All families / PF15223
PF15223: EPOP
Elongin BC and Polycomb repressive complex 2-associated protein
- Curation status
- SEEDED
- Seed status
- EX DUF
- Characterization
- UNSCORED
Grounding
PF15223: Elongin BC and Polycomb repressive complex 2-associated protein
IPR027971: integrated entry for Elongin BC and Polycomb repressive complex 2-associated protein
Source description
This family of proteins is found in eukaryotes. Family members are approximately 835 amino acids in length and include the polycomb repressive complex 2-associated factor EPOP (Elongin BC and Polycomb Repressive Complex 2 (PRC2) Associated Protein, also termed C17orf96, esPRC2p48, E130012A19Rik), a scaffold protein expressed in the inner cell mass of the mouse blastocyst serving as a bridging partner between the PRC2/EED-EZH2 complex and the elongin BC complex, and fine-tuning the transcriptional status of Polycomb group (PcG) target genes in embryonic stem cells. Both EPOP and Elongin BC are required to maintain low levels of expression at PRC2 genomic targets [InterPro reference PUB00083907]. EPOP interacts with the H2B deubiquitinase USP7 to modulate transcriptional processes in mESCs similar to MYC [InterPro reference PUB00083908]. Functional studies found that the C-terminal region of EPOP directly interacts with PRC2 and that this region associates with the VEFS-box of the PRC2 core member SUZ12. Thus, suggesting that EPOP may directly affect PRC2 chromatin binding by altering the functionality of Suz12. This region is proposed to have evolved in early vertebrates and is also present in the paralog SKIDA1 (C10orf140) another novel PRC2-interacting protein, supporting the idea that proteins possessing this sequence are PRC2 regulators in the entire vertebrate branch [InterPro reference PUB00111127]. The family is found in association with PF02437 (Pfam entry).
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
4 verified sequence examples. FASTA
| UniProt | Protein / organism | Sequence | Provenance |
|---|---|---|---|
| A6NHQ4 | Elongin BC and Polycomb repressive complex 2-associated protein Homo sapiens | 379 aa; version 1 UniProt 2026_03 | UNIPROT FETCH2 sibling references |
| Q1XH10 | SKI/DACH domain-containing protein 1 Homo sapiens | 908 aa; version 2 UniProt 2026_03 | UNIPROT FETCH2 sibling references |
| Q7TNS8 | Elongin BC and Polycomb repressive complex 2-associated protein Mus musculus | 369 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 sibling references |
| Q80YR3 | SKI/DACH domain-containing protein 1 Mus musculus | 822 aa; version 1 UniProt 2026_03 | UNIPROT FETCH1 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
- 888
- matches
- 905
- proteomes
- 644
- taxa
- 2,016
- structures
- 1
- alphafold models
- 764
- domain architectures
- 6
Classification basis
pfam previous unknown name
No scoring reasons supplied.
Related Mech records
This family joined the worklist after the frozen cross-Mech scan, so other Mechs were not searched for it. Missing links here are not evidence that other Mechs lack it; rows shown come from mentions of a former DUF/UPF name.
No cross-Mech examples are present in the supplied snapshot.
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.