title: TRAP220 is modulated by the antineoplastic agent 6-Mercaptopurine, and mediates the activation of the NR4A subgroup of nuclear receptors.
abstract: The NR4A1-3 (Nur77, NURR1 and NOR-1) subfamily of nuclear hormone receptors (NRs) has been implicated in Parkinson's disease, schizophrenia, manic depression, atherogenesis, Alzheimer's disease, rheumatoid arthritis, cancer and apoptosis. This has driven investigations into the mechanism of action, and the identification of small molecule regulators, that may provide the platform for pharmaceutical and therapeutic exploitation. Recently, we found that the purine antimetabolite 6-Mercaptopurine (6-MP), which is widely used as an anti-neoplastic and anti-inflammatory drug, modulated the NR4A1-3 subfamily. Interestingly, the agonist-mediated activation did not involve modulation of primary coactivators' (e.g. p300 and SRC-2/GRIP-1) activity and/or recruitment. However, the role of the subsequently recruited coactivators, for example CARM-1 and TRAP220, in 6-MP-mediated activation of the NR4A1-3 subfamily remains obscure. In this study we demonstrate that 6-MP modulates the activity of the coactivator TRAP220 in a dose-dependent manner. Moreover, we demonstrate that TRAP220 potentiates NOR-1-mediated transactivation, and interacts with the NR4A1-3 subgroup in an AF-1-dependent manner in a cellular context. The region of TRAP220 that mediated 6-MP activation and NR4A interaction was delimited to amino acids 1-800, and operates independently of the critical PKC and PKA phosphorylation sites. Interestingly, TRAP220 expression does not increase the relative induction by 6-MP, however the absolute level of NOR-1-mediated trans-activation is increased. This study demonstrates that 6-MP modulates the activity of the NR4A subgroup, and the coactivator TRAP220.
authors.affiliation: Institute for Molecular Bioscience, University of Queensland St Lucia, 4072 Queensland, Australia.
authors.forename: K D Senali Abayratna
authors.initials: KD
authors.lastname: Wansa
authors.forename: George E O
authors.initials: GE
authors.lastname: Muscat
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000819:agonists* / Q000378:metabolism; D056913:Mediator Complex Subunit 1; D015122:Mercaptopurine / Q000494:pharmacology*; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000819:agonists* / Q000378:metabolism; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D010957:Plasmids; D011493:Protein Kinase C / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists* / Q000378:metabolism; D011987:Receptors, Steroid / Q000819:agonists* / Q000378:metabolism; D011988:Receptors, Thyroid Hormone; D014157:Transcription Factors / Q000819:agonists* / Q000378:metabolism / Q000502:physiology*
chemical_list: D000970:Antineoplastic Agents; D017931:DNA Primers; D004268:DNA-Binding Proteins; C538856:Med1 protein, mouse; D056913:Mediator Complex Subunit 1; D009419:Nerve Tissue Proteins; C539818:Nr4a1 protein, mouse; C539883:Nr4a2 protein, mouse; C490411:Nr4a3 protein, mouse; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D011988:Receptors, Thyroid Hormone; D014157:Transcription Factors; D015122:Mercaptopurine; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C