Assembly and dynamic regulation of the tip filament of the <i>Bordetella</i> type III secretion system injectisome.

ABSTRACT: Many gram-negative bacteria utilize a type III secretion system (T3SS) injectisome to translocate effector proteins directly into host cells. In Bordetella bronchiseptica, a respiratory pathogen of diverse mammals, the T3SS injectisome contains a unique needle tip filament formed by the Bsp22 protein, which is essential for bacterial persistence in mice. Here, we used B. bronchiseptica and Bordetella pertussis strains with in-frame insertions of peptide tags into Bsp22 to investigate filament formation using super-resolution imaging with fluorophore-labeled nanobodies and biarsenic probes. During cultivation on glass coverslips, more than 50% of the bacteria had flexible Bsp22 filaments with an average length of 1 µm after 3 hours of incubation. Filament growth occurre

SUBMITTER: Malcova I 

PROVIDER: S-EPMC12607632 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature