DEFB109B

Summary

DEFB109B (defensin beta 109B, HGNC:33469) is a protein-coding gene on chromosome 8p23.1, encoding Beta-defensin 109B (Q30KR1). Has antibacterial activity.

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.

Source: NCBI Gene 641517 — RefSeq curated summary.

At a glance

• GWAS associations: 1
• Clinical variants (ClinVar): 2 total — 1 pathogenic
• MANE Select transcript: NM_001037380

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:33469
Approved symbol	DEFB109B
Name	defensin beta 109B
Location	8p23.1
Locus type	gene with protein product
Status	Approved
Ensembl gene	ENSG00000206034
Ensembl biotype	protein_coding
Entrez	641517

Gene structure

Transcript identifiers

Ensembl transcripts: 1 — 1 protein_coding

ENST00000382656

RefSeq mRNA: 1 — MANE Select: NM_001037380 NM_001037380

Canonical transcript exons

ENST00000382656 — 2 exons

Exon	Start	End
ENSE00002060697	7319746	7320096
ENSE00002079298	7312722	7312903

Expression profiles

Bgee: expression breadth broad, 84 present calls, max score 63.35.

Top tissues by expression

108 total, by Bgee expression score (0-100, higher = more expressed):

Tissue	Anatomy ID	Expression score	Quality
corpus callosum	UBERON:0002336	63.35	gold quality
mucosa of transverse colon	UBERON:0004991	52.39	gold quality
hindlimb stylopod muscle	UBERON:0004252	50.11	gold quality
rectum	UBERON:0001052	47.59	gold quality
ganglionic eminence	UBERON:0004023	44.42	gold quality
granulocyte	CL:0000094	44.40	silver quality
cortical plate	UBERON:0005343	43.42	gold quality
colonic epithelium	UBERON:0000397	37.20	gold quality
ventricular zone	UBERON:0003053	36.48	gold quality
calcaneal tendon	UBERON:0003701	36.33	gold quality
bone marrow cell	CL:0002092	36.16	gold quality
skeletal muscle tissue	UBERON:0001134	35.33	gold quality
muscle tissue	UBERON:0002385	34.66	silver quality
bone marrow	UBERON:0002371	33.68	silver quality
cortex of kidney	UBERON:0001225	33.03	gold quality
smooth muscle tissue	UBERON:0001135	32.47	gold quality
urinary bladder	UBERON:0001255	32.41	gold quality
duodenum	UBERON:0002114	32.33	gold quality
placenta	UBERON:0001987	31.43	gold quality
sural nerve	UBERON:0015488	30.93	gold quality
right adrenal gland cortex	UBERON:0035827	30.80	gold quality
primary visual cortex	UBERON:0002436	30.37	gold quality
vermiform appendix	UBERON:0001154	30.22	silver quality
stromal cell of endometrium	CL:0002255	29.87	gold quality
superior frontal gyrus	UBERON:0002661	29.61	gold quality
fundus of stomach	UBERON:0001160	29.46	gold quality
tonsil	UBERON:0002372	29.34	gold quality
islet of Langerhans	UBERON:0000006	29.04	gold quality
uterine cervix	UBERON:0000002	28.96	silver quality
kidney	UBERON:0002113	28.95	gold quality

Single-cell (SCXA)

Detected in 1 experiment(s), a significant marker in 0.

Experiment	Marker?	Max mean expression
E-ANND-3	no	0.29

Regulation

Is transcription factor: no

Cross-species orthologs

2 orthologs

Organism	Symbol	Gene ID
mus_musculus	Defb48	ENSMUSG00000075574
rattus_norvegicus	Defb42	ENSRNOG00000038762

Paralogs (6): DEFB4A (ENSG00000171711), DEFB4B (ENSG00000177257), DEFB109C (ENSG00000205989), DEFB130A (ENSG00000232948), DEFB130B (ENSG00000233050), DEFB109D (ENSG00000254866)

Protein

Protein identifiers

Beta-defensin 109B — Q30KR1 (reviewed: Q30KR1)

Alternative names: Defensin beta 109B

All UniProt accessions (1): Q30KR1

UniProt curated annotations — full annotation on UniProt →

Function. Has antibacterial activity.

Subcellular location. Secreted.

Tissue specificity. Constitutively expressed in all regions of the ocular surface with predominant expression in the uppermost layers of the corneal epithelium and lower levels in basal layers (at protein level). Also detected in some keratocytes in the corneal stroma (at protein level). Expressed in all layers of the limbal epithelium with no expression found in limbal keratocytes (at protein level). Strongly expressed in the conjunctival epithelium with decreased expression in basal layers (at protein level). Also strongly expressed in tonsil tissue (at protein level).

Induction. Down-regulated on the ocular surface following inflammation and bacterial and viral infection.

Similarity. Belongs to the beta-defensin family.

RefSeq proteins (1): NP_001032457* (*=MANE)

Domains & families (InterPro)

UniProt features (5 total): disulfide bond 3, signal peptide 1, chain 1

Structure

Experimental structures (PDB)

0 structures.

Predicted structure (AlphaFold)

Model	pLDDT	Fraction very-high
AF-Q30KR1-F1	81.73	0.30

Functional residue map

Curated UniProt residues grouped by drug-discovery relevance — catalytic, ligand-binding, modification, and mutation-validated positions. Source: UniProtKB sequence features.

Disulfide bonds (3): 31–59, 38–53, 43–60

Function

Pathways and Gene Ontology

Reactome pathways

1 pathways

ID	Pathway
R-HSA-1461957	Beta defensins

MSigDB gene sets: 23 (showing top): REACTOME_INNATE_IMMUNE_SYSTEM, GOBP_CELL_CHEMOTAXIS, GOBP_TAXIS, GOMF_G_PROTEIN_COUPLED_RECEPTOR_BINDING, GOBP_DEFENSE_RESPONSE_TO_BACTERIUM, GOMF_SIGNALING_RECEPTOR_BINDING, GOBP_POSITIVE_CHEMOTAXIS, GOMF_CHEMOATTRACTANT_ACTIVITY, GOMF_CCR_CHEMOKINE_RECEPTOR_BINDING, GOBP_RESPONSE_TO_BACTERIUM, GOMF_SIGNALING_RECEPTOR_REGULATOR_ACTIVITY, GOMF_CCR6_CHEMOKINE_RECEPTOR_BINDING, REACTOME_ANTIMICROBIAL_PEPTIDES, GOBP_LOCOMOTION, GOBP_BIOLOGICAL_PROCESS_INVOLVED_IN_INTERSPECIES_INTERACTION_BETWEEN_ORGANISMS

GO Biological Process (4): defense response to bacterium (GO:0042742), cell chemotaxis (GO:0060326), defense response (GO:0006952), positive chemotaxis (GO:0050918)

GO Molecular Function (2): CCR6 chemokine receptor binding (GO:0031731), chemoattractant activity (GO:0042056)

GO Cellular Component (2): obsolete extracellular space (GO:0005615), extracellular region (GO:0005576)

Reactome top-level categories

Rollup of top-1 pathways:

Category	Pathways
Defensins	1

GO top-level categories

Rollup of top GO terms by namespace:

Category	Terms
chemotaxis	2
defense response	1
response to bacterium	1
cell migration	1
cellular response to chemical stimulus	1
response to stress	1
CCR chemokine receptor binding	1
receptor ligand activity	1
positive chemotaxis	1
cellular anatomical structure	1

Protein interactions and networks

STRING

0 interactions, top by confidence (×1000):

IntAct

2 interactions, top by confidence:

A	B	Type	Score
DEFB109B	CHST10	psi-mi:“MI:0914”(association)	0.350

ESM2 similar proteins: A4H220, A4H221, A4H222, A4H223, A4H225, A4H227, A4H228, A4H238, A4H240, A4H253, A4H254, A4H255, A4H257, A4H258, A4H259, A4H262, A4H263, A4H264, A4H265, P0C8A8, P0DY26, P0DY27, Q29RT9, Q30KJ7, Q30KK0, Q30KK1, Q30KK9, Q30KL1, Q30KL7, Q30KP3, Q30KP5, Q30KQ4, Q30KQ5, Q30KQ8, Q30KR1, Q30KT5, Q32P86, Q32ZH2, Q32ZH6, Q3UW43

Diamond homologs: P0DP73, P0DP74, P0DY26, P0DY27, Q30KJ9, Q30KL7, Q30KR1

SIGNOR signaling

0 interactions.

Disease & clinical

Clinical variants and AI predictions

ClinVar

2 variants total. Per-class counts are floors (≥ shown; pagination cap):

Classification	Count (floor)
Pathogenic	1
Likely pathogenic	0
Uncertain significance	0
Likely benign	0
Benign	1

Top pathogenic / likely-pathogenic (1)

Variant ID	HGVS	Classification
4755349	GRCh38/hg38 8p23.1(chr8:7296514-12636756)x1	Pathogenic

SpliceAI

0 predictions. Top by Δscore:

AlphaMissense

0 scored. Top likely-pathogenic:

dbSNP variants (sampled 300 via entrez): RS1000175733 (8:7315970 T>C), RS1000246538 (8:7307819 G>A), RS1000704437 (8:7315745 G>A,C), RS1000805630 (8:7308052 T>A,C), RS1001374306 (8:7311905 T>A,C), RS1001404474 (8:7319629 T>A,C), RS1002378946 (8:7313363 G>A), RS1002481931 (8:7310724 G>A,C,T), RS1002527772 (8:7310414 A>C,G,T), RS1003039750 (8:7309984 C>T), RS1003140426 (8:7318218 T>C), RS1003541137 (8:7312510 A>C,G), RS1004196868 (8:7309281 C>T), RS1004653924 (8:7308773 T>A,C), RS1004744988 (8:7316393 CT>C,CTT)

Disease associations

OMIM: gene `` | disease phenotypes:

GenCC curated gene-disease

Mondo (0):

Orphanet (0):

HPO phenotypes

0 total (0 of 0 shown, HPO-id order):

GWAS associations

1 associations (top):

Study	Trait	p-value
GCST007565_164	Morning person	1.000000e-13

EFO canonical traits (1, from GWAS)

EFO ID	Trait name
EFO:0008328	chronotype measurement

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (VIP=true, CPIC=false)

CTD chemical–gene interactions

5 total (human), top 5 by PubMed support.

Chemical	Actions (top 5)	PubMed papers
butyraldehyde	decreases expression	1
CGP 52608	increases reaction, affects binding	1
Cadmium	decreases expression, increases abundance	1
Valproic Acid	decreases methylation	1
Cadmium Chloride	decreases expression, increases abundance	1

Clinical trials (associated diseases)

0 trials via MONDO — disease-level, not drug-specific.