Specialized and shared functions of diguanylate cyclases and phosphodiesterases in Streptomyces development

Mol Microbiol. 2020 Nov;114(5):808-822. doi: 10.1111/mmi.14581. Epub 2020 Aug 14.


The second messenger bis-3,5-cyclic di-guanosine monophosphate (c-di-GMP) determines when Streptomyces initiate sporulation. c-di-GMP signals are integrated into the genetic differentiation network by the regulator BldD and the sigma factor σWhiG . However, functions of the development-specific diguanylate cyclases (DGCs) CdgB and CdgC, and the c-di-GMP phosphodiesterases (PDEs) RmdA and RmdB, are poorly understood. Here, we provide biochemical evidence that the GGDEF-EAL domain protein RmdB from S. venezuelae is a monofunctional PDE that hydrolyzes c-di-GMP to 5'pGpG. Despite having an equivalent GGDEF-EAL domain arrangement, RmdA cleaves c-di-GMP to GMP and exhibits residual DGC activity. We show that an intact EAL motif is crucial for the in vivo function of both enzymes since strains expressing protein variants with an AAA motif instead of EAL are delayed in development, similar to null mutants. Transcriptome analysis of ∆cdgB, ∆cdgC, ∆rmdA, and ∆rmdB strains revealed that the c-di-GMP specified by these enzymes has a global regulatory role, with about 20% of all S. venezuelae genes being differentially expressed in the cdgC mutant. Our data suggest that the major c-di-GMP-controlled targets determining the timing and mode of sporulation are genes involved in cell division and the production of the hydrophobic sheath that covers Streptomyces aerial hyphae and spores.

Keywords: Streptomyces; EAL; GGDEF; c-di-GMP; diguanylate cyclase; phosphodiesterase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence / genetics
  • Bacterial Proteins / metabolism
  • Cyclic GMP / metabolism
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Gene Expression / genetics
  • Gene Expression Regulation, Bacterial / genetics
  • Phosphoric Diester Hydrolases / genetics
  • Phosphoric Diester Hydrolases / metabolism*
  • Phosphorus-Oxygen Lyases / genetics
  • Phosphorus-Oxygen Lyases / metabolism*
  • Second Messenger Systems / genetics
  • Sigma Factor / metabolism
  • Signal Transduction / genetics
  • Streptomyces / genetics
  • Streptomyces / metabolism*


  • Bacterial Proteins
  • Escherichia coli Proteins
  • Sigma Factor
  • Phosphoric Diester Hydrolases
  • Phosphorus-Oxygen Lyases
  • diguanylate cyclase
  • Cyclic GMP