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Gap junction protein, beta 2, 26kDa
Protein GJB2 PDB 1XIR.png
Rendering based on PDB 1XIR​.
Available structures
PDB Ortholog search: PDBe, RCSB
External IDs OMIM121011 MGI95720 HomoloGene2975 IUPHAR: 716 GeneCards: GJB2 Gene
Species Human Mouse
Entrez 2706 14619
Ensembl ENSG00000165474 ENSMUSG00000046352
UniProt P29033 Q00977
RefSeq (mRNA) NM_004004 NM_008125
RefSeq (protein) NP_003995 NP_032151
Location (UCSC) Chr 13:
20.19 – 20.19 Mb
Chr 14:
57.1 – 57.1 Mb
PubMed search [1] [2]

Gap junction beta-2 protein (GJB2), also known as connexin 26 (Cx26) — is a protein that in humans is encoded by the GJB2 gene. Defects in this gene lead to the most common form of congenital deafness in developed countries, called DFNB1 (also known as connexin 26 deafness or GJB2-related deafness).


Gap junctions were first characterized by electron microscopy as regionally specialized structures on plasma membranes of contacting adherent cells. These structures were shown to consist of cell-to-cell channels. Proteins, called connexins, purified from fractions of enriched gap junctions from different tissues differ. The connexins are designated by their molecular mass. Another system of nomenclature divides gap junction proteins into two categories, alpha and beta, according to sequence similarities at the nucleotide and amino acid levels. For example, CX43 (MIM 121014) is designated alpha-1 gap junction protein, whereas CX32 (GJB1; MIM 304040) and CX26 (this protein) are called beta-1 and beta-2 gap junction proteins, respectively. This nomenclature emphasizes that CX32 and CX26 are more homologous to each other than either of them is to CX43.[1]

See also[edit]


Further reading[edit]

  • Kenneson A, Van Naarden Braun K, Boyle C (2002). "GJB2 (connexin 26) variants and nonsyndromic sensorineural hearing loss: a HuGE review.". Genet. Med. 4 (4): 258–74. doi:10.1097/00125817-200207000-00004. PMID 12172392. 
  • Thalmann R, Henzl MT, Killick R; et al. (2003). "Toward an understanding of cochlear homeostasis: the impact of location and the role of OCP1 and OCP2.". Acta Otolaryngol. 123 (2): 203–8. doi:10.1080/0036554021000028100. PMID 12701741. 
  • Yotsumoto S, Hashiguchi T, Chen X; et al. (2003). "Novel mutations in GJB2 encoding connexin-26 in Japanese patients with keratitis-ichthyosis-deafness syndrome.". Br. J. Dermatol. 148 (4): 649–53. doi:10.1046/j.1365-2133.2003.05245.x. PMID 12752120. 
  • Apps SA, Rankin WA, Kurmis AP (2007). "Connexin 26 mutations in autosomal recessive deafness disorders: a review.". International journal of audiology 46 (2): 75–81. doi:10.1080/14992020600582190. PMID 17365058. 
  • Welch KO, Marin RS, Pandya A, Arnos KS (2007). "Compound heterozygosity for dominant and recessive GJB2 mutations: effect on phenotype and review of the literature.". Am. J. Med. Genet. A 143 (14): 1567–73. doi:10.1002/ajmg.a.31701. PMID 17431919. 
  • Harris, A. and Locke, D. (2009). Connexins, A Guide. New York: Springer. p. 574. ISBN 978-1-934115-46-6. 

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