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Title: Type IV secretion systems: Advances in structure, function, and activation
Abstract Bacterial type IV secretion systems (T4SSs) are a functionally diverse translocation superfamily. They consist mainly of two large subfamilies: (i) conjugation systems that mediate interbacterial DNA transfer and (ii) effector translocators that deliver effector macromolecules into prokaryotic or eukaryotic cells. A few other T4SSs export DNA or proteins to the milieu, or import exogenous DNA. The T4SSs are defined by 6 or 12 conserved “core” subunits that respectively elaborate “minimized” systems in Gram‐positive or ‐negative bacteria. However, many “expanded” T4SSs are built from “core” subunits plus numerous others that are system‐specific, which presumptively broadens functional capabilities. Recently, there has been exciting progress in defining T4SS assembly pathways and architectures using a combination of fluorescence and cryoelectron microscopy. This review will highlight advances in our knowledge of structure–function relationships for model Gram‐negative bacterial T4SSs, including “minimized” systems resembling theAgrobacteriumtumefaciensVirB/VirD4 T4SS and “expanded” systems represented by theHelicobacterpyloriCag,LegionellapneumophilaDot/Icm, and F plasmid‐encoded Tra T4SSs. Detailed studies of these model systems are generating new insights, some at atomic resolution, to long‐standing questions concerning mechanisms of substrate recruitment, T4SS channel architecture, conjugative pilus assembly, and machine adaptations contributing to T4SS functional versatility.  more » « less
Award ID(s):
1902392
PAR ID:
10453228
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Molecular Microbiology
Volume:
115
Issue:
3
ISSN:
0950-382X
Page Range / eLocation ID:
p. 436-452
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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