title: Regulation of androgen receptor and histone deacetylase 1 by Mdm2-mediated ubiquitylation.
abstract: The androgen receptor (AR) is a member of the nuclear hormone receptor family of transcription factors and plays a critical role in regulating the expression of genes involved in androgen-dependent and -independent tumour formation. Regulation of the AR is achieved by alternate binding of either histone acetyltransferase (HAT)-containing co-activator proteins, or histone deacetylase 1 (HDAC1). Factors that control AR stability may also constitute an important regulatory mechanism, a notion that has been confirmed with the finding that the AR is a direct target for Mdm2-mediated ubiquitylation and proteolysis. Using chromatin immunoprecipitation (ChIP) and re-ChIP analyses, we show that Mdm2 associates with AR and HDAC1 at the active androgen-responsive PSA promoter in LNCaP prostate cancer cells. Furthermore, we demonstrate that Mdm2-mediated modification of AR and HDAC1 catalyses protein destabilization and attenuates AR sactivity, suggesting that ubiquitylation of the AR and HDAC1 may constitute an additional mechanism for regulating AR function. We also show that HDAC1 and Mdm2 function co-operatively to reduce AR-mediated transcription that is attenuated by the HAT activity of the AR co-activator Tip60, suggesting interplay between acetylation status and receptor ubiquitylation in AR regulation. In all, our data indicates a novel role for Mdm2 in regulating components of the AR transcriptosome.
authors.affiliation: Prostate Research Group, Northern Institute for Cancer Research Paul, O'Gorman Building University of Newcastle Upon Tyne, Medical School Framlington Place, Newcastle Upon Tyne NE2 4HH, UK.
authors.forename: Luke
authors.initials: L
authors.lastname: Gaughan
authors.forename: Ian R
authors.initials: IR
authors.lastname: Logan
authors.forename: David E
authors.initials: DE
authors.lastname: Neal
authors.forename: Craig N
authors.initials: CN
authors.lastname: Robson
mesh_terms: D000728:Androgens / Q000494:pharmacology; D000818:Animals; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D015536:Down-Regulation; D006655:Histone Deacetylases / Q000378:metabolism*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D016315:Proto-Oncogene Proteins c-abl / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2; D011944:Receptors, Androgen / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: D000728:Androgens; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D011944:Receptors, Androgen; D014452:Ubiquitins; D051736:Proto-Oncogene Proteins c-mdm2; D016315:Proto-Oncogene Proteins c-abl; D006655:Histone Deacetylases