Epstein-Barr virus protein kinase BGLF4 is a virion tegument protein that dissociates from virions in a phosphorylation-dependent process and phosphorylates the viral immediate-early protein BZLF1
Epstein-Barr virus protein kinase BGLF4 is a virion tegument protein that dissociates from virions in a phosphorylation-dependent process and phosphorylates the viral immediate-early protein BZLF1
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DOI：
10.1128/jvi.02674-05
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发表时间：
2006-06-01
影响因子：
5.4
通讯作者：
Kawaguchi, Yasushi
中科院分区：
文献类型：
--
作者：
Asai, Risa;Kato, Ai;Kawaguchi, Yasushi
EB病毒（EBV）BGLF 4是一种病毒蛋白激酶，在感染的裂解期表达，并包装在病毒体中。我们在这里报告说，BGLF 4是一种被膜蛋白，从病毒体中解离的磷酸化依赖的过程。我们还提供了BGLF 4与BZLF 1相互作用并使其磷酸化的证据，BZLF 1是裂解性感染的关键病毒调节因子。这些结论是根据以下意见得出的。(i)在体外被膜释放试验中，在生理NaCl浓度存在下，BGLF 4的显著部分从病毒体释放。(ii)加入生理浓度的ATP和MgCl 2的病毒粒子增强BGLF 4的释放，但磷酸酶处理的病毒粒子显着降低BGLF 4的释放。(iii)纯化的重组BGLF 4在体外特异性磷酸化含有BZLF 1结构域的重组蛋白，BGLF 4在体内改变BZLF 1的翻译后修饰。(iv)在12-O-十四烷酰佛波醇-13-乙酸酯处理的B 95 -8细胞和瞬时表达这两种病毒蛋白的COS-I细胞中，BZLFI与BGLF 4特异性免疫共沉淀。(v)在用抗人免疫球蛋白G处理的Akata细胞中，BGLF 4和BZLFI共定位于核内球状结构中，类似于病毒复制区室。我们的研究结果表明，BGLF 4不仅在裂解感染的细胞中通过磷酸化病毒和细胞靶点发挥作用，而且在病毒穿透后立即发挥作用，就像其他疱疹病毒被膜蛋白一样。
Epstein-Barr virus (EBV) BGLF4 is a viral protein kinase that is expressed in the lytic phase of infection and is packaged in virions. We report here that BGLF4 is a tegument protein that dissociates from the virion in a phosphorylation-dependent process. We also present evidence that BGLF4 interacts with and phosphorylates BZLF1, a key viral regulator of lytic infection. These conclusions are based on the following observations. (i) In in vitro tegument release assays, a significant fraction of BGLF4 was released from virions in the presence of physiological NaCl concentrations. (ii) Addition of physiological concentrations of ATP and MgCl2 to virions enhanced BGLF4 release, but phosphatase treatment of virions significantly reduced BGLF4 release. (iii) A recombinant protein containing a domain of BZLF1 was specifically phosphorylated by purified recombinant BGLF4 in vitro, and BGLF4 altered BZLF1 posttranslational modification in vivo. (iv) BZLFI was specifically coimmunoprecipitated with BGLF4 in 12-O-tetradecanoylphorbol-13-acetate-treated B95-8 cells and in COS-I cells transiently expressing both of these viral proteins. (v) BGLF4 and BZLFI were colocalized in intranuclear globular structures, resembling the viral replication compartment, in Akata cells treated with anti-human immunoglobulin G. Our results suggest that BGLF4 functions not only in lytically infected cells by phosphorylating viral and cellular targets but also immediately after viral penetration like other herpesvirus tegument proteins.