title: 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.affiliation: Centre for Cutaneous Research, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, Whitechapel, London E1 2AT, UK.
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Di
authors.forename: James
authors.initials: J
authors.lastname: Monypenny
authors.forename: John E A
authors.initials: JE
authors.lastname: Common
authors.forename: Cameron T C
authors.initials: CT
authors.lastname: Kennedy
authors.forename: Katalin A
authors.initials: KA
authors.lastname: Holland
authors.forename: Irene M
authors.initials: IM
authors.lastname: Leigh
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Rugg
authors.forename: Daniel
authors.initials: D
authors.lastname: Zicha
authors.forename: David P
authors.initials: DP
authors.lastname: Kelsell
mesh_terms: D001706:Biopsy; D002450:Cell Communication / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D002462:Cell Membrane; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D049452:Green Fluorescent Proteins; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000473:pathology; D007642:Keratosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016297:Mutagenesis, Site-Directed; D010523:Peripheral Nervous System Diseases / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection
chemical_list: D017630:Connexins; D017931:DNA Primers; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; C068044:GJB3 protein, human; D049452:Green Fluorescent Proteins