STING Trafficking, Activation and Signaling Beyond Interferon

项目总结 SING介导的I型干扰素信号在先天免疫应答中发挥重要作用 感染。刺痛通路是独一无二的，因为它需要内质网到ERGIC/高尔基体转位才能激活 下行信令。TMEM173编码STING的功能增益突变在STING中已有报道。 婴儿期起病相关血管病变(SAVI)。我们证明了这些突变体结构性地激活了 不依赖于配体结合的诱捕、贩运和信号传递。除了干扰素，STING还驱动其他细胞 以及似乎不需要干扰素信号的生理反应，如T细胞增殖和存活。 这些新的刺激性功能是如何发挥作用的，目前尚不清楚。到目前为止，有限的证据表明NFkB 牵涉到诱骗和贩卖。在这里，我们建议研究刺痛激活和信号调节 T细胞的存活。这项拟议的研究是基于我们最近对Sting-N153S进行表征的发现 (人类叮咬中的N154S)敲入小鼠，它具有许多人类疾病的病理特征， 包括肺部炎症和T细胞减少。N153S小鼠出现独立于病毒的疾病 IRF3/干扰素，增加了非干扰素功能的刺痛在疾病病理中的作用。 N153S鼠标。在我们的初步研究中，我们将STING介导的干扰素和NFkB信号基序映射到不同的 C-末端的区域。在人Jurkat T细胞中诱导表达N154S也会导致细胞死亡。因此， 我们假设，疾病相关的刺痛突变，如N154S，从ER- TO-ERGIC/Golgi，并慢性激活一个新的NFkB或未知的信号级联导致T细胞死亡。 我们将首先确定内质网到ERGIC/高尔基体转位是如何激活STING信号的，这是一种机制 配体依赖的和非配体依赖的STING激活所共有的。然后，我们将调查如何刺痛 利用工程化人类T细胞和获得功能的Sting-N153S，在T细胞中激活诱导细胞死亡 老鼠。最后，我们将研究一种新的敲入鼠标Sting-S365A，它可以扰乱Sing的激活能力 IRF3/干扰素在保持其他信号功能的同时，在各种生理条件下，如感染， 细胞增殖和细胞死亡。这里提出的研究将建立一种新的叮咬生物学范式 鉴定在生理相关条件下调节T细胞存活的一个重要的新功能 疾病设置。

PROJECT SUMMARY STING-mediated type I interferon (IFN) signaling plays an important role in innate immune response to infections. The STING pathway is unique in that it requires ER-to-ERGIC/Golgi translocation to activate downstream signaling. Gain-of-function mutations in TMEM173 encoding STING have been reported in STING- associated vasculopathy with onset in infancy (SAVI). We showed that these mutants constitutively activate STING trafficking and signaling independent of ligand binding. In addition to IFN, STING also drives other cellular and physiological responses that do not appear to require IFN signaling, such as T cell proliferation and survival. How are these new STING functions engaged remains unknown. Limited evidence thus far suggests that NFkB and STING trafficking are involved. Here, we propose to study STING activation and signaling that regulate the survival of T cells. The proposed study is based on our recent findings from characterizing the Sting-N153S (N154S in human STING) knock-in mouse, which develop many pathological features of the human disease, including inflammation within the lung and T cell cytopenia. N153S mice develop disease independent of IRF3/IFN, raising the possibility that non-IFN functions of STING is responsible for disease pathology in the N153S mouse. In our preliminary studies, we mapped STING-mediated IFN and NFkB signaling motifs to distinct regions of the C-terminus. Inducible expression of N154S in human Jurkat T cells also caused cell death. Thus, we hypothesize that disease-associated STING mutations such as N154S constitutively translocates from ER- to-ERGIC/Golgi and chronically activates a novel NFkB or unknown signaling cascade leading to T cell death. We will first determine how STING signaling is activated by ER-to-ERGIC/Golgi translocation, a mechanism shared by both ligand-dependent and –independent activation of STING. Then, we will investigate how STING activation in T cells induces cell death, using engineered human T cells and the gain-of-function Sting-N153S mouse. Lastly, we will study a new knock-in mouse Sting-S365A, which disrupts STING's ability to activate IRF3/IFN while retaining other signaling capabilities, under a variety of physiological conditions such as infection, cell proliferation and cell death. Studies proposed here will establish a new paradigm of STING biology by characterizing an important new function of STING that regulates T cell survival under physiologically relevant disease settings.