Seroatlas · Human Serome Atlas

F8A1

40-kDa huntingtin-associated protein

Also known as: DXS522E, F8A, F8A2, F8A3, HAP40_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P23610
Gene
F8A1
Ensembl
ENSG00000288722
Chromosome
X
Canonical length
371 aa
Protein class
Disease related genes, Predicted intracellular proteins

OverviewNCBI Gene

This gene is contained entirely within intron 22 of the factor VIII gene; spans less than 2 kb, and is transcribed in the direction opposite of factor VIII. A portion of intron 22 (int22h), containing F8A, is repeated twice extragenically closer to the Xq telomere. Although its function is unknown, the observation that this gene is conserved in the mouse implies it has some function. Unlike factor VIII, this gene is transcribed abundantly in a wide variety of cell types. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

371 residues, UniProt reviewed canonical sequence.

>P23610|F8A1
     1  MAAAAAGLGG GGAGPGPEAG DFLARYRLVS NKLKKRFLRK PNVAEAGEQF GQLGRELRAQ
    61  ECLPYAAWCQ LAVARCQQAL FHGPGEALAL TEAARLFLRQ ERDARQRLVC PAAYGEPLQA
   121  AASALGAAVR LHLELGQPAA AAALCLELAA ALRDLGQPAA AAGHFQRAAQ LQLPQLPLAA
   181  LQALGEAASC QLLARDYTGA LAVFTRMQRL AREHGSHPVQ SLPPPPPPAP QPGPGATPAL
   241  PAALLPPNSG SAAPSPAALG AFSDVLVRCE VSRVLLLLLL QPPPAKLLPE HAQTLEKYSW
   301  EAFDSHGQES SGQLPEELFL LLQSLVMATH EKDTEAIKSL QVEMWPLLTA EQNHLLHLVL
   361  QETISPSGQG V

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against F8A1 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
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.36
Highest tissue expression
8.3 nTPM

Expression across tissuesHPA

Tissue

  • parathyroid gland: 8.3 nTPM
  • liver: 6.7 nTPM
  • skeletal muscle: 5.6 nTPM
  • cerebral cortex: 5.4 nTPM
  • basal ganglia: 4.5 nTPM
  • heart muscle: 4.4 nTPM

Single-cell type

  • podocytes: 0.3 nCPM
  • proximal tubule cells: 0.3 nCPM
  • colonocytes: 0.1 nCPM
  • distal convoluted tubule cells: 0.1 nCPM
  • loop of henle epithelial cells: 0.1 nCPM
  • megakaryocyte progenitors: 0.1 nCPM

Immune cell

  • eosinophil: 1.5 nTPM
  • gdT-cell: 0.3 nTPM
  • memory CD4 T-cell: 0.3 nTPM
  • MAIT T-cell: 0.2 nTPM
  • memory CD8 T-cell: 0.2 nTPM
  • myeloid DC: 0.2 nTPM

Brain region

  • cerebral cortex: 4.8 nTPM
  • medulla oblongata: 4.1 nTPM
  • hypothalamus: 4 nTPM
  • basal ganglia: 3.9 nTPM
  • white matter: 3.8 nTPM
  • pons: 3.7 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 missense Z
0.67

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 7% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of F8A1 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads F8A1 as an antibody target. Whether an autoantibody or antibody against F8A1 could matter depends on whether native F8A1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

F8A1 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label F8A1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/F8A1. 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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