Seroatlas · Human Serome Atlas

BTN3A1

Butyrophilin subfamily 3 member A1

Also known as: BT3.1, BT3A1_HUMAN, BTF5, BTN3.1, CD277

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
O00481
Gene
BTN3A1
Ensembl
ENSG00000026950
Chromosome
6
Canonical length
513 aa
Protein class
CD markers, Predicted intracellular proteins, Predicted membrane proteins
Subcellular location
Vesicles
Quaternary structure
Homodimer

OverviewNCBI Gene

The butyrophilin (BTN) genes are a group of major histocompatibility complex (MHC)-associated genes that encode type I membrane proteins with 2 extracellular immunoglobulin (Ig) domains and an intracellular B30.2 (PRYSPRY) domain. Three subfamilies of human BTN genes are located in the MHC class I region: the single-copy BTN1A1 gene (MIM 601610) and the BTN2 (e.g., BTN2A1; MIM 613590) and BTN3 (e.g., BNT3A1) genes, which have undergone tandem duplication, resulting in 3 copies of each (summary by Smith et al., 2010 [PubMed 20208008]).[supplied by OMIM, Nov 2010]

Canonical amino-acid sequenceUniProt

513 residues, UniProt reviewed canonical sequence.

>O00481|BTN3A1
     1  MKMASFLAFL LLNFRVCLLL LQLLMPHSAQ FSVLGPSGPI LAMVGEDADL PCHLFPTMSA
    61  ETMELKWVSS SLRQVVNVYA DGKEVEDRQS APYRGRTSIL RDGITAGKAA LRIHNVTASD
   121  SGKYLCYFQD GDFYEKALVE LKVAALGSDL HVDVKGYKDG GIHLECRSTG WYPQPQIQWS
   181  NNKGENIPTV EAPVVADGVG LYAVAASVIM RGSSGEGVSC TIRSSLLGLE KTASISIADP
   241  FFRSAQRWIA ALAGTLPVLL LLLGGAGYFL WQQQEEKKTQ FRKKKREQEL REMAWSTMKQ
   301  EQSTRVKLLE ELRWRSIQYA SRGERHSAYN EWKKALFKPA DVILDPKTAN PILLVSEDQR
   361  SVQRAKEPQD LPDNPERFNW HYCVLGCESF ISGRHYWEVE VGDRKEWHIG VCSKNVQRKG
   421  WVKMTPENGF WTMGLTDGNK YRTLTEPRTN LKLPKPPKKV GVFLDYETGD ISFYNAVDGS
   481  HIHTFLDVSF SEALYPVFRI LTLEPTALTI CPA

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against BTN3A1 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Cell surface
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.31
Highest tissue expression
79 nTPM

Expression across tissuesHPA

Tissue

  • spleen: 79 nTPM
  • lymph node: 59 nTPM
  • tonsil: 49 nTPM
  • appendix: 42 nTPM
  • lung: 39 nTPM
  • small intestine: 33 nTPM

Single-cell type

  • nk-cells: 97 nCPM
  • t-cells: 78 nCPM
  • plasma cells: 57 nCPM
  • b-cells: 40 nCPM
  • kupffer cells: 40 nCPM
  • innate lymphoid cells: 36 nCPM

Immune cell

  • basophil: 54 nTPM
  • gdT-cell: 45 nTPM
  • memory CD8 T-cell: 42 nTPM
  • NK-cell: 41 nTPM
  • MAIT T-cell: 41 nTPM
  • T-reg: 36 nTPM

Brain region

  • medulla oblongata: 27 nTPM
  • pons: 19 nTPM
  • spinal cord: 18 nTPM
  • hypothalamus: 18 nTPM
  • white matter: 17 nTPM
  • thalamus: 16 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.19
gnomAD pLI
0
gnomAD missense Z
0.18
DepMap mean gene effect
-0.02
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads BTN3A1 as an antibody target. Whether an autoantibody or antibody against BTN3A1 could matter depends on whether native BTN3A1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

BTN3A1 is annotated at the cell surface, where native BTN3A1 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label BTN3A1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/BTN3A1. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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