Novel cyclic di-GMP effectors of the YajQ protein family control bacterial virulence

Thumbnail Image
SA_NovelPV2014.pdf(1.77 MB)
Published Version
journal.ppat.1004429.s001.TIF(2.44 MB)
Additional File 1: Figure S1.
journal.ppat.1004429.s002.TIF(294.44 KB)
Additional File 2: Figure S2.
journal.ppat.1004429.s003.TIF(113.51 KB)
Additional File 3: Figure S3.
journal.ppat.1004429.s004.TIF(242.35 KB)
Additional File 4: Figure S4.
An, Shi-Qi
Caly, Delphine L.
McCarthy, Yvonne
Murdoch, Sarah L.
Ward, Joseph
Febrer, Melanie
Dow, J. Maxwell
Ryan, Robert P.
Journal Title
Journal ISSN
Volume Title
Public Library of Science
Research Projects
Organizational Units
Journal Issue
Bis-(3 ',5 ') cyclic di-guanylate (cyclic di-GMP) is a key bacterial second messenger that is implicated in the regulation of many critical processes that include motility, biofilm formation and virulence. Cyclic di-GMP influences diverse functions through interaction with a range of effectors. Our knowledge of these effectors and their different regulatory actions is far from complete, however. Here we have used an affinity pull-down assay using cyclic di-GMP-coupled magnetic beads to identify cyclic di-GMP binding proteins in the plant pathogen Xanthomonas campestris pv. campestris (Xcc). This analysis identified XC_3703, a protein of the YajQ family, as a potential cyclic di-GMP receptor. Isothermal titration calorimetry showed that the purified XC_3703 protein bound cyclic di-GMP with a high affinity (K-d similar to 2 mu M). Mutation of XC_3703 led to reduced virulence of Xcc to plants and alteration in biofilm formation. Yeast two-hybrid and far-western analyses showed that XC_3703 was able to interact with XC_2801, a transcription factor of the LysR family. Mutation of XC_2801 and XC_3703 had partially overlapping effects on the transcriptome of Xcc, and both affected virulence. Electromobility shift assays showed that XC_3703 positively affected the binding of XC_2801 to the promoters of target virulence genes, an effect that was reversed by cyclic di-GMP. Genetic and functional analysis of YajQ family members from the human pathogens Pseudomonas aeruginosa and Stenotrophomonas maltophilia showed that they also specifically bound cyclic di-GMP and contributed to virulence in model systems. The findings thus identify a new class of cyclic di-GMP effector that regulates bacterial virulence.
PilZ domain proteins , Campestris pv. campestris , Diffusible signal factor , Airway epithelial cells , Cystic fibrosis airway , Xanthomonas campestris , Pseudomonas aeruginosa , HD-GYP , Biofilm formation , 2nd messenger
An S-q, Caly DL, McCarthy Y, Murdoch SL, Ward J, Febrer M, et al. (2014) Novel Cyclic di-GMP Effectors of the YajQ Protein Family Control Bacterial Virulence. PLoS Pathog 10(10): e1004429. doi:10.1371/journal.ppat.1004429
Link to publisher’s version