Assembly with the Cul4A-DDB1DCAF1 ubiquitin ligase protects HIV-1 vpr from proteasomal degradation
Assembly with the Cul4A-DDB1DCAF1 ubiquitin ligase protects HIV-1 vpr from proteasomal degradation
复制标题
DOI：
10.1074/jbc.m710298200
复制
发表时间：
2008-08-01
影响因子：
4.8
通讯作者：
Margottin-Goguet, Florence
中科院分区：
文献类型：
--
作者：
Le Rouzic, Erwann;Morel, Marina;Margottin-Goguet, Florence
许多病毒破坏宿主泛素蛋白酶体系统以优化其生命周期。我们最近记录了人类免疫缺陷病毒 1 型 Vpr 蛋白的这种机制，它通过招募 Cul4A-DDB1 泛素连接酶的 DCAF1 接头来促进细胞周期停滞，这一发现现已得到多个研究小组的证实。在这里，我们检查了 Cul4A-DDB1(DCAF1) 对 Vpr 稳定性的影响。我们发现，DCAF1 结合缺陷的 Vpr(Q65R) 突变体以比野生型 Vpr 更高的速率经历蛋白酶体介导的降解。 DCAF1 过表达可稳定野生型 Vpr 并导致其在细胞质中积累，而对 Vpr(Q65R) 突变体则没有影响。相反，小干扰RNA介导的DCAF1沉默会降低病毒蛋白的稳态量。 DCAF1（人类免疫缺陷病毒 2 型和 SIVmac 毒株的 Vpr 物种所保守）的稳定作用会导致 G(2) 阻滞增加，并且需要 DDB1 的存在，表明它是通过 Vpr 与功能性 Cul4A-DDB1(DCAF1) 复合物组装而发生的。此外，在人类免疫缺陷病毒 1 型感染的细胞中，从传入的病毒颗粒发出的 Vpr 蛋白在 DCAF1 或 DDB1 沉默下不稳定。结合我们之前的发现，我们的数据表明，Cul4A-DDB1（DCAF1）通过为 Vpr 提供降解特定宿主蛋白的设备以及通过另一种细胞 E3 泛素连接酶抵消其蛋白酶体靶向来发挥双重作用。这种保护机制可能代表了一种优化 Vpr 分子活性的有效方法，这些分子是在新合成发生之前由传入病毒传递的。因此，针对 Vpr-DCAF1 相互作用可能会带来治疗兴趣。
Many viruses subvert the host ubiquitin-proteasome system to optimize their life cycle. We recently documented such a mechanism for the human immunodeficiency virus type 1 Vpr protein, which promotes cell cycle arrest by recruiting the DCAF1 adaptor of the Cul4A-DDB1 ubiquitin ligase, a finding now confirmed by several groups. Here we examined the impact of Cul4A-DDB1(DCAF1) on Vpr stability. We show that the Vpr(Q65R) mutant, which is defective in DCAF1 binding, undergoes proteasome-mediated degradation at a higher rate than wild-type Vpr. DCAF1 overexpression stabilizes wild-type Vpr and leads to its cytoplasmic accumulation, whereas it has no effect on the Vpr(Q65R) mutant. Conversely, small interfering RNA-mediated silencing of DCAF1 decreases the steady state amount of the viral protein. Stabilization by DCAF1, which is conserved by Vpr species from human immunodeficiency virus type 2 and the SIVmac strain, results in increased G(2) arrest and requires the presence of DDB1, indicating that it occurs through assembly of Vpr with a functional Cul4A-DDB1(DCAF1) complex. Furthermore, in human immunodeficiency virus type 1-infected cells, the Vpr protein, issued from the incoming viral particle, is destabilized under DCAF1 or DDB1 silencing. Together with our previous findings, our data suggest that Cul4A-DDB1(DCAF1) acts at a dual level by providing Vpr with the equipment for the degradation of specific host proteins and by counteracting its proteasome targeting by another cellular E3 ubiquitin ligase. This protection mechanism may represent an efficient way to optimize the activity of Vpr molecules that are delivered by the incoming virus before neosynthesis takes place. Targeting the Vpr-DCAF1 interaction might therefore present therapeutic interest.