identifier: traitmech:000527 label: ferrosome definition: A morphology trait in which a bacterial cell forms membrane-bound ferrosome organelles that store intracellular iron as non-crystalline iron phosphate biomineral. definition_source: DOI:10.1038/s41586-022-04741-x trait_category: MORPHOLOGY term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000066 evidence: - reference: DOI:10.1038/s41586-022-04741-x snippet: Overall, this work establishes ferrosomes as a new class of iron storage organelles notes: Grant et al. establish ferrosomes as an iron-storage organelle class. - reference: DOI:10.1038/s41586-022-04741-x snippet: we identify three ferrosome-associated (Fez) proteins that are responsible for forming ferrosomes notes: Grant et al. support Fez protein-dependent ferrosome formation in Desulfovibrio magneticus. - reference: DOI:10.1038/s41586-022-04741-x snippet: fez operons are sufficient for ferrosome formation in foreign hosts notes: Grant et al. support fez operon sufficiency for ferrosome formation in heterologous bacterial hosts. - reference: DOI:10.1038/s41586-023-06719-9 snippet: Here we report that C. difficile undergoes an intracellular iron biomineralization process and stores iron in membrane-bound ferrosome organelles containing non-crystalline iron phosphate biominerals. notes: Pi et al. support membrane-bound ferrosome organelles storing non-crystalline iron phosphate in Clostridioides difficile. - reference: DOI:10.1038/s41586-023-06719-9 snippet: We found that a membrane protein (FezA) and a P1B6-ATPase transporter (FezB), repressed by both iron and the ferric uptake regulator Fur, are required for ferrosome formation notes: Pi et al. support FezA- and FezB-dependent ferrosome formation in C. difficile. canonical_examples: - taxon_id: NCBITaxon:1496 taxon_label: Clostridioides difficile note: Pi et al. showed that C. difficile forms membrane-bound ferrosome organelles containing non-crystalline iron phosphate biominerals. reference: DOI:10.1038/s41586-023-06719-9 causal_graphs: - graph_id: ferrosome_iron_storage title: Fez proteins form iron-storing ferrosomes description: Evidence-backed causal sketch linking Fez-dependent formation to membrane-bound iron-storage organelles. scope_status: NONMECHANISTIC scope_notes: The graph captures broad Fez-dependent formation and ferrosome iron storage at process and organelle level without asserting one taxon-universal Fez component roster, individual Fez-protein activity, accession-level protein examples, iron-remobilization mechanism, membrane-localization path, iron-deficiency trigger, or host-colonization output. nodes: - node_id: ferrosome_trait label: ferrosome node_type: TRAIT grounding: traitmech:000527 description: Membrane-bound organelle storing intracellular iron as non-crystalline iron phosphate. - node_id: ferrosome_formation label: ferrosome formation node_type: BIOLOGICAL_PROCESS description: Fez-dependent biogenesis of membrane-bound intracellular ferrosome organelles. - node_id: non_crystalline_iron_phosphate label: non-crystalline iron phosphate biomineral node_type: CHEMICAL description: Non-crystalline iron phosphate mineral stored inside ferrosomes. - node_id: iron_storage label: iron storage node_type: BIOLOGICAL_PROCESS description: Intracellular storage of iron in a recoverable organelle-associated pool. edges: - subject: ferrosome_formation predicate: has output predicate_id: RO:0002234 object: ferrosome_trait description: Fez-dependent ferrosome formation produces the ferrosome intracellular organelle. evidence: - reference: DOI:10.1038/s41586-022-04741-x snippet: Overall, this work establishes ferrosomes as a new class of iron storage organelles notes: Grant et al. establish ferrosomes as an iron-storage organelle class. - reference: DOI:10.1038/s41586-022-04741-x snippet: we identify three ferrosome-associated (Fez) proteins that are responsible for forming ferrosomes notes: Grant et al. support Fez protein-dependent ferrosome formation in Desulfovibrio magneticus. - reference: DOI:10.1038/s41586-022-04741-x snippet: fez operons are sufficient for ferrosome formation in foreign hosts notes: Grant et al. support fez operon sufficiency for ferrosome formation in heterologous bacterial hosts. - reference: DOI:10.1038/s41586-023-06719-9 snippet: We found that a membrane protein (FezA) and a P1B6-ATPase transporter (FezB), repressed by both iron and the ferric uptake regulator Fur, are required for ferrosome formation notes: Pi et al. support FezA- and FezB-dependent ferrosome formation in C. difficile. - subject: non_crystalline_iron_phosphate predicate: located in predicate_id: biolink:located_in object: ferrosome_trait description: Non-crystalline iron phosphate biominerals are stored within ferrosome organelles. evidence: - reference: DOI:10.1038/s41586-023-06719-9 snippet: Here we report that C. difficile undergoes an intracellular iron biomineralization process and stores iron in membrane-bound ferrosome organelles containing non-crystalline iron phosphate biominerals. notes: Pi et al. support membrane-bound ferrosome organelles storing non-crystalline iron phosphate in Clostridioides difficile. - subject: ferrosome_trait predicate: enables predicate_id: RO:0002327 object: iron_storage description: Ferrosome organelles realize intracellular iron storage. evidence: - reference: DOI:10.1038/s41586-022-04741-x snippet: Overall, this work establishes ferrosomes as a new class of iron storage organelles notes: Grant et al. establish ferrosomes as an iron-storage organelle class. - reference: DOI:10.1038/s41586-023-06719-9 snippet: Here we report that C. difficile undergoes an intracellular iron biomineralization process and stores iron in membrane-bound ferrosome organelles containing non-crystalline iron phosphate biominerals. notes: Pi et al. support membrane-bound ferrosome organelles storing non-crystalline iron phosphate in Clostridioides difficile. discussions: - discussion_id: ferrosome-xref-gap prompt: Resolve exact external ontology xrefs for the bacterial ferrosome morphology trait. kind: CURATION_TODO status: OPEN rationale: No exact active METPO, GO, or OBO class was accepted for the organism-level ferrosome morphology trait. GO:0110143 magnetosome, GO:0031411 gas vesicle, GO:0031470 carboxysome, and GO:0070088 PHA granule are sibling organelles or inclusions rather than ferrosome equivalents. posed_by: codex posed_date: '2026-10-01' curation_history: - timestamp: '2026-10-01T22:05:50Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted ferrosome as a DOI-backed MORPHOLOGY TraitRecord under the intracellular inclusion parent after an ignored-and-hidden duplicate review found no exact same-scope TraitMech, METPO, history, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v404. llm_assisted: true