title: Classical Xenopus laevis progesterone receptor associates to the plasma membrane through its ligand-binding domain.
abstract: During the last decade, considerable evidence is accumulating that supports the view that the classic progesterone receptor (xPR-1) is mediating Xenopus laevis oocyte maturation through a non-genomic mechanism. Overexpression and depletion of oocyte xPR-1 have been shown to accelerate and to block progesterone-induced oocyte maturation, respectively. In addition, rapid inhibition of plasma membrane adenylyl cyclase (AC) by the steroid hormone, supports the idea that xPR-1 should be localized at the oocyte plasma membrane. To test this hypothesis, we transiently transfected xPR-1 cDNA into Cos-7 cells and analyzed its subcellular distribution. Through Western blot and immunofluorescence analysis, we were able to detect xPR-1 associated to the plasma membrane of transfected Cos-7 cells. Additionally, using Progesterone-BSA-FITC, we identified specific progesterone-binding sites at the cell surface of xPR-1 expressing cells. Finally, we found that the receptor ligand-binding domain displayed membrane localization, in contrast to the N-terminal domain, which expressed in similar levels, remained cytosolic. Overall, these results indicate that a fraction of xPR-1 expressed in Cos-7 cells, associates to the plasma membrane through its LBD.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Silvana
authors.initials: S
authors.lastname: Martinez
authors.forename: Pamela
authors.initials: P
authors.lastname: Pastén
authors.forename: Karina
authors.initials: K
authors.lastname: Suarez
authors.forename: Andrea
authors.initials: A
authors.lastname: García
authors.forename: Francisco
authors.initials: F
authors.lastname: Nualart
authors.forename: Martín
authors.initials: M
authors.lastname: Montecino
authors.forename: María Victoria
authors.initials: MV
authors.lastname: Hinrichs
authors.forename: Juan
authors.initials: J
authors.lastname: Olate
mesh_terms: D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism*; D002522:Chlorocebus aethiops; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D008024:Ligands; D008856:Microscopy, Fluorescence; D011374:Progesterone / Q000031:analogs & derivatives / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011980:Receptors, Progesterone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D014162:Transfection; D029867:Xenopus Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D005456:Fluorescent Dyes; D008024:Ligands; D011980:Receptors, Progesterone; C419774:XPR-1 protein, Xenopus; D029867:Xenopus Proteins; D012710:Serum Albumin, Bovine; D011374:Progesterone; D016650:Fluorescein-5-isothiocyanate