Journal Article

Molecular interaction of connexin 30.3 and connexin 31 suggests a dominant-negative mechanism associated with erythrokeratodermia variabilis

Laure Plantard, Marcel Huber, Francoise Macari, Paolo Meda and Daniel Hohl

in Human Molecular Genetics

Volume 12, issue 24, pages 3287-3294
Published in print December 2003 | ISSN: 0964-6906
Published online December 2003 | e-ISSN: 1460-2083 | DOI: http://dx.doi.org/10.1093/hmg/ddg364
Molecular interaction of connexin 30.3 and connexin 31 suggests a dominant-negative mechanism associated with erythrokeratodermia variabilis

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Connexins are homologous four-transmembrane-domain proteins and major components of gap junctions. We recently identified mutations in either GJB3 or GJB4 genes, encoding respectively connexin 31 (Cx31) or 30.3 (Cx30.3), as causally involved in erythrokeratodermia variabilis (EKV), a mostly autosomal dominant disorder of keratinization. Despite slight differences, phenotypes of EKV Mendes Da Costa (Cx31) and EKV Cram–Mevorah (Cx30.3) show major clinical overlap and both Cx30.3 and Cx31 are expressed in the upper epidermal layers. These similarities suggested to us that Cx30.3 and Cx31 may interact at a molecular level. Indeed, expression of wild-type Cx30.3 in HeLa cell resulted only in minor amounts of protein addressed to the plasma membrane. Mutant Cx30.3 was hardly detectable and disturbed intercellular coupling. In sharp contrast, co-expression of both wild-type proteins led to a gigantic increase of stabilized heteromeric gap junctions. Furthermore, co-expressed wild-type Cx30.3 and Cx31 coprecipitate, which demonstrates a physical interaction. Inhibitor experiments revealed that this interaction begins in the endoplasmic reticulum. These results not only provide new insights into epidermal connexin synthesis and polymerization, but also allow a novel molecular explanation for the similarity of EKV phenotypes.

Journal Article.  5207 words.  Illustrated.

Subjects: Genetics and Genomics

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