Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
Virology. 2014 Jan 20;449:82-7. doi: 10.1016/j.virol.2013.11.004. Epub 2013 Nov 26.
Vif is essential for HIV-1 replication in T cells and macrophages. Vif recruits a host ubiquitin ligase complex to promote proteasomal degradation of the APOBEC3 restriction factors by poly-ubiquitination. The cellular transcription cofactor CBFβ is required for Vif function by stabilizing the Vif protein and promoting recruitment of a cellular Cullin5-RING ubiquitin ligase complex. Interaction between Vif and CBFβ is a promising therapeutic target, but little is known about the interfacial residues. We now demonstrate that Vif conserved residues E88/W89 are crucial for CBFβ binding. Substitution of E88/W89 to alanines impaired binding to CBFβ, degradation of APOBEC3, and virus infectivity in the presence of APOBEC3 in single-cycle infection. In spreading infection, NL4-3 with Vif E88A/W89A mutation replicated comparably to wild-type virus in permissive CEM-SS cells, but not in multiple APOBEC3 expressing non-permissive CEM cells. These results support a model in which HIV-1 Vif residues E88/W89 may participate in binding CBFβ.
Vif 对于 HIV-1 在 T 细胞和巨噬细胞中的复制是必不可少的。Vif 招募宿主泛素连接酶复合物通过多泛素化促进 APOBEC3 限制因子的蛋白酶体降解。细胞转录共因子 CBFβ 通过稳定 Vif 蛋白并促进细胞 Cullin5-RING 泛素连接酶复合物的募集来发挥 Vif 功能。Vif 和 CBFβ 之间的相互作用是一个有前途的治疗靶点，但关于界面残基知之甚少。我们现在证明 Vif 保守残基 E88/W89 对于 CBFβ 结合至关重要。E88/W89 的取代会损害与 CBFβ 的结合、APOBEC3 的降解以及在存在 APOBEC3 的情况下单循环感染中的病毒感染性。在扩散感染中，带有 Vif E88A/W89A 突变的 NL4-3 在允许的 CEM-SS 细胞中与野生型病毒复制相当，但在多个表达 APOBEC3 的非允许的 CEM 细胞中则不行。这些结果支持一种模型，即 HIV-1 Vif 残基 E88/W89 可能参与与 CBFβ 的结合。
