The Epstein-Barr virus latent membrane protein 2A PY motif recruits WW domain-containing ubiquitin-protein ligases
The Epstein-Barr virus latent membrane protein 2A PY motif recruits WW domain-containing ubiquitin-protein ligases
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DOI：
10.1006/viro.1999.0166
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发表时间：
2000-03-01
期刊：
影响因子：
3.7
通讯作者：
Longnecker, R
中科院分区：
文献类型：
--
作者：
Ikeda, M;Ikeda, A;Longnecker, R
潜伏膜蛋白2A（LMP 2A）在潜伏性EB病毒（EBV）感染中表达。LMP 2A在体外下调EBV永生化B细胞中B细胞信号转导和病毒从潜伏期的再活化，并在体内为细胞提供存活和发育信号。与LMP 2A相关的蛋白的鉴定对于阐明LMP 2A用于调节B细胞信号转导和EBV潜伏期的机制是重要的。LMP 2A是组成性酪氨酸磷酸化的，并且当特定的LMP 2A酪氨酸被磷酸化时，与蛋白酪氨酸激酶如林恩和Syk相关。LMP 2A的氨基末端结构域包括多个富含脯氨酸的区域，这些区域可能为含有SH 3或WW结构域的蛋白质提供结合位点。在这项研究中，我们证明了四种细胞蛋白质特异性结合到两个PPPPY（PY）基序内存在的LMP 2A氨基末端结构域。蛋白质微序列分析确定这些蛋白质中的三个是AIP 4、WWP 2/AIP 2和Nedd 4。所有这些蛋白质都是Nedd 4样泛素蛋白连接酶家族的成员，并且具有保守的结构域，包括C2、WW和泛素蛋白连接酶结构域。两个PY基序的突变完全消除了这些蛋白质与LMP 2A的结合活性，并且在表达LMP 2A、WWP 2和AIP 4的细胞系中证实了AIP 4和WWP 2与LMP 2A的相互作用。此外，在表达LMP 2A的细胞中观察到林恩水平的降低以及LMP 2A和林恩的快速转换。这些发现表明，LMP 2A招募Nedd 4样泛素蛋白连接酶和B细胞信号转导分子，导致LMP 2A和林恩通过泛素依赖性机制降解。这提供了LMP 2A可以调节B细胞信号转导的新手段。(C)北京大学出版社.
Latent membrane protein 2A (LMP2A) is expressed in latent Epstein-Barr virus (EBV) infection. LMP2A functions to downregulate B-cell signal transduction and viral reactivation from latency in EBV-immortalized B cells in vitro, and acts to provide a cells with both a survival and developmental signal in vivo. Identification of proteins associated with LMP2A is important for elucidation of the mechanism that LMP2A employs to regulate B-cell signal transduction and EBV latency. LMP2A is constitutively tyrosine phosphorylated and is associated with protein tyrosine kinases such as Lyn and Syk when specific LMP2A tyrosines are phosphorylated. The amino-terminal domain of LMP2A includes multiple proline-rich regions, which may provide binding sites for proteins containing SH3 or WW domains. In this study, we demonstrate that four cellular proteins bind specifically to two PPPPY (PY) motifs present within the LMP2A amino-terminal domain. Protein microsequence analysis determined that three of these proteins were AIP4, WWP2/AIP2, and Nedd4. All of these proteins are members of the Nedd4-like ubiquitin-protein ligases family and have conserved domains including the C2, WW, and ubiquitin-protein ligase domain. The mutation of both PY motifs completely abolished binding activity of these proteins to LMP2A and the interaction of AIP4 and WWP2 with LMP2A was confirmed in cell lines expressing LMP2A, WWP2, and AIP4. Furthermore, a reduction in the level of Lyn and the rapid turnover of LMP2A and Lyn were observed in LMP2A-expressing cells. These findings suggest that LMP2A recruits Nedd4-like ubiquitin-protein ligases and B-cell signal transduction molecules, resulting in the degradation of LMP2A and Lyn by a ubiquitin-dependent mechanism. This provides a new means by which LMP2A may modulate B-cell signal transduction. (C) 2000 Academic Press.