Classical Xenopus laevis progesterone receptor associates to the plasma membrane through its ligand-binding domain

• Published in: Journal of cellular physiology Vol. 211; no. 2; pp. 560 - 567
• Main Authors: Martinez, Silvana, Pastén, Pamela, Suarez, Karina, García, Andrea, Nualart, Francisco, Montecino, Martín, Hinrichs, María Victoria, Olate, Juan
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-05-2007
• Subjects: Animals; Binding Sites; Blotting, Western; Cell Membrane - metabolism; Cercopithecus aethiops; COS Cells; Fluorescein-5-isothiocyanate - analogs & derivatives; Fluorescein-5-isothiocyanate - metabolism; Fluorescent Dyes - metabolism; Ligands; Microscopy, Fluorescence; Progesterone - analogs & derivatives; Progesterone - metabolism; Protein Structure, Tertiary; Receptors, Progesterone - chemistry; Receptors, Progesterone - genetics; Receptors, Progesterone - metabolism; Serum Albumin, Bovine - metabolism; Transfection; Xenopus laevis; Xenopus Proteins - chemistry; Xenopus Proteins - genetics; Xenopus Proteins - metabolism
• ISSN: 0021-9541; 1097-4652
• DOI: 10.1002/jcp.20964

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. J. Cell. Physiol. 211: 560–567, 2007. © 2007 Wiley‐Liss, Inc.