Robert H. Lurie Comprehensive Cancer Center and Division of Hematology-Oncology, Northwestern University Medical School, Chicago, IL 60611, USA.
Proc Natl Acad Sci U S A. 2012 May 15;109(20):7723-8. doi: 10.1073/pnas.1118122109. Epub 2012 May 1.
IFNs transduce signals by binding to cell surface receptors and activating cellular pathways and regulatory networks that control transcription of IFN-stimulated genes (ISGs) and mRNA translation, leading to generation of protein products that mediate biological responses. Previous studies have shown that type I IFN receptor-engaged pathways downstream of AKT and mammalian target of rapamycin complex (mTORC) 1 play important roles in mRNA translation of ISGs and the generation of IFN responses, but the roles of mTORC2 complexes in IFN signaling are unknown. We provide evidence that mTORC2 complexes control IFN-induced phosphorylation of AKT on serine 473 and their function is ultimately required for IFN-dependent gene transcription via interferon-stimulated response elements. We also demonstrate that such complexes exhibit regulatory effects on other IFN-dependent mammalian target of rapamycin-mediated signaling events, likely via engagement of the AKT/mTORC1 axis, including IFN-induced phosphorylation of S6 kinase and its effector rpS6, as well as phosphorylation of the translational repressor 4E-binding protein 1. We also show that induction of ISG protein expression and the generation of antiviral responses are defective in Rictor and mLST8-KO cells. Together, our data provide evidence for unique functions of mTORC2 complexes in the induction of type I IFN responses and suggest a critical role for mTORC2-mediated signals in IFN signaling.
IFNs 通过与细胞表面受体结合并激活细胞内途径和调控网络来传递信号,这些途径和网络控制 IFN 刺激基因 (ISGs) 的转录和 mRNA 翻译,从而产生介导生物学反应的蛋白产物。先前的研究表明,AKT 和雷帕霉素哺乳动物靶标复合物 (mTORC) 1 下游的 I 型 IFN 受体参与的途径在 ISGs 的 mRNA 翻译和 IFN 反应的产生中发挥重要作用,但 mTORC2 复合物在 IFN 信号转导中的作用尚不清楚。我们提供的证据表明,mTORC2 复合物控制 IFN 诱导的 AKT 丝氨酸 473 磷酸化,并且它们的功能最终通过干扰素刺激反应元件是 IFN 依赖性基因转录所必需的。我们还证明,这些复合物对其他 IFN 依赖性雷帕霉素哺乳动物靶标 (mTOR) 介导的信号事件具有调节作用,可能通过 AKT/mTORC1 轴的参与,包括 IFN 诱导的 S6 激酶及其效应物 rpS6 的磷酸化,以及翻译抑制剂 4E 结合蛋白 1 的磷酸化。我们还表明,在 Rictor 和 mLST8-KO 细胞中,ISG 蛋白表达的诱导和抗病毒反应的产生存在缺陷。总之,我们的数据为 mTORC2 复合物在诱导 I 型 IFN 反应中的独特功能提供了证据,并表明 mTORC2 介导的信号在 IFN 信号转导中具有关键作用。