identifier: traitmech:000303 label: Stk2 system definition: An abortive infection system in which an organism possesses a phage-defense locus encoding the Stk2 serine/threonine kinase, which can be activated by a phage protein to phosphorylate host proteins and induce host-cell death that prevents bacteriophage propagation. definition_source: DOI:10.1016/j.chom.2016.08.010 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000214 synonyms: - synonym_text: Stk2 synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md evidence: - reference: DOI:10.1016/j.chom.2016.08.010 snippet: Here we identify Stk2, a staphylococcal serine/threonine kinase that provides efficient immunity against bacteriophages by inducing abortive infection notes: Depardieu et al. identify Stk2 as a staphylococcal serine/threonine kinase that provides bacteriophage immunity through abortive infection. - reference: DOI:10.1016/j.chom.2016.08.010 snippet: A phage protein of unknown function activates the Stk2 kinase notes: Depardieu et al. connect an unidentified phage protein to Stk2 kinase activation. - reference: DOI:10.1016/j.chom.2016.08.010 snippet: This leads to the Stk2-dependent phosphorylation of several proteins involved in translation, global transcription control, cell-cycle control, stress response, DNA topology, DNA repair, and central metabolism notes: Depardieu et al. describe Stk2-dependent phosphorylation of multiple host-protein targets after Stk2 activation. - reference: DOI:10.1016/j.chom.2016.08.010 snippet: Bacterial host cells die as a consequence of Stk2 activation, thereby preventing propagation of the phage to the rest of the bacterial population notes: Depardieu et al. connect Stk2 activation to host-cell death and the resulting block of phage propagation. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Stk2 | 10\.1016/j\.chom\.2016\.08\.010 | A eukaryotic-like Serine/threonine kinase protects staphylococci against phages notes: The DefenseFinder article registry maps the named Stk2 system to the Depardieu et al. final article. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Stk2\tStk2\t1\t1\tStk2__Stk2" notes: The DefenseFinder rules table models Stk2 as a one-component system requiring the Stk2__Stk2 profile. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Stk2__Stk2 | Stk2__Stk2 | Stk2 | Custom | 150 |' notes: The DefenseFinder HMM inventory records the Stk2__Stk2 profile under the Stk2 model namespace. causal_graphs: - graph_id: stk2_activation_aborts_phage_infection title: Stk2 kinase activation aborts phage infection description: Conservative system-level sketch linking possession of a Stk2 phage-defense locus to phage-protein-triggered kinase activation, host protein phosphorylation, host-cell death, and the Stk2 abortive-infection trait without asserting the unresolved direct phage activator or lethal phosphorylation target. scope_status: NONMECHANISTIC scope_notes: The graph captures Stk2 as a named DefenseFinder single-profile abortive-infection system with a phage-activated serine/threonine kinase output while leaving the activating phage protein, the direct lethal phosphorylation event, target conservation, and phage-specific escape routes unresolved. nodes: - node_id: stk2_locus label: Stk2 locus node_type: GENETIC_ELEMENT description: A Stk2 abortive-infection phage-defense locus represented by the DefenseFinder Stk2__Stk2 profile. - node_id: stk2_kinase_activation label: Stk2 kinase activation node_type: BIOLOGICAL_PROCESS description: Activation of the Stk2 serine/threonine kinase by a phage protein of unknown function. - node_id: host_protein_phosphorylation label: host protein phosphorylation node_type: BIOLOGICAL_PROCESS description: Stk2-dependent phosphorylation of host proteins after Stk2 kinase activation. - node_id: host_cell_death label: host cell death node_type: BIOLOGICAL_PROCESS description: Stk2-activation-dependent death of infected bacterial host cells. - node_id: phage_propagation label: phage propagation node_type: BIOLOGICAL_PROCESS description: Propagation of bacteriophage through a bacterial host population. - node_id: stk2_system_trait label: Stk2 system node_type: TRAIT grounding: traitmech:000303 description: Possession of a genome-encoded Stk2 abortive-infection phage-defense system. - node_id: abortive_infection_system label: abortive infection system node_type: TRAIT grounding: traitmech:000214 description: Possession of a bacteriophage abortive-infection defense system. edges: - subject: stk2_locus predicate: contributes to predicate_id: RO:0002326 object: stk2_kinase_activation description: Depardieu et al. identify the Stk2 serine/threonine kinase as a phage-immunity factor, and DefenseFinder models Stk2 as a single-profile system. evidence: - reference: DOI:10.1016/j.chom.2016.08.010 snippet: Here we identify Stk2, a staphylococcal serine/threonine kinase that provides efficient immunity against bacteriophages notes: Depardieu et al. identify Stk2 as a bacteriophage-immunity factor. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Stk2\tStk2\t1\t1\tStk2__Stk2" notes: The DefenseFinder rules table models Stk2 as a one-component system requiring the Stk2__Stk2 profile. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Stk2__Stk2 | Stk2__Stk2 | Stk2 | Custom | 150 |' notes: The DefenseFinder HMM inventory records the Stk2__Stk2 profile under the Stk2 model namespace. - subject: stk2_kinase_activation predicate: enables predicate_id: RO:0002327 object: host_protein_phosphorylation description: Phage-protein activation of Stk2 leads to Stk2-dependent phosphorylation of several host proteins. evidence: - reference: DOI:10.1016/j.chom.2016.08.010 snippet: A phage protein of unknown function activates the Stk2 kinase notes: Depardieu et al. show phage-protein activation of Stk2. - reference: DOI:10.1016/j.chom.2016.08.010 snippet: This leads to the Stk2-dependent phosphorylation of several proteins notes: Depardieu et al. connect Stk2 activation to host-protein phosphorylation. - subject: stk2_kinase_activation predicate: contributes to predicate_id: RO:0002326 object: host_cell_death description: Stk2 activation is followed by death of infected bacterial host cells. evidence: - reference: DOI:10.1016/j.chom.2016.08.010 snippet: Bacterial host cells die as a consequence of Stk2 activation notes: Depardieu et al. connect Stk2 activation to host-cell death. - subject: host_cell_death predicate: mitigates predicate_id: METPO:2007407 object: phage_propagation description: Stk2-triggered host-cell death prevents propagation of the phage through the rest of the bacterial population. evidence: - reference: DOI:10.1016/j.chom.2016.08.010 snippet: Bacterial host cells die as a consequence of Stk2 activation, thereby preventing propagation of the phage to the rest of the bacterial population notes: Depardieu et al. connect Stk2-dependent host-cell death to phage-propagation prevention. - subject: host_cell_death predicate: confers predicate_id: METPO:2007700 object: stk2_system_trait description: Stk2-triggered host-cell death realizes the Stk2 abortive-infection trait. evidence: - reference: DOI:10.1016/j.chom.2016.08.010 snippet: provides efficient immunity against bacteriophages by inducing abortive infection notes: Depardieu et al. classify the Stk2-dependent immunity mechanism as abortive infection. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Stk2 | 10\.1016/j\.chom\.2016\.08\.010 | A eukaryotic-like Serine/threonine kinase protects staphylococci against phages notes: The DefenseFinder article registry maps the named Stk2 system to the Depardieu et al. final article. - subject: stk2_system_trait predicate: is a predicate_id: rdfs:subClassOf object: abortive_infection_system description: Stk2 system possession is an abortive-infection system trait. evidence: - reference: DOI:10.1016/j.chom.2016.08.010 snippet: provides efficient immunity against bacteriophages by inducing abortive infection notes: Depardieu et al. support Stk2 as an abortive-infection system. discussions: - discussion_id: stk2-activator-and-death-target-gap prompt: Resolve the Stk2-activating phage protein and lethal host-phosphorylation target before minting narrower Stk2 mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Depardieu et al. support Stk2 as a named phage-activated serine/threonine kinase system whose activation causes host-protein phosphorylation, bacterial host-cell death, and abortive infection, and DefenseFinder represents Stk2 with a one-profile model. This system-level record leaves the direct phage activator, the lethal Stk2 phosphorylation target, target conservation across Stk2 loci, and phage escape routes unresolved. attaches_to: - causal_graphs#stk2_activation_aborts_phage_infection posed_by: codex posed_date: '2026-09-20' curation_history: - timestamp: '2026-09-20T07:41:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Stk2 system as a DOI-backed GENOMICS TraitRecord under the abortive infection 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_v180. llm_assisted: true