GO:0061939 c-di-GMP signaling: Bacterial Second Messenger Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0061939 (c-di-GMP signaling) describes any process that mediates the transfer of information from one cell to another using cyclic di-GMP (c-di-GMP) as the signal.
• c-di-GMP is synthesized by diguanylate cyclases (DGCs) and degraded by specific phosphodiesterases (PDEs), establishing a dynamic second-messenger pool.
• The signal is received by diverse effectors, including PilZ-domain proteins, transcription factors, and riboswitches, which alter motility, biofilm formation, and virulence.
• c-di-GMP signaling is central to bacterial pathogenesis, controlling the switch between motile and sessile lifestyles in organisms such as Vibrio cholerae, Pseudomonas aeruginosa, and Bordetella species.
• In Streptomyces, c-di-GMP controls progression through the complex life cycle, linking second-messenger signaling to developmental decisions.
• The pathway is a validated target for anti-biofilm and anti-virulence small molecules, and its components are widely studied using genetic knockouts, point mutations, and reporter fusions.
Description
Cyclic di-GMP (c-di-GMP) is a ubiquitous bacterial second messenger that governs the transition between motile and sessile lifestyles, biofilm formation, and virulence. The Gene Ontology term GO:0061939, c-di-GMP signaling, captures any process that mediates the transfer of information from one cell to another using c-di-GMP as the signal. This term is essential for annotating bacterial signal transduction pathways and for understanding how bacteria adapt to changing environments. Since its discovery, c-di-GMP signaling has emerged as a paradigm for second-messenger control in prokaryotes, with implications for infectious disease, microbiome engineering, and antimicrobial development. The pathway is defined by three core activities: synthesis by diguanylate cyclases (DGCs), degradation by phosphodiesterases (PDEs), and reception by effectors that translate the signal into cellular responses. Researchers studying bacterial physiology, pathogenesis, and biofilm biology rely on GO:0061939 to systematically classify genes and processes involved in this signaling network.
c-di-GMP signaling At A Glance
| GO ID | GO:0061939 |
|---|---|
| GO term | c-di-GMP signaling |
| Ontology | biological_process |
| Synonym | 3',5'-cyclic di-GMP signaling; cyclic di-(3':5')-guanosine monophosphate signaling; cyclic di-GMP signaling; cyclic diguanylate signaling |
| Definition | Any process that mediates the transfer of information from one cell to another using c-di-GMP as the signal. |
| Major function | Second-messenger signaling controlling bacterial motility, biofilm formation, virulence, and cell cycle progression. |
| Key enzymes | Diguanylate cyclases (DGCs) with GGDEF domains; phosphodiesterases (PDEs) with EAL or HD-GYP domains. |
| Key effectors | PilZ-domain proteins, transcription factors, riboswitches, and degenerate GGDEF/EAL proteins. |
| Representative organisms | Vibrio cholerae, Pseudomonas aeruginosa, Escherichia coli, Streptomyces, Bordetella pertussis, Vibrio parahaemolyticus. |
What Is GO:0061939?
GO:0061939 (c-di-GMP signaling) is defined as any process that mediates the transfer of information from one cell to another using c-di-GMP as the signal. In practice, this includes the enzymatic synthesis of c-di-GMP from two GTP molecules by diguanylate cyclases, its degradation by phosphodiesterases, and its perception by effector proteins or RNA elements that trigger downstream cellular responses. The term encompasses both the intracellular signaling events and the intercellular communication mediated by c-di-GMP, distinguishing it from other second-messenger systems such as cAMP or cGMP signaling.
Why Is c-di-GMP signaling Important in Cell Biology?
c-di-GMP signaling is a master regulator of bacterial lifestyle decisions, controlling the switch between planktonic motility and surface-attached biofilm communities. Because biofilms are associated with chronic infections and increased antibiotic tolerance, understanding this pathway is critical for developing new anti-virulence strategies. The pathway also plays essential roles in bacterial development, as seen in Streptomyces where c-di-GMP controls the transition from vegetative growth to sporulation. In pathogenic species such as Bordetella pertussis and Vibrio parahaemolyticus, c-di-GMP signaling regulates virulence factor production and host colonization. Consequently, GO:0061939 is a high-priority annotation target for microbiologists, infectious disease researchers, and drug discovery scientists.
• Controls the motile-to-sessile transition, a fundamental lifestyle switch in bacteria.
• Regulates biofilm formation, which contributes to chronic infections and antibiotic resistance.
• Modulates virulence gene expression in pathogens such as Vibrio cholerae and Bordetella species.
• Influences cell cycle progression and developmental decisions in Streptomyces.
• Serves as a target for small-molecule inhibitors that disrupt biofilm formation and motility.
• Involved in host-microbe interactions and immune modulation.
• Provides a model for understanding second-messenger signaling in prokaryotes.
• Enables synthetic biology applications through engineered c-di-GMP circuits.
• Links environmental sensing to global gene expression changes.
• Offers a paradigm for studying allosteric regulation and protein-protein interactions in signaling.
What Happens During c-di-GMP signaling?
Synthesis of c-di-GMP by Diguanylate Cyclases
In simple terms: Enzymes called diguanylate cyclases build c-di-GMP from two GTP molecules.
Diguanylate cyclases (DGCs) contain a conserved GGDEF domain and catalyze the condensation of two GTP molecules into one c-di-GMP molecule, releasing two pyrophosphate groups. DGC activity is often allosterically regulated by c-di-GMP binding to inhibitory sites, ensuring tight control of the second-messenger pool. Many bacterial genomes encode multiple DGCs, allowing integration of diverse environmental signals into c-di-GMP production.
Degradation of c-di-GMP by Phosphodiesterases
In simple terms: Phosphodiesterases break down c-di-GMP to terminate the signal.
Specific phosphodiesterases (PDEs) hydrolyze c-di-GMP, either to linear pGpG or to two GMP molecules, depending on the enzyme family (EAL or HD-GYP domains). This degradation is essential for resetting the signaling system and allowing dynamic responses to changing conditions. The balance between DGC and PDE activities determines the intracellular concentration of c-di-GMP.
Reception by PilZ-Domain Effectors
In simple terms: PilZ proteins bind c-di-GMP and change their shape to trigger responses.
PilZ domain proteins are the most widespread c-di-GMP receptors and undergo conformational changes upon binding the second messenger, often modulating protein-protein interactions or enzymatic activities. These effectors are frequently associated with flagellar motors, cellulose synthases, or secretion systems, directly linking c-di-GMP to motility and biofilm matrix production.
Transcriptional and Post-Transcriptional Regulation
In simple terms: c-di-GMP can also control gene expression by binding to transcription factors or riboswitches.
Beyond protein effectors, c-di-GMP binds to riboswitches (e.g., the Vc2 riboswitch) and transcription factors, altering mRNA translation or DNA binding. This expands the regulatory reach of c-di-GMP to include global changes in gene expression, such as those required for biofilm formation or virulence.
Integration into Cellular Networks
In simple terms: c-di-GMP signaling is wired into larger networks that control bacterial behavior.
c-di-GMP signaling intersects with other second messengers (e.g., cAMP) and two-component systems, enabling fine-tuned responses to multiple cues. In Streptomyces, c-di-GMP is integrated into the developmental program that governs morphological differentiation and antibiotic production. In Bordetella species, c-di-GMP signaling is architecturally organized to regulate virulence and persistence.
Key Genes Involved in GO:0061939 c-di-GMP signaling
The following genes and proteins are core components of c-di-GMP signaling, as established in the literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| dgcA (Vibrio cholerae) | Diguanylate cyclase; synthesizes c-di-GMP | Controls biofilm formation and motility |
| cdgA (Escherichia coli) | Diguanylate cyclase | Model for studying DGC regulation |
| pdeA (Pseudomonas aeruginosa) | Phosphodiesterase; degrades c-di-GMP | Regulates biofilm dispersal and virulence |
| pilZ (Various bacteria) | PilZ-domain effector; binds c-di-GMP | Mediates motility and cellulose synthesis |
| vpsT (Vibrio cholerae) | Transcriptional regulator; binds c-di-GMP | Controls biofilm matrix gene expression |
| flaA (Vibrio parahaemolyticus) | Flagellin; motility | Regulated by c-di-GMP signaling |
| bvgA (Bordetella pertussis) | Two-component response regulator | Interacts with c-di-GMP signaling |
| cdgB (Streptomyces coelicolor) | Diguanylate cyclase | Controls life cycle progression |
| rsiG (Streptomyces venezuelae) | c-di-GMP receptor | Regulates sporulation |
| lapD (Pseudomonas fluorescens) | c-di-GMP effector | Controls biofilm formation |
| bcsA (Escherichia coli) | Cellulose synthase; PilZ domain | c-di-GMP-activated cellulose production |
| adrA (Salmonella enterica) | Diguanylate cyclase | Regulates cellulose and biofilm |
| yfiN (Escherichia coli) | Diguanylate cyclase | Involved in biofilm regulation |
| mbaA (Vibrio cholerae) | Phosphodiesterase | Modulates biofilm architecture |
| rocS (Bacillus subtilis) | c-di-GMP receptor | Regulates motility and biofilm |
| cdgH (Vibrio parahaemolyticus) | Diguanylate cyclase | Affects motility and biofilm |
| vpsR (Vibrio cholerae) | Transcriptional regulator | c-di-GMP-dependent biofilm gene activation |
How Is c-di-GMP signaling Regulated?
c-di-GMP signaling is regulated at multiple levels. The intracellular concentration of c-di-GMP is controlled by the opposing activities of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), whose expression and activity are modulated by environmental signals such as oxygen, nutrients, and host factors. Allosteric feedback inhibition of DGCs by c-di-GMP ensures homeostasis. Additionally, effector proteins and riboswitches provide feedback loops that adjust the signaling output. In pathogenic bacteria, c-di-GMP signaling is integrated with two-component systems and quorum sensing to coordinate virulence gene expression.
c-di-GMP signaling and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| dgcA (Vibrio cholerae) | Cholera pathogenesis; biofilm formation | Vibrio cholerae knockout and overexpression strains |
| pdeA (Pseudomonas aeruginosa) | Chronic lung infections in cystic fibrosis | P. aeruginosa deletion mutants in biofilm models |
| bvgA (Bordetella pertussis) | Whooping cough; respiratory colonization | Bordetella pertussis point mutants |
| cdgB (Streptomyces coelicolor) | Antibiotic production; developmental cycle | Streptomyces knockout and complemented strains |
| cdgH (Vibrio parahaemolyticus) | Gastroenteritis; motility regulation | V. parahaemolyticus knockout and reporter fusions |
c-di-GMP signaling in chronic bacterial infections
Biofilms formed by Pseudomonas aeruginosa and other opportunistic pathogens are a major cause of chronic infections, and c-di-GMP signaling is a key driver of biofilm formation. Elevated c-di-GMP levels promote the production of exopolysaccharides and adhesins, enhancing surface attachment and antibiotic tolerance. Targeting c-di-GMP signaling is therefore a promising anti-virulence strategy.
Role in Vibrio cholerae pathogenesis
In Vibrio cholerae, c-di-GMP signaling controls the switch between motile, planktonic cells and sessile, biofilm-forming cells, which is critical for intestinal colonization and transmission. The second messenger regulates the expression of virulence factors such as cholera toxin and the toxin-coregulated pilus.
c-di-GMP signaling in Bordetella infections
Classical Bordetella species, including B. pertussis and B. bronchiseptica, utilize c-di-GMP signaling to regulate virulence and persistence in the host respiratory tract. The pathway is architecturally organized to integrate host-derived signals into adaptive responses.
c-di-GMP signaling in Streptomyces development
While not a human pathogen, Streptomyces species are important producers of antibiotics, and c-di-GMP signaling controls their developmental life cycle, including sporulation and secondary metabolite production. Understanding this pathway can inform industrial strain engineering.
From c-di-GMP signaling-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate c-di-GMP levels? | Knockout of DGC or PDE gene, followed by c-di-GMP quantification |
| Does a point mutation in a GGDEF domain abolish DGC activity? | Site-directed point mutation in the GGDEF motif |
| Does c-di-GMP binding to an effector require a specific residue? | Knock-in of a binding-deficient point mutant |
| Where is the effector protein localized? | Tagged knock-in with fluorescent protein |
| Does overexpression of a DGC increase biofilm formation? | Overexpression plasmid or inducible promoter |
| Can a small molecule inhibit c-di-GMP signaling? | Wild-type strain treated with inhibitor, biofilm assay |
How to Study the c-di-GMP signaling Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS/MS | Intracellular c-di-GMP concentration | Quantifying second-messenger levels in mutants |
| Fluorescent biosensors | Real-time c-di-GMP dynamics | Live-cell imaging of signaling |
| Biofilm assay (crystal violet) | Biofilm biomass | Phenotypic screen of DGC/PDE mutants |
| Motility assay | Swimming/swarming/twitching | Linking c-di-GMP to flagellar function |
| RNA-seq | Global gene expression changes | Identifying c-di-GMP regulons |
| ChIP-seq | DNA binding by c-di-GMP-dependent transcription factors | Mapping regulatory targets |
| Isothermal titration calorimetry | Binding affinity of c-di-GMP to effectors | Characterizing PilZ domain interactions |
| X-ray crystallography | Three-dimensional structure of c-di-GMP complexes | Structural basis of signal reception |
Quantification of c-di-GMP levels
Intracellular c-di-GMP concentrations are commonly measured using HPLC-MS/MS, LC-MS/MS, or fluorescent biosensors. These methods enable direct correlation of second-messenger levels with phenotypic outputs such as biofilm formation or motility.
Genetic approaches to dissect signaling
Knockout, point mutation, and overexpression of DGCs, PDEs, and effectors are standard approaches to establish causality in c-di-GMP signaling. Complementation and allelic exchange are used to confirm specificity.
Phenotypic assays for motility and biofilm
Swimming, swarming, and twitching motility assays, along with crystal violet biofilm assays and confocal microscopy, are widely used to link c-di-GMP signaling to bacterial behavior. These assays are often combined with reporter gene fusions.
Structural and biophysical studies
X-ray crystallography, NMR, and isothermal titration calorimetry are used to determine how c-di-GMP binds to effectors such as PilZ domains and riboswitches. These studies reveal the molecular basis of signal reception.
How CRISPR Can Be Used to Study GO:0061939 c-di-GMP signaling
Knockout
CRISPR-Cas9 knockout of diguanylate cyclase or phosphodiesterase genes enables researchers to determine their contribution to c-di-GMP pools and downstream phenotypes such as biofilm formation and motility. Clean deletions are preferred to avoid polar effects, and complemented strains validate specificity.
Point Mutation
CRISPR-mediated point mutations in conserved motifs (e.g., GGDEF or EAL domains) allow precise dissection of catalytic activity versus allosteric regulation. Such mutants are invaluable for separating c-di-GMP synthesis from protein-protein interaction functions.
Knock-in
Knock-in of epitope tags or fluorescent proteins at endogenous loci enables visualization and quantification of c-di-GMP signaling components in live bacteria. This approach preserves native expression levels and regulation.
Overexpression
CRISPR activation (CRISPRa) or inducible plasmid-based overexpression of DGCs or PDEs is used to artificially elevate or deplete c-di-GMP levels, revealing dose-dependent effects on bacterial physiology. Overexpression models are particularly useful for testing small-molecule inhibitors.
How EDITGENE Supports c-di-GMP signaling Research
Researchers studying c-di-GMP signaling-related genes often need to determine whether a candidate gene is causally involved in second-messenger signaling, biofilm formation, or virulence. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered bacterial strains, enabling functional validation of DGCs, PDEs, and effectors in diverse species.
Contact EDITGENE today to design your custom CRISPR model for c-di-GMP signaling research.
Frequently Asked Questions About c-di-GMP signaling
What is c-di-GMP signaling?
c-di-GMP signaling (GO:0061939) is any process that mediates the transfer of information from one cell to another using cyclic di-GMP as the signal, controlling bacterial motility, biofilm formation, and virulence.
What genes are involved in c-di-GMP signaling?
Key genes include diguanylate cyclases (e.g., dgcA, adrA), phosphodiesterases (e.g., pdeA, mbaA), and effectors such as pilZ and vpsT.
How does c-di-GMP control biofilm formation?
c-di-GMP binds to PilZ-domain effectors and transcription factors, activating the synthesis of exopolysaccharides and adhesins that promote biofilm formation.
What is the role of c-di-GMP in bacterial pathogenesis?
c-di-GMP signaling regulates the switch between motile and sessile lifestyles and controls virulence gene expression in pathogens such as Vibrio cholerae and Bordetella pertussis.
Which enzymes synthesize and degrade c-di-GMP?
Diguanylate cyclases (DGCs) with GGDEF domains synthesize c-di-GMP, while phosphodiesterases (PDEs) with EAL or HD-GYP domains degrade it.
What are PilZ domain proteins?
PilZ domain proteins are the most common c-di-GMP receptors; they undergo conformational changes upon binding c-di-GMP to modulate motility, cellulose synthesis, and other functions.
How is c-di-GMP signaling studied experimentally?
Common methods include LC-MS/MS quantification, fluorescent biosensors, genetic knockouts, motility and biofilm assays, and structural biology techniques.
Can c-di-GMP signaling be targeted for new antibiotics?
Yes, small molecules that inhibit c-di-GMP synthesis or binding are being developed as anti-biofilm and anti-virulence agents.
What is the connection between c-di-GMP and Streptomyces development?
In Streptomyces, c-di-GMP signaling controls the life cycle transition from vegetative growth to sporulation and influences antibiotic production.
How does c-di-GMP signaling differ between bacterial species?
The core components (DGCs, PDEs, effectors) are conserved, but the number and regulation of these proteins vary widely, reflecting species-specific adaptations.
Conclusion
GO:0061939 (c-di-GMP signaling) represents a fundamental bacterial second-messenger system that governs motility, biofilm formation, virulence, and developmental transitions. Its widespread conservation and critical roles in pathogenesis make it a prime target for anti-virulence therapies and a rich area for basic research. Advances in CRISPR-based genetic tools and high-throughput screening continue to illuminate the complex regulatory networks controlled by c-di-GMP. Understanding this pathway at the molecular level offers new opportunities to combat chronic infections and engineer beneficial bacterial behaviors.
References
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- 3. Yao P et al.. 2025. Investigating c-di-GMP Signaling in Vibrio parahaemolyticus: Biological Effects and Mechanisms of Regulation.. Curr Microbiol 82(7):319 PMID: 40455311
- 4. Opoku-Temeng C et al.. 2017. Targeting c-di-GMP Signaling, Biofilm Formation, and Bacterial Motility with Small Molecules.. Methods Mol Biol 1657:419-430 PMID: 28889311
- 5. Cheang QW et al.. 2019. Emerging paradigms for PilZ domain-mediated C-di-GMP signaling.. Biochem Soc Trans 47(1):381-388 PMID: 30710060
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- 7. Gallagher KA et al.. 2024. How c-di-GMP controls progression through the Streptomyces life cycle.. Curr Opin Microbiol 80:102516 PMID: 39059031
- 8. Vondrova D et al.. 2026. Architecture and regulatory functions of c-di-GMP signaling in classical Bordetella species.. FEMS Microbiol Rev 50 PMID: 41452322
