JukAB system

traitmech:000305 · CLASS · PROPOSED

A phage defense system in which an organism possesses a two-gene jukAB locus encoding a JukA sensor that binds a PhiKZ-like gp241 early phage protein at the EPI vesicle and directly recruits the pore-forming-toxin-like JukB effector to destabilize the vesicle, suppress early phage gene expression, and prevent phage DNA replication and nucleus assembly.

Trait evidence (9)

DOI:10.1016/j.cell.2025.02.016
a two-component immune system that terminates infection of φKZ-like phages

Li et al. define Juk as a two-component immune system that terminates PhiKZ-like jumbo-phage infection.
DOI:10.1101/2022.09.17.508391
jukA and jukB together, but not either gene alone, conferred resistance against

Li et al. show that the JukA sensor and JukB effector are jointly required for heterologous PhiKZ resistance.
DOI:10.1016/j.cell.2025.02.016
JukA (formerly YaaW) rapidly senses the EPI vesicle by binding to an early-expressed phage protein, gp241, and then directly recruits JukB

Li et al. identify JukA binding to the PhiKZ-like early phage protein gp241 at the EPI vesicle as the JukAB input that recruits JukB.
DOI:10.1016/j.cell.2025.02.016
The JukB effector structurally resembles a pore-forming toxin and destabilizes the EPI vesicle

Li et al. connect the recruited JukB effector to destabilization of the early phage infection vesicle.
DOI:10.1016/j.cell.2025.02.016
suppressing the expression of early phage genes and preventing phage DNA replication and phage nucleus assembly while saving the cell

Li et al. describe the downstream anti-phage outcome of two-component Juk immunity.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
JukAB | 10\.1101/2022\.09\.17\.508391 | A family of novel immune systems targets early infection of nucleus-forming jumbo phages

The DefenseFinder article registry maps the named JukAB system to the Li et al. Juk immune-system preprint.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
JukAB JukAB 2 2 JukAB__JukA, JukAB__JukB

The DefenseFinder rules table models JukAB as a two-component system requiring JukAB__JukA and JukAB__JukB profiles.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| JukAB__JukA | JukAB__JukA | JukAB | Custom | 20 |

The DefenseFinder HMM inventory records JukAB__JukA under the JukAB model namespace.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| JukAB__JukB | JukAB__JukB | JukAB | Custom | 20 |

The DefenseFinder HMM inventory records JukAB__JukB under the JukAB model namespace.

JukAB blocks early jumbo-phage infection

Conservative system-level sketch linking a jukAB locus to gp241/EPI-vesicle sensing by JukA, JukB recruitment, JukB-mediated EPI-vesicle destabilization, suppression of early PhiKZ-like jumbo-phage development, and JukAB system possession.

NONMECHANISTIC · The graph captures JukAB as a named DefenseFinder two-profile system in which JukA binds the PhiKZ gp241 early phage protein at the EPI vesicle and recruits JukB to destabilize that vesicle. It summarizes the direct two-component system without minting separate sequence feature traits for jukA, jukB, gp241, or other JukA-associated effector families.

Edge evidence

jukAB locus contributes to JukA gp241 EPI-vesicle sensing RO:0002326
The JukAB locus encodes JukA, the sensor that binds the early phage protein gp241 at the EPI vesicle.
- DOI:10.1016/j.cell.2025.02.016 JukA (formerly YaaW) rapidly senses the EPI vesicle by binding to an early-expressed phage protein, gp241 Li et al. identify gp241/EPI-vesicle binding by JukA as the characterized JukAB sensor input.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv JukAB JukAB 2 2 JukAB__JukA, JukAB__JukB DefenseFinder requires the JukA profile in its JukAB system rule.
JukA gp241 EPI-vesicle sensing contributes to JukB effector recruitment RO:0002326
JukA sensing of gp241 at the EPI vesicle directly recruits the JukB effector.
- DOI:10.1016/j.cell.2025.02.016 JukA (formerly YaaW) rapidly senses the EPI vesicle by binding to an early-expressed phage protein, gp241, and then directly recruits JukB Li et al. place direct JukB recruitment downstream of JukA-gp241 binding at the EPI vesicle.
JukB effector recruitment contributes to EPI vesicle destabilization RO:0002326
Recruited JukB is a pore-forming-toxin-like effector that destabilizes the EPI vesicle.
- DOI:10.1016/j.cell.2025.02.016 The JukB effector structurally resembles a pore-forming toxin and destabilizes the EPI vesicle Li et al. connect JukB to the vesicle destabilization step of JukAB immunity.
EPI vesicle destabilization mitigates early jumbo-phage progression METPO:2007407
EPI-vesicle destabilization by the JukAB response blocks early jumbo-phage gene expression, DNA replication, and nucleus assembly.
- DOI:10.1016/j.cell.2025.02.016 suppressing the expression of early phage genes and preventing phage DNA replication and phage nucleus assembly while saving the cell Li et al. define the anti-phage output of the two-component Juk system.
EPI vesicle destabilization confers JukAB system METPO:2007700
JukB-associated EPI-vesicle destabilization realizes the JukAB defense trait.
- DOI:10.1016/j.cell.2025.02.016 a two-component immune system that terminates infection of φKZ-like phages Li et al. frame two-component Juk as an immune system that terminates PhiKZ-like phage infection.
JukAB system is a phage defense system rdfs:subClassOf
JukAB system possession is a phage-defense-system trait.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md JukAB | 10\.1101/2022\.09\.17\.508391 | A family of novel immune systems targets early infection of nucleus-forming jumbo phages DefenseFinder associates JukAB with the Li et al. nucleus-forming-jumbo-phage immune system paper.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1016/j.cell.2025.02.016

Parent traits (1)

phage defense system traitmech:000209

Synonyms (2)

JukAB RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
jumbo phage killer RELATED_SYNONYM · DOI:10.1016/j.cell.2025.02.016

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:10.1101/2022.09.17.508391 Li et al. discovered the native jukA-jukB operon in Pseudomonas aeruginosa PA14 and showed that the two-gene Juk locus provides immunity against PhiKZ-related nucleus-forming jumbo phages.

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 JukB vesicle-destabilization chemistry and the boundaries of other JukA-containing systems before minting narrower mechanism children.

KNOWLEDGE GAP OPEN jukab-vesicle-effector-family-gap · raised by codex · 2026-09-20

Attached to causal_graphs#jukab_recruits_effector_to_block_jumbo_phage

Li et al. resolve gp241/EPI-vesicle sensing by JukA and direct recruitment of JukB as a two-component JukAB strategy, but the exact chemistry of JukB-mediated vesicle destabilization and the relationship between canonical JukAB and JukA homologs paired with diverse other putative effectors still need narrower review.

Curation history

2026-09-20T08:47:10Z · MINTED_TRAITMECH_ID · codex
Minted JukAB system as a DOI-backed GENOMICS TraitRecord under phage defense system 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_v182.