Related Experiment Video
Updated: Sep 25, 2025

A Visual Assay to Monitor T6SS-mediated Bacterial Competition
Published on: March 20, 2013
A unique bacterial secretion machinery with multiple secretion centers
Liqiang Song1, John D Perpich2, Chenggang Wu1
1Department of Microbiology and Molecular Genetics, McGovern Medical School, Houston, TX 77030.
Abstract:
The Porphyromonas gingivalis type IX secretion system (T9SS) promotes periodontal disease by secreting gingipains and other virulence factors. By in situ cryoelectron tomography, we report that the P. gingivalis T9SS consists of 18 PorM dimers arranged as a large, caged ring in the periplasm. Near the outer membrane, PorM dimers interact with a PorKN ring complex of ∼52 nm in diameter. PorMKN translocation complexes of a given T9SS adopt distinct conformations energized by the proton motive force, suggestive of different activation states. At the inner membrane, PorM associates with a cytoplasmic complex that exhibits 12-fold symmetry and requires both PorM and PorL for assembly. Activated motors deliver substrates across the outer membrane via one of eight Sov translocons arranged in a ring. The T9SSs are unique among known secretion systems in bacteria and eukaryotes in their assembly as supramolecular machines composed of apparently independently functioning translocation motors and export pores.
More Related Videos
11:33Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
09:12Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System
Published on: March 10, 2020
Related Concept Videos
Gram-negative Bacterial Protein Secretion Systems
Bacterial Translocation and Protein Secretion
Bacterial Signaling
Exocrine Glands: Unicellular and Multicellular Glands
Overview of Secretory Vesicles
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Cytoskeletal Proteins in Bacteria