Bundle-forming pilus retraction enhances enteropathogenic Escherichia coli infectivity

Eitan E. Zahavi, Joshua A. Lieberman, Michael S. Donnenberg, Mor Nitzan, Kobi Baruch, Ilan Rosenshine, Jerrold R. Turner, Naomi Melamed-Book, Naomi Feinstein, Efrat Zlotkin-Rivkin, Benjamin Aroeti*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Enteropathogenic Escherichia coli (EPEC) is an important human pathogen that causes acute infantile diarrhea. The type IV bundle-forming pili (BFP) of typical EPEC strains are dynamic fibrillar organelles that can extend out and retract into the bacterium. The bfpF gene encodes for BfpF, a protein that promotes pili retraction. The BFP are involved in bacterial autoaggregation and in mediating the initial adherence of the bacterium with its host cell. Importantly, BFP retraction is implicated in virulence in experimental human infection. How pili retraction contributes to EPEC pathogenesis at the cellular level remains largely obscure, however. In this study, an effort has been made to address this question using engineered EPEC strains with induced BFP retraction capacity. We show that the retraction is important for tight-junction disruption and, to a lesser extent, actin-rich pedestal formation by promoting efficient translocation of bacterial protein effectors into the host cells. A model is proposed whereby BFP retraction permits closer apposition between the bacterial and the host cell surfaces, thus enabling timely and effective introduction of bacterial effectors into the host cell via the type III secretion apparatus. Our studies hence suggest novel insights into the involvement of pili retraction in EPEC pathogenesis.

Original languageAmerican English
Pages (from-to)2436-2447
Number of pages12
JournalMolecular Biology of the Cell
Issue number14
StatePublished - 15 Jul 2011


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