2026/01/09 by Przemysław Dutka, Yuxi Liu, Stefano Maggi +9 · 1 voice
Biochemistry, Genetics and Molecular Biology · Immunology and Microbiology · #Legionella and Acanthamoeba research #Toxoplasma gondii Research Studies #Yersinia bacterium, plague, ectoparasites research
paper · pdf · doi:10.1002/1873-3468.70270
openalex publication_date 2026/01/09 · openalex created_date 2026/01/09 · openalex updated_date 2026/07/27
The Dot/Icm type IV secretion system (T4SS) is essential for Legionella pneumophila infection, but its in situ architecture and mechanism remain incompletely understood. Using cryo-electron tomography, we performed subtomogram averaging and 3D classification to resolve structural heterogeneity within the complex. We identified multiple assembly states of the inner membrane complex, including a fully assembled form with a hexamer-of-dimers DotO ATPase and symmetry mismatches between subcomplexes. A composite in situ model revealed a central channel above the inner membrane, likely used for substrate secretion. Imaging of infected macrophages showed T4SSs tethered to host vacuoles and extracellular vesicle release, suggesting additional effector delivery routes. These findings provide insight into Dot/Icm T4SS structure and infection-related dynamics.