identifier: traitmech:000239 label: AVAST system definition: 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. definition_source: DOI:10.1126/science.aba0372 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: antiviral ATPase/NTPase of the STAND superfamily system synonym_type: EXACT_SYNONYM source: DOI:10.1126/science.aba0372 - synonym_text: antiviral STAND system synonym_type: EXACT_SYNONYM source: DOI:10.1126/science.aba0372 evidence: - reference: DOI:10.1126/science.aba0372 snippet: AVAST, antiviral ATPase/NTPase of the STAND superfamily notes: Gao et al. coined AVAST as a recurring antiviral STAND ATPase/NTPase defense-system family in their pangenome-scale antiphage-system discovery screen. - reference: DOI:10.1126/science.abm4096 snippet: Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal notes: 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. - reference: DOI:10.1016/j.molcel.2026.01.004 snippet: AVAST type 5 (Avs5) systems, part of the signal transduction ATPases of numerous domains (STAND) superfamily, confer conserved immunity against jumbo phages notes: Muralidharan et al. extend the named AVAST family with Avs5 systems that defend against nucleus-forming jumbo phages. - reference: DOI:10.1016/j.molcel.2026.01.004 snippet: Recognition of phage infection triggers the Sir2-like effector domain of Avs5 across three Avs5 clades notes: Muralidharan et al. support a subtype-specific Avs5 effector activation mechanism downstream of phage infection sensing. canonical_examples: - taxon_id: NCBITaxon:287 taxon_label: Pseudomonas aeruginosa note: Muralidharan et al. characterized the Pseudomonas aeruginosa Avs5-1 system and showed that its Sir2-like effector domain is activated during jumbo-phage infection. reference: DOI:10.1016/j.molcel.2026.01.004 causal_graphs: - graph_id: avast_stand_pattern_recognition_defense title: AVAST STAND receptors detect phage proteins during antiphage defense description: Evidence-backed process sketch linking an AVAST locus to Avs STAND receptor activation, subtype-specific antiviral effector activity, and inhibition of bacteriophage replication. scope_status: NONMECHANISTIC scope_notes: 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. nodes: - node_id: avast_locus label: AVAST locus node_type: GENETIC_ELEMENT description: A phage-defense locus encoding a STAND-superfamily antiviral ATPase/NTPase that functions as a modular Avs receptor-effector. - node_id: avs_stand_receptor_activation label: Avs STAND receptor activation node_type: BIOLOGICAL_PROCESS description: Activation of an Avs STAND-family receptor after detection of a conserved phage protein during bacteriophage infection. - node_id: avast_effector_output label: AVAST antiviral effector output node_type: BIOLOGICAL_PROCESS description: Subtype-specific nuclease, NADase, or membrane-associated antiviral activity triggered by an activated AVAST receptor. - node_id: phage_replication label: phage replication node_type: BIOLOGICAL_PROCESS description: Bacteriophage genome replication and production inside an infected bacterial host. - node_id: avast_system_trait label: AVAST system node_type: TRAIT grounding: traitmech:000239 description: Possession of a genome-encoded AVAST phage-defense system. - node_id: phage_defense_system label: phage defense system node_type: TRAIT grounding: traitmech:000209 description: Possession of one or more genome-encoded immune systems that inhibit bacteriophage infection. edges: - subject: avast_locus predicate: contributes to predicate_id: RO:0002326 object: avs_stand_receptor_activation description: AVAST loci encode Avs STAND-family receptors that are activated when their cognate conserved phage protein is present. evidence: - reference: DOI:10.1126/science.abm4096 snippet: Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal notes: Gao et al. support Avs1 through Avs4 as phage-protein-sensing AVAST receptors. - reference: DOI:10.1016/j.molcel.2026.01.004 snippet: Avs5 localizes to early infection vesicles, where it senses an essential, early-expressed phage protein named JADA notes: Muralidharan et al. support phage-infection recognition by Avs5 receptors. - subject: avs_stand_receptor_activation predicate: activates predicate_id: RO:0002213 object: avast_effector_output description: Detection of a phage cue activates the effector domain coupled to the cognate Avs STAND receptor. evidence: - reference: DOI:10.1016/j.molcel.2026.01.004 snippet: Recognition of phage infection triggers the Sir2-like effector domain of Avs5 across three Avs5 clades notes: Muralidharan et al. connect phage recognition to subtype-specific Avs5 Sir2-like effector activation. - subject: avast_effector_output predicate: mitigates predicate_id: METPO:2007407 object: phage_replication description: Subtype-specific AVAST effector activities restrict bacteriophage replication or propagation after recognition of a phage cue. evidence: - reference: DOI:10.1126/science.abm4096 snippet: In all four cases, target recognition led to Avs protein activation and antiviral activity notes: Gao et al. support Avs effector outputs as downstream antiviral activities in Avs1 through Avs4 systems. - reference: DOI:10.1016/j.molcel.2026.01.004 snippet: 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 notes: Muralidharan et al. support Avs5 Sir2-like effector activity as a jumbo-phage-restricting AVAST output. - subject: avast_effector_output predicate: confers predicate_id: METPO:2007700 object: avast_system_trait description: Activated AVAST effector outputs realize the AVAST phage-defense-system trait. evidence: - reference: DOI:10.1016/j.molcel.2026.01.004 snippet: AVAST type 5 (Avs5) systems, part of the signal transduction ATPases of numerous domains (STAND) superfamily, confer conserved immunity against jumbo phages notes: Muralidharan et al. connect a characterized AVAST subtype to conserved antiphage immunity. - subject: avast_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: AVAST system possession is a phage-defense-system trait. evidence: - reference: DOI:10.1126/science.aba0372 snippet: AVAST, antiviral ATPase/NTPase of the STAND superfamily notes: Gao et al. identified AVAST among candidate phage-defense systems. discussions: - discussion_id: avast-subtype-effector-gap prompt: Resolve AVAST subtype sensors, phage triggers, and effector outputs before minting narrower Avs1-Avs5 mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: 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. posed_by: codex posed_date: '2026-09-18' curation_history: - timestamp: '2026-09-18T10:44:12Z' curator: codex action: MINTED_TRAITMECH_ID changes: 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. llm_assisted: true