Genetic dissection of Escherichia coli's master diguanylate cyclase DgcE: Role of the N-terminal MASE1 domain and direct signal input from a GTPase partner system

PLoS Genet. 2019 Apr 25;15(4):e1008059. doi: 10.1371/journal.pgen.1008059. eCollection 2019 Apr.


The ubiquitous second messenger c-di-GMP promotes bacterial biofilm formation by playing diverse roles in the underlying regulatory networks. This is reflected in the multiplicity of diguanylate cyclases (DGC) and phosphodiesterases (PDE) that synthesize and degrade c-di-GMP, respectively, in most bacterial species. One of the 12 DGCs of Escherichia coli, DgcE, serves as the top-level trigger for extracellular matrix production during macrocolony biofilm formation. Its multi-domain architecture-a N-terminal membrane-inserted MASE1 domain followed by three PAS, a GGDEF and a degenerate EAL domain-suggested complex signal integration and transmission through DgcE. Genetic dissection of DgcE revealed activating roles for the MASE1 domain and the dimerization-proficient PAS3 region, whereas the inhibitory EALdeg domain counteracts the formation of DgcE oligomers. The MASE1 domain is directly targeted by the GTPase RdcA (YjdA), a dimer or oligomer that together with its partner protein RdcB (YjcZ) activates DgcE, probably by aligning and promoting dimerization of the PAS3 and GGDEF domains. This activation and RdcA/DgcE interaction depend on GTP hydrolysis by RdcA, suggesting GTP as an inhibitor and the pronounced decrease of the cellular GTP pool during entry into stationary phase, which correlates with DgcE-dependent activation of matrix production, as a possible input signal sensed by RdcA. Furthermore, DgcE exhibits rapid, continuous and processive proteolytic turnover that also depends on the relatively disordered transmembrane MASE1 domain. Overall, our study reveals a novel GTP/c-di-GMP-connecting signaling pathway through the multi-domain DGC DgcE with a dual role for the previously uncharacterized MASE1 signaling domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Escherichia coli / genetics*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics*
  • Escherichia coli Proteins / metabolism*
  • Extracellular Matrix / metabolism
  • GTP Phosphohydrolases / chemistry
  • GTP Phosphohydrolases / genetics
  • GTP Phosphohydrolases / metabolism
  • Gene Expression Regulation, Bacterial*
  • Phosphorus-Oxygen Lyases / chemistry
  • Phosphorus-Oxygen Lyases / genetics*
  • Phosphorus-Oxygen Lyases / metabolism*
  • Protein Binding
  • Protein Domains
  • Protein Interaction Domains and Motifs
  • Signal Transduction


  • Escherichia coli Proteins
  • GTP Phosphohydrolases
  • Phosphorus-Oxygen Lyases
  • diguanylate cyclase

Grant support

Financial support was provided by the Deutsche Forschungsgemeinschaft (; grants He 1556/17-1 and He 1556/21-1 to RH). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.