ferrosome

cellstructuremech:ferrosome · Membrane organelle · Membrane bounded organelle · Proposed

A bacterial lipid-bounded iron-storage organelle that contains iron-, phosphorus- and oxygen-rich material and forms through Fez protein-dependent machinery. [DOI:10.1038/s41586-022-04741-x]

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Essential	Role
ferrosome-associated Fez proteins	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	fezA, fezB, fezC	UNKNOWN	Ferrosome-associated proteins that drive lipid-bounded ferrosome formation. `DOI:10.1038/s41586-022-04741-x` Grant et al. 2022 used proteomics and genetics to identify Fez proteins required for ferrosome formation in Solidesulfovibrio magneticus RS-1.
ferrosome membrane lipids	Lipid	part of	Reviewed label only (reviewed name; no accession asserted)		ESSENTIAL	Form the lipid boundary that separates the ferrosome from the cytoplasm. `DOI:10.1038/s41586-022-04741-x` Grant et al. 2022 characterized ferrosomes as a distinct class of lipid-bounded iron-storage organelles.
ferrosome iron-phosphorus-oxygen core	Small molecule	part of	Reviewed label only (reviewed name; no accession asserted)		UNKNOWN	Electron-dense storage material enriched in iron, phosphorus and oxygen within the lipid-bounded ferrosome. `DOI:10.1073/pnas.1001290107` Byrne et al. 2010 observed membrane-surrounded amorphous iron-phosphorus granules in Desulfovibrio magneticus RS-1. `DOI:10.1038/s41586-022-04741-x` Grant et al. 2022 connected the D. magneticus ferrosome compartment with intracellular iron storage.

Taxonomic distribution

NCBITaxon:573370 Solidesulfovibrio magneticus RS-1 — COMMON: The RS-1 strain was the model used for Fez proteomics and genetics that connected the Fez cluster to ferrosome formation and iron-storage function. [DOI:10.1038/s41586-022-04741-x]

Canonical examples

NCBITaxon:573370 Solidesulfovibrio magneticus RS-1 — Magnetotactic bacterial strain in which membrane-surrounded iron-phosphorus granules were distinguished ultrastructurally from bullet-shaped magnetosomes. [DOI:10.1073/pnas.1001290107]

Functions

anaerobic iron storage — Ferrosomes store intracellular iron for use during anaerobic metabolism.
- DOI:10.1038/s41586-022-04741-x Grant et al. 2022 tested ferrosome formation and function as an iron-storage organelle during anaerobic growth.

Mechanism graphs

Fez proteins form lipid-bounded ferrosomes for iron storage (ASSEMBLY)

Fez proteins drive formation of lipid-bounded ferrosomes whose iron-, phosphorus- and oxygen-rich material stores iron during anaerobic metabolism.

Subject	Predicate	Object	Evidence
ferrosome-associated Fez proteins	drive formation of	ferrosome	`DOI:10.1038/s41586-022-04741-x` Grant et al. 2022 identified Fez proteins that drive ferrosome formation.
ferrosome membrane lipids	bound	ferrosome	`DOI:10.1038/s41586-022-04741-x` Grant et al. 2022 characterized ferrosomes as lipid-bounded organelles.
ferrosome iron-phosphorus-oxygen core	accumulates within	ferrosome	`DOI:10.1073/pnas.1001290107` Byrne et al. 2010 resolved membrane-surrounded iron-phosphorus granules in D. magneticus RS-1.
ferrosome	supports	anaerobic iron storage	`DOI:10.1038/s41586-022-04741-x` Grant et al. 2022 connected ferrosomes to iron storage during anaerobic metabolism.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral groundings and component boundaries for Fez proteins in characterized ferrosome systems. FezA, FezB and FezC are kept as one label-only cohort because the first ferrosome pass did not verify exact family accessions for all three proteins or decide whether Fez proteins should be split by family.
CURATION_TODO (OPEN): Resolve the exact chemical composition and CHEBI grounding of the ferrosome iron-phosphorus-oxygen storage material. Byrne et al. 2010 established membrane-surrounded amorphous granules enriched in iron and phosphorus, but the exact stored chemical species remains label-only here rather than mapped to an imprecise mineral or ion CURIE.

Evidence

DOI:10.1073/pnas.1001290107 Byrne et al. 2010, Desulfovibrio magneticus RS-1 contains an iron- and phosphorus-rich organelle distinct from its bullet-shaped magnetosomes, Proceedings of the National Academy of Sciences.
DOI:10.1038/s41586-022-04741-x Grant et al. 2022, Distinct gene clusters drive formation of ferrosome organelles in bacteria, Nature.

Curation history

2026-09-11T14:03:57Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-11T14:04:31Z codex · EXPANDED_RECORD — Added membrane-bounded-organelle parentage, Fez protein, lipid boundary and iron-rich core components, Solidesulfovibrio magneticus RS-1 taxonomic scope, iron-storage function, DOI evidence, a nonmechanistic Fez formation graph, and grounding TODOs for Fez proteins and core chemistry.
2026-09-11T14:05:08Z codex · REFINED_GRAPH — Changed the terminal ferrosome graph edge from a stores-process relationship to a supports-process relationship and clarified the definition wording.
2026-09-11T14:10:21Z codex · ADDRESS_REVIEW — Resolved #494 by narrowing the taxonomic note to Grant-backed Fez evidence and resolved #495 by switching the canonical example to the Byrne-backed ultrastructure finding.

Source: data/structures/membrane_organelle/ferrosome.yaml