Injection of flagellin into the host cell cytosol by Salmonella enterica serotype typhimurium

Yao Hui Sun, Hortensia García Rolán, Renee M Tsolis

Research output: Contribution to journalArticlepeer-review

122 Scopus citations


Bacterial flagellins are potent inducers of innate immunity. Three signaling pathways have been implicated in the sensing of flagellins; these involve toll-like receptor 5 (TLR5) and the cytosolic proteins Birc1e/Naip5 and Ipaf. Although the structural basis of TLR5-flagellin interaction is known, little is known about how flagellin enters the host cell cytosol to induce signaling via Birc1e/Naip5 and Ipaf. Here we demonstrate for the first time the translocation of bacterial flagellin into the cytosol of host macrophages by the vacuolar pathogen, Salmonella enterica serotype Typhimurium. Translocation of flagellin into the host cell cytosol was directly demonstrated using β-lactamase reporter constructs. Flagellin translocation required the Salmonella Pathogenicity Island 1 Type III secretion system (SPI-1 T3SS) but not the flagellar T3SS.

Original languageEnglish (US)
Pages (from-to)33897-33901
Number of pages5
JournalJournal of Biological Chemistry
Issue number47
StatePublished - Nov 23 2007

ASJC Scopus subject areas

  • Biochemistry


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