Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
PamGene International B.V., Wolvenhoek 10, 5211 HH 's-Hertogenbosch, The Netherlands.
Biochim Biophys Acta Proteins Proteom. 2017 Sep;1865(9):1195-1206. doi: 10.1016/j.bbapap.2017.06.011. Epub 2017 Jun 20.
Retinoic Acid Receptor alpha (RARα/NR1B1), Retinoic Acid Receptor beta (RARβ/NR1B2) and Retinoic Acid Receptor gamma (RARγ/NR1B3) are transcription factors regulating gene expression in response to retinoids. Within the RAR genomic pathways, binding of RARs to coregulators is a key intermediate regulatory phase. However, ligand-dependent interactions between the wide variety of coregulators that may be present in a cell and the different RAR subtypes are largely unknown. The aim of this study is to characterize the coregulator binding profiles of RARs in the presence of the pan-agonist all-trans-Retinoic Acid (AtRA); the subtype-selective agonists Am80 (RARα), CD2314 (RARβ) and BMS961 (RARγ); and the antagonist Ro415253. To this end, we used a microarray assay for coregulator-nuclear receptor interactions to assess RAR binding to 154 motifs belonging to >60 coregulators. The results revealed a high number of ligand-dependent RAR-coregulator interactions among all RAR variants, including many binding events not yet described in literature. Next, this work confirmed a greater ligand-independent activity of RARβ compared to the other RAR subtypes based on both higher basal and lower ligand-driven coregulator binding. Further, several coregulator motifs showed selective binding to a specific RAR subtype. Next, this work showed that subtype-selective agonists can be successfully discriminated by using coregulator binding assays. Finally this study demonstrated the possible applications of a coregulator binding assay as a tool to discriminate between agonistic/antagonistic actions of ligands. The RAR-coregulator interactions found will be of use to direct further studies to better understand the mechanisms driving the eventual actions of retinoids.
维甲酸受体α（RARα/NR1B1）、维甲酸受体β（RARβ/NR1B2）和维甲酸受体γ（RARγ/NR1B3）是转录因子，可调节视黄酸应答基因的表达。在 RAR 基因组途径中，RAR 与共激活子的结合是关键的中间调节阶段。然而，细胞中存在的各种共激活子与不同的 RAR 亚型之间的配体依赖性相互作用在很大程度上是未知的。本研究旨在描述在 pan-agonist 全反式视黄酸（AtRA）；亚型选择性激动剂 Am80（RARα）、CD2314（RARβ）和 BMS961（RARγ）；和拮抗剂 Ro415253 的存在下，RAR 的共激活子结合谱。为此，我们使用核受体相互作用的共激活子微阵列测定法来评估 154 个基序与 >60 个共激活子的 RAR 结合。结果显示，所有 RAR 变体之间存在大量配体依赖性的 RAR-共激活子相互作用，包括许多尚未在文献中描述的结合事件。接下来，这项工作基于更高的基础和更低的配体驱动的共激活子结合，证实了 RARβ 比其他 RAR 亚型具有更高的配体非依赖性活性。此外，一些共激活子基序显示出对特定 RAR 亚型的选择性结合。接下来，这项工作表明，共激活子结合测定可成功区分亚型选择性激动剂。最后，本研究证明了共激活子结合测定作为区分配体激动/拮抗作用的工具的可能应用。发现的 RAR-共激活子相互作用将有助于指导进一步的研究，以更好地理解驱动视黄酸最终作用的机制。
