title: Ultraspiracle promotes the nuclear localization of ecdysteroid receptor in mammalian cells.
abstract: The heterodimer consisting of ecdysteroid receptor (EcR) and ultraspiracle (USP), both of which are members of the nuclear receptor superfamily, is considered to be the functional ecdysteroid receptor. Here we analyzed the subcellular distribution of EcR and USP fused to fluorescent proteins. The experiments were carried out in mammalian COS-7, CHO-K1 and HeLa cells to facilitate investigation of the subcellular trafficking of EcR and USP in the absence of endogenous expression of these two receptors. The distribution of USP tagged with a yellow fluorescent protein (YFP-USP) was almost exclusively nuclear in all cell types analyzed. The nuclear localization remained constant for at least 1 day after the first visible signs of expression. In contrast, the intracellular distribution of EcR tagged with a yellow fluorescent protein (YFP-EcR) varied and was dependent on time and cell type, although YFP-EcR alone was also able to partially translocate into the nuclear compartment. Coexpression of YFP-EcR with USP tagged with a cyan fluorescent protein (CFP-USP) resulted in exclusively nuclear localization of both proteins in all cell types analyzed. The USP-induced nuclear localization of YFP-EcR was stable for at least 20 hours. These experiments suggest that USP has a profound effect on the subcellular distribution of EcR.
authors.affiliation: Department of General Zoology and Endocrinology, University of Ulm, D-89069 Ulm, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Nieva
authors.forename: Tomasz
authors.initials: T
authors.lastname: Gwóźdź
authors.forename: Joanna
authors.initials: J
authors.lastname: Dutko-Gwóźdź
authors.forename: Jörg
authors.initials: J
authors.lastname: Wiedenmann
authors.forename: Margarethe
authors.initials: M
authors.lastname: Spindler-Barth
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Wieczorek
authors.forename: Jurek
authors.initials: J
authors.lastname: Dobrucki
authors.forename: Danuta
authors.initials: D
authors.lastname: Duś
authors.forename: Vince
authors.initials: V
authors.lastname: Henrich
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ozyhar
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Spindler
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D016466:CHO Cells; D019556:COS Cells; D002467:Cell Nucleus / Q000378:metabolism*; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003412:Cricetulus; D003593:Cytoplasm / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D047488:Retinoid X Receptors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C485182:Cyan Fluorescent Protein; D008164:Luminescent Proteins; D011987:Receptors, Steroid; D011993:Recombinant Fusion Proteins; D047488:Retinoid X Receptors; C034808:ecdysteroid receptor; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins