title: USP2-45 represses aldosterone mediated responses by decreasing mineralocorticoid receptor availability.
abstract: OBJECTIVE
  Ligand activation of the mineralocorticoid receptor (MR) induces several post-translational modifications (PTMs). Among the different PTMs, MR is known to be dynamically ubiquitylated with impact on its stability and transcriptional activity. Previously, we have shown that MR is monoubiquitylated at the basal state and that aldosterone stimulation induces monoubiquitylation removal prompting polyubiquitin-dependent destabilization of the receptor and proteasomal degradation. This study investigated the role of the aldosterone induced ubiquitin-specific protease USP2-45 on the ubiquitylation state of MR.
  
  
  METHODS
  Renal epithelial cells M1 were co-transfected with MR with or without wild-type or inactive USP2-45. The association of MR with USP2-45 or TSG101 as well as MR ubiquitylation state were determined by immunoprecipitation and immunoblotting. MR transcriptional activity was assessed via a luciferase reporter gene.
  
  
  RESULTS
  We show that USP2-45 is able to bind MR and, similarly to aldosterone, induce MR monoubiquitylation removal, disruption of MR/TSG101 association and destabilization of MR at protein level.
  
  
  CONCLUSIONS
  This study provides a novel role for USP2-45 by playing a pivotal role in the regulation of the ubiquitylation state of MR and reveals the existence of a negative feedback loop for limiting the aldosterone induced response.
authors.affiliation: Institute of Anatomy, University of Zurich, Zurich, Switzerland.
authors.forename: Nourdine
authors.initials: N
authors.lastname: Faresse
authors.forename: Anne
authors.initials: A
authors.lastname: Debonneville
authors.forename: Olivier
authors.initials: O
authors.lastname: Staub
mesh_terms: D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D010450:Endopeptidases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism; D047468:Immunoprecipitation; D051379:Mice; D018345:Mice, Knockout; D000451:Mineralocorticoid Receptor Antagonists / Q000494:pharmacology*; D011485:Protein Binding; D018161:Receptors, Mineralocorticoid / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D043222:Ubiquitin Thiolesterase; D064570:Ubiquitin-Specific Proteases; D054875:Ubiquitination; D000099177:Tsg101 Protein
chemical_list: D000450:Aldosterone; D004268:DNA-Binding Proteins; D010450:Endopeptidases; D056827:Endosomal Sorting Complexes Required for Transport; D000451:Mineralocorticoid Receptor Antagonists; D018161:Receptors, Mineralocorticoid; D014157:Transcription Factors; D043222:Ubiquitin Thiolesterase; D064570:Ubiquitin-Specific Proteases; D000099177:Tsg101 Protein; C579224:Usp2 protein, mouse