Epstein-Barr Virus Latent Membrane Protein 1 (LMP1) C-Terminal-Activating Region 3 Contributes to LMP1-Mediated Cellular Migration via Its Interaction with Ubc9
Epstein-Barr Virus Latent Membrane Protein 1 (LMP1) C-Terminal-Activating Region 3 Contributes to LMP1-Mediated Cellular Migration via Its Interaction with Ubc9
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DOI：
10.1128/jvi.05035-11
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发表时间：
2011-10-01
影响因子：
5.4
通讯作者：
Pagano, Joseph S.
中科院分区：
文献类型：
--
作者：
Bentz, Gretchen L.;Whitehurst, Christopher B.;Pagano, Joseph S.
EB病毒潜伏膜蛋白1（LMP 1）是EB病毒的主要癌蛋白，属于肿瘤坏死因子受体超家族成员，是一种组成型活性膜信号蛋白，通过其C末端激活区1（CTAR 1）和CTAR 2以及研究较少的CTAR 3调控多种信号转导途径。由于蛋白质类小泛素化在其他翻译后修饰中可以调节LMP 1诱导的许多信号通路，我们研究了在EBV潜伏期LMP 1是否调节控制细胞活化和细胞反应的类小泛素化过程。通过免疫沉淀实验，我们发现LMP 1与Ubc 9相互作用，Ubc 9是唯一报道的SUMO结合酶。LMP 1-Ubc 9相互作用的要求包括酶活性Ubc 9：无活性Ubc 9（Ubc 9 C93 S）的表达抑制LMP 1-Ubc 9相互作用。LMP 1 CTAR 3，而不是CTAR 1和CTAR 2，参与LMP 1-Ubc 9相互作用，CTAR 3中发现的氨基酸序列，包括JAK相互作用基序，有助于这种相互作用。此外，LMP 1的表达与细胞蛋白类小泛素化的增加相一致，并且Ubc 9-LMP 1 CTAR 3相互作用的破坏几乎完全废除了LMP 1诱导的蛋白类小泛素化，这表明这种相互作用促进了下游靶标的类小泛素化。LMP 1 CTAR 3-Ubc 9相互作用的破坏的其他结果揭示了对细胞迁移的影响，这是肿瘤发生的标志。总之，这些数据表明LMP 1 CTAR 3实际上在细胞内信号传导中起作用并导致生物学效应。我们认为LMP 1通过与Ubc 9相互作用，调节SUMO化过程，从而调节影响与肿瘤发生相关的表型变化的信号转导途径。
Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1), the principal viral oncoprotein and a member of the tumor necrosis factor receptor superfamily, is a constitutively active membrane signaling protein that regulates multiple signal transduction pathways via its C-terminal-activating region 1 (CTAR1) and CTAR2, and also the less-studied CTAR3. Because protein sumoylation among other posttranslational modifications may regulate many signaling pathways induced by LMP1, we investigated whether during EBV latency LMP1 regulates sumoylation processes that control cellular activation and cellular responses. By immunoprecipitation experiments, we show that LMP1 interacts with Ubc9, the single reported SUMO-conjugating enzyme. Requirements for LMP1-Ubc9 interactions include enzymatically active Ubc9: expression of inactive Ubc9 (Ubc9 C93S) inhibited the LMP1-Ubc9 interaction. LMP1 CTAR3, but not CTAR1 and CTAR2, participated in the LMP1-Ubc9 interaction, and amino acid sequences found in CTAR3, including the JAK-interacting motif, contributed to this interaction. Furthermore, LMP1 expression coincided with increased sumoylation of cellular proteins, and disruption of the Ubc9-LMP1 CTAR3 interaction almost completely abrogated LMP1-induced protein sumoylation, suggesting that this interaction promotes the sumoylation of downstream targets. Additional consequences of the disruption of the LMP1 CTAR3-Ubc9 interaction revealed effects on cellular migration, a hallmark of oncogenesis. Together, these data demonstrate that LMP1 CTAR3 does in fact function in intracellular signaling and leads to biological effects. We propose that LMP1, by interaction with Ubc9, modulates sumoylation processes, which regulate signal transduction pathways that affect phenotypic changes associated with oncogenesis.