acidocalcisome membrane

GO:0033102 · Membrane organelle · Membrane · Proposed

The lipid bilayer surrounding an acidocalcisome. [GO:0033102]

Synonyms: acidocalcisomal membrane

Part of: acidocalcisome (GO:0020022)

Xrefs: uniprot.location:SL-0003 — Acidocalcisome membrane

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

Components

Component	Type	Part of / acts on	Grounding	Essential	Role
acidocalcisome lipid bilayer	Lipid	part of	Reviewed label only (reviewed name; no accession asserted)	ESSENTIAL	Bounding bilayer that separates the acidic, polyphosphate-rich acidocalcisome lumen from the cytosol. `GO:0033102` GO:0033102 defines the acidocalcisome membrane as the lipid bilayer surrounding an acidocalcisome. `uniprot.location:SL-0003` — Acidocalcisome membrane UniProt Subcellular Location SL-0003 maps directly to GO:0033102 and denotes the membrane of an acidocalcisome.
acidocalcisome proton pumps	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Membrane proton pumps that acidify the acidocalcisome lumen and energize uptake of ions into the organelle. `DOI:10.1038/nrmicro1097` Docampo et al. 2005 review V-H+-PPase and V-H+-ATPase activities in acidocalcisome membranes. `DOI:10.1074/jbc.M304548200` Seufferheld et al. 2003 localized vacuolar proton pyrophosphatase activity to bacterial acidocalcisome-like organelles.
acidocalcisome cation transporters	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Transport proteins that exchange calcium and other cations across the acidocalcisome membrane. `DOI:10.1128/MMBR.00042-23` Docampo and Huang 2024 review cation transport systems of acidocalcisome membranes.

Taxonomic distribution

NCBITaxon:2 Bacteria — VARIABLE: Acidocalcisome-like compartments have been characterized in bacteria, but this compartment is not universal across bacteria. [DOI:10.1038/nrmicro1097]
NCBITaxon:2759 Eukaryota — VARIABLE: Acidocalcisomes occur across diverse unicellular eukaryotes and metazoan cell types, but are not present in every eukaryotic cell. [DOI:10.1128/MMBR.00042-23]

Canonical examples

NCBITaxon:358 Agrobacterium tumefaciens — Bacterial species whose calcium- and polyphosphate-rich volutin granules were shown to be membrane-bound acidocalcisome-like organelles. [DOI:10.1074/jbc.M304548200]

Functions

acidocalcisome lumen acidification — Proton pumps in the acidocalcisome membrane generate an acidic lumen that supports polyphosphate and cation storage.
- DOI:10.1038/nrmicro1097 Docampo et al. 2005 review proton pumps in the acidocalcisome membrane and the acidic lumen they maintain.
acidocalcisome cation transport — Transport systems in the acidocalcisome membrane move calcium and other cations into and out of the organelle.
- DOI:10.1128/MMBR.00042-23 Docampo and Huang 2024 review calcium and cation transport across acidocalcisome membranes.

Mechanism graphs

Acidocalcisome membrane pumps support ion storage (FUNCTION)

The acidocalcisome membrane bounds the acidic polyphosphate organelle and carries proton pumps and cation transporters that help generate and maintain its lumenal cation store.

Subject	Predicate	Object	Evidence
acidocalcisome membrane	bounds	acidocalcisome	`GO:0033102` GO:0033102 defines the membrane as the lipid bilayer surrounding an acidocalcisome.
acidocalcisome proton pumps	acidify	acidic acidocalcisome lumen	`DOI:10.1038/nrmicro1097` Docampo et al. 2005 review the proton pumps that acidify acidocalcisomes.
acidocalcisome cation transporters	exchange ions across	acidocalcisome membrane	`DOI:10.1128/MMBR.00042-23` Docampo and Huang 2024 review cation transport systems of acidocalcisome membranes.
acidic acidocalcisome lumen	supports	acidocalcisome cation store	`DOI:10.1038/nrmicro1097` Docampo et al. 2005 describe acidity and cation storage as defining acidocalcisome properties.

Discussions

CURATION_TODO (OPEN): Resolve exact acidocalcisome membrane lipid, proton-pump and cation-transporter groundings instead of the grouped reviewed-label-only components. The membrane record captures the lipid boundary plus acidification and cation-transport roles, but the exact lipid and protein families can differ between bacterial and eukaryotic acidocalcisome membranes.

Evidence

GO:0033102 Gene Ontology cellular-component term for the acidocalcisome membrane.
GO:0016020 Gene Ontology cellular-component term for membrane.
GO:0020022 Gene Ontology cellular-component term for the acidocalcisome.
uniprot.location:SL-0003 — Acidocalcisome membrane UniProt Subcellular Location entry SL-0003 maps to GO:0033102 and lists acidocalcisomal membrane as an exact synonym.
DOI:10.1038/nrmicro1097 Docampo et al. 2005 review acidocalcisome conservation and acidocalcisome membrane pumps and exchangers.
DOI:10.1074/jbc.M304548200 Seufferheld et al. 2003 characterized membrane-bounded acidocalcisome-like organelles in bacteria.
DOI:10.1128/MMBR.00042-23 Docampo and Huang 2024 review acidocalcisome membrane transport systems and polyphosphate organelle biology.

Curation history

2026-09-12T17:23:02Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-12T17:23:37Z codex · EXPANDED_RECORD — Added the UniProt SL xref and synonym, membrane parentage, acidocalcisome parthood, membrane pump and transporter components, bacterial and eukaryotic distributions, an Agrobacterium tumefaciens example, acidification and cation-transport functions, a nonmechanistic ion-transport graph, and a transporter-grounding TODO.
2026-09-12T17:23:57Z codex · REFINED_SCOPE — Cited the 2005 review for the broad bacterial distribution row, marked grouped proton pumps as unknown for acidocalcisome membrane assembly, and made the generic cation-transporter graph edge direction-neutral.
2026-09-12T17:31:01Z codex · ADDRESS_REVIEW — Resolved #683 by narrowing the lipid-bilayer component and marking it reviewed-label-only; resolved #684 by retargeting the cation-exchange graph edge to the acidocalcisome membrane.

Source: data/structures/membrane_organelle/acidocalcisome_membrane.yaml