identifier: traitmech:000059
label: amphitrichous
definition: A flagellar arrangement with flagella (single filaments or tufts) at both
  poles of the cell.
definition_source: DOI:10.1093/femsre/fuv034
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- traitmech:000056
evidence:
- reference: DOI:10.1093/femsre/fuv034
  notes: Schuhmacher et al. describe bipolar (amphitrichous) flagellation among the
    flagellation patterns governed by FlhF/FlhG.
- reference: DOI:10.3390/biom9070279
  notes: Flagellum review supports polar flagellar filaments as locomotory organelles.
canonical_examples:
- taxon_id: NCBITaxon:968
  taxon_label: Spirillum volutans
  note: "Large spiral bacterium with amphitrichous flagellar tufts (bipolar flagellar bundles)."
  reference: PMID:16561638
causal_graphs:
- graph_id: amphitrichous_bipolar_flagella
  title: Amphitrichous flagellation — bipolar flagella
  description: Evidence-backed causal sketch linking bacterial flagella at both poles
    to the amphitrichous arrangement.
  nodes:
  - node_id: amphitrichous_trait
    label: amphitrichous
    node_type: TRAIT
    grounding: traitmech:000059
    description: Flagella (single filaments or tufts) at both cell poles.
  - node_id: bacterial_flagellum
    label: bacterial-type flagellum
    node_type: CELLULAR_LOCALIZATION
    grounding: GO:0009288
    description: Helical proteinaceous locomotory organelle.
  - node_id: bipolar_placement
    label: bipolar placement
    node_type: QUALITY
    description: Flagella positioned at both poles of the cell.
  - node_id: flhf_gtpase
    label: FlhF
    node_type: GENE_OR_PROTEIN
    description: SRP-type GTPase that positions and recruits flagellar building blocks
      to the cell pole.
    grounding: UniProtKB:A0A656AC42
  - node_id: flhg_atpase
    label: FlhG
    node_type: GENE_OR_PROTEIN
    description: MinD/ParA-family ATPase that regulates FlhF activity and polar flagellar
      number.
    grounding: UniProtKB:Q2N2M1
  - node_id: flig_protein
    label: FliG
    node_type: GENE_OR_PROTEIN
    description: Flagellar C-ring switch protein engaged early by FlhF during assembly.
    grounding: UniProtKB:A0A016XEK1
  - node_id: flif_msring
    label: FliF (MS-ring)
    node_type: GENE_OR_PROTEIN
    description: Transmembrane MS-ring forming protein, an early flagellar assembly
      intermediate.
  - node_id: fipa_protein
    label: FipA
    node_type: GENE_OR_PROTEIN
    description: Membrane protein that facilitates polar recruitment of FlhF.
    grounding: UniProtKB:A0A023UGD7
  - node_id: cell_pole
    label: cell pole
    node_type: CELLULAR_LOCALIZATION
    description: Polar membrane region where flagellar assembly is nucleated.
    grounding: GO:0060187
  - node_id: flhf_polar_localization
    label: FlhF polar localization
    node_type: BIOLOGICAL_PROCESS
    description: Recruitment and confinement of FlhF to the cell pole.
  - node_id: polar_flagellar_number
    label: polar flagellar number
    node_type: QUALITY
    description: Number of flagella formed at the cell pole.
  edges:
  - subject: bacterial_flagellum
    predicate: defines
    object: amphitrichous_trait
    description: Flagella at both cell poles define the amphitrichous arrangement.
    evidence:
    - reference: DOI:10.1093/femsre/fuv034
      notes: Schuhmacher et al. describe bipolar (amphitrichous) flagellation governed
        by FlhF/FlhG.
    predicate_id: METPO:2007500
  - subject: amphitrichous_trait
    predicate: associated with
    object: bipolar_placement
    description: The amphitrichous pattern places flagella at both poles.
    evidence:
    - reference: DOI:10.3390/biom9070279
      notes: Flagellum review supports polar flagellar filaments as locomotory organelles.
    predicate_id: biolink:associated_with
  - subject: flhf_gtpase
    predicate: binds
    object: flig_protein
    description: FlhF specifically interacts with the polar-system FliG to initiate
      assembly.
    evidence:
    - reference: DOI:10.1038/s41467-024-50274-4
      notes: FlhF exhibited a strong interaction with FliG and specifically interacts
        with FliG from the polar flagellar system.
  - subject: flig_protein
    predicate: binds
    object: flif_msring
    description: FlhF-bound FliG captures FliF, promoting MS-ring formation at the
      pole.
    evidence:
    - reference: DOI:10.1038/s41467-024-50274-4
      notes: When bound to FlhF, FliG was able to interact with the cytoplasmic domain
        of the MS-ring forming protein FliF.
  - subject: flhf_gtpase
    predicate: localizes to
    object: cell_pole
    description: GTP-bound dimeric FlhF localizes to the cell pole to nucleate flagellar
      assembly.
    evidence:
    - reference: DOI:10.7554/eLife.93004.3
      notes: GTP-bound dimeric FlhF localizes to the cell pole where it recruits the
        initial flagellar building blocks.
    predicate_id: biolink:located_in
  - subject: fipa_protein
    predicate: directly interacts with
    object: flhf_gtpase
    description: FipA directly interacts with FlhF and facilitates its polar recruitment.
    evidence:
    - reference: DOI:10.7554/eLife.93004.3
      notes: In all three species, FipA directly interacts with FlhF and facilitates
        its recruitment to the membrane at the cell pole.
  - subject: fipa_protein
    predicate: promotes
    object: flhf_polar_localization
    description: Loss of FipA significantly decreases polar localization of FlhF.
    evidence:
    - reference: DOI:10.7554/eLife.93004.3
      notes: In the absence of FipA, polar localization of FlhF was significantly
        decreased in all three species.
    predicate_id: RO:0002213
  - subject: flhg_atpase
    predicate: stimulates GTPase activity of
    object: flhf_gtpase
    description: ATP-bound FlhG dimer stimulates FlhF GTPase activity, controlling
      its polar dynamics.
    evidence:
    - reference: DOI:10.7554/eLife.93004.3
      notes: The ATP-bound FlhG dimer can interact with the GTP-bound FlhF dimer,
        thereby stimulating its GTPase activity.
  - subject: flhg_atpase
    predicate: restricts
    object: polar_flagellar_number
    description: FlhG links flagella synthesis with transcription and restricts polar
      flagellar number.
    evidence:
    - reference: DOI:10.7554/eLife.93004.3
      notes: FlhG links flagella synthesis with transcription regulation and effectively
        restricts the number of polar flagella that are formed.
curation_history:
- timestamp: '2026-06-03T00:00:00Z'
  curator: claude
  action: PROPOSED_FROM_RESEARCH
  changes: Proposed candidate MORPHOLOGY trait (amphitrichous flagellation); sub-variant
    of flagellar arrangement.
  llm_assisted: true
- timestamp: '2026-06-09T15:00:00Z'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added evidence-backed causal graph (bipolar flagella) with GO node grounding
    and METPO/biolink predicate groundings; promoted PROPOSED to REVIEWED.
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 7 evidence-backed generic edges (8 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:12Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (biolink:located_in×1, RO:0002213×1).
  llm_assisted: true
- timestamp: '2026-06-24T17:23:33Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (GO:0060187×1).
  llm_assisted: true
- timestamp: '2026-06-26T07:15:19Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 4 causal-node grounding field(s) via mappings/node_grounding.tsv
    (UniProtKB:A0A656AC42×1, UniProtKB:Q2N2M1×1, UniProtKB:A0A016XEK1×1, UniProtKB:A0A023UGD7×1).
  llm_assisted: true