Seroatlas · Human Serome Atlas

GJB4

Gap junction beta-4 protein

Also known as: CX30.3, CXB4_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9NTQ9
Gene
GJB4
Ensembl
ENSG00000189433
Chromosome
1
Canonical length
266 aa
Protein class
Disease related genes, Human disease related genes, Potential drug targets, Predicted membrane proteins, Transporters
Subcellular location
Cell Junctions

OverviewNCBI Gene

This gene encodes a transmembrane connexin protein that is a component of gap junctions. Mutations in this gene have been associated with erythrokeratodermia variabilis, progressive symmetric erythrokeratoderma and hearing impairment. [provided by RefSeq, Dec 2009]

Canonical amino-acid sequenceUniProt

266 residues, UniProt reviewed canonical sequence.

>Q9NTQ9|GJB4
     1  MNWAFLQGLL SGVNKYSTVL SRIWLSVVFI FRVLVYVVAA EEVWDDEQKD FVCNTKQPGC
    61  PNVCYDEFFP VSHVRLWALQ LILVTCPSLL VVMHVAYREE RERKHHLKHG PNAPSLYDNL
   121  SKKRGGLWWT YLLSLIFKAA VDAGFLYIFH RLYKDYDMPR VVACSVEPCP HTVDCYISRP
   181  TEKKVFTYFM VTTAAICILL NLSEVFYLVG KRCMEIFGPR HRRPRCRECL PDTCPPYVLS
   241  QGGHPEDGNS VLMKAGSAPV DAGGYP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against GJB4 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
Cell surface
Secreted
No
Transmembrane segments
4
Mean surface accessibility (rSASA)
0.39
Highest tissue expression
59 nTPM

Expression across tissuesHPA

Tissue

  • skin: 59 nTPM
  • urinary bladder: 7.4 nTPM
  • epididymis: 5.2 nTPM
  • gallbladder: 4.5 nTPM
  • esophagus: 4.2 nTPM
  • breast: 2.5 nTPM

Single-cell type

  • ocular epithelial cells: 105 nCPM
  • esophageal apical cells: 32 nCPM
  • urothelial cells: 14 nCPM
  • esophageal suprabasal cells: 14 nCPM
  • prostatic hillock cells: 13 nCPM
  • retinal pigment epithelial cells: 8.5 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

  • cerebral cortex: 1.3 nTPM
  • basal ganglia: 1.2 nTPM
  • hippocampal formation: 1.2 nTPM
  • white matter: 0.9 nTPM
  • amygdala: 0.8 nTPM
  • cerebellum: 0.7 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about GJB4.

Disease | AllUniProt

Conditions GJB4 is implicated in, by any mechanism.

  • Erythrokeratodermia variabilis et progressiva 2 (EKVP2) MIM:617524

Disease | GeneticClinVar

6 pathogenic / likely-pathogenic of 134 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

  • Erythrokeratodermia variabilis et progressiva 2

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)
1.74
gnomAD pLI
0
gnomAD missense Z
-0.64
DepMap mean gene effect
-0.08
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% 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

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads GJB4 as an antibody target. Whether an autoantibody or antibody against GJB4 could matter depends on whether native GJB4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

GJB4 is annotated at the cell surface, where native GJB4 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label GJB4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/GJB4. 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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