Wang Lucai, Qiu Xiangqi, Wang Lele, Yang Xilong, Li Mengjie, Zhao Xuyang, Zhu Wenhui, Lv Lijie, Kang Yunzhe, Yao Lulu, Zhang Gaiping, Sun Aijun, Zhuang Guoqing
International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China.
Longhu Laboratory of Advanced Immunology, Zhengzhou, China.
PLoS Pathog. 2025 Aug 13;21(8):e1013234. doi: 10.1371/journal.ppat.1013234. eCollection 2025 Aug.
The ERK-mediated phosphorylation of the core m6A methyltransferase METTL3 has been linked to the regulation of embryonic stem cell differentiation and tumorigenesis. However, its role in the antiviral innate immune response remains unclear. In this study, we found that during infection with the prototypical alpha-herpesvirus Pseudorabies virus (PRV), ERK2 protein expression increased significantly, while METTL3 expression decreased both in vitro and in vivo. Overexpressing ERK2 and METTL3 effectively reduced PRV replication, while their knockdown promoted viral replication. The C-terminal domain and enzymatic active site of METTL3 were essential for suppressing viral replication. Mechanistically, ERK2 phosphorylates METTL3 at serine 43. We further found that ERK2-mediated phosphorylation at this site enhances the type I interferon (IFN-β)-induced innate immune response by activating the NF-κB pathway, increasing m6A modification, and elevating protein translation levels. Notably, combined treatment with ERK2 and METTL3 inhibitors promoted viral replication, intensified organ damage, and hastened mortality in mice by suppressing IFN-β production. In conclusion, our study reveals phosphorylation-dependent crosstalk between MAPK signaling and the m6A machinery in antiviral defense, identifies Ser43 as a functional hotspot for METTL3's immunoregulatory activity, and indicates that the ERK-METTL3 axis is a novel regulator of the antiviral innate immune response during alpha-herpesvirus infection. This work establishes a paradigm shift in understanding how post-translational modifications of RNA-modifying enzymes orchestrate antiviral immunity, providing new avenues for host-directed antiviral strategies.
ERK介导的核心m6A甲基转移酶METTL3的磷酸化与胚胎干细胞分化和肿瘤发生的调控有关。然而，其在抗病毒先天免疫反应中的作用仍不清楚。在本研究中，我们发现，在感染典型的α-疱疹病毒伪狂犬病病毒（PRV）期间，ERK2蛋白表达显著增加，而METTL3表达在体外和体内均降低。过表达ERK2和METTL3可有效减少PRV复制，而敲低它们则促进病毒复制。METTL3的C末端结构域和酶活性位点对于抑制病毒复制至关重要。机制上，ERK2在丝氨酸43处使METTL3磷酸化。我们进一步发现，ERK2介导的该位点磷酸化通过激活NF-κB途径、增加m6A修饰和提高蛋白质翻译水平来增强I型干扰素（IFN-β）诱导的先天免疫反应。值得注意的是，联合使用ERK2和METTL3抑制剂通过抑制IFN-β产生促进了病毒复制，加剧了器官损伤，并加速了小鼠的死亡。总之，我们的研究揭示了MAPK信号通路与m6A机制在抗病毒防御中的磷酸化依赖性相互作用，确定丝氨酸43是METTL3免疫调节活性的功能热点，并表明ERK-METTL3轴是α-疱疹病毒感染期间抗病毒先天免疫反应的新型调节因子。这项工作在理解RNA修饰酶的翻译后修饰如何协调抗病毒免疫方面实现了范式转变，为宿主导向的抗病毒策略提供了新途径。
