Functional heterogeneity of the UpaH autotransporter protein from Uropathogenic Escherichia coli

Allsopp, Luke P., Beloin, Christophe, Moriel, Danilo Gomes, Totsika, Makrina, Ghigo, Jean-Marc, & Schembri, Mark A. (2012) Functional heterogeneity of the UpaH autotransporter protein from Uropathogenic Escherichia coli. Journal of Bacteriology, 194(21), pp. 5769-5782.

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Abstract

Uropathogenic 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 adhesin-involved-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 (UpaHCR) and a hydrophobic region (UpaHHR). 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.

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14 citations in Scopus
14 citations in Web of Science®
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ID Code: 77386
Item Type: Journal Article
Refereed: Yes
DOI: 10.1128/JB.01264-12
ISSN: 0021-9193
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright 2012 American Society for Microbiology
Deposited On: 14 Oct 2014 01:48
Last Modified: 22 Jun 2017 22:02

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