title: Functional interactions of VirB11 traffic ATPases with VirB4 and VirD4 molecular motors in type IV secretion systems.
abstract: Pilus biogenesis and substrate transport by type IV secretion systems require energy, which is provided by three molecular motors localized at the base of the secretion channel. One of these motors, VirB11, belongs to the superfamily of traffic ATPases, which includes members of the type II secretion system and the type IV pilus and archaeal flagellar assembly apparatus. Here, we report the functional interactions between TrwD, the VirB11 homolog of the conjugative plasmid R388, and TrwK and TrwB, the motors involved in pilus biogenesis and DNA transport, respectively. Although these interactions remained standing upon replacement of the traffic ATPase by a homolog from a phylogenetically related conjugative system, namely, TraG of plasmid pKM101, this homolog could not replace the TrwD function for DNA transfer. This result suggests that VirB11 works as a switch between pilus biogenesis and DNA transport and reinforces a mechanistic model in which VirB11 proteins act as traffic ATPases by regulating both events in type IV secretion systems.
authors.affiliation: Departamento de Biología Molecular, Universidad de Cantabria, and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), UC-CSIC-SODERCAN, Santander, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Ripoll-Rozada
authors.forename: Sandra
authors.initials: S
authors.lastname: Zunzunegui
authors.forename: Fernando
authors.initials: F
authors.lastname: de la Cruz
authors.forename: Ignacio
authors.initials: I
authors.lastname: Arechaga
authors.forename: Elena
authors.initials: E
authors.lastname: Cabezón
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D058947:Bacterial Secretion Systems / Q000235:genetics; D001692:Biological Transport; D003227:Conjugation, Genetic; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010957:Plasmids; D054730:Protein Interaction Domains and Motifs
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D020409:Molecular Motor Proteins; D000251:Adenosine Triphosphatases