Protein Export via the Type III Secretion System of the Bacterial Flagellum

Biomolecules. 2021 Jan 29;11(2):186. doi: 10.3390/biom11020186.

Abstract

The bacterial flagellum and the related virulence-associated injectisome system of pathogenic bacteria utilize a type III secretion system (T3SS) to export substrate proteins across the inner membrane in a proton motive force-dependent manner. The T3SS is composed of an export gate (FliPQR/FlhA/FlhB) located in the flagellar basal body and an associated soluble ATPase complex in the cytoplasm (FliHIJ). Here, we summarise recent insights into the structure, assembly and protein secretion mechanisms of the T3SS with a focus on energy transduction and protein transport across the cytoplasmic membrane.

Keywords: ATPase; bacterial flagellum; flagellar assembly; proton motive force; secretion model; type III protein export.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Bacterial Proteins / metabolism*
  • Cell Membrane / metabolism
  • Cytoplasm / metabolism
  • Flagella / metabolism*
  • Gram-Negative Bacteria / metabolism*
  • Hydrolysis
  • Membrane Proteins / metabolism
  • Protein Denaturation
  • Protein Transport
  • Substrate Specificity
  • Type III Secretion Systems / metabolism*

Substances

  • Bacterial Proteins
  • FlhA protein, Bacteria
  • Membrane Proteins
  • Type III Secretion Systems
  • Adenosine Triphosphatases