Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto 607-8412, Japan.
Laboratory of Cell Signaling, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan.
Biochem J. 2021 Jan 15;478(1):261-279. doi: 10.1042/BCJ20200885.
Herpes simplex virus 1 (HSV-1) is a human DNA virus that causes cold sores, keratitis, meningitis, and encephalitis. Ubiquitination is a post-translational protein modification essential for regulation of cellular events, such as proteasomal degradation, signal transduction, and protein trafficking. The process is also involved in events for establishing viral infection and replication. The first step in ubiquitination involves ubiquitin (Ub) binding with Ub-activating enzyme (E1, also termed UBE1) via a thioester linkage. Our results show that HSV-1 infection alters protein ubiquitination pattern in host cells, as evidenced by MS spectra and co-immunoprecipitation assays. HSV-1 induced ubiquitination of UBE1a isoform via an isopeptide bond with Lys604. Moreover, we show that ubiquitination of K604 in UBE1a enhances UBE1a activity; that is, the activity of ubiquitin-transfer to E2 enzyme. Subsequently, we investigated the functional role of UBE1a and ubiquitination of K604 in UBE1a. We found that UBE1-knockdown increased HSV-1 DNA replication and viral production. Furthermore, overexpression of UBE1a, but not a UBE1a K604A mutant, suppressed viral replication. Furthermore, we found that UBE1a and ubiquitination at K604 in UBE1a retarded expression of HSV-1 major capsid protein, ICP5. Our findings show that UBE1a functions as an antiviral factor that becomes activated upon ubiquitination at Lys604.
单纯疱疹病毒 1（HSV-1）是一种人类 DNA 病毒，可引起唇疱疹、角膜炎、脑膜炎和脑炎。泛素化是一种翻译后蛋白质修饰，对于调节细胞事件至关重要，如蛋白酶体降解、信号转导和蛋白质运输。该过程还涉及建立病毒感染和复制的事件。泛素化的第一步涉及通过硫酯键与泛素激活酶（E1，也称为 UBE1）结合的泛素（Ub）。我们的结果表明，HSV-1 感染通过 MS 光谱和共免疫沉淀测定改变宿主细胞中的蛋白质泛素化模式。HSV-1 通过与 Lys604 的异肽键诱导 UBE1a 同种型的泛素化。此外，我们表明 UBE1a 中 K604 的泛素化增强了 UBE1a 的活性；也就是说，泛素转移到 E2 酶的活性。随后，我们研究了 UBE1a 和 UBE1a 中 K604 的泛素化在病毒复制中的功能作用。我们发现 UBE1 敲低增加了 HSV-1 的 DNA 复制和病毒产生。此外，UBE1a 的过表达而非 UBE1a K604A 突变体抑制了病毒复制。此外，我们发现 UBE1a 和 UBE1a 中的 K604 泛素化会延迟 HSV-1 主要衣壳蛋白 ICP5 的表达。我们的研究结果表明，UBE1a 作为一种抗病毒因子发挥作用，在 Lys604 泛素化后被激活。
