Composition, formation, and regulation of the cytosolic c-ring, a dynamic component of the type III secretion injectisome.

ABSTRACT: Many gram-negative pathogens employ a type III secretion injectisome to translocate effector proteins into eukaryotic host cells. While the structure of the distal "needle complex" is well documented, the composition and role of the functionally important cytosolic complex remain less well understood. Using functional fluorescent fusions, we found that the C-ring, an essential and conserved cytosolic component of the system, is composed of ~22 copies of SctQ (YscQ in Yersinia enterocolitica), which require the presence of YscQC, the product of an internal translation initiation site in yscQ, for their cooperative assembly. Photoactivated localization microscopy (PALM) reveals that in vivo, YscQ is present in both a free-moving cytosolic and a stable injectisome-bound state. Notably, fluore

SUBMITTER: Diepold A 

PROVIDER: S-EPMC4295842 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature