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polyphosphate granule

traitmech:000068 · CLASS · REVIEWED

An intracellular storage inclusion of inorganic polyphosphate (a polymer of many phosphate residues), historically called a volutin or metachromatic granule, serving as a phosphate and energy reserve.

Polyphosphate granules store phosphate and energy as inorganic polyP

Evidence-backed causal sketch linking inorganic polyphosphate accumulation to volutin/metachromatic granules supporting growth and survival.

Polyphosphate granules store phosphate and energy as inorganic polyP Interactive directed graph showing evidence-backed causal relationships for polyphosphate granule.

Edge evidence

  • inorganic polyphosphate located in polyphosphate granule biolink:located_in

    Inorganic polyphosphate accumulates as granules in the cytoplasm.

    • DOI:10.1146/annurev.biochem.77.083007.093039 Rao, Gómez-García & Kornberg review polyphosphate accumulation as granules.
  • polyphosphate granule contributes to phosphate / energy reserve RO:0002326

    PolyP granules supply phosphate and energy for growth and survival.

    • DOI:10.1038/s41579-020-0413-0 Greening & Lithgow include polyphosphate bodies among bacterial intracellular inclusions.
  • polyphosphate kinase (PPK) synthesizes inorganic polyphosphate

    Polyphosphate kinase (PPK) synthesizes inorganic polyP using ATP.

    • DOI:10.1371/journal.pbio.3002558 Polyphosphate is synthesized by polyphosphate kinase (PPK), which rapidly synthesizes polyP using ATP as a co-substrate.
  • exopolyphosphatase (PPX) degrades inorganic polyphosphate METPO:2000007

    Exopolyphosphatase (PPX) degrades inorganic polyphosphate.

    • DOI:10.1371/journal.pbio.3002558 Polyphosphate is degraded by exopolyphosphatase PPX; canonical core metabolism edge.
  • inorganic polyphosphate binds divalent cations

    PolyP chelates/binds divalent cations, affecting polyP biophysics and granule composition.

    • DOI:10.3390/biom14080937 PolyP granules contain associated cations; polyP can bind iron and inhibit Fenton chemistry. Strong general biochemical edge.
  • inorganic polyphosphate promotes stress survival / stress response RO:0002213

    PolyP accumulation promotes survival in stationary phase and nutrient starvation.

    • DOI:10.3390/biom14080937 PolyP serves as phosphate/energy storage and supports survival in stationary phase and nutrient starvation; ppk mutants show stress sensitivity.

Provenance

Source
METPO (2025-11-25)
Definition source
DOI:10.1146/annurev.biochem.77.083007.093039

Parent traits (1)

Synonyms (2)

  • volutin granule RELATED_SYNONYM · DOI:10.1146/annurev.biochem.77.083007.093039
  • metachromatic granule RELATED_SYNONYM · DOI:10.1146/annurev.biochem.77.083007.093039

kg-microbe context

Matched 1 kg-microbe node via parent_proxy.

  • METPO:1000059 [-2.682, -2.070, -3.656, -0.652, …]

512-dim DeepWalkSkipGramEnsmallen embedding from kg-microbe (2026-04-25).

Nearest neighbors in embedding space

Top-8 cosine-similar METPO traits from the 2026-04-25 deepwalk (512-D).

Curation history

  1. · PROPOSED_FROM_RESEARCH · claude

    Proposed candidate MORPHOLOGY trait (polyphosphate/volutin granule); storage sub-variant of intracellular inclusion.

  2. · CURATED_CAUSAL_GRAPH · claude

    Added evidence-backed causal graph (polyP granule phosphate/energy reserve) with RO/biolink predicate groundings; promoted PROPOSED to REVIEWED.

  3. · ENRICH_CAUSAL_GRAPH · claude

    Added 4 evidence-backed generic edges (4 new nodes) from the deep-research report.

  4. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002213×1).

  5. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000007×1).