title: CdpA is a Burkholderia pseudomallei cyclic di-GMP phosphodiesterase involved in autoaggregation, flagellum synthesis, motility, biofilm formation, cell invasion, and cytotoxicity.
abstract: Cyclic diguanylic acid (c-di-GMP) is an intracellular signaling molecule involved in regulation of cellular functions such as motility, biofilm formation and virulence. Intracellular level of c-di-GMP is controlled through opposing diguanylate cyclase (DGC) and phosphodiesterase (PDE) activities of GGDEF and EAL domain proteins, respectively. We report the identification and characterization of cdpA, a gene encoding a protein containing an EAL domain in the Gram-negative soil bacillus and human pathogen Burkholderia pseudomallei KHW. Purified recombinant CdpA protein exhibited PDE activity in vitro. Evidence that CdpA is a major c-di-GMP-specific PDE in B. pseudomallei KHW was shown by an 8-fold-higher c-di-GMP level in the cdpA-null mutant as compared to the wild type and the complemented cdpA mutant. The presence of higher intracellular c-di-GMP levels in the cdpA-null mutant was associated with increased production of exopolysaccharides, increased cell-to-cell aggregation, absence of flagella and swimming motility, and increased biofilm formation. The relevance of CdpA in B. pseudomallei virulence was demonstrated by a 3-fold reduction in invasion of human lung epithelial cells and a 6-fold reduction in cytotoxicity on human macrophage cells infected with the cdpA mutant.
authors.affiliation: Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore.
authors.forename: Hwee Siang
authors.initials: HS
authors.lastname: Lee
authors.forename: Feiyu
authors.initials: F
authors.lastname: Gu
authors.forename: Shi Min
authors.initials: SM
authors.lastname: Ching
authors.forename: Yulin
authors.initials: Y
authors.lastname: Lam
authors.forename: Kim Lee
authors.initials: KL
authors.lastname: Chua
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000172:deficiency / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development; D016957:Burkholderia pseudomallei / Q000201:enzymology* / Q000472:pathogenicity / Q000502:physiology*; D002460:Cell Line; D002470:Cell Survival; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology; D005407:Flagella / Q000502:physiology; D055786:Gene Knockout Techniques; D006801:Humans; D008124:Locomotion; D008264:Macrophages / Q000382:microbiology; D014774:Virulence; D037521:Virulence Factors / Q000172:deficiency / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; C062025:bis(3',5')-cyclic diguanylic acid; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D006152:Cyclic GMP