Stimulator of interferon genes (STING) is essential for the type I interferon response against a variety of DNA pathogens. Upon emergence of cytosolic DNA, STING translocates from the endoplasmic reticulum to the Golgi where STING activates the downstream kinase TBK1, then to lysosome through recycling endosomes (REs) for its degradation. Although the molecular machinery of STING activation is extensively studied and defined, the one underlying STING degradation and inactivation has not yet been fully elucidated. Here we show that STING is degraded by the endosomal sorting complexes required for transport (ESCRT)-driven microautophagy. Airyscan super-resolution microscopy and correlative light/electron microscopy suggest that STING-positive vesicles of an RE origin are directly encapsulated into Lamp1-positive compartments. Screening of mammalian Vps genes, the yeast homologues of which regulate Golgi-to-vacuole transport, shows that ESCRT proteins are essential for the STING encapsulation into Lamp1-positive compartments. Knockdown of Tsg101 and Vps4, components of ESCRT, results in the accumulation of STING vesicles in the cytosol, leading to the sustained type I interferon response. Knockdown of Tsg101 in human primary T cells leads to an increase the expression of interferon-stimulated genes. STING undergoes K63-linked ubiquitination at lysine 288 during its transit through the Golgi/REs, and this ubiquitination is required for STING degradation. Our results reveal a molecular mechanism that prevents hyperactivation of innate immune signalling, which operates at REs.

干扰素基因刺激物 (STING) 对于针对多种 DNA 病原体的 I 型干扰素反应至关重要。细胞溶质 DNA 出现后，STING 从内质网转移到高尔基体，STING 在高尔基体中激活下游激酶 TBK1，然后通过再循环核内体 (REs) 转移到溶酶体以进行降解。尽管对 STING 激活的分子机制进行了广泛研究和定义，但尚未完全阐明潜在的 STING 降解和失活机制。在这里，我们表明 STING 被运输 (ESCRT) 驱动的微自噬所需的内体分选复合物降解。Airyscan 超分辨率显微镜和相关的光学/电子显微镜表明，RE 来源的 STING 阳性囊泡被直接封装到 Lamp1 阳性隔室中。哺乳动物筛选Vps基因是调节高尔基体到液泡转运的酵母同源物，表明 ESCRT 蛋白对于将 STING 封装到 Lamp1 阳性隔室中是必不可少的。敲低 ESCRT 的组分 Tsg101 和 Vps4 会导致细胞质中 STING 囊泡的积累，从而导致持续的 I 型干扰素反应。人类原代 T 细胞中 Tsg101 的敲低导致干扰素刺激基因的表达增加。STING 在通过高尔基体/RE 的过程中在第 288 位赖氨酸处经历 K63 连接的泛素化，而这种泛素化是 STING 降解所必需的。我们的结果揭示了一种防止先天免疫信号过度激活的分子机制，该信号在 REs 起作用。