The cataract causing Cx50-S50P mutant inhibits Cx43 and intercellular communication in the lens epithelium
| Autor: | Adam M. DeRosa, Xiaohua Gong, Thomas W. White, Peter R. Brink, Leping Li, Gülistan Meşe, Caterina Sellitto |
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| Rok vydání: | 2008 |
| Předmět: |
Cell signaling
Patch-Clamp Techniques Protein Conformation Mutant Molecular Sequence Data Xenopus Connexin Cell Communication Biology medicine.disease_cause Cataract Connexins Article Mice Xenopus laevis Conditional gene knockout Lens Crystalline medicine Animals Humans Amino Acid Sequence Eye Proteins Mice Knockout Mutation Gap Junctions Epithelial Cells Cell Biology biology.organism_classification Epithelium Cell biology medicine.anatomical_structure Connexin 43 cardiovascular system Oocytes sense organs biological phenomena cell phenomena and immunity Intracellular HeLa Cells |
| Zdroj: | Experimental cell research. 315(6) |
| ISSN: | 1090-2422 |
| Popis: | Mutations in Connexin50 (Cx50) cause cataracts in both humans and mice. The mechanism(s) behind how mutated connexins lead to a variety of cataracts have yet to be fully elucidated. Here, we tested whether the cataract inducing Cx50-S50P mutant interacts with wild-type Connexin43 (Cx43) to form mixed channels with attenuated function. Using dual whole-cell voltage clamp, immunofluorescent microscopy and in situ dye transfer analysis we identified a unique interaction between the mutant subunit and wild-type Cx43. In paired Xenopus oocytes, co-expression of Cx50-S50P with Cx43 reduced electrical coupling ≥ 90%, without a reduction in protein expression. In transfected cells, Cx50-S50P did not target to cell–cell interfaces by itself, but co-expression of Cx50-S50P with Cx43 resulted in its localization at areas of cell–cell contact. We used Cx43 conditional knockout, Cx50 knockout and Cx50-S50P mutant mice to examine this interaction in vivo. Mice expressing both Cx43 and Cx50-S50P in the lens epithelium revealed a unique expression pattern for Cx43 and a reduction in Cx43 protein. In situ dye transfer experiments showed that the Cx50-S50P mutant, but not the Cx50, or Cx43 conditional knockout, greatly inhibited epithelial cell gap junctional communication in a manner similar to a double knockout of Cx43 and Cx50. The inhibitory affects of Cx50-S50P lead to diminished electrical coupling in vitro, as well as a discernable reduction in epithelial cell dye permeation. These data suggest that dominant inhibition of Cx43 mediated epithelial cell coupling may play a role in the lens pathophysiology caused by the Cx50-S50P mutation. |
| Databáze: | OpenAIRE |
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