Alteration of protein localization and intracellular calcium content due to connexin26 D50A and A88V mutations

Abstract

Abstract Introduction Connexins (Cx) play essential roles in cellular homeostasis by forming gap junctions and non-junctional hemichannels. In vitro characterization of Cx26 mutations causing keratitis-ichthyosis-deafness (KID) syndrome, were shown to form leaky hemichannels. The molecular/cellular mechanisms affected by aberrant hemichannels have recently been elucidated. Here, we further wanted to characterize Cx26 KID syndrome mutations, D50A and A88V, which were shown to form aberrant hemichannels and remained unaddressed in the literature. Methods Neurobiotin uptake assay in HeLa and N2A cells transfected with Cx26-WT, D50A or A88V verified the presence of aberrant hemichannels and immunofluorescent staining with fluorescent microscopy determined cellular localization of Cx26. Finally, intracellular calcium content was examined by using calcium indicator, Fluo-3AM, and flow cytometer. Results Cx26-D50A and A88V mutations prevented the formation of gap junction plaques at cell-cell appositions and mutant proteins were observed to localize to the Golgi apparatus. Further, comparison of intracellular calcium content showed an increase in calcium amount in cells containing Cx26-D50A and A88V relative to Cx26-WT. Conclusion Retention of Cx26 in the Golgi apparatus and alteration in the intracellular calcium content due to KID syndrome mutations may influence various cellular processes that might contribute to development of epidermal phenotypes.