Deamidation-mediated metabolic reprogramming by KSHV in cell proliferation and tumorigenesis

项目总结 人类卡波西肉瘤相关疱疹病毒(KSHV)是多种癌症的病原体。然而， 关于KSHV肿瘤发生的分子细节还不是很清楚。我们最近的研究表明 疱疹病毒利用蛋白质去酰胺化来逃避先天免疫反应。探索蛋白质的作用 在基本的生物学过程中，我们进行了针对细胞谷氨酰胺的聚焦筛选 氨基转移酶(GAT)，一个潜在的蛋白质脱酰胺酶家族。我们鉴定了一种谷氨酰胺氨基转移酶 作为核因子-κB激活的负性调节因子。在我们的初步研究中，我们发现GAT具有内在的 蛋白质去酰胺化核因子-κB转录因子以抑制其反式激活核因子-κB的能力 基因。值得注意的是，脱酰胺促进了有氧糖酵解，从而促进了细胞的增殖和肿瘤的发生。 此外，KSHV还劫持了诱导NF-κB脱酰胺并促进细胞增殖的细胞机制， 从而诱导肿瘤的形成。我们的发现支持核苷酸生物合成的主要假设。 酶使核因子-κB亚基去胺化以重新编程新陈代谢，从而促进细胞增殖和 肿瘤发生，并认为KSHV劫持这一机制，以实现持续感染。为了测试这个中心 假设，我在这个项目中提出了三个目标：1)阐明GAT介导的一个NF-κB亚基的脱酰胺化 并下调NF-κB的活性；2)通过GAT介导的代谢重编程 去酰胺化；以及3)描述一种劫持细胞去酰胺化以促进增殖的病毒机制 以及在KSHV潜伏感染期间的肿瘤形成。 在K99阶段，我将实现以下三个子目标：1)表征NF-κB的分子细节 去酰胺化(目标1A)；2)研究去酰胺化在先天性免疫防御中的作用(目标1B)；以及3)解剖 脱酰胺化介导的代谢重编程的机制(目标2A)。 在R00阶段，我将通过定义NF-κB脱酰胺在增殖和 不同癌细胞系的肿瘤发生。此外，我还将研究KSHV通过什么机制 在KSHV感染过程中促进NF-κB脱酰胺并确定其在代谢和肿瘤发生中的作用。 总之，K99/R00项目将描述一种细胞代谢酶(核苷酸)的新功能 合成)和一个关键转录因子(一个核因子-κB亚单位)，并阐明了一种新的代谢调控机制 重新编程以推动细胞增殖，从而为KSHV期间的代谢调节提供了新的见解 感染。这将为我的长期职业目标奠定基础，研究细胞中的蛋白质脱氨基 新陈代谢、KSHV相关肿瘤发生和翻译应用于抗病毒/抗肿瘤治疗。

PROJECT SUMMARY Human Kaposi’s Sarcoma-associated Herpesvirus (KSHV) is the etiological agent of multiple cancers. However, the molecular details concerning the tumorigenesis of KSHV are not well understood. Our recent studies indicate that herpesviruses employ protein deamidation to evade innate immune response. To probe the role of protein deamidation in fundamental biological processes, we performed a focused screen targeting cellular glutamine amidotransferases (GAT), a potential protein deamidases family. We identified one glutamine amidotransferase as a negative regulator of NF-κB activation. In our preliminary studies, we found that the GAT possessed intrinsic protein deamidating ability to deamidate NF-κB transcription factor to dampen its ability to transactivate NF-κB genes. Remarkably, deamidation promoted aerobic glycolysis to promote cell proliferation and tumorigenesis. Furthermore, KSHV hijacks the cellular mechanism to induce NF-κB deamidation and promote cell proliferation, thereby inducing tumor formation. Our findings support the overarching hypothesis a nucleotide biosynthetic enzyme deamidates a NF-κB subunit to reprogram metabolism, thus promoting cell proliferation and tumorigenesis, and that KSHV hijacks this mechanism to achieve persistent infection. To test this central hypothesis, I propose three aims in this project: 1) Elucidate the GAT-mediated deamidation of a NF-κB subunit and downregulation of NF-κB activation; 2) Delineate the metabolic reprogramming by GAT-mediated deamidation; and 3) Characterize a viral mechanism that hijacks the cellular deamidation to promote proliferation and tumor formation during KSHV latent infection. In the K99 phase, I will achieve the following three sub aims: 1) characterize the molecular detail of the NF-κB deamidation (Aim 1A); 2) examine the role of deamidation in innate immune defense (Aim 1B); and 3) dissect the mechanism of deamidation-mediated metabolic reprogramming (Aim 2A). In the R00 phase, I will complete Aim 2 by defining the role of NF-κB deamidation in proliferation and tumorigenesis of diverse cancer cell lines. Furthermore, I will investigate the mechanism by which KSHV promotes NF-κB deamidation and define its role in metabolism and tumorigenesis during KSHV infection. In summary, the K99/R00 project will characterize novel functions of a cellular metabolic enzyme (in nucleotide synthesis) and a key transcription factor (a NF-κB subunit), and elucidate a new mechanism governing metabolic reprogramming to drive cell proliferation, thereby offering fresh insight into the metabolic regulation during KSHV infection. It will establish the foundation for my long-term career goals to study protein deamidations in cellular metabolism, KSHV-associated tumorigenesis and translational applications to antiviral/antitumor therapies.