Impact of O-glycosylation on the molecular and cellular adhesion properties of the Escherichia coli autotransporter protein Ag43

Reidl, Sebastian; Lehmann, Annika; Schiller, Roswitha; Khan, Abdul Salam; Dobrindt, Ulrich

doi:10.1016/j.ijmm.2009.01.001

Cited by 33 publications

(33 citation statements)

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“…All mutants affected in these functionalities were also affected in either autoaggregation or adhesion. Similar observations were made in previous studies with AIDA-I (8,14) and Ag43 (21,35). This suggests that adhesion and autoaggregation are the main functions of SAATs, whereas biofilm formation and invasion are secondary to these two functions.…”

Section: Discussionsupporting

confidence: 90%

“…The three proteins have been grouped together because of their functional similarities. They can all mediate bacterial autoaggregation, biofilm formation, as well as adhesion and invasion of epithelial cells (1,5,11,15,20,35,40,41). The three proteins also share a peculiar primary structure: the N terminus of the passenger domain of these three proteins is composed of repeats of the same 19-amino-acid consensus sequence.…”

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confidence: 99%

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Structure-Function Analysis of the TibA Self-Associating Autotransporter Reveals a Modular Organization

Côté

Mourez

2011

Infect Immun

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Some enterotoxigenic Escherichia coli strains express the TibA adhesin/invasin, a multifunctional autotransporter that mediates the autoaggregation of bacteria, biofilm formation, adhesion to cultured epithelial cells, and invasion of these cells. To elucidate the structure-function relationship in TibA, we generated mutants by transposon-based linker scanning mutagenesis and by site-directed mutagenesis. Several insertion mutants had a defect in either adhesion or autoaggregation. Mutants with a defect in autoaggregation were found in the N-terminal half of the extracellular domain, while mutants with a defect in adhesion were found in the C-terminal half. The deletion of the putative N-terminal autoaggregation domain abolished the autoaggregation of the bacteria but did not affect adhesion. The deletion of a proline-rich region located at the C terminus of the extracellular domain abolished the adhesion properties of TibA but did not affect invasion. This finding suggests that adhesion and invasion may rely on distinct mechanisms. Thus, our results reveal that TibA possesses a modular organization, with the extracellular domain being separated into an autoaggregation module and an adhesion module.

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Section: Discussionsupporting

confidence: 90%

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confidence: 99%

Structure-Function Analysis of the TibA Self-Associating Autotransporter Reveals a Modular Organization

Côté

Mourez

2011

Infect Immun

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“…Significant UpaH-mediated binding was observed to collagen V, fibronectin, and laminin. Binding to ECM molecules has also been demonstrated for other AT proteins, including Ag43, AIDA-I, UpaG, and YadA (27,39,54,69,71,74). The YadA trimeric AT adhesin from Yersinia enterocolitica has been extensively characterized (4,25,27,68,69,71).…”

Section: Discussionmentioning

confidence: 97%

Functional Heterogeneity of the UpaH Autotransporter Protein from Uropathogenic Escherichia coli

et al. 2012

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bUropathogenic Escherichia coli (UPEC) is responsible for the majority of urinary tract infections (UTI). To cause a UTI, UPEC must adhere to the epithelial cells of the urinary tract and overcome the shear flow forces of urine. This function is mediated primarily by fimbrial adhesins, which mediate specific attachment to host cell receptors. Another group of adhesins that contributes to UPEC-mediated UTI is autotransporter (AT) proteins. AT proteins possess a range of virulence properties, such as adherence, aggregation, invasion, and biofilm formation. One recently characterized AT protein of UPEC is UpaH, a large adhesininvolved-in-diffuse-adherence (AIDA-I)-type AT protein that contributes to biofilm formation and bladder colonization. In this study we characterized a series of naturally occurring variants of UpaH. We demonstrate that extensive sequence variation exists within the passenger-encoding domain of UpaH variants from different UPEC strains. This sequence variation is associated with functional heterogeneity with respect to the ability of UpaH to mediate biofilm formation. In contrast, all of the UpaH variants examined retained a conserved ability to mediate binding to extracellular matrix (ECM) proteins. Bioinformatic analysis of the UpaH passenger domain identified a conserved region (UpaH CR ) and a hydrophobic region (UpaH HR ). Deletion of these domains reduced biofilm formation but not the binding to ECM proteins. Despite variation in the upaH sequence, the transcription of upaH was repressed by a conserved mechanism involving the global regulator H-NS, and mutation of the hns gene relieved this repression. Overall, our findings shed new light on the regulation and functions of the UpaH AT protein. Uropathogenic Escherichia coli (UPEC) is the major cause of urinary tract infections (UTI) in humans. Infection of the urinary tract by UPEC involves initial adherence to uroepithelial cells to resist the hydrodynamic forces of urine flow and subsequent inflammation triggered by host and bacterial cell signaling pathways. UPEC can also invade bladder epithelial cells, replicate, and establish biofilm-like intracellular bacterial communities (IBCs) that contain large numbers of bacteria (3,20,49,55).UPEC possesses a range of virulence factors, including adhesins (e.g., type 1 and P fimbrial), toxins (e.g., hemolysin), and siderophore-mediated systems for iron acquisition (e.g., enterobactin, salmochelin, aerobactin), that enable them to colonize the urinary tract and cause disease (37,62,80). Adhesion represents a critical initial step for UPEC colonization of the urinary tract and is mediated primarily by fimbriae. However, UPEC also produces a number of autotransporter (AT) proteins that contribute with varying degrees to adherence, aggregation, and biofilm formation (1, 2, 72, 74). Several AT proteins have been characterized from UPEC, and these include the secreted toxin Sat (19, 23, 41), the phase-variable outer membrane protein antigen 43 (Ag43) (35,72), the trimeric AT protein UpaG (74), and ...

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“…Ag43 was another immunogenic protein that participates in autoaggregation and biofilm formation and also may act as an adhesin with certain extracellular matrix proteins (73,74). Other studies demonstrate that this protein is an autotransporter with an N-proximal passenger domain (␣43), which is processed by a yet unidentified protease, and a C-terminal ␤-barrel domain (the ␤ subunit of Ag43 [␤43]) that forms an integral outer membrane protein (75).…”

Section: Discussionmentioning

confidence: 99%

Immunoproteomic Analysis To Identify Shiga Toxin-Producing Escherichia coli Outer Membrane Proteins Expressed during Human Infection

et al. 2014

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b Shiga-toxin producing Escherichia coli (STEC) is the etiologic agent of acute diarrhea, dysentery, and hemolytic-uremic syndrome (HUS). There is no approved vaccine for STEC infection in humans, and antibiotic use is contraindicated, as it promotes Shiga toxin production. In order to identify STEC-associated antigens and immunogenic proteins, outer membrane proteins (OMPs) were extracted from STEC O26:H11, O103, O113:H21, and O157:H7 strains, and commensal E. coli strain HS was used as a control. SDS-PAGE, two-dimensional-PAGE analysis, Western blot assays using sera from pediatric HUS patients and controls, and matrix-assisted laser desorption ionization-tandem time of flight analyses were used to identify 12 immunogenic OMPs, some of which were not reactive with control sera. Importantly, seven of these proteins have not been previously reported to be immunogenic in STEC strains. Among these seven proteins, OmpT and Cah displayed IgG and IgA reactivity with sera from HUS patients. Genes encoding these two proteins were present in a majority of STEC strains. Knowledge of the antigens produced during infection of the host and the immune response to those antigens will be important for future vaccine development.

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Impact of O-glycosylation on the molecular and cellular adhesion properties of the Escherichia coli autotransporter protein Ag43

Cited by 33 publications

References 50 publications

Structure-Function Analysis of the TibA Self-Associating Autotransporter Reveals a Modular Organization

Structure-Function Analysis of the TibA Self-Associating Autotransporter Reveals a Modular Organization

Functional Heterogeneity of the UpaH Autotransporter Protein from Uropathogenic Escherichia coli

Immunoproteomic Analysis To Identify Shiga Toxin-Producing Escherichia coli Outer Membrane Proteins Expressed during Human Infection

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