Type III secretion: a secretory pathway serving both motility and virulence (Review)

• Published in: Molecular membrane biology Vol. 22; no. 1-2; pp. 41 - 50
• Main Authors: Journet, Laure, Hughes, Kelly T., Cornelis, Guy R.
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.01.2005; Taylor & Francis
• Subjects: Bacterial Proteins; Bacterial Proteins - metabolism; Bacterial Proteins - physiology; Biochemistry, Molecular Biology; effectors; Flagella; Flagella - physiology; Flagellum; Gram-Negative Bacteria; Gram-Negative Bacteria - pathogenicity; Gram-Negative Bacteria - physiology; Life Sciences; Membrane Proteins; Membrane Proteins - physiology; microbial pathogenesis; Microbiology and Parasitology; nanomachines; Protein Transport; Virulence; effectors; microbial pathogenesis; nanomachines; Flagellum
• ISSN: 0968-7688; 1464-5203
• DOI: 10.1080/09687860500041858

'Type III secretion' (T3S) refers to a secretion pathway that is common to the flagellae of eubacteria and the injectisomes of some Gram-negative bacteria. Flagellae are rotary nanomachines allowing motility but they contain a built-in secretion apparatus that exports their own distal components to the distal end of the growing structure where they polymerize. In some cases they have been shown to export non-flagellar proteins. Injectisomes are transkingdom communication apparatuses allowing bacteria docked at the surface of a eukaryotic cell membrane to inject effector proteins across the two bacterial membranes and the eukaryotic cell membrane. Both nanomachines share a similar basal body embedded in the two bacterial membranes, topped either by a hook and a filament or by a stiff short needle. Both appear to be assembled in the same fashion. They recognize their substrate by a loose N-terminal peptide signal and the help of individual chaperones of a new type.