PF15854: GPR15L

G-protein coupled receptor ligand 15

Curation status: SEEDED
Seed status: EX DUF
Characterization: UNSCORED

Grounding

PF15854: G-protein coupled receptor ligand 15
IPR031713: integrated entry for G-protein coupled receptor ligand 15

Source description

GPR15 is an orphan G protein-coupled receptor (GPCR) that is found in lymphocytes. It functions as a co-receptor of simian immunodeficiency virus and HIV-2 and plays a role in the trafficking of T cells to the lamina propria in the colon and to the skin [InterPro reference PUB00088053]. An activating ligand named GPR15L is shown to bind GPR15 and attract GPR15-expressing T cells including lymphocytes in colon-draining lymph nodes and thymic precursors of dermal epithelial T cell. This 9kDa CC-motif containing cationic polypeptide has been previously described as the 57 amino acid antimicrobial peptide AP-57, and as a Sushi Containing Domain-2 (SUSD2)-binding factor (CSBF), capable of inhibiting the growth of intestinal epithelial cancer cell lines. The chemokine is expressed by epithelial cells in gastrointestinal and genitourinary mucosae and in the skin [InterPro reference PUB00088054]. In humans GPR15L, is encoded by the gene C10ORF99 and has some features similar to the CC family of chemokines [InterPro reference PUB00088053]. However, it lacks significant homology to classic CC and CXC chemokines, yet shares many features with them, including a cationic domain predicted to comprise two disulfide bonds and a highly conserved GPCR-activating terminal peptide. Furthermore, the activating peptides of CC chemokines are typically located at the N-terminus, while that of GPR15L is C-terminal, a feature that it shares with some other GPCR ligands like chemerin and apela [InterPro reference PUB00088054].

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
A0A0B4J1N3	Protein GPR15LG Mus musculus	78 aa; version 1 UniProt 2026_03	UNIPROT FETCH 1 sibling references ProteinTraitsMech: Pfam:PF15854
I3LGZ3	Protein GPR15LG Sus scrofa	81 aa; version 1 UniProt 2026_03	UNIPROT FETCH 1 sibling references ProteinTraitsMech: Pfam:PF15854
Q6UWK7	Protein GPR15LG Homo sapiens	81 aa; version 1 UniProt 2026_03	UNIPROT FETCH 2 sibling references ProteinTraitsMech: GO:2000404 ProteinTraitsMech: Pfam:PF15854

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: 121
matches: 122
proteomes: 114
taxa: 422
structures: 1
alphafold models: 106
domain architectures: 4

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

data/families/PF15854.yaml
Family YAML in this build

Download this family (JSON)

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.