mucR

UniProt ID: Q9I310
Organism: Pseudomonas aeruginosa PAO1
Review Status: COMPLETE
📝 Provide Detailed Feedback

Gene Description

MucR (PA1727) is an inner-membrane bifunctional diguanylate cyclase and c-di-GMP phosphodiesterase of Pseudomonas aeruginosa. An N-terminal MHYT sensor domain with seven predicted transmembrane helices anchors the protein, and the cytosolic GGDEF and EAL domains synthesise and hydrolyse c-di-GMP, respectively. MucR generates a localized c-di-GMP pool that activates alginate production through the c-di-GMP receptor Alg44, and its activity balance appears to shift with growth mode. mucR mutants are impaired in biofilm dispersion in response to nitric oxide and glutamate.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0005886 plasma membrane
EXP
PMID:19088322
MucR, a novel membrane-associated regulator of alginate bios... 		ACCEPT
Summary: LacZ and PhoA fusions place MucR in the cytoplasmic membrane.
Reason: Direct topology evidence plus seven predicted transmembrane helices.
Supporting Evidence:
PMID:19088322
Translational reporter enzyme fusions with LacZ and PhoA suggested that MucR is located in the cytoplasmic membrane with a cytosolic C terminus.
GO:0005886 plasma membrane
IEA
GO_REF:0000044 		ACCEPT
Summary: UniProt subcellular location mapping; consistent with the EXP row.
Reason: Consistent with the experimental row on the same term.
Supporting Evidence:
PMID:19088322
Translational reporter enzyme fusions with LacZ and PhoA suggested that MucR is located in the cytoplasmic membrane with a cytosolic C terminus.
GO:0052621 diguanylate cyclase activity
IDA
PMID:16477007
Analysis of Pseudomonas aeruginosa diguanylate cyclases and ... 		ACCEPT
Summary: IDA from the Kulasakara et al. survey of P. aeruginosa DGCs and PDEs.
Reason: Abstract only, so the assay is not seen, but the activity is independently supported by PMID:23729646 and by the requirement of the GGDEF domain for MucR function; deferring to the curator.
Supporting Evidence:
PMID:23729646
In contrast, MucR displayed both diguanylate cyclase and PDE activity in vitro, which seemed regulated in a growth-dependent manner in vivo.
GO:0052621 diguanylate cyclase activity
IDA
PMID:23729646
NO-induced biofilm dispersion in Pseudomonas aeruginosa is m... 		ACCEPT
Summary: PseudoCAP IDA; the abstract states in vitro DGC activity of MucR.
Reason: Direct in vitro activity stated in the abstract. Not a seed row.
Supporting Evidence:
PMID:23729646
In contrast, MucR displayed both diguanylate cyclase and PDE activity in vitro, which seemed regulated in a growth-dependent manner in vivo.
GO:0052621 diguanylate cyclase activity
IEA
GO_REF:0000003 		ACCEPT
Summary: EC 2.7.7.65 mapping; consistent with experimental rows.
Reason: Consistent with the IDA rows on the same term.
Supporting Evidence:
PMID:19088322
Deletion of the proposed C-terminal GGDEF domain abolished MucR function.
GO:0071111 cyclic-guanylate-specific phosphodiesterase activity
IBA
GO_REF:0000033 		ACCEPT
Summary: IBA from PTN002403463 (PTHR44757 SF2 GGDEF-EAL clade, 14 leaves), seeded by E. coli PdeR, DipA (PA5017) and MucR itself.
Reason: Expected self-seed reflecting MucR's own IDA. The IBD stands without this seed on PdeR (IDA PMID:17010156, EXP PMID:23708798) and DipA (IDA PMID:22493016).
Supporting Evidence:
PMID:23729646
In contrast, MucR displayed both diguanylate cyclase and PDE activity in vitro, which seemed regulated in a growth-dependent manner in vivo.
GO:0071111 cyclic-guanylate-specific phosphodiesterase activity
IDA
PMID:23729646
NO-induced biofilm dispersion in Pseudomonas aeruginosa is m... 		ACCEPT
Summary: PseudoCAP IDA and a seed of PTN002403463. The abstract states that MucR has PDE activity in vitro.
Reason: Seed verdict SOUND. The abstract states the in vitro activity outright, and crystal structures of the MucR EAL domain with c-di-GMP and Mg2+ support an intact active site.
Supporting Evidence:
PMID:23729646
In contrast, MucR displayed both diguanylate cyclase and PDE activity in vitro, which seemed regulated in a growth-dependent manner in vivo.
PMID:28186120
We have studied the EAL signature motif-containing phosphodiesterase domains from the Pseudomonas aeruginosa proteins PA3825 (PA3825EAL) and PA1727 (MucREAL).
GO:0071111 cyclic-guanylate-specific phosphodiesterase activity
IEA
GO_REF:0000120 		ACCEPT
Summary: Combined automated annotation; consistent with the experimental row.
Reason: Consistent with the IDA and IBA rows on the same term.
Supporting Evidence:
PMID:23729646
In contrast, MucR displayed both diguanylate cyclase and PDE activity in vitro, which seemed regulated in a growth-dependent manner in vivo.
GO:0071732 cellular response to nitric oxide
IEA
GO_REF:0000117 		KEEP AS NON CORE
Summary: ARBA prediction; mirrors the IMP row.
Reason: Same claim as the IMP row and kept consistent with it; the dispersion defect is shared with glutamate, so the NO response is peripheral to MucR's role.
Supporting Evidence:
PMID:23729646
Inactivation of mucR impaired biofilm dispersion in response to NO and glutamate
GO:0071732 cellular response to nitric oxide
IMP
PMID:23729646
NO-induced biofilm dispersion in Pseudomonas aeruginosa is m... 		KEEP AS NON CORE
Summary: PseudoCAP IMP; the mucR mutant is impaired in NO-induced dispersion.
Reason: The phenotype is real, but not NO-specific (glutamate-induced dispersion is also impaired) and MucR is not shown to be NO-induced, unlike NbdA, the NO-specific paralog for which the term is core. Not a seed row.
Supporting Evidence:
PMID:23729646
Inactivation of mucR impaired biofilm dispersion in response to NO and glutamate

Core Functions

Inner-membrane bifunctional c-di-GMP turnover enzyme that synthesises c-di-GMP (GGDEF) to supply a localized pool that activates alginate production.

Molecular Function:
diguanylate cyclase activity
Cellular Locations:
plasma membrane
Supporting Evidence:
  • PMID:19088322
    MucR specifically regulates alginate biosynthesis by activation of alginate production through generation of a localized c-di-GMP pool in the vicinity of Alg44
  • PMID:23729646
    In contrast, MucR displayed both diguanylate cyclase and PDE activity in vitro, which seemed regulated in a growth-dependent manner in vivo.

EAL-domain c-di-GMP phosphodiesterase activity of the same protein, proposed to dominate under planktonic conditions and to contribute to biofilm dispersion.

Molecular Function:
cyclic-guanylate-specific phosphodiesterase activity
Cellular Locations:
plasma membrane
Supporting Evidence:
  • PMID:23729646
    In contrast, MucR displayed both diguanylate cyclase and PDE activity in vitro, which seemed regulated in a growth-dependent manner in vivo.

References

Loading supporting content…

Download this section (compressed HTML)

Suggested Questions for Experts

Q: What signal does the MHYT domain sense, and how is the balance between MucR's cyclase and phosphodiesterase activities switched between planktonic and biofilm growth?

Suggested Experiments

Experiment: Assay full-length MucR reconstituted in membranes for DGC and PDE activity with GGDEF and EAL active-site mutants, in the presence of candidate MHYT ligands (NO, O2, CO), to define how the sensor controls the activity balance.

📚 Additional Documentation

Notes

(mucR-notes.md)

Loading supporting content…

Download this section (compressed HTML)

📄 View Raw YAML

Loading supporting content…

Download this section (compressed HTML)