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AVAST system

traitmech:000239 · CLASS · PROPOSED

A phage defense system in which an organism possesses a locus encoding a STAND-superfamily antiviral ATPase/NTPase that functions as a modular Avs receptor-effector, recognizes conserved bacteriophage proteins, and activates subtype-specific antiphage outputs to inhibit bacteriophage replication.

Trait evidence (4)

  • DOI:10.1126/science.aba0372
    AVAST, antiviral ATPase/NTPase of the STAND superfamily

    Gao et al. coined AVAST as a recurring antiviral STAND ATPase/NTPase defense-system family in their pangenome-scale antiphage-system discovery screen.

  • DOI:10.1126/science.abm4096
    Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal

    Gao et al. characterized Avs1 through Avs4 as prokaryotic STAND-family innate immune receptors that detect conserved phage proteins and trigger subtype-specific antiviral effector outputs.

  • DOI:10.1016/j.molcel.2026.01.004
    AVAST type 5 (Avs5) systems, part of the signal transduction ATPases of numerous domains (STAND) superfamily, confer conserved immunity against jumbo phages

    Muralidharan et al. extend the named AVAST family with Avs5 systems that defend against nucleus-forming jumbo phages.

  • DOI:10.1016/j.molcel.2026.01.004
    Recognition of phage infection triggers the Sir2-like effector domain of Avs5 across three Avs5 clades

    Muralidharan et al. support a subtype-specific Avs5 effector activation mechanism downstream of phage infection sensing.

AVAST STAND receptors detect phage proteins during antiphage defense

Evidence-backed process sketch linking an AVAST locus to Avs STAND receptor activation, subtype-specific antiviral effector activity, and inhibition of bacteriophage replication.

NONMECHANISTIC · The graph stays at the AVAST-family level and does not assert that all Avs subtypes detect the same phage protein, carry the same nuclease or Sir2-like effector domain, act on the same molecular substrate, or inhibit the same class of phages.

AVAST STAND receptors detect phage proteins during antiphage defense Interactive directed graph showing evidence-backed causal relationships for AVAST system.

Edge evidence

  • AVAST locus contributes to Avs STAND receptor activation RO:0002326

    AVAST loci encode Avs STAND-family receptors that are activated when their cognate conserved phage protein is present.

    • DOI:10.1126/science.abm4096 Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal Gao et al. support Avs1 through Avs4 as phage-protein-sensing AVAST receptors.
    • DOI:10.1016/j.molcel.2026.01.004 Avs5 localizes to early infection vesicles, where it senses an essential, early-expressed phage protein named JADA Muralidharan et al. support phage-infection recognition by Avs5 receptors.
  • Avs STAND receptor activation activates AVAST antiviral effector output RO:0002213

    Detection of a phage cue activates the effector domain coupled to the cognate Avs STAND receptor.

    • DOI:10.1016/j.molcel.2026.01.004 Recognition of phage infection triggers the Sir2-like effector domain of Avs5 across three Avs5 clades Muralidharan et al. connect phage recognition to subtype-specific Avs5 Sir2-like effector activation.
  • AVAST antiviral effector output mitigates phage replication METPO:2007407

    Subtype-specific AVAST effector activities restrict bacteriophage replication or propagation after recognition of a phage cue.

    • DOI:10.1126/science.abm4096 In all four cases, target recognition led to Avs protein activation and antiviral activity Gao et al. support Avs effector outputs as downstream antiviral activities in Avs1 through Avs4 systems.
    • DOI:10.1016/j.molcel.2026.01.004 Upon sensing Jumbo J phage, Avs5-1 underwent oligomerization, which activated the enzymatic activity of its Sir2 effector, resulting in rapid NAD + hydrolysis, disruption of phage nucleus formation, and arrest of infection Muralidharan et al. support Avs5 Sir2-like effector activity as a jumbo-phage-restricting AVAST output.
  • AVAST antiviral effector output confers AVAST system METPO:2007700

    Activated AVAST effector outputs realize the AVAST phage-defense-system trait.

    • DOI:10.1016/j.molcel.2026.01.004 AVAST type 5 (Avs5) systems, part of the signal transduction ATPases of numerous domains (STAND) superfamily, confer conserved immunity against jumbo phages Muralidharan et al. connect a characterized AVAST subtype to conserved antiphage immunity.
  • AVAST system is a phage defense system rdfs:subClassOf

    AVAST system possession is a phage-defense-system trait.

    • DOI:10.1126/science.aba0372 AVAST, antiviral ATPase/NTPase of the STAND superfamily Gao et al. identified AVAST among candidate phage-defense systems.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1126/science.aba0372

Parent traits (1)

Children (5)

Synonyms (2)

  • antiviral ATPase/NTPase of the STAND superfamily system EXACT_SYNONYM · DOI:10.1126/science.aba0372
  • antiviral STAND system EXACT_SYNONYM · DOI:10.1126/science.aba0372

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Canonical examples (1)

Organisms cited as exemplars of this trait. Taxon ids are NCBITaxon and link out to the NCBI record.

  • Pseudomonas aeruginosa NCBITaxon:287 DOI:10.1016/j.molcel.2026.01.004 Muralidharan et al. characterized the Pseudomonas aeruginosa Avs5-1 system and showed that its Sir2-like effector domain is activated during jumbo-phage infection.

Discussions and Knowledge Gaps (1)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Resolve AVAST subtype sensors, phage triggers, and effector outputs before minting narrower Avs1-Avs5 mechanism children.

KNOWLEDGE GAP OPEN avast-subtype-effector-gap · raised by codex · 2026-09-18

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

Gao et al. support phage-protein pattern recognition by Avs1 through Avs4, while Muralidharan et al. support Avs5 immunity against nucleus-forming jumbo phages through phage-triggered Sir2-like effector activation. The first TraitRecord therefore stays at the AVAST-system level until separate review resolves which phage cues, effector domains, and antiviral substrates generalize across AVAST loci.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Minted AVAST system as a DOI-backed GENOMICS TraitRecord under the phage defense system parent after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v116.