title: The interaction and cellular localization of HSP27 and ERbeta are modulated by 17beta-estradiol and HSP27 phosphorylation.
abstract: Recently, we identified heat shock protein 27 (HSP27) as an estrogen receptor-beta (ERbeta) associated protein that acts as a co-repressor of estrogen signaling and serves as a biomarker of atherosclerosis. In this study, we sought to further characterize the subcellular interaction of HSP27 and ERbeta, as well as explore the factors that may modulate this interaction. In vitro we determined that phosphorylated HSP27 is retained in the cytoplasm after treatment with 17beta-estradiol and to a lesser extent with heat shock. Under all experimental conditions ERbeta was found to be slightly more abundant in the cytoplasm compared to the nucleus. HSP27 and ERbeta associate in both the cytoplasm and nucleus, however, co-localization studies reveal that in the presence of 17beta-estradiol, a significant portion of this interaction occurs outside of the nucleus. These data highlight an extranuclear interaction between ERbeta and HSP27 that may be of potential importance in modulating estrogen signaling.
authors.affiliation: University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, Ontario K1Y 4W7, Canada.
authors.forename: Ashraf Said
authors.initials: AS
authors.lastname: Al-Madhoun
authors.forename: Yong-Xiang
authors.initials: YX
authors.lastname: Chen
authors.forename: Leila
authors.initials: L
authors.lastname: Haidari
authors.forename: Katey
authors.initials: K
authors.lastname: Rayner
authors.forename: William
authors.initials: W
authors.lastname: Gerthoffer
authors.forename: Heidi
authors.initials: H
authors.lastname: McBride
authors.forename: Edward R
authors.initials: ER
authors.lastname: O'Brien
mesh_terms: D004958:Estradiol / Q000494:pharmacology*; D047629:Estrogen Receptor beta / Q000378:metabolism*; D005453:Fluorescence; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D018869:Heat-Shock Response / Q000187:drug effects; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000187:drug effects
chemical_list: D047629:Estrogen Receptor beta; D006360:Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; D004958:Estradiol