早幼粒细胞白血病蛋白(PML)体涉及在响应干扰素(IFN)的抗病毒状态的建立的关键途径之一,然而,桥接串扰的分子机制仍然难以捉摸。在这里,我们报道了PML体的主要组成成分,Sp100A,普遍存在于各种细胞类型的胞质溶胶中,是对多种细胞外刺激的即时反应者,包括病毒感染,IFN,表皮生长因子(EGF),胶质细胞源性神经因子(GDNF),等。,信号通过磷脂酰肌醇3-激酶(PI3K)途径。IFN-β诱导Sp100A在Ser188上的磷酸化,这增强了Sp100A与丙酮酸激酶2(PKM2)的结合,并通过细胞外信号调节激酶1/2(ERK1/2)-PKM2-PIN1-输入蛋白轴促进其核输入。阻断PI3K通路信号传导或干扰ERK1/2-PKM2-PIN1-importin轴独立地阻碍Sp100A响应IFN的核易位,反映了管理这一事件的双重调节机制。在细胞核中,Sp100A富含必需的抗病毒干扰素刺激基因(ISGs)的启动子区域,例如IFI16、OAS2和RIG-I的编码,并激活它们的转录。重要的是,Sp100A的核进口,但不是对IFN没有反应的突变Sp100A的积累,在感染过程中,这些抗病毒ISGs的转录增强和限制病毒的繁殖。这些发现描述了细胞溶质中PML体的新型IFN应答机制,并阐明了PML体的复杂传感调节网络。重要性PML身体坐在各种重要的生物过程的中心阶段;然而,这些大分子蛋白质复合物的信号转导网络仍然是神秘的。本研究表明,详细地和第一次,信号接收的过程,processing,以及PML体对IFN和病毒感染的反应。它显示PML体组成成分Sp100A通过细胞溶质中的PI3K途径通过IFN信号在Ser188上磷酸化,与PKM2共位入核,富集在必需抗病毒ISGs的启动子区域,如编码IFI16,RIG-I,OAS2等。,并介导它们的转录激活。
Promyelocytic leukemia protein (
PML) bodies are implicated in one of the key pathways in the establishment of antiviral status in response to interferon (IFN), yet the molecular mechanisms bridging the cross talk remain elusive. Herein, we report that a major constitutive component of the
PML body, Sp100A, is ubiquitously located in the cytosol of various cell types and is an immediate responder to multiple extracellular stimuli, including virus infection, IFN, epidermal growth factor (EGF), glial cell-derived nerve factor (GDNF), etc., signaling through the phosphatidylinositol 3-kinase (PI3K) pathway. IFN-β induces phosphorylation of Sp100A on Ser188, which fortifies the binding of Sp100A to pyruvate kinase 2 (PKM2) and facilitates its nuclear importation through the extracellular signal-regulated kinase 1/2 (ERK1/2)-PKM2-PIN1-importin axes. Blocking PI3K pathway signaling or interference with the ERK1/2-PKM2-PIN1-importin axes independently hampers nuclear translocation of Sp100A in response to IFN, reflecting a dual-regulation mechanism governing this event. In the nucleus, Sp100A is enriched in the promoter regions of essential antiviral interferon-stimulated genes (ISGs), such as those coding for IFI16, OAS2, and RIG-I, and activates their transcription. Importantly, nuclear importation of Sp100A, but not accumulation of a mutant Sp100A that failed to respond to IFN, during infection potently enhanced transcription of these antiviral ISGs and restricted virus propagation. These findings depict a novel IFN response mechanism by
PML bodies in the cytosol and shed light on the complex sensing-regulatory network of
PML bodies. IMPORTANCE
PML bodies sit at the center stage of various important biological processes; however, the signal transduction networks of these macromolecular protein complexes remain enigmatic. The present study illustrates, in detail and for the first time, the course of signal receiving, processing, and implementation by PML bodies in response to IFN and virus infection. It shows that PML body constitutive component Sp100A was phosphorylated on Ser188 by IFN signaling through the PI3K pathway in the cytosol, cotranslocated into the nucleus with PKM2, enriched on the promoter regions of essential antiviral ISGs such as those coding for IFI16, RIG-I, OAS2, etc., and mediating their transcriptional activation.