Seroatlas · Human Serome Atlas

BPIFA3

BPI fold-containing family A member 3

Also known as: bA49G10.4, BPIA3_HUMAN, C20orf71, SPLUNC3

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

Protein identityUniProt · HPA

UniProt accession: Q9BQP9
Gene: BPIFA3
Ensembl: ENSG00000131059
Chromosome: 20
Canonical length: 254 aa
Protein class: Predicted secreted proteins
Secretome location: Secreted in male reproductive system

OverviewNCBI Gene

Predicted to enable lipid binding activity. Predicted to be located in extracellular region. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

254 residues, UniProt reviewed canonical sequence.

>Q9BQP9|BPIFA3
     1  MMCPLWRLLI FLGLLALPLA PHKQPWPGLA QAHRDNKSTL ARIIAQGLIK HNAESRIQNI
    61  HFGDRLNASA QVAPGLVGWL ISGRKHQQQQ ESSINITNIQ LDCGGIQISF HKEWFSANIS
   121  LEFDLELRPS FDNNIVKMCA HMSIVVEFWL EKDEFGRRDL VIGKCDAEPS SVHVAILTEA
   181  IPPKMNQFLY NLKENLQKVL PHMVESQVCP LIGEILGQLD VKLLKSLIEQ EAAHEPTHHE
   241  TSQPSACQAG ESPS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against BPIFA3 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.4
Highest tissue expression: 52 nTPM

Expression across tissuesHPA

Tissue

testis: 52 nTPM
adipose tissue: 0 nTPM
adrenal gland: 0 nTPM
amygdala: 0 nTPM
appendix: 0 nTPM
basal ganglia: 0 nTPM

Single-cell type

late spermatids: 5,536 nCPM
early spermatids: 822 nCPM
late primary spermatocytes: 299 nCPM
leydig cells: 7.8 nCPM
sertoli cells: 6.2 nCPM
undifferentiated spermatogonia: 3.7 nCPM

Immune cell

basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM
MAIT T-cell: 0 nTPM

Brain region

amygdala: 0 nTPM
basal ganglia: 0 nTPM
cerebellum: 0 nTPM
cerebral cortex: 0 nTPM
choroid plexus: 0 nTPM
hippocampal formation: 0 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): 1.77
gnomAD pLI: 0
gnomAD missense Z: -0.45
DepMap mean gene effect: -0.09
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 1% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Molecular functions

lipid binding

Cellular components

extracellular region

Protein domainsUniProt · Pfam · InterPro

Lipid-binding serum glycoprotein, N-terminal
Bactericidal permeability-increasing protein, alpha/beta domain superfamily
LBP / BPI / CETP family, N-terminal domain
BPI fold-containing family A member 3

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads BPIFA3 as an antibody target. Whether an autoantibody or antibody against BPIFA3 could matter depends on whether native BPIFA3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

BPIFA3 is annotated as secreted, so native BPIFA3 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label BPIFA3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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