Seroatlas · Human Serome Atlas

APOA4

Apolipoprotein A-IV

Also known as: APOA4_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P06727
Gene
APOA4
Ensembl
ENSG00000110244
Chromosome
11
Canonical length
396 aa
Protein class
Candidate cardiovascular disease genes, Plasma proteins, Predicted secreted proteins
Subcellular location
Vesicles
Secretome location
Secreted to blood
Quaternary structure
Homodimer

OverviewNCBI Gene

Apoliprotein (apo) A-IV gene contains 3 exons separated by two introns. A sequence polymorphism has been identified in the 3'UTR of the third exon. The primary translation product is a 396-residue preprotein which after proteolytic processing is secreted its primary site of synthesis, the intestine, in association with chylomicron particles. Although its precise function is not known, apo A-IV is a potent activator of lecithin-cholesterol acyltransferase in vitro. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

396 residues, UniProt reviewed canonical sequence.

>P06727|APOA4
     1  MFLKAVVLTL ALVAVAGARA EVSADQVATV MWDYFSQLSN NAKEAVEHLQ KSELTQQLNA
    61  LFQDKLGEVN TYAGDLQKKL VPFATELHER LAKDSEKLKE EIGKELEELR ARLLPHANEV
   121  SQKIGDNLRE LQQRLEPYAD QLRTQVSTQA EQLRRQLTPY AQRMERVLRE NADSLQASLR
   181  PHADELKAKI DQNVEELKGR LTPYADEFKV KIDQTVEELR RSLAPYAQDT QEKLNHQLEG
   241  LTFQMKKNAE ELKARISASA EELRQRLAPL AEDVRGNLRG NTEGLQKSLA ELGGHLDQQV
   301  EEFRRRVEPY GENFNKALVQ QMEQLRQKLG PHAGDVEGHL SFLEKDLRDK VNSFFSTFKE
   361  KESQDKTLSL PELEQQQEQQ QEQQQEQVQM LAPLES

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against APOA4 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)
0.42
Highest tissue expression
2,930 nTPM

Expression across tissuesHPA

Tissue

  • small intestine: 2,930 nTPM
  • duodenum: 2,075 nTPM
  • liver: 237 nTPM
  • colon: 5.7 nTPM
  • stomach: 4.4 nTPM
  • smooth muscle: 2.8 nTPM

Single-cell type

  • enterocytes: 10,360 nCPM
  • paneth cells: 159 nCPM
  • goblet cells: 108 nCPM
  • hepatocytes: 70 nCPM
  • neuroendocrine cells: 29 nCPM
  • gastric chief cells: 9.8 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

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about APOA4.

Disease | AllUniProt

Conditions APOA4 is implicated in, by any mechanism.

  • Tubulointerstitial kidney disease, autosomal dominant 6 (ADTKD6) MIM:621106

Disease | GeneticClinVar

2 pathogenic / likely-pathogenic of 188 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

  • Tubulointerstitial kidney disease, autosomal dominant 6

Disease | ImmuneIEDB

Conditions an epitope on APOA4 was assayed in.

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
-1.21
DepMap mean gene effect
0.11
DepMap dependency class
none

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

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads APOA4 as an antibody target. Whether an autoantibody or antibody against APOA4 could matter depends on whether native APOA4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

APOA4 is annotated as secreted, so native APOA4 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 APOA4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/APOA4. 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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