GJB2

Gap junction protein, beta 2, 26kDa
Rendering based on PDB 1XIR.
Available structures PDB 1XIR, 2ZW3, 3IZ1, 3IZ2
Identifiers
Symbols	GJB2; CX26; DFNA3; DFNA3A; DFNB1; DFNB1A; HID; KID; NSRD1; PPK
External IDs	OMIM: 121011 MGI: 95720 HomoloGene: 2975 GeneCards: GJB2 Gene
Gene Ontology Molecular function • protein binding • gap-junction channel activity Cellular component • ER-Golgi intermediate compartment • plasma membrane • connexon complex • integral to membrane • lateral plasma membrane • cell junction Biological process • transport • cell-cell signaling • sensory perception of sound • cellular membrane organization • gap junction assembly • male genitalia development Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	2706	14619
Ensembl	ENSG00000165474	ENSMUSG00000046352
UniProt	P29033	Q3TZE5
RefSeq (mRNA)	NM_004004.5	NM_008125.3
RefSeq (protein)	NP_003995.2	NP_032151.1
Location (UCSC)	Chr 13: 20.76 – 20.77 Mb	Chr 14: 57.72 – 57.72 Mb
PubMed search	[1]	[2]

Gap junction beta-2 (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.

Function

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 2 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

• Connexin
• Gap junction
• Vohwinkel syndrome
• Bart–Pumphrey syndrome

References

1. ^ "Entrez Gene: GJB2 gap junction protein, beta 2, 26kDa". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=2706. 

Further reading

• 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. pp. 574. ISBN 978-1-934115-46-6. http://www.springer.com/978-1-934115-46-6. 

External links

• GeneReviews/NCBI/NIH/UW entry on Nonsyndromic Hearing Loss and Deafness, DFNA3
• GeneReviews/NCBI/NIH/UW entry on Nonsyndromic Hearing Loss and Deafness, DFNB1