title: Biogenesis, architecture, and function of bacterial type IV secretion systems.
abstract: Type IV secretion (T4S) systems are ancestrally related to bacterial conjugation machines. These systems assemble as a translocation channel, and often also as a surface filament or protein adhesin, at the envelopes of Gram-negative and Gram-positive bacteria. These organelles mediate the transfer of DNA and protein substrates to phylogenetically diverse prokaryotic and eukaryotic target cells. Many basic features of T4S are known, including structures of machine subunits, steps of machine assembly, substrates and substrate recognition mechanisms, and cellular consequences of substrate translocation. A recent advancement also has enabled definition of the translocation route for a DNA substrate through a T4S system of a Gram-negative bacterium. This review emphasizes the dynamics of assembly and function of model conjugation systems and the Agrobacterium tumefaciens VirB/D4 T4S system. We also summarize salient features of the increasingly studied effector translocator systems of mammalian pathogens.
authors.affiliation: Department of Microbiology and Molecular Genetics, UT-Houston Medical School, Houston, Texas 77030, USA. Peter.J.Christie@uth.tmc.edu
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Christie
authors.forename: Krishnamohan
authors.initials: K
authors.lastname: Atmakuri
authors.forename: Vidhya
authors.initials: V
authors.lastname: Krishnamoorthy
authors.forename: Simon
authors.initials: S
authors.lastname: Jakubowski
authors.forename: Eric
authors.initials: E
authors.lastname: Cascales
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000235:genetics; D006090:Gram-Negative Bacteria / Q000235:genetics / Q000472:pathogenicity*; D006094:Gram-Positive Bacteria / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D021381:Protein Transport; D014170:Transformation, Genetic
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial