flgM

UniProt ID: Q88EQ8
Organism: Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440)
Review Status: DRAFT
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Gene Description

flgM encodes the anti-sigma-28 factor that negatively regulates flagellin gene transcription by binding FliA until flagellar assembly has reached the appropriate stage.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0045892 negative regulation of DNA-templated transcription
IEA
GO_REF:0000002
ACCEPT
Summary: This annotation is appropriate. FlgM is the anti-sigma-28 factor that prevents FliA-dependent transcription of flagellin genes until flagellar assembly is ready.
Reason: Negative regulation of DNA-templated transcription captures the direct anti-sigma regulatory effect.
Supporting Evidence:
file:PSEPK/flgM/flgM-uniprot.txt
Responsible for the coupling of flagellin expression to
file:PSEPK/flgM/flgM-uniprot.txt
preventing expression of the flagellin genes
file:PSEPK/flgM/flgM-goa.tsv
GO:0045892 negative regulation of DNA-templated transcription
file:PSEPK/flgM/flgM-deep-research-falcon.md
FlgM is a **cytoplasmic anti-σ factor** that antagonizes **FliA (σ28)**, thereby acting as a **negative regulator of late flagellar gene expression** (including flagellin/filament genes).
file:PSEPK/flgM/flgM-deep-research-falcon.md
PP_4395** is explicitly annotated as **“Negative regulator of flagellin synthesis FlgM”** and is downregulated when FliA is absent, matching the canonical FliA–FlgM regulatory pair.
PMID:27663176
FliA and the cytoplasmic anti‐sigma factor FlgM depresses transcription of class IV flagellar genes by inhibiting the FliA‐RNA polymerase association until completion of the hook‐basal body complex, at which point the anti‐sigma factor is secreted
GO:0016989 sigma factor antagonist activity
ISS
file:PSEPK/flgM/flgM-uniprot.txt
NEW
Summary: FlgM directly antagonizes the flagellar sigma factor FliA, so sigma factor antagonist activity captures the direct molecular mechanism behind the transcriptional repression.
Reason: GO:0016989 is defined as binding to a sigma factor and reducing its transcriptional activity, matching the conserved anti-sigma-28 function of FlgM.
Supporting Evidence:
file:PSEPK/flgM/flgM-uniprot.txt
AltName: Full=Anti-sigma-28 factor
file:PSEPK/flgM/flgM-uniprot.txt
preventing expression of the flagellin genes
file:PSEPK/flgM/flgM-uniprot.txt
Anti-sigma factor FlgM
file:PSEPK/flgM/flgM-deep-research-falcon.md
FlgM is a **protein anti-sigma factor** that binds the flagellar sigma factor **FliA (σ28)** and inhibits FliA-dependent transcription of late/class III-IV flagellar genes until assembly reaches the proper checkpoint.
file:PSEPK/flgM/flgM-deep-research-falcon.md
whose primary molecular role is to **bind/sequester FliA**, preventing FliA from associating with RNA polymerase and thereby blocking FliA-dependent transcription until a defined assembly checkpoint is satisfied.
PMID:27663176
FliA and the cytoplasmic anti‐sigma factor FlgM depresses transcription of class IV flagellar genes by inhibiting the FliA‐RNA polymerase association until completion of the hook‐basal body complex, at which point the anti‐sigma factor is secreted

Core Functions

FlgM is an anti-sigma-28 factor that binds and inhibits FliA (sigma-28), negatively regulating transcription of FliA-dependent late flagellar genes (including flagellin) to time their expression with the flagellar assembly checkpoint.

Supporting Evidence:
  • file:PSEPK/flgM/flgM-uniprot.txt
    RecName: Full=Negative regulator of flagellin synthesis
  • file:PSEPK/flgM/flgM-uniprot.txt
    preventing expression of the flagellin genes
  • file:PSEPK/flgM/flgM-uniprot.txt
    AltName: Full=Anti-sigma-28 factor
  • file:PSEPK/flgM/flgM-uniprot.txt
    Anti-sigma factor FlgM
  • file:PSEPK/flgM/flgM-deep-research-falcon.md
    FlgM is a **protein anti-sigma factor** that binds the flagellar sigma factor **FliA (σ28)** and inhibits FliA-dependent transcription of late/class III-IV flagellar genes until assembly reaches the proper checkpoint.
  • file:PSEPK/flgM/flgM-deep-research-falcon.md
    FlgM is a **cytoplasmic anti-σ factor** that antagonizes **FliA (σ28)**, thereby acting as a **negative regulator of late flagellar gene expression** (including flagellin/filament genes).

References

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Suggested Questions for Experts

Q: Which assembly checkpoint controls FlgM release or inactivation in P. putida KT2440?

Suggested Experiments

Experiment: Measure FliA-dependent promoter activity and flagellin abundance in flgM deletion, fliA deletion, and assembly-defective backgrounds.

Hypothesis: FlgM restrains FliA-dependent flagellin transcription until the basal body-hook assembly checkpoint is satisfied.

Type: epistasis and promoter reporter assay

Deep Research

Falcon

(flgM-deep-research-falcon.md)

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