Dual-function enzyme acts as a global c-di-GMP sink and local anti sigma factor antagonist to drive cellular differentiation
Buse Cınar Cakmak, Johanna D. Saric, Katrin Wrede, Neil A. Holmes, Julian Haist, Maria A. Schumacher, Mark J. Buttner, Natalia Tschowri
Abstract
Soil bacteria of the genus Streptomyces are natural producers of over two-thirds of clinically used antibiotics. Their ability to generate these valuable metabolites is tightly linked to a developmental program involving the transition from vegetative hyphae to spores. The second messenger cyclic di-GMP (c-di-GMP) stabilizes effector complexes that block sporulation, including the RsiG-σWhiG complex leading to sequestration of the developmental sigma factor by its anti sigma factor.
Introduction
Nucleotides fulfil many different functions essential for cellular life. They are crucial building blocks of nucleic acids, represent important players in energy transfer and energy storage reactions, act as co-enzymes and are often employed as second messengers in signalling networks of cells.
Materials and methods
Bacterial strains and growth conditions
Bacterial strains used in this study are listed in S1 Table. For standard cultivation, E. coli strains were grown in LB at 37 °C and S. venezuelae strains in liquid or solid MYM media supplemented with trace element solution at 30 °C. Liquid cultures were inoculated with spores to a final concentration of 106 CFU/ml. To track S. venezuelae development on solid media, 12 µl of 2 × 10⁵ CFU/µl spores were spotted on MYM and incubated at 30 °C.
Results
Deletion of rmdB leads to increased c-di-GMP in S. venezuelae
Synthesis of c-di-GMP from two molecules of GTP depends on the well-defined GGDEF domain, which is characteristic for all active DGCs. On the other hand, c-di-GMP-specific PDEs carry either an EAL or a HD-GYP domain [23,14]. S. venezuelae has 10 enzymes involved in c-di-GMP metabolism [19].
Discussion
Second messenger signaling systems provide bacteria with an exceptional capacity for rapid and adjusted responses to environmental cues. In Streptomyces, the second messenger, c-di-GMP, functions as the central regulator of the developmental transition from vegetative hyphae to sporulation through the modulation of key effectors, including the transcriptional repressor BldD and the sigma factor σWhiG [19–21].
Acknowledgments
We thank the research core unit metabolomics at the Hannover Medical School for support with LC-MS/MS analysis and Dr. Susan Schlimpert and Dr. Matt Bush, John Innes Centre, Norwich, for help with the µMACS epitope tag protein isolation procedure.
Citation: Cınar Cakmak B, Saric JD, Wrede K, Holmes NA, Haist J, Schumacher MA, et al. (2026) Dual-function enzyme acts as a global c-di-GMP sink and local anti sigma factor antagonist to drive cellular differentiation. PLoS Genet 22(6): e1012161. https://doi.org/10.1371/journal.pgen.1012161
Editor: Kai Papenfort, Friedrich-Schiller-Universitat Jena, GERMANY
Received: January 15, 2026; Accepted: May 8, 2026; Published: June 3, 2026
Copyright: © 2026 Cınar Cakmak et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the manuscript and its Supporting Information files.
Funding: This work was supported by the European Research Council under the European Union’s Horizon 2020 research programme (grant 101039556, SecMessFunctions, to N.T.); by zukunft.niedersachsen, the joint science funding program of the Lower Saxony Ministry of Science and Culture and the Volkswagen Foundation to N.T.; and by the National Institutes of Health (R35GM130290 to M.A.S.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
