Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
NHC Key Laboratory of Systems Biology of Pathogens, National Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China.
J Virol. 2024 Oct 22;98(10):e0107224. doi: 10.1128/jvi.01072-24. Epub 2024 Sep 17.
The Envelope (E) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an integral structural protein in the virus particles. However, its role in the assembly of virions and the underlying molecular mechanisms are yet to be elucidated, including whether the function of E protein is regulated by post-translational modifications. In the present study, we report that SARS-CoV-2 E protein is palmitoylated at C40, C43, and C44 by palmitoyltransferases zDHHC3, 6, 12, 15, and 20. Mutating these three cysteines to serines (C40/43/44S) reduced the stability of E protein, decreased the interaction of E with structural proteins Spike, Membrane, and Nucleocapsid, and thereby inhibited the production of virus-like particles (VLPs) and VLP-mediated luciferase transcriptional delivery. Specifically, the C40/43/44S mutation of E protein reduced the density of VLPs. Collectively, these results demonstrate that palmitoylation of E protein is vital for its function in the assembly of SARS-CoV-2 particles.IMPORTANCEIn this study, we systematically examined the biochemistry of palmitoylation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) E protein and demonstrated that palmitoylation of SARS-CoV-2 E protein is required for virus-like particle (VLP) production and maintaining normal particle density. These results suggest that palmitoylated E protein is central for proper morphogenesis of SARS-CoV-2 VLPs in densities required for viral infectivity. This study presents a significant advancement in the understanding of how palmitoylation of viral proteins is vital for assembling SARS-CoV-2 particles and supports that palmitoyl acyltransferases can be potential therapeutic targets for the development of SARS-CoV-2 inhibitors.
新型冠状病毒 2（SARS-CoV-2）的包膜（E）蛋白是病毒颗粒中的一种结构蛋白。然而，其在病毒粒子组装中的作用以及潜在的分子机制仍有待阐明，包括 E 蛋白的功能是否受翻译后修饰的调节。在本研究中，我们报告 SARS-CoV-2 E 蛋白可被 zDHHC3、6、12、15 和 20 型棕榈酰转移酶酰化于 C40、C43 和 C44。将这三个半胱氨酸突变为丝氨酸（C40/43/44S）会降低 E 蛋白的稳定性，减少 E 与结构蛋白 Spike、Membrane 和 Nucleocapsid 的相互作用，从而抑制病毒样颗粒（VLPs）的产生和 VLPs 介导的荧光素酶转录传递。具体而言，E 蛋白的 C40/43/44S 突变降低了 VLPs 的密度。总之，这些结果表明 E 蛋白的棕榈酰化对于其在 SARS-CoV-2 颗粒组装中的功能至关重要。
本研究系统地研究了 SARS-CoV-2 E 蛋白棕榈酰化的生物化学特性，并证实了 SARS-CoV-2 E 蛋白的棕榈酰化对于 VLP 的产生和维持正常颗粒密度是必需的。这些结果表明，棕榈酰化的 E 蛋白对于 SARS-CoV-2 VLPs 的正确形态发生以及维持病毒感染力所需的颗粒密度是至关重要的。本研究对理解棕榈酰化的病毒蛋白对于组装 SARS-CoV-2 颗粒的重要性有了重要进展，并支持棕榈酰基转移酶可以成为开发 SARS-CoV-2 抑制剂的潜在治疗靶点。
