Phosphorylation of p27Kip1 by Epstein-Barr Virus Protein Kinase Induces Its Degradation through SCFSkp2 Ubiquitin Ligase Actions during Viral Lytic Replication
Phosphorylation of p27Kip1 by Epstein-Barr Virus Protein Kinase Induces Its Degradation through SCFSkp2 Ubiquitin Ligase Actions during Viral Lytic Replication
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DOI：
10.1074/jbc.m109.015123
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发表时间：
2009-07-10
影响因子：
4.8
通讯作者：
Tsurumi, Tatsuya
中科院分区：
文献类型：
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作者：
Iwahori, Satoko;Murata, Takayuki;Tsurumi, Tatsuya
EB病毒（EBV）的生产性复制发生在具有高细胞周期蛋白依赖性激酶（CDK）活性的S期样细胞环境中。由病毒BGLF 4基因编码的EBV蛋白激酶（PK）是一种Ser/Thr蛋白激酶，其磷酸化病毒和细胞蛋白，修饰细胞环境以进行有效的病毒生产性复制。我们在这里提供的证据表明，EBV PK磷酸化的CDK抑制剂p27（Kip 1），导致泛素化和降解的蛋白酶体依赖的方式在EBV生产性复制。通过小干扰RNA和BGLF 4敲除病毒敲除BGLF 4的实验阐明了EBV PK参与裂解复制后的p27（Kip 1）降解。转染BGLF 4表达载体后发现，单独的EBV PK可以磷酸化p27（Kip 1）的Thr-187残基，并且p27（Kip 1）的泛素化和降解以SCFSkp 2泛素连接酶依赖的方式发生。在体外，EBV PK证明能够在Thr-187磷酸化p27（Kip 1）。与细胞周期蛋白E-CDK 2活性不同，p27（Kip 1）不抑制EBV PK活性。总体而言，EBV PK增强p27（Kip 1）的降解有效地对EBV生产性复制，有助于建立一个S期样的细胞环境与高CDK活性。
Epstein-Barr virus (EBV) productive replication occurs in an S-phase-like cellular environment with high cyclin-dependent kinase (CDK) activity. The EBV protein kinase (PK), encoded by the viral BGLF4 gene, is a Ser/Thr protein kinase, which phosphorylates both viral and cellular proteins, modifying the cellular environment for efficient viral productive replication. We here provide evidence that the EBV PK phosphorylates the CDK inhibitor p27(Kip1), resulting in ubiquitination and degradation in a proteasome-dependent manner during EBV productive replication. Experiments with BGLF4 knockdown by small interfering RNA and BGLF4 knock-out viruses clarified that EBV PK is involved in p27(Kip1) degradation upon lytic replication. Transfection of the BGLF4 expression vector revealed that EBV PK alone could phosphorylate the Thr-187 residue of p27(Kip1) and that the ubiquitination and degradation of p27(Kip1) occurred in an SCFSkp2 ubiquitin ligase-dependent manner. In vitro, EBV PK proved capable of phosphorylating p27(Kip1) at Thr-187. Unlike cyclin E-CDK2 activity, the EBV PK activity was not inhibited by p27(Kip1). Overall, EBV PK enhances p27(Kip1) degradation effectively upon EBV productive replication, contributing to establishment of an S-phase-like cellular environment with high CDK activity.