Type III Secretion: Building and Operating a Remarkable Nanomachine
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Updated: Mar 31, 2026

A Visual Assay to Monitor T6SS-mediated Bacterial Competition
Published on: March 20, 2013
Athina G Portaliou1, Konstantinos C Tsolis1, Maria S Loos2
1KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, 3000 Leuven, Belgium; Institute of Molecular Biology and Biotechnology, FORTH, University of Crete, PO Box 1385, Iraklio, Crete, GR-711 10 Greece; Department of Biology, University of Crete, PO Box 1385, GR-711 10 Iraklio, Crete, Greece.
Abstract:
The Type III secretion system (T3SS) is a protein export pathway that is widespread in Gram-negative bacteria and delivers effector proteins directly into eukaryotic cells. At its core lie the injectisome (a sophisticated transmembrane secretion apparatus) and a complex network of specialized chaperones that target secretory proteins to the antechamber of the injectisome. The assembly of the system, and the subsequent secretion of proteins through it, undergo fine-tuned, hierarchical regulation. Here, we present the current understanding of the injectisome assembly process, secretion hierarchy, and the role of chaperones. We discuss these events in light of available structural and biochemical dissection and propose future directions essential to revealing mechanistic insight into this fascinating nanomachine.
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