Seroatlas · Human Serome Atlas

DEFB109B

Beta-defensin 109B

Also known as: DB109_HUMAN, DEFB109P1B

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

Protein identityUniProt · HPA

UniProt accession
Q30KR1
Gene
DEFB109B
Ensembl
ENSG00000206034
Chromosome
8
Canonical length
87 aa
Protein class
Predicted secreted proteins
Secretome location
Secreted in male reproductive system

OverviewNCBI Gene

Predicted to enable CCR6 chemokine receptor binding activity and chemoattractant activity. Predicted to be involved in cell chemotaxis and defense response to bacterium. Predicted to be located in extracellular region. Predicted to be active in extracellular space. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

87 residues, UniProt reviewed canonical sequence.

>Q30KR1|DEFB109B
     1  MRLHLLLLIL LLFSILLSPV RGGLGPAEGH CLNLFGVCRT DVCNIVEDQI GACRRRMKCC
    61  RAWWILMPIP TPLIMSDYQE PLKPNLK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against DEFB109B 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)
0.53
Highest tissue expression
15 nTPM

Expression across tissuesHPA

Tissue

  • epididymis: 15 nTPM
  • cerebral cortex: 1.9 nTPM
  • thyroid gland: 1.8 nTPM
  • retina: 1.7 nTPM
  • skin: 1.5 nTPM
  • lymph node: 0.9 nTPM

Single-cell type

  • epicardial cells: 6.8 nCPM
  • cardiomyocytes: 3 nCPM
  • oligodendrocytes: 2.6 nCPM
  • bergmann glia: 1.9 nCPM
  • retinal amacrine cells: 1.4 nCPM
  • oligodendrocyte progenitor cells: 1.3 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

  • white matter: 46 nTPM
  • cerebral cortex: 42 nTPM
  • basal ganglia: 40 nTPM
  • hypothalamus: 40 nTPM
  • thalamus: 40 nTPM
  • cerebellum: 38 nTPM

OntologyGO

Biological processes

Molecular functions

Cellular components

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads DEFB109B as an antibody target. Whether an autoantibody or antibody against DEFB109B could matter depends on whether native DEFB109B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

DEFB109B is annotated as secreted, so native DEFB109B 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 DEFB109B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/DEFB109B. 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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