Subcellular location characteristics of the Pseudomonas aeruginosa GGDEF protein, WspR, indicate that it produces cyclic-di-GMP in response to growth on surfaces

Mol Microbiol. 2007 Dec;66(6):1459-73. doi: 10.1111/j.1365-2958.2007.06008.x. Epub 2007 Nov 19.


The Pseudomonas aeruginosa Wsp signal transduction system produces cyclic-di-GMP (c-di-GMP), an intracellular messenger that stimulates biofilm formation and suppresses motility. The Wsp system is homologous to chemotaxis systems and includes a membrane-bound receptor protein, WspA, and a response regulator GGDEF protein, WspR, that catalyses c-di-GMP synthesis when phosphorylated. We found that the subcellular distributions of fluorescent protein-tagged WspA and WspR differed markedly from their chemotaxis counterparts. WspA-YFP formed patches in cells whereas WspR-YFP was dispersed when unphosphorylated and formed bright cytoplasmic clusters when phosphorylated. WspR formed clusters in cells of a DeltawspF mutant, a genetic background that causes constitutive phosphorylation of WspR, but was dispersed in cells of a wspA mutant, a genetic background necessary for WspR phosphorylation. In addition, WspR mutated at Asp70, its predicted site of phosphorylation, did not form clusters. C-di-GMP synthesis was not required for cluster formation. WspR-YFP was dispersed in liquid-grown wild-type cells, but formed clusters that sometimes appeared and disappeared over the course of a few minutes in cells grown on an agar surface. Our results suggest that the compartmentalized production of c-di-GMP in response to a stimulus associated with growth on a surface is an important functional characteristic of the Wsp system.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cyclic GMP / analogs & derivatives*
  • Cyclic GMP / metabolism
  • Cytoplasm / metabolism
  • Microscopy, Fluorescence
  • Models, Biological
  • Mutagenesis, Site-Directed
  • Mutation
  • Phosphorylation
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*
  • Signal Transduction / genetics
  • Signal Transduction / physiology


  • Bacterial Proteins
  • Recombinant Fusion Proteins
  • bis(3',5')-cyclic diguanylic acid
  • Cyclic GMP