Seroatlas · Human Serome Atlas

APEX1

DNA repair nuclease/redox regulator APEX1

Also known as: APE, APE-1, APEN, APEX, APEX1_HUMAN, APX, HAP1, REF-1, REF1

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

Protein identityUniProt · HPA

UniProt accession
P27695
Gene
APEX1
Ensembl
ENSG00000100823
Chromosome
14
Canonical length
318 aa
Protein class
Cancer-related genes, Enzymes, Plasma proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Centrosome
Quaternary structure
Homodimer

OverviewNCBI Gene

The APEX gene encodes the major AP endonuclease in human cells. It encodes the APEX endonuclease, a DNA repair enzyme with apurinic/apyrimidinic (AP) activity. Such AP activity sites occur frequently in DNA molecules by spontaneous hydrolysis, by DNA damaging agents or by DNA glycosylases that remove specific abnormal bases. The AP sites are the most frequent pre-mutagenic lesions that can prevent normal DNA replication. Splice variants have been found for this gene; all encode the same protein. Disruptions in the biological functions related to APEX are associated with many various malignancies and neurodegenerative diseases.[provided by RefSeq, Dec 2019]

Canonical amino-acid sequenceUniProt

318 residues, UniProt reviewed canonical sequence.

>P27695|APEX1
     1  MPKRGKKGAV AEDGDELRTE PEAKKSKTAA KKNDKEAAGE GPALYEDPPD QKTSPSGKPA
    61  TLKICSWNVD GLRAWIKKKG LDWVKEEAPD ILCLQETKCS ENKLPAELQE LPGLSHQYWS
   121  APSDKEGYSG VGLLSRQCPL KVSYGIGDEE HDQEGRVIVA EFDSFVLVTA YVPNAGRGLV
   181  RLEYRQRWDE AFRKFLKGLA SRKPLVLCGD LNVAHEEIDL RNPKGNKKNA GFTPQERQGF
   241  GELLQAVPLA DSFRHLYPNT PYAYTFWTYM MNARSKNVGW RLDYFLLSHS LLPALCDSKI
   301  RSKALGSDHC PITLYLAL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against APEX1 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)
0.3
Highest tissue expression
174 nTPM

Expression across tissuesHPA

Tissue

  • ovary: 174 nTPM
  • bone marrow: 146 nTPM
  • thymus: 117 nTPM
  • tonsil: 114 nTPM
  • lymph node: 105 nTPM
  • adrenal gland: 102 nTPM

Single-cell type

  • decidual stromal cells: 277 nCPM
  • migrating cytotrophoblasts: 263 nCPM
  • extravillous trophoblasts: 237 nCPM
  • cytotrophoblasts: 236 nCPM
  • esophageal basal cells: 218 nCPM
  • enteric stem cells: 211 nCPM

Immune cell

  • plasmacytoid DC: 236 nTPM
  • myeloid DC: 209 nTPM
  • total PBMC: 200 nTPM
  • memory B-cell: 155 nTPM
  • naive B-cell: 141 nTPM
  • naive CD4 T-cell: 134 nTPM

Brain region

  • white matter: 54 nTPM
  • thalamus: 51 nTPM
  • hypothalamus: 50 nTPM
  • cerebellum: 49 nTPM
  • spinal cord: 48 nTPM
  • medulla oblongata: 48 nTPM

ReferencesPubMed · IEDB

Publications for APEX1 from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Reference: AutoantibodyPubMed

2 publications

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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)
1.27
gnomAD pLI
0
gnomAD missense Z
0.12
DepMap mean gene effect
-0.09
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% 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

InteractionsUniProt · HPA

Protein binding partners of APEX1 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 APEX1 as an antibody target. Whether an autoantibody or antibody against APEX1 could matter depends on whether native APEX1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

APEX1 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 APEX1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/APEX1. 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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