All families / PF04402
PF04402: SIMPL
Protein of unknown function (DUF541)
- Curation status
- SEEDED
- Seed status
- EX DUF
- Characterization
- UNSCORED
Grounding
PF04402: Protein of unknown function (DUF541)
IPR007497: integrated entry for Protein of unknown function (DUF541)
Source description
Members of this family have so far been found in bacteria and mouse SwissProt or TrEMBL entries. However possible family members have also been identified in translated rat (Genbank:AW144450) and human (Genbank:AI478629) ESTs. A mouse family member has been named SIMPL (signalling molecule that associates with mouse pelle-like kinase). SIMPL appears to facilitate and/or regulate complex formation between IRAK/mPLK (IL-1 receptor-associated kinase) and IKK (inhibitor of kappa-B kinase) containing complexes, and thus regulate NF-kappa-B activity [InterPro reference PUB00010115]. Separate experiments demonstrate that a mouse family member (named LaXp180) binds the Listeria monocytogenes surface protein ActA, which is a virulence factor that induces actin polymerisation. It may also bind stathmin, a protein involved in signal transduction and in the regulation of microtubule dynamics [InterPro reference PUB00009982]. In bacteria its function is unknown, but it is thought to be located in the periplasm or outer membrane.
Evidence and references
- InterPro entry and its literature references. PUB identifiers are internal InterPro references, not PubMed identifiers. Unresolved citations link to the originating entry.
- Frozen description source: InterPro/Pfam API
Source descriptions and links are provenance, not independent functional validation.
Evidence counts: not scored.
Curated functional assertions
No curated functional assertions supplied.
Protein sequence examples
3 verified sequence examples. FASTA
| UniProt | Protein / organism | Sequence | Provenance |
|---|---|---|---|
| P0ADS6 | Uncharacterized protein YggE Escherichia coli (strain K12) | 246 aa; version 1 UniProt 2026_03 | PTM REGISTRY MIRROR |
| Q5VVH5 | Interleukin-1 receptor-associated kinase 1-binding protein 1 Homo sapiens | 260 aa; version 1 UniProt 2026_03 | PTM REGISTRY MIRROR |
| Q9ESJ7 | Interleukin-1 receptor-associated kinase 1-binding protein 1 Mus musculus | 259 aa; version 1 UniProt 2026_03 | UNIPROT FETCH2 sibling references |
Pfam membership is not functional evidence. Whole-protein sequences do not establish domain boundaries. A coverage gap here is not absence from UniProt.
Sequences and metadata: UniProt Consortium, CC BY 4.0.
Domain matches
No residue-level domain match evidence is available in this build. Structure and AlphaFold counters do not supply coordinates or establish function.
Snapshot counters
- proteins
- 16,767
- matches
- 16,828
- proteomes
- 13,193
- taxa
- 20,114
- structures
- 3
- alphafold models
- 10,934
- domain architectures
- 17
Classification basis
name matches duf; name says unknown function; description says unknown function; pfam previous unknown name
No scoring reasons supplied.
Related Mech records
| Family | Mech | Record | Protein | Link basis |
|---|---|---|---|---|
| SIMPL (PF04402) | ProteinTraitsMech | oxidative stress defense protein | P0ADS6 Uncharacterized protein YggE | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541) | P0ADS6 Uncharacterized protein YggE | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541) | Q5VVH5 Interleukin-1 receptor-associated kinase 1-binding protein 1 | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541) | Q9ESJ7 Interleukin-1 receptor-associated kinase 1-binding protein 1 | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541) | trait identifier | |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541), domain 1 | P0ADS6 Uncharacterized protein YggE | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541), domain 1 | Q5VVH5 Interleukin-1 receptor-associated kinase 1-binding protein 1 | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541), domain 1 | Q9ESJ7 Interleukin-1 receptor-associated kinase 1-binding protein 1 | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541), domain 2 | P0ADS6 Uncharacterized protein YggE | canonical example family classification |
| SIMPL (PF04402) | ProteinTraitsMech | Protein of unknown function (DUF541), domain 2 | Q5VVH5 Interleukin-1 receptor-associated kinase 1-binding protein 1 | canonical example family classification |
Curation history and reviews
No retained curation events supplied.
No retained review supplied.
Record source
Status and evidence
- Seed status
- A name-based classification of frozen InterPro/Pfam metadata. UNKNOWN CANDIDATE means the metadata explicitly says the function is unknown. KNOWN HISTORICAL DUF means a DUF name matched without that wording; this heuristic is not proof of a known function and does not establish experimental characterization. EX DUF means Pfam renamed the family away from a DUF/UPF name, as recorded in Pfam's previous identifiers; a rename usually follows published work on some members but is naming history, not proof of function for every member. Some EX DUF families' current names or descriptions still say the function is unknown; their classification basis lists this, and scoring does not treat them as characterized. FALSE POSITIVE TEXT HIT means the naming rules did not match.
- Characterization
- A separate evidence-scoring result. UNSCORED means no score has been calculated; it is not evidence that the family lacks a known function. Missing scores are not negative evidence. PARTIALLY CHARACTERIZED has partial support; KNOWN HISTORICAL DUF can inherit the seed label or reflect a known-function signal. Neither label implies experimental validation.
- Evidence counts
- Source-specific signals, not unique proteins, publications, or confidence scores. Known counts Rhea reactions and experimentally supported GO molecular-function annotations. Partial counts functional/domain assignments. Context counts structural, environmental, orthology, interaction and neighborhood signals; context alone does not assign function. Repeated annotations may not be independent.
- Curation status
- Reported separately from seed classification and characterization. SNAPSHOT ONLY means no curated metadata was supplied for this build. SEEDED denotes a source-derived record, not an expert-reviewed functional claim.
- Missing counts
- Not available means the source did not supply that counter. A zero is a reported count. Not scored means evidence counts are unavailable.