SDIC4 system

traitmech:000421 · CLASS · PROPOSED

A phage defense system in which an organism possesses an SDIC4 locus encoding an SDIC4A component and a VasI-like SDIC4B component that can reduce adsorption of invading bacteriophages.

Trait evidence (6)

DOI:10.1016/j.celrep.2024.115055
SDIC4 comprises SDIC4A, a protein of unknown function, and SDIC4B, harboring the VasI-like domain

Cummins et al. describe the SDIC4 locus as encoding an SDIC4A component of unknown function and a VasI-like SDIC4B component.
DOI:10.1016/j.celrep.2024.115055
SDIC4-mediated anti-phage activity is more modest (R10- to 200-fold) but still significant

Cummins et al. report significant SDIC4-mediated anti-phage activity when SDIC4 was expressed in E. coli.
DOI:10.1016/j.celrep.2024.115055
In the presence of full-length SDIC4 or SDIC4B, we observed a decrease in the adsorption rate

Cummins et al. connect full-length SDIC4 and SDIC4B with a decreased bacteriophage adsorption rate.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
SDIC4 | 10\.1016/j\.celrep\.2024\.115055 | Multi-conflict islands are a widespread trend within Serratia spp

The pinned DefenseFinder article registry maps the SDIC4 source key to the Cummins et al. Serratia multi-conflict-island paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| SDIC4__SDIC4A | | SDIC4 | Custom | 100 |

The pinned DefenseFinder HMM inventory records SDIC4__SDIC4A as a custom SDIC4 profile.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| SDIC4__SDIC4B | | SDIC4 | Custom | 100 |

The pinned DefenseFinder HMM inventory records SDIC4__SDIC4B as a custom SDIC4 profile.

SDIC4 loci reduce bacterial phage adsorption

Conservative system-level sketch linking the SDIC4 locus to reduced adsorption of invading bacteriophages.

NONMECHANISTIC · The graph captures SDIC4 as a named anti-phage system with SDIC4A and SDIC4B DefenseFinder profiles while leaving natural host breadth, sensitive-phage breadth, the SDIC4 type I versus type II boundary, the exact SDIC4A/SDIC4B profile-to-protein correspondence, the receptor or phage target, and rule-level detection criteria unresolved.

Edge evidence

SDIC4 locus contributes to reduced phage adsorption rate RO:0002326
The SDIC4 locus contributes to reduced adsorption of invading bacteriophages.
- DOI:10.1016/j.celrep.2024.115055 In the presence of full-length SDIC4 or SDIC4B, we observed a decrease in the adsorption rate Cummins et al. report decreased phage adsorption for full-length SDIC4 and SDIC4B.
- DOI:10.1016/j.celrep.2024.115055 SDIC4 type I and type II elicit protection against phage infection by reducing the adsorption rate of invading phages Cummins et al. connect both tested SDIC4 subtypes with reduced phage adsorption.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | SDIC4__SDIC4A | | SDIC4 | Custom | 100 | The pinned DefenseFinder HMM inventory records SDIC4__SDIC4A as a custom SDIC4 profile.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | SDIC4__SDIC4B | | SDIC4 | Custom | 100 | The pinned DefenseFinder HMM inventory records SDIC4__SDIC4B as a custom SDIC4 profile.
reduced phage adsorption rate confers SDIC4 system METPO:2007700
Reduced phage adsorption realizes the SDIC4 system trait.
- DOI:10.1016/j.celrep.2024.115055 SDIC4-mediated anti-phage activity is more modest (R10- to 200-fold) but still significant Cummins et al. report significant SDIC4-mediated anti-phage activity.
SDIC4 system is a phage defense system rdfs:subClassOf
SDIC4 system possession is a phage-defense-system trait.
- DOI:10.1016/j.celrep.2024.115055 SDIC4-mediated anti-phage activity is more modest (R10- to 200-fold) but still significant Cummins et al. report SDIC4-mediated anti-phage activity.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md SDIC4 | 10\.1016/j\.celrep\.2024\.115055 | Multi-conflict islands are a widespread trend within Serratia spp The pinned DefenseFinder article registry maps the SDIC4 source key to the Cummins et al. Serratia multi-conflict-island paper.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1016/j.celrep.2024.115055

Parent traits (1)

phage defense system traitmech:000209

Synonyms (3)

SDIC4 EXACT_SYNONYM · DOI:10.1016/j.celrep.2024.115055
SDIC4__SDIC4A RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
SDIC4__SDIC4B RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md

kg-microbe context

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

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 SDIC4 natural host breadth, sensitive-phage breadth, type I versus type II component scope, SDIC4A/SDIC4B component functions, receptor or phage target, and rule-level detection criteria before minting narrower SDIC4 mechanism children.

KNOWLEDGE GAP OPEN sdic4-defensefinder-model-gap · raised by codex · 2026-09-27

Attached to causal_graphs#sdic4_locus_reduces_phage_adsorption

Cummins et al. support SDIC4 as a VasI-like anti-phage system that reduces phage adsorption, and the pinned DefenseFinder HMM inventory records SDIC4A and SDIC4B profile rows. The pinned rules table has no SDIC4 row, and the first-pass record does not resolve natural host breadth, sensitive-phage breadth, type I versus type II system boundaries, the exact profile-to-component mapping, the SDIC4A/SDIC4B relationship, or the phage-adsorption target.

Evidence

DOI:10.1016/j.celrep.2024.115055
SDIC4 comprises SDIC4A, a protein of unknown function, and SDIC4B, harboring the VasI-like domain
DOI:10.1016/j.celrep.2024.115055
SDIC4 type I and type II elicit protection against phage infection by reducing the adsorption rate of invading phages
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
SDIC4 | 10\.1016/j\.celrep\.2024\.115055 | Multi-conflict islands are a widespread trend within Serratia spp
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| SDIC4__SDIC4A | | SDIC4 | Custom | 100 |
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| SDIC4__SDIC4B | | SDIC4 | Custom | 100 |
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv

Curation history

2026-09-27T23:47:56Z · MINTED_TRAITMECH_ID · codex
Minted SDIC4 system as a DOI-backed GENOMICS TraitRecord under phage defense system after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, history, or prior proposal record; kept the graph at candidate-locus level because the pinned DefenseFinder SDIC4 HMM rows are not backed by a rules row; proposals/metpo_traitmech_v298 reserves the replacement placeholder.
2026-09-27T23:47:57Z · REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP · codex
Reviewed SDIC4 system canonical_examples and left them empty because Cummins et al. support plasmid-expressed E. coli and S. marcescens phage-challenge and phage-adsorption assays plus a DefenseFinder SDIC4 system model, but not a direct native microbial isolate exemplar with experimentally verified endogenous SDIC4 activity. No paid research was used.