DEFB105A

Summary

DEFB105A (defensin beta 105A, HGNC:18087) is a protein-coding gene on chromosome 8p23.1, encoding Beta-defensin 105 (Q8NG35). Has antibacterial activity.

Defensins form a family of antimicrobial and cytotoxic peptides made by neutrophils. Defensins are short, processed peptide molecules that are classified by structure into three groups: alpha-defensins, beta-defensins and theta-defensins. All beta-defensin genes are densely clustered in four to five syntenic chromosomal regions. Chromosome 8p23 contains at least two copies of the duplicated beta-defensin cluster. This duplication results in two identical copies of defensin, beta 105, DEFB105A and DEFB105B, in tail-to-tail orientation. This gene, DEFB105A, represents the more centromeric copy.

Source: NCBI Gene 245908 — RefSeq curated summary.

At a glance

• Clinical variants (ClinVar): 8 total
• MANE Select transcript: NM_152250

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:18087
Approved symbol	DEFB105A
Name	defensin beta 105A
Location	8p23.1
Locus type	gene with protein product
Status	Approved
Aliases	DEFB-5
Ensembl gene	ENSG00000186562
Ensembl biotype	protein_coding
Entrez	245908

Gene structure

Transcript identifiers

Ensembl transcripts: 1 — 1 protein_coding

ENST00000334773

RefSeq mRNA: 1 — MANE Select: NM_152250 NM_152250

CCDS: CCDS34832

Canonical transcript exons

ENST00000334773 — 3 exons

Exon	Start	End
ENSE00001674146	7821004	7822132
ENSE00001794453	7823382	7823423
ENSE00002172401	7823769	7823880

Expression profiles

Bgee: expression breadth broad, 28 present calls, max score 37.20.

Top tissues by expression

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

Tissue	Anatomy ID	Expression score	Quality
colonic epithelium	UBERON:0000397	37.20	gold quality
ventricular zone	UBERON:0003053	36.48	gold quality
cortical plate	UBERON:0005343	36.47	gold quality
bone marrow cell	CL:0002092	36.16	gold quality
ganglionic eminence	UBERON:0004023	35.49	gold quality
skeletal muscle tissue	UBERON:0001134	33.38	gold quality
muscle tissue	UBERON:0002385	33.08	silver quality
hindlimb stylopod muscle	UBERON:0004252	32.15	gold quality
bone marrow	UBERON:0002371	31.74	gold quality
stromal cell of endometrium	CL:0002255	29.87	gold quality
prefrontal cortex	UBERON:0000451	29.04	gold quality
duodenum	UBERON:0002114	28.14	gold quality
liver	UBERON:0002107	28.04	gold quality
lymph node	UBERON:0000029	27.57	gold quality
blood	UBERON:0000178	27.08	gold quality
tonsil	UBERON:0002372	27.05	gold quality
leukocyte	CL:0000738	26.55	gold quality
islet of Langerhans	UBERON:0000006	26.55	gold quality
monocyte	CL:0000576	26.45	gold quality
vermiform appendix	UBERON:0001154	26.42	gold quality
gall bladder	UBERON:0002110	25.98	gold quality
olfactory segment of nasal mucosa	UBERON:0005386	25.89	gold quality
placenta	UBERON:0001987	25.81	gold quality
urinary bladder	UBERON:0001255	25.72	gold quality
cortex of kidney	UBERON:0001225	25.53	gold quality
endometrium	UBERON:0001295	24.65	silver quality
primary visual cortex	UBERON:0002436	24.61	gold quality
superior frontal gyrus	UBERON:0002661	24.08	gold quality
kidney	UBERON:0002113	23.95	gold quality
pancreas	UBERON:0001264	23.89	gold quality

Single-cell (SCXA)

Detected in 2 experiment(s), a significant marker in 0.

Experiment	Marker?	Max mean expression
E-HCAD-38	no	2600.27
E-ANND-3	no	0.07

Regulation

Is transcription factor: no

Literature-anchored findings (GeneRIF, showing 3)

• The epididymis-specific expression pattern of the beta-defensin isoform BD-5 has been characterized. (PMID:12193721)
• Defensin-beta 105 displays antimicrobial activity against S. aureus and E. coli, among other bacteria. (PMID:21861459)
• The native disulfide array of human defensin 5 is a requirement for its activity against Staphylococcus aureus. (PMID:21861459)

Cross-species orthologs

4 orthologs

Organism	Symbol	Gene ID
mus_musculus	Defb12	ENSMUSG00000043787
mus_musculus	Defb35	ENSMUSG00000058052
rattus_norvegicus	Defb105b	ENSRNOG00000083461
rattus_norvegicus	Defb105a	ENSRNOG00000090398

Paralogs (1): DEFB105B (ENSG00000186599)

Protein

Protein identifiers

Beta-defensin 105 — Q8NG35 (reviewed: Q8NG35)

Alternative names: Beta-defensin 5, Defensin, beta 105

All UniProt accessions (2): Q8NG35, A0A0K0K1I4

UniProt curated annotations — full annotation on UniProt →

Function. Has antibacterial activity.

Subcellular location. Secreted.

Tissue specificity. Specifically expressed in testis.

Similarity. Belongs to the beta-defensin family.

RefSeq proteins (1): NP_689463* (*=MANE)

Domains & families (InterPro)

ID	Name	Type
IPR025933	Beta_defensin_dom	Domain

Pfam: PF13841

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

Structure

Experimental structures (PDB)

0 structures.

Predicted structure (AlphaFold)

Model	pLDDT	Fraction very-high
AF-Q8NG35-F1	72.22	0.11

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): 43–74, 53–67, 57–73

Function

Pathways and Gene Ontology

Reactome pathways

2 pathways

ID	Pathway
R-HSA-1461957	Beta defensins
R-HSA-1461973	Defensins

MSigDB gene sets: 11 (showing top): REACTOME_INNATE_IMMUNE_SYSTEM, GOBP_DEFENSE_RESPONSE_TO_OTHER_ORGANISM, GOBP_DEFENSE_RESPONSE_TO_BACTERIUM, ACEVEDO_METHYLATED_IN_LIVER_CANCER_DN, GOBP_RESPONSE_TO_BACTERIUM, REACTOME_ANTIMICROBIAL_PEPTIDES, SCHERER_PBMC_YF_VAX_AGE_18_40YO_4_TO_7DY_UP, GOBP_BIOLOGICAL_PROCESS_INVOLVED_IN_INTERSPECIES_INTERACTION_BETWEEN_ORGANISMS, REACTOME_DEFENSINS, REACTOME_BETA_DEFENSINS, chr8p23

GO Biological Process (3): defense response to bacterium (GO:0042742), innate immune response (GO:0045087), defense response (GO:0006952)

GO Molecular Function (0):

GO Cellular Component (1): extracellular region (GO:0005576)

Reactome top-level categories

Rollup of top-2 pathways:

Category	Pathways
Defensins	1
Antimicrobial peptides	1

GO top-level categories

Rollup of top GO terms by namespace:

Category	Terms
defense response	1
response to bacterium	1
immune response	1
defense response to symbiont	1
response to stress	1
cellular anatomical structure	1

Protein interactions and networks

STRING

184 interactions, top by confidence (×1000):

Protein A	Protein B	Partner UniProt	Score
DEFB105A	DEFB106A	Q8N104	928
DEFB105A	DEFB104A	Q8WTQ1	914
DEFB105A	DEFB107A	Q8IZN7	883
DEFB105A	DEFB103A	P81534	880
DEFB105A	A0A0G2JN59	A0A0G2JN59	832
DEFB105A	DEFB108B	Q8NET1	815
DEFB105A	DEFB1	P60022	811
DEFB105A	DEFB4A	O15263	697
DEFB105A	PRR23D1	E9PI22	583
DEFB105A	DEFB110	Q30KQ9	570
DEFB105A	DEFB126	Q9BYW3	552
DEFB105A	DEFA5	Q01523	546
DEFB105A	USP17L4	A6NCW7	518
DEFB105A	FAM90A7	A6NKC0	515
DEFB105A	PRR23B	Q6ZRT6	509

IntAct

3 interactions, top by confidence:

A	B	Type	Score
	DEFB105A	psi-mi:“MI:0915”(physical association)	0.560
	DEFB105A	psi-mi:“MI:0915”(physical association)	0.000

BioGRID (2): DEFB105A (Two-hybrid), DEFB105B (Two-hybrid)

ESM2 similar proteins: A0A096LNP1, A4H206, A4H207, A4H208, A4H209, A4H212, A4H213, P0C8A5, P0C8B0, P0DP73, P0DP74, P59861, P82020, P82172, Q30KJ3, Q30KJ5, Q30KJ6, Q30KJ8, Q30KJ9, Q30KK8, Q30KL4, Q30KL6, Q30KM9, Q30KP5, Q30KP6, Q30KP8, Q30KQ1, Q30KQ6, Q30KQ7, Q30KQ9, Q32ZF3, Q32ZF7, Q32ZG3, Q32ZH4, Q32ZH5, Q32ZH6, Q32ZI1, Q32ZI2, Q4QY38, Q6QLQ7

Diamond homologs: A4H206, A4H207, A4H208, A4H209, Q30KQ1, Q32ZH6, Q32ZH9, Q5IAB6, Q8K4N3, Q8NG35, Q8R2I3, Q30KJ6, Q30KU3, Q30KQ6, Q32ZH8

SIGNOR signaling

0 interactions.

Disease & clinical

Clinical variants and AI predictions

ClinVar

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

Classification	Count (floor)
Pathogenic	0
Likely pathogenic	0
Uncertain significance	4
Likely benign	2
Benign	2

Top pathogenic / likely-pathogenic (0)

SpliceAI

363 predictions. Top by Δscore:

Variant	Effect	Δscore
8:7823378:TTACC:T	donor_loss	0.9900
8:7823379:TACCT:T	donor_loss	0.9900
8:7823380:A:AT	donor_loss	0.9900
8:7823765:TTACC:T	donor_loss	0.9900
8:7823766:TACC:T	donor_loss	0.9900
8:7823767:A:AC	donor_gain	0.9900
8:7823767:A:AT	donor_loss	0.9900
8:7823768:C:CC	donor_gain	0.9900
8:7823768:C:CG	donor_loss	0.9900
8:7823823:T:TA	donor_gain	0.9900
8:7823421:ACCC:A	acceptor_loss	0.9800
8:7823422:CC:C	acceptor_gain	0.9800
8:7823423:CC:C	acceptor_gain	0.9800
8:7823424:CTAA:C	acceptor_loss	0.9800
8:7823425:T:A	acceptor_loss	0.9800
8:7822202:C:CT	acceptor_gain	0.9700
8:7822205:C:CT	acceptor_gain	0.9700
8:7823377:CTTA:C	acceptor_loss	0.9700
8:7823378:TTA:T	acceptor_loss	0.9700
8:7823379:TACC:T	acceptor_loss	0.9700
8:7823380:A:AG	acceptor_loss	0.9700
8:7823420:CACC:C	acceptor_gain	0.9700
8:7823424:C:CC	acceptor_gain	0.9700
8:7823767:AC:A	donor_gain	0.9700
8:7823768:CC:C	donor_gain	0.9700
8:7823768:CCT:C	donor_gain	0.9700
8:7822206:A:T	acceptor_gain	0.9600
8:7823376:ACTT:A	acceptor_loss	0.9600
8:7823380:A:AC	donor_gain	0.9600
8:7823381:C:CC	donor_gain	0.9600

AlphaMissense

509 scored. Top likely-pathogenic:

Variant	Protein change	am_pathogenicity
8:7822087:C:G	C53S	0.941
8:7822088:A:T	C53S	0.941
8:7822108:C:G	C46S	0.916
8:7822109:A:T	C46S	0.916
8:7822088:A:G	C53R	0.912
8:7822076:A:G	C57R	0.899
8:7822075:C:G	C57S	0.897
8:7822076:A:T	C57S	0.897
8:7822045:C:G	C67S	0.895
8:7822046:A:T	C67S	0.895
8:7822027:C:G	C73S	0.894
8:7822028:A:T	C73S	0.894
8:7822108:C:T	C46Y	0.893
8:7822024:C:G	C74S	0.881
8:7822025:A:T	C74S	0.881
8:7822086:G:C	C53W	0.862
8:7822028:A:G	C73R	0.861
8:7822026:G:C	C73W	0.860
8:7822044:G:C	C67W	0.845
8:7822109:A:G	C46R	0.843
8:7822046:A:G	C67R	0.841
8:7822107:G:C	C46W	0.838
8:7822074:G:C	C57W	0.834
8:7822108:C:A	C46F	0.827
8:7822023:G:C	C74W	0.823
8:7822118:A:G	C43R	0.823
8:7822087:C:T	C53Y	0.820
8:7822025:A:G	C74R	0.817
8:7822087:C:A	C53F	0.810
8:7822117:C:G	C43S	0.806

dbSNP variants (sampled 300 via entrez): RS1000234208 (8:7823030 C>T), RS1010340219 (8:7821456 C>G,T), RS1020354130 (8:7822042 C>T), RS1024826176 (8:7824724 C>G,T), RS112399468 (8:7824719 CTT>C), RS113792280 (8:7822603 T>A), RS1156451028 (8:7823439 A>G), RS1156552300 (8:7824850 A>G), RS1157488093 (8:7821094 T>G), RS1157708231 (8:7823315 C>G,T), RS1157848324 (8:7821274 T>C), RS1158329291 (8:7821713 G>C), RS1158788226 (8:7825141 T>C), RS1159258551 (8:7821751 T>G), RS1159772138 (8:7821289 A>C)

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

0 associations (top):

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

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

CTD chemical–gene interactions

2 total (human), top 2 by PubMed support.

Chemical	Actions (top 5)	PubMed papers
CGP 52608	affects binding, increases reaction	1
Aflatoxin B1	increases methylation	1

Clinical trials (associated diseases)

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