• Cx26

    Single channel recordings on Cx26 wild-type oligomers inserted in a planar lipid bilayer

    Gaßmann et al. (2009)

Cx26 | Connexin 26

Family:
Connexins

Topology:
Connexins form so-called gap junctions. Each gap junction is composed of two hemichannels, or connexons, which consist of homo- or heterohexameric arrays of connexins, and the connexon in one plasma membrane docks end-to-end with a connexon in the membrane of a closely opposed cell. The hemichannel is made of six connexin subunits which are themselves each constructed out of six connexin molecules. Connexins contain four highly ordered transmembrane segments (TMSs). The connexin gene family is diverse, with twenty-one identified members in the sequenced human genome.

Function:
Connexins (Cx) are structurally related transmembrane proteins that assemble to form vertebrate gap junctions. Gap junctions are essential for many physiological processes, such as the coordinated depolarization of cardiac muscle, proper embryonic development, and the conducted response in microvasculature. By forming a syncytium between cell, connexins provide electric coupling and direct cell-cell communication of small molecules.

Cx26 Background Information


Overview:

Gap junction beta-2 protein (GJB2), also known as connexin 26 (Cx26) is a structural component of gap junctions. Mutations in this gene are responsible for hearing loss. Connexin-associated deafness is thought to be the result of defective development of auditory sensory epithelium due to connexion dysfunction. Furthermore, mutations in this gene are associated with skin disorders.


Data Sheet:

Gene:
GJB2

Human Protein:
UniProt P29033

Tissue:
Expressed in the cochlea, weakly in the suprabasal layer of the epidermis and in epithelial cells of the mammary gland and endometre

Function/ Application:
Acts via forming gap junctions by enhancing intercellular electrical and chemical transmission (passive diffusion of low molecular weight materials up to 1 kDa, including nutrients, metabolites (glucose), ions and second messengers (IP3, cAMP)). Cx26 assembles to form channels between cells in the cochlear supporting cells, allowing the rapid removal of K+ away from the base of hair cells, resulting in the recycling of this ion back to the endolymph to maintain cochlear homeostasis

Pathology:
Deafness, autosomal recessive, 1A (DFNB1A), Deafness, autosomal dominant, 3A (DFNA3A), Vohwinkel syndrome (VOWNKL), Keratoderma, palmoplantar, with deafness (PPKDFN), Keratitis-ichthyosis-deafness syndrome (KID syndrome), Knuckle pads, leukonychia, and sensorineural deafness (KPLD) may be caused by mutations of GJB2.

Interaction:
Interacts with further connexins (GJA3, GJA8, GJB1, GJB2, GJB3, GJB6), CNST, SKP1

Modulator:
Flufenamic acid, carbenoxolone, octanol, extracellular Ca2+

Assays:

icon pap   &   Icon Orbit Mini   Bilayer recordings on Port-a-Patch and Orbit mini 

Reviews and Links

Publications

2014 - Temperature-sensitive gating of hCx26: high-resolution Raman spectroscopy sheds light on conformational changes

icon pap   Port-a-Patch and   icon vpp   Vesicle Prep Pro publication in Biomedical Optics Express (2014)

Authors:
Kniggendorf A.-K., Meinhardt-Wollweber M., Yuan X., Roth B., Seifert A., Fertig N., Zeilinger C.

2009 - The M34A mutant of Connexin26 reveals active conductance states in pore-suspending membranes

icon pap  Port-a-Patch and   icon vpp   Vesicle Prep Pro publication in Journal of Structural Biology (2009)

Authors:
Gaßmann O., Kreir M., Ambrosi C., Pranskevich J., Oshima A, Röling C., Sosinsky G., Fertig N., Steinem C.

 

 

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