Biology subjects

Rossez, Y.

Publications and source records attributed to Rossez, Y..

2 recordsLinked to original sources

bioRxiv2020

Bacterial flagella disrupt host cell membranes and interact with cytoskeletal components

Bacterial flagella have many established roles beyond swimming motility. Despite clear evidence of flagella-dependent adherence, the specificity of ligands and mechanisms of binding are still debated. In this study, the molecular basis of E. coli O157:H7 and S. Typhimurium flagella binding to epithelial cell cultures was investigated. Flagella interactions with host cell surfaces were intimate and crossed cellular boundaries as demarcated by actin and membrane labelling. SEM revealed flagella disappearing into cellular surfaces and TEM of S. Typhiumurium indicated host membrane deformation and disruption in proximity to flagella. Motor mutants of E. coli O157:H7 and S. Typhimurium caused reduced haemolysis compared to wild-type, indicating that membrane disruption was in part due to flagella rotation. Flagella from E. coli O157 (H7), EPEC O127 (H6), and S. Typhimurium (P1 & P2 flagella) were shown to bind to purified intracellular components of the actin cytoskeleton and directly increase in vitro actin polymerisation rates.

microbiology↗

bioRxiv2019

Flagella methylation promotes bacterial adhesion and host cell invasion

The flagellum is the motility device of many bacteria and the long external filament is made of several thousand copies of a single protein, flagellin. While posttranslational modifications of flagellin are common among bacterial pathogens, the role of lysine methylation remained unknown. Here, we show that both flagellins of Salmonella enterica, FliC and FljB, are methylated at surface-exposed lysine residues. A Salmonella mutant deficient in flagellin methylation was outcompeted for gut colonization in a gastroenteritis mouse model. In support, methylation of flagellin promoted invasion of epithelial cells in vitro. Lysine methylation increased the surface hydrophobicity of flagellin and enhanced flagella-dependent adhesion of Salmonella to phosphatidylcholine vesicles and epithelial cells. In summary, posttranslational flagellin methylation constitutes a novel mechanism how flagellated bacteria facilitate adhesion to hydrophobic host cell surfaces and thereby contributes to efficient gut colonization and successful infection of the host.

microbiology↗