Institute of Medical Virology, University of Zurich, 8057, Zurich, Switzerland.
Life Science Zurich Graduate School, ETH and University of Zurich, 8057, Zurich, Switzerland.
Nat Commun. 2024 May 27;15(1):4484. doi: 10.1038/s41467-024-48800-5.
Deciphering the intricate dynamic events governing type I interferon (IFN) signaling is critical to unravel key regulatory mechanisms in host antiviral defense. Here, we leverage TurboID-based proximity labeling coupled with affinity purification-mass spectrometry to comprehensively map the proximal human proteomes of all seven canonical type I IFN signaling cascade members under basal and IFN-stimulated conditions. This uncovers a network of 103 high-confidence proteins in close proximity to the core members IFNAR1, IFNAR2, JAK1, TYK2, STAT1, STAT2, and IRF9, and validates several known constitutive protein assemblies, while also revealing novel stimulus-dependent and -independent associations between key signaling molecules. Functional screening further identifies PJA2 as a negative regulator of IFN signaling via its E3 ubiquitin ligase activity. Mechanistically, PJA2 interacts with TYK2 and JAK1, promotes their non-degradative ubiquitination, and limits the activating phosphorylation of TYK2 thereby restraining downstream STAT signaling. Our high-resolution proximal protein landscapes provide global insights into the type I IFN signaling network, and serve as a valuable resource for future exploration of its functional complexities.
解析调控 I 型干扰素 (IFN) 信号转导的复杂动态事件，对于揭示宿主抗病毒防御的关键调控机制至关重要。在这里，我们利用 TurboID 基近邻标记结合亲和纯化-质谱法，全面绘制了基础状态和 IFN 刺激条件下所有七种经典 I 型 IFN 信号级联成员的近端人蛋白质组图谱。这揭示了一个由 103 个高可信度蛋白组成的网络，与 IFNAR1、IFNAR2、JAK1、TYK2、STAT1、STAT2 和 IRF9 的核心成员紧密相关，并验证了几个已知的组成型蛋白组装体，同时还揭示了关键信号分子之间新的刺激依赖性和非依赖性关联。功能筛选进一步表明，PJA2 通过其 E3 泛素连接酶活性，作为 IFN 信号转导的负调节剂。在机制上，PJA2 与 TYK2 和 JAK1 相互作用，促进它们的非降解泛素化，并限制 TYK2 的激活磷酸化，从而抑制下游 STAT 信号转导。我们的高分辨率近端蛋白质图谱为 I 型 IFN 信号网络提供了全局见解，并为进一步探索其功能复杂性提供了有价值的资源。
