HIV-1 Nef promotes ubiquitination and proteasomal degradation of p53 tumor suppressor protein by using E6AP
HIV-1 Nef promotes ubiquitination and proteasomal degradation of p53 tumor suppressor protein by using E6AP
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DOI：
10.1016/j.bbrc.2020.05.188
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发表时间：
2020-09-03
影响因子：
3.1
通讯作者：
Banerjea, Akhil C.
中科院分区：
文献类型：
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作者：
Ali, Amjad;Farooqui, Sabihur Rahman;Banerjea, Akhil C.
人类免疫缺陷病毒-1(HIV-1)Nef促进P53蛋白降解，保护HIV-1感染细胞免受P53诱导的细胞凋亡。我们发现Nef介导的P53降解是通过泛素蛋白酶体途径以不依赖于MDM2的方式完成的。通过GST下拉实验和免疫沉淀实验，我们发现在Nef基因转导的HEK-293T细胞和HIV-1感染的MOLT3细胞中，Nef与E3泛素连接酶E6AP相互作用。Nef与E6AP联用可促进P53泛素化和降解，而与E6AP-C843A(显性阴性E6AP突变体)联用则不能促进P53泛素化和降解。我们发现Nef与E6AP结合并促进E6AP依赖的P53泛素化。外源性表达P53蛋白后，Nef可抑制P53基因缺失的H1299细胞的凋亡。Nef与E6AP共同表达后，H1299细胞对P53的依赖性凋亡进一步减少。然而，当Nef与E6AP-C843A共表达时，Nef介导的P53诱导的H1299细胞凋亡的减少被恢复。因此，Nef和E6AP协同促进P53泛素化和降解，从而抑制P53依赖的细胞凋亡。CHME3细胞是HIV-1的自然宿主，也显示出P53泛素化和Nef和E6AP的降解。这些结果表明，在HIV-1感染过程中，Nef通过细胞E3连接酶E6AP诱导P53降解，从而抑制细胞凋亡。(C)2020 Elsevier Inc.保留所有权利。
Human Immunodeficiency Virus-1 (HIV-1) Nef promotes p53 protein degradation to protect HIV-1 infected cells from p53 induced apoptosis. We found that Nef mediated p53 degradation is accom-plished through ubiquitin proteasome pathway in an Mdm2-independent manner. By GST pulldown and immunoprecipitation assays, we have shown that Nef interacts with E3 ubiquitin ligase E6AP in both Nef transfected HEK-293T cells and HIV-1 infected MOLT3 cells. The p53 ubiquitination and degradation was found to be enhanced by Nef with E6AP but not by Nef with E6AP-C843A, a dominant negative E6AP mutant. We show that Nef binds with E6AP and promotes E6AP dependent p53 ubiquitination. Further, Nef inhibits apoptosis of p53 null H1299 cells after exogenous expression of p53 protein. The p53 dependent apoptosis of H1299 cells was further reduced after the expression of Nef with E6AP. However, Nef mediated reduction in p53 induced apoptosis of H1299 cells was restored when Nef was co -expressed with E6AP-C843A. Thus, Nef and E6AP co-operate to promote p53 ubiquitination and degradation in order to suppress p53 dependent apoptosis. CHME3 cells, which are a natural host of HIV -1, also show p53 ubiquitination and degradation by Nef and E6AP. These results establish that Nef in-duces p53 degradation via cellular E3 ligase E6AP to inhibit apoptosis during HIV-1 infection. (C) 2020 Elsevier Inc. All rights reserved.