Seroatlas · Human Serome Atlas

DEFA1

Neutrophil defensin 1

Also known as: DEF1, DEF1_HUMAN, DEFA1B, DEFA2, HNP-1, MRS

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

Protein identityUniProt · HPA

UniProt accession
P59665
Gene
DEFA1
Ensembl
ENSG00000206047
Chromosome
8
Canonical length
94 aa
Protein class
Cancer-related genes, Plasma proteins, Predicted secreted proteins, Transporters
Secretome location
Secreted to blood

OverviewNCBI Gene

Defensins are a family of antimicrobial and cytotoxic peptides thought to be involved in host defense. They are abundant in the granules of neutrophils and also found in the epithelia of mucosal surfaces such as those of the intestine, respiratory tract, urinary tract, and vagina. Members of the defensin family are highly similar in protein sequence and distinguished by a conserved cysteine motif. The protein encoded by this gene, defensin, alpha 1, is found in the microbicidal granules of neutrophils and likely plays a role in phagocyte-mediated host defense. Several alpha defensin genes are clustered on chromosome 8. This gene differs from defensin, alpha 3 by only one amino acid. This gene and the gene encoding defensin, alpha 3 are both subject to copy number variation. [provided by RefSeq, Oct 2014]

Canonical amino-acid sequenceUniProt

94 residues, UniProt reviewed canonical sequence.

>P59665|DEFA1
     1  MRTLAILAAI LLVALQAQAE PLQARADEVA AAPEQIAADI PEVVVSLAWD ESLAPKHPGS
    61  RKNMACYCRI PACIAGERRY GTCIYQGRLW AFCC

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against DEFA1 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)
0.55
Highest tissue expression
59,494 nTPM

Expression across tissuesHPA

Tissue

  • bone marrow: 59,494 nTPM
  • thymus: 217 nTPM
  • spleen: 78 nTPM
  • salivary gland: 65 nTPM
  • skin: 59 nTPM
  • lung: 26 nTPM

Single-cell type

  • neutrophil progenitors: 0.5 nCPM
  • adipocytes: 0 nCPM
  • adrenal cortex cells: 0 nCPM
  • adrenal medulla cells: 0 nCPM
  • alveolar cells type 1: 0 nCPM
  • alveolar cells type 2: 0 nCPM

Immune cell

  • total PBMC: 16,296 nTPM
  • neutrophil: 2,666 nTPM
  • gdT-cell: 128 nTPM
  • classical monocyte: 74 nTPM
  • naive CD4 T-cell: 13 nTPM
  • eosinophil: 8.6 nTPM

Brain region

  • cerebral cortex: 3.3 nTPM
  • medulla oblongata: 1.2 nTPM
  • pons: 1.2 nTPM
  • midbrain: 1 nTPM
  • amygdala: 0.9 nTPM
  • thalamus: 0.9 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about DEFA1.

Disease | ImmuneIEDB

Conditions an epitope on DEFA1 was assayed in.

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% 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 DEFA1 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 DEFA1 as an antibody target. Whether an autoantibody or antibody against DEFA1 could matter depends on whether native DEFA1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

DEFA1 is annotated as secreted, so native DEFA1 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 DEFA1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/DEFA1. 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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