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Connexin43 gap junction channel structure in digitonin
Structural highlights
DiseaseCXA1_HUMAN Autosomal recessive non-syndromic sensorineural deafness type DFNB;Hypoplastic left heart syndrome;Oculodentodigital dysplasia;Craniometaphyseal dysplasia;Syndactyly type 3. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease may be caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. FunctionCXA1_HUMAN Gap junction protein that acts as a regulator of bladder capacity. A gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell. May play a critical role in the physiology of hearing by participating in the recycling of potassium to the cochlear endolymph. Negative regulator of bladder functional capacity: acts by enhancing intercellular electrical and chemical transmission, thus sensitizing bladder muscles to cholinergic neural stimuli and causing them to contract (By similarity). Publication Abstract from PubMedGap junction channels (GJCs) mediate intercellular communication by connecting two neighbouring cells and enabling direct exchange of ions and small molecules. Cell coupling via connexin-43 (Cx43) GJCs is important in a wide range of cellular processes in health and disease (Churko and Laird, 2013; Liang et al., 2020; Poelzing and Rosenbaum, 2004), yet the structural basis of Cx43 function and regulation has not been determined until now. Here, we describe the structure of a human Cx43 GJC solved by cryo-EM and single particle analysis at 2.26 A resolution. The pore region of Cx43 GJC features several lipid-like densities per Cx43 monomer, located close to a putative lateral access site at the monomer boundary. We found a previously undescribed conformation on the cytosolic side of the pore, formed by the N-terminal domain and the transmembrane helix 2 of Cx43 and stabilized by a small molecule. Structures of the Cx43 GJC and hemichannels (HCs) in nanodiscs reveal a similar gate arrangement. The features of the Cx43 GJC and HC cryo-EM maps and the channel properties revealed by molecular dynamics simulations suggest that the captured states of Cx43 are consistent with a closed state. Structure of the connexin-43 gap junction channel in a putative closed state.,Qi C, Acosta Gutierrez S, Lavriha P, Othman A, Lopez-Pigozzi D, Bayraktar E, Schuster D, Picotti P, Zamboni N, Bortolozzi M, Gervasio FL, Korkhov VM Elife. 2023 Aug 3;12:RP87616. doi: 10.7554/eLife.87616. PMID:37535063[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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