title: The VieB auxiliary protein negatively regulates the VieSA signal transduction system in Vibrio cholerae.
abstract: BACKGROUND
  Vibrio cholerae is a facultative pathogen that lives in the aquatic environment and the human host. The ability of V. cholerae to monitor environmental changes as it transitions between these diverse environments is vital to its pathogenic lifestyle. One way V. cholerae senses changing external stimuli is through the three-component signal transduction system, VieSAB, which is encoded by the vieSAB operon. The VieSAB system plays a role in the inverse regulation of biofilm and virulence genes by controlling the concentration of the secondary messenger, cyclic-di-GMP. While the sensor kinase, VieS, and the response regulator, VieA, behave similar to typical two-component phosphorelay systems, the role of the auxiliary protein, VieB, is unclear.
  
  
  RESULTS
  Here we show that VieB binds to VieS and inhibits its autophosphorylation and phosphotransfer activity thus preventing phosphorylation of VieA. Additionally, we show that phosphorylation of the highly conserved Asp residue in the receiver domain of VieB regulates the inhibitory activity of VieB.
  
  
  CONCLUSIONS
  Taken together, these data point to an inhibitory role of VieB on the VieSA phosphorelay, allowing for additional control over the signal output. Insight into the function and regulatory mechanism of the VieSAB system improves our understanding of how V. cholerae controls gene expression as it transitions between the aquatic environment and human host.
authors.affiliation: Howard Hughes Medical Institute and the Department of Molecular Biology and Microbiology, Tufts University, School of Medicine, Boston, USA. stephanie.mitchell@tufts.edu.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Mitchell
authors.affiliation: Howard Hughes Medical Institute and the Department of Molecular Biology and Microbiology, Tufts University, School of Medicine, Boston, USA. aymaninbox@gmail.com.
authors.forename: Ayman M
authors.initials: AM
authors.lastname: Ismail
authors.affiliation: Wyatt Technology Corporation, Santa Barbara, USA. skenrick@wyatt.com.
authors.forename: Sophia A
authors.initials: SA
authors.lastname: Kenrick
authors.affiliation: Howard Hughes Medical Institute and the Department of Molecular Biology and Microbiology, Tufts University, School of Medicine, Boston, USA. andrew.camilli@tufts.edu.
authors.forename: Andrew
authors.initials: A
authors.lastname: Camilli
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D011485:Protein Binding; D025941:Protein Interaction Mapping; D015398:Signal Transduction; D014734:Vibrio cholerae / Q000235:genetics* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; C112165:VieA protein, Vibrio cholerae; C112166:VieB protein, Vibrio cholerae; C112167:VieS protein, Vibrio cholerae