Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik
Permanent URI for this collectionhttps://hdl.handle.net/11147/9
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Conference Object Keratitis-Ichthyosis Syndrome Associated Mutations Impair the Localization and Functions of Connexin 26(Nature Publishing Group, 2015) Aypek, Hande; Meşe, GülistanConnexins (Cx) form gap junctions and non-junctional hemichannels that play roles in several cellular mechanisms, including proliferation and differentiation. The importance of connexins for human physiology was shown by the association of mutations in several isoforms with various human hereditary disorders. Mutations in Cx26 cause both non-syndromic and syndromic deafness associated with skin disorders including keratitis-ichthyosis-deafness (KID) syndrome. In vitro characterization of Cx26 mutations suggested that mutations causing non-syndromic deafness and syndromic deafness show different properties, where the former ones result in loss-of-function and the latter ones cause gain-of-function mutations.Article Citation - WoS: 45Citation - Scopus: 48Connexin26 Mutations Causing Palmoplantar Keratoderma and Deafness Interact With Connexin43, Modifying Gap Junction and Hemichannel Properties(Nature Publishing Group, 2016) Shuja, Zunaira; Li, Leping; Gupta, Shashank; Meşe, Gülistan; White, Thomas W.Mutations in GJB2 (connexin [Cx]26) cause either deafness or deafness associated with skin diseases. That different disorders can be caused by distinct mutations within the same gene suggests that unique channel activities are influenced by each class of mutation. We have examined the functional characteristics of two human mutations, Cx26-H73R and Cx26-S183F, causing palmoplantar keratoderma (PPK) and deafness. Both failed to form gap junction channels or hemichannels when expressed alone. Coexpression of the mutants with wild-type Cx43 showed a transdominant inhibition of Cx43 gap junction channels, without reductions in Cx43 protein synthesis. In addition, the presence of mutant Cx26 shifted Cx43 channel gating and kinetics toward a more Cx26-like behavior. Coimmunoprecipitation showed Cx43 being pulled down more efficiently with mutant Cx26 than wild-type, confirming the enhanced formation of heteromeric connexons. Finally, the formation of heteromeric connexons resulted in significantly increased Cx43 hemichannel activity in the presence of Cx26 mutants. These findings suggest a common mechanism whereby Cx26 mutations causing PPK and deafness transdominantly influence multiple functions of wild-type Cx43. They also implicate a role for aberrant hemichannel activity in the pathogenesis of PPK and further highlight an emerging role for Cx43 in genetic skin diseases. © 2015 The Authors. Published by Elsevier, Inc. on behalf of the Society for Investigative Dermatology.