title: The carboxy-tail of connexin-43 localizes to the nucleus and inhibits cell growth.
abstract: Gap junctions are plasma membrane intercellular communication channels that in addition to ensuring electrical coupling and coordinated mechanical activity, can act as growth suppressors. To define the role of a non-channel forming domain of connexin-43 (Cx43), the main constituent of cardiomyocyte gap junctions, on growth regulation, we expressed its C-terminal portion (CT-Cx43) in cardiomyocytes and HeLa cells. In addition to broad cytoplasmic localization, CT-Cx43 was also localized to the nucleus of both cell types, detected by immunofluorescence as well as immunoblotting of subcellular fractions. Furthermore, stable expression of CT-Cx43 in HeLa cells induced a significant decrease in proliferation. It is therefore suggested that plasma membrane localization and formation of channels are not required for growth inhibition by Cx43, and that nuclear localization of CT-Cx43 may exert effects on gene expression and growth.
authors.affiliation: Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada.
authors.forename: Xitong
authors.initials: X
authors.lastname: Dang
authors.forename: Bradley W
authors.initials: BW
authors.lastname: Doble
authors.forename: Elissavet
authors.initials: E
authors.lastname: Kardami
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D015153:Blotting, Western; D002455:Cell Division; D002467:Cell Nucleus / Q000737:chemistry*; D018031:Connexin 43 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017629:Gap Junctions / Q000737:chemistry; D006131:Growth Inhibitors / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D051381:Rats
chemical_list: D018031:Connexin 43; D006131:Growth Inhibitors