Liganded androgen receptor interaction with beta-catenin: nuclear co-localization and modulation of transcriptional activity in neuronal cells.
A yeast two-hybrid assay was employed to identify androgen receptor (AR) protein partners in gonadotropin-releasing hormone neuronal cells. By using an AR deletion construct (AR-(Delta371-485)) as a bait, beta-catenin was identified as an AR-interacting protein from a gonadotropin-releasing hormone neuronal cell library. Immunolocalization of co-transfected AR and FLAG-beta-catenin demonstrated that FLAG-beta-catenin was predominantly cytoplasmic in the absence of androgen. In the presence of 5alpha-dihydrotestosterone, FLAG-beta-catenin completely co-localized to the nucleus with AR. This effect was specific to AR because liganded progesterone, glucocorticoid, or estrogen alpha receptors did not translocate FLAG-beta-catenin to the nucleus. Agonist-bound AR was required because the AR antagonists casodex and hydroxyflutamide failed to translocate beta-catenin. Time course experiments demonstrated that co-translocation occurred with similar kinetics. Nuclear co-localization was independent of the glycogen synthase kinase-3beta, p42/44 ERK mitogen-activated protein kinase, and phosphatidylinositol 3-kinase pathways because inhibitors of these pathways had no effect. Transcription assays demonstrated that liganded AR repressed beta-catenin/T cell factor-responsive reporter gene activity. Conversely, co-expression of beta-catenin/T cell factor repressed AR stimulation of AR-responsive reporter gene activity. Our data suggest that liganded AR shuttles beta-catenin to the nucleus and that nuclear interaction of AR with beta-catenin may modulate transcriptional activity in androgen target tissues.
Pawlowski
John E
JE
Research Service, Veterans Affairs Medical Center and Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80220, USA.
Ertel
Jessica R
JR
Allen
Melissa P
MP
Xu
Mei
M
Butler
Cheryl
C
Wilson
Elizabeth M
EM
Wierman
Margaret E
ME
D000726:Androgen Antagonists / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D047628:Estrogen Receptor alpha; D007150:Immunohistochemistry; D008024:Ligands; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D021381:Protein Transport; D011944:Receptors, Androgen / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D015534:Trans-Activators; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D051176:beta Catenin
D000726:Androgen Antagonists; C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; D047628:Estrogen Receptor alpha; D008024:Ligands; D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D011965:Receptors, Glucocorticoid; D011980:Receptors, Progesterone; D015534:Trans-Activators; D051176:beta Catenin