Expression of HIV-1 accessory protein Vif is controlled uniquely to be low and optimal by proteasome degradation
Expression of HIV-1 accessory protein Vif is controlled uniquely to be low and optimal by proteasome degradation
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DOI：
10.1016/j.micinf.2004.04.011
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发表时间：
2004-07-01
影响因子：
5.8
通讯作者：
Adachi, A
中科院分区：
文献类型：
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作者：
Fujita, M;Akari, H;Adachi, A
虽然 1 型人类免疫缺陷病毒 (HIV-1) 的 Vif 蛋白对于病毒在不允许的细胞中复制至关重要，但它会在细胞内迅速降解。我们之前已经提出，Vif 的快速周转对于防止该蛋白在高表达水平时产生有害影响具有生物学意义。我们现在通过检查脉冲/追踪实验中蛋白酶抑制剂的阻断作用以及监测 Vif 泛素化的程度来研究 Vif 降解的机制。 Vif 的快速周转可以被蛋白酶体抑制剂阻断，并且 Vif 是高度泛素化的。研究发现细胞骨架 Vif 比可溶性胞质 Vif 更稳定。 Vif 的这些降解特征与细胞类型无关，并且在非许可细胞和许可细胞中均观察到。一系列 vif 缺失突变体的表征表明，预测对 β 链结构形成很重要的氨基酸（氨基酸编号 63-70 和 86-89）对于维持 Vif 的正常表达水平和病毒感染性至关重要。最后，我们对四种 HIV-1 辅助蛋白进行了比较稳定性分析。 Vif 的独特之处在于其半衰期短和降解程度大。综上所述，我们得出结论，HIV-1 Vif 的蛋白酶体降解是一个病毒学重要过程，对于 Vif 的功能至关重要。 (C) 2004 年爱思唯尔 SAS。版权所有。
While the Vif protein of human immunodeficiency virus type 1 (HIV-1) is essential for viral replication in non-permissive cells, it is rapidly degraded intracellularly. We have previously suggested that the rapid turn-over of Vif is biologically meaningful to prevent detrimental effects of this protein at high expression levels. We now studied the mechanism of Vif degradation by examining the blocking effect of protease inhibitors in pulse/chase experiments and by monitoring the extent of Vif ubiquitination. The rapid turn-over of Vif could be blocked by proteasome inhibitors, and Vif was highly ubiquitinated. Cytoskeletal Vif was found to be more stable than soluble cytosolic Vif. These degradation characteristics of Vif were cell type-independent and observed in both non-permissive and permissive cells. Characterization of a series of vif deletion mutants showed that amino acids predicted to be important for formation of beta-strand structures (amino acid nos. 63-70 and 86-89) were critical for maintaining a normal expression level of Vif and for viral infectivity. Finally, we performed comparative stability analysis of the four HIV-1 accessory proteins. Vif was unique in its short half-life and in the magnitude of the degradation. Taken together, we conclude that the proteasome degradation of HIV-1 Vif is a virologically important process and crucial for the function of Vif. (C) 2004 Elsevier SAS. All rights reserved.