secretion. Over time, new toxin secretion systems like the type III secretion system have been discovered in many pathogenic Gram-negative bacteria. With this system, the bacterial toxins are directly injected into the cytoplasm of the target cell through a special secretory apparatus without any exposure to the extracellular environment, and therefore with no opportunity for antibodies to neutralize the toxin. However, antibodies against the V-antigen, which is located on the needle-shaped tip of the bacterial secretion apparatus, can inhibit toxin translocation, thus raising the hope that the toxin may be susceptible to antibody targeting. Because multi-drug resistant bacteria are now prevalent, inhibiting this secretion mechanism is an attractive alternative or adjunctive therapy against lethal bacterial infections. Thus, it is not unreasonable to define the blocking effect of anti-V-antigen antibodies as the fifth mechanism for immunoglobulin action against bacterial infections.

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The type III secretion system needle, tip, and translocon

Cited by 47 publications

References 123 publications

The HrpG/HrpX Regulon of Xanthomonads—An Insight to the Complexity of Regulation of Virulence Traits in Phytopathogenic Bacteria

The HrpG/HrpX Regulon of Xanthomonads—An Insight to the Complexity of Regulation of Virulence Traits in Phytopathogenic Bacteria

Analysis of HrpG regulons and HrpG‐interacting proteins by ChIP‐seq and affinity proteomics in Xanthomonas campestris

Immunoglobulin for Treating Bacterial Infections: One More Mechanism of Action

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