GR SUMOylation and formation of an SUMO-SMRT/NCoR1-HDAC3 repressing complex is mandatory for GC-induced IR nGRE-mediated transrepression
GR SUMOylation and formation of an SUMO-SMRT/NCoR1-HDAC3 repressing complex is mandatory for GC-induced IR nGRE-mediated transrepression
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DOI：
10.1073/pnas.1522821113
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发表时间：
2016-02-02
影响因子：
11.1
通讯作者：
Chambon, Pierre
中科院分区：
文献类型：
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作者：
Hua, Guoqiang;Paulen, Laetitia;Chambon, Pierre
在核受体超家族中独有的糖皮质激素（GC）受体（GR）可以发挥三种不同的转录调节功能，以结合单个天然（人类和小鼠中皮质酮的皮质醇）和合成的单个天然（例如，dexamethasone（Dex））的荷尔蒙。部分理解了GC诱导的阳性GC响应元件[（+）GRE]介导的转录激活的分子机制。相反，这些机制对于GC诱导的进化保守的反复重复GC响应元件（IR NGRE）介导的直接反抑制以及由DNA结合的NF-kappa B/激活剂介导的束缚间接变形的倒置，仍然难以捉摸。 /STAT3激活剂，并在GC诱导的抗炎活性中发挥作用。我们在这里证明，赖氨酸K293（小鼠K310）位于人类GR N末端结构域中进化保守序列内的Sumoylation允许形成GR-Small泛素蛋白相关的修饰符（SUMOS）-NCOR1/SMRT-HDAC3对于GC诱导的IR NGRE介导的直接抑制在体外，但不会影响反式激活。重要的是，在体内验证了这些结果：在K310R突变小鼠和在核受体核心核心1（NCOR1）/沉默介质中选择性地消融的小鼠中，用于视黄素或甲状腺激素受体（SMRT）核心核心，在脱皮的直接重新定位重新定义重新定位和甲状腺素中，在IR NGRE上的抑制复合物的形成受损，而反式激活不受影响。在选择性烧蚀性组蛋白脱乙酰基酶3（HDAC3）中，在皮肤角质形成细胞中，GC诱导的直接抑制作用，但没有GR和Corepressors NCOR1/SMRT的结合，表明HDAC3在IR NGRE NGRE介导的抑制中有用。此外，我们证明了HDAC3与体内IR ngres的结合是通过与SMRT/NCOR1相互作用介导的。我们还表明，SMRT介导的抑制不需要GR配体结合结构域（LBD），这可以通过LBD截断的GR介导，而NCOR1介导的抑制是通过与LBD中的K579的相互作用进行的。
Unique among the nuclear receptor superfamily, the glucocorticoid (GC) receptor (GR) can exert three distinct transcriptional regulatory functions on binding of a single natural (cortisol in human and corticosterone in mice) and synthetic [e.g., dexamethasone (Dex)] hormone. The molecular mechanisms underlying GC-induced positive GC response element [(+)GRE]-mediated activation of transcription are partially understood. In contrast, these mechanisms remain elusive for GC-induced evolutionary conserved inverted repeated negative GC response element (IR nGRE)-mediated direct transrepression and for tethered indirect transrepression that is mediated by DNA-bound NF-kappa B/activator protein 1 (AP1)/STAT3 activators and instrumental in GC-induced anti-inflammatory activity. We demonstrate here that SUMOylation of lysine K293 (mouse K310) located within an evolutionary conserved sequence in the human GR N-terminal domain allows the formation of a GR-small ubiquitin-related modifiers (SUMOs)-NCoR1/SMRT-HDAC3 repressing complex mandatory for GC-induced IR nGRE-mediated direct repression in vitro, but does not affect transactivation. Importantly, these results were validated in vivo: in K310R mutant mice and in mice ablated selectively for nuclear receptor corepressor 1 (NCoR1)/silencing mediator for retinoid or thyroid-hormone receptors (SMRT) corepressors in skin keratinocytes, Dex-induced direct repression and the formation of repressing complexes on IR nGREs were impaired, whereas transactivation was unaffected. In mice selectively ablated for histone deacetylase 3 (HDAC3) in skin keratinocytes, GC-induced direct repression, but not bindings of GR and of corepressors NCoR1/SMRT, was abolished, indicating that HDAC3 is instrumental in IR nGRE-mediated repression. Moreover, we demonstrate that the binding of HDAC3 to IR nGREs in vivo is mediated through interaction with SMRT/NCoR1. We also show that the GR ligand binding domain (LBD) is not required for SMRT-mediated repression, which can be mediated by a LBD-truncated GR, whereas it is mandatory for NCoR1-mediated repression through an interaction with K579 in the LBD.