Connexin interaction patterns in keratinocytes revealed morphologically and by FRET analysis.
Multiple connexins, the major proteins of gap junctions, have overlapping expression in the human epidermis and are postulated to have a key role in keratinocyte differentiation and homeostasis. The functional importance of connexins in the epidermis is emphasised by the association of mutations in four human connexins with various hyperproliferative skin disorders. As immunohistochemistry demonstrated overlapping expression of specific connexins in keratinocytes, we performed colocalisation analyses and applied a modified FRET methodology to assess possible heteromeric interactions between different combinations of four wild-type (wt) and mutant connexins. The data generated indicate that there is evidence for multiple connexin interactions at the plasma membrane between (wt)Cx26, (wt)Cx30 and (wt)Cx31 in keratinocytes and thus, the potential for the formation of a large number of different channel types each with different channel properties. In addition, we demonstrate that the inherent in vitro trafficking defect of the skin disease mutations (D50N)Cx26 and (G11R)Cx30 can be overcome partially by the coexpression of different wild-type connexins but this rescue does not result in large gap junction aggregates at the plasma membrane. These data indicate that skin disease associated Cx26 or Cx30 mutations are likely to disrupt a number of different channel types important in distinct aspects of keratinocyte biology.
Di
Wei-Li
WL
Centre for Cutaneous Research, Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, 4 Newark Street, London E1 2AT, UK.
Gu
Yan
Y
Common
John E A
JE
Aasen
Trond
T
O'Toole
Edel A
EA
Kelsell
David P
DP
Zicha
Daniel
D
D000072259:Connexin 26; D017630:Connexins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D006801:Humans; D015603:Keratinocytes / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism*; D009154:Mutation
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26; D049452:Green Fluorescent Proteins