Defective trafficking and cell death is characteristic of skin disease-associated connexin 31 mutations.

Abstract

Distinct germline mutations in the gene (GJB3) encoding connexin 31 (Cx31) underlie the skin disease erythrokeratoderma variabilis (EKV) or sensorineural hearing loss with/without peripheral neuropathy. Here we describe a number of functional analyses to investigate the effect of these different disease-associated Cx31 mutants on connexon trafficking and intercellular communication. Immunostaining of a biopsy taken from an EKV patient harbouring the R42P mutation revealed sparse epidermal staining of Cx31, and, when present, it had a perinuclear localization. Transfection and microinjection studies in both keratinocytes and fibroblast cell lines also demonstrated that R42P and four other EKV-associated mutant Cx31 proteins displayed defective trafficking to the plasma membrane. The deafness/neuropathy only mutant 66delD had primarily a cytoplasmic localization, but some protein was visualized at the plasma membrane in a few transfected cells. Both 66delD- and R32W-Cx31/EGFP proteins had significantly impaired dye transfer rates compared to wild-type Cx31/EGFP protein. A striking characteristic feature observed with the dominant skin disease Cx31 mutations was a high incidence of cell death. This was not observed with wild-type, R32W 66delD Cx31 proteins. In conclusion, we have identified some key cellular phenotypic differences with respect to disease-associated Cx31 mutations.

• Authors: Wei-Li Di, James Monypenny, John E A Common, Cameron T C Kennedy, Katalin A Holland, Irene M Leigh, Elizabeth L Rugg, Daniel Zicha, David P Kelsell
• Journal: Human molecular genetics (Hum Mol Genet) Vol. 11 Issue 17 Pg. 2005-14 (Aug 15 2002) ISSN: 0964-6906 [Print] England
• PMID: 12165562 (Publication Type: Journal Article)

Chemical References

• Connexins
• DNA Primers
• Luminescent Proteins
• Recombinant Fusion Proteins
• GJB3 protein, human
• Green Fluorescent Proteins

Topics

• Biopsy
• Cell Communication (physiology)
• Cell Death (physiology)
• Cell Membrane
• Connexins (genetics, metabolism)
• DNA Primers (chemistry)
• Fibroblasts (metabolism, pathology)
• Green Fluorescent Proteins
• Humans
• Keratinocytes (metabolism, pathology)
• Keratosis (genetics, metabolism, pathology)
• Luminescent Proteins (genetics, metabolism)
• Microscopy, Confocal
• Microscopy, Fluorescence
• Mutagenesis, Site-Directed
• Peripheral Nervous System Diseases (genetics, metabolism)
• Recombinant Fusion Proteins (metabolism)
• Transfection