p53-Derived Host Restriction of HIV-1 Replication by Protein Kinase R-Mediated Tat Phosphorylation and Inactivation
p53-Derived Host Restriction of HIV-1 Replication by Protein Kinase R-Mediated Tat Phosphorylation and Inactivation
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p53 衍生宿主通过蛋白激酶 R 介导的 Tat 磷酸化和失活来限制 HIV-1 复制
DOI：
10.1128/jvi.03087-14
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发表时间：
2015
影响因子：
5.4
通讯作者：
Y. Bae
中科院分区：
文献类型：
--
作者：
C. Yoon;Sang;S. Byeon;Yideul Jeong;Jinjoo Lee;K. Kim;Jinseu Park;Y. Bae
肿瘤抑制因子p53被认为是抑制HIV-1复制的宿主限制因子，但其详细的分子机制几十年来一直难以捉摸。在这里，我们证明p53介导的HIV-1抑制归因于双链RNA （dsRNA）依赖性蛋白激酶（PKR）介导的HIV-1反式激活子（Tat）磷酸化和失活。p53沉默可显著增强感染细胞中的HIV-1复制。p53的异位表达抑制了Tat的活性，这是通过PKR沉默来挽救的。此外，PKR的异位表达使p53−/−和eIF2αCA细胞中的Tat活性降低。最后，我们发现HIV-1感染激活p53，随后诱导和激活PKR。PKR直接与HIV-1 Tat相互作用，并在5个Ser/Thr残基（T23, T40, S46， S62和S68）上磷酸化Tat的第一个外显子，从而在三个关键步骤中抑制Tat介导的前病毒转录：(i)富含精氨酸基序（ARM）附近的磷酸化抑制Tat易位进入细胞核，（ii） Tat磷酸化的积累消除了Tat- Tat响应区（TAR）的结合，（iii） T23和/或T40处的Tat磷酸化消除了Tat-cyclin T1的相互作用。这5个Ser/Thr位点在欧洲和美国流行的HIV-1毒株中高度保守。综上所述，我们的研究结果表明，p53衍生的宿主对HIV-1复制的限制可能至少部分归因于HIV-1感染和艾滋病发病机制中非规范的p53/PKR/Tat磷酸化和失活途径。hiv -1介导的疾病在初次感染后持续数年至数十年发展为艾滋病。宿主限制和相关的病毒潜伏期已经研究了几十年。p53被认为是抑制HIV-1复制的重要宿主限制因子。然而，其具体的分子机制尚不清楚。在本研究中，我们发现p53介导的HIV-1限制归因于p53/PKR/ tat失活途径。HIV-1感染激活p53，随后诱导PKR表达和激活。PKR直接磷酸化Tat的5个特定的Ser/Thr残基，这伴随着HIV-1复制的显著抑制。Tat磷酸化在这些位点的积累通过阻断Tat的核定位、Tat与TAR的结合以及Tat-cyclin T1的相互作用来抑制Tat的功能。我们的发现有助于更好地理解p53衍生宿主在艾滋病发病机制中抑制HIV-1复制的机制，并可能有助于进一步研究HIV-1的潜在治疗靶点。
ABSTRACT Tumor suppressor p53 has been suggested to be a host restriction factor against HIV-1 replication, but the detailed molecular mechanism has remained elusive for decades. Here, we demonstrate that p53-mediated HIV-1 suppression is attributed to double-stranded RNA (dsRNA)-dependent protein kinase (PKR)-mediated HIV-1 trans-activator (Tat) phosphorylation and inactivation. p53 silencing significantly enhanced HIV-1 replication in infected cells. Ectopic expression of p53 suppressed Tat activity, which was rescued by PKR silencing. In addition, ectopic expression of PKR abolished Tat activity in p53−/− and eIF2αCA cells. Finally, we found that HIV-1 infection activates p53, followed by the induction and activation of PKR. PKR directly interacted with HIV-1 Tat and phosphorylates the first exon of Tat exclusively at five Ser/Thr residues (T23, T40, S46, S62, and S68), which inhibits Tat-mediated provirus transcription in three critical steps: (i) phosphorylation near the arginine-rich motif (ARM) inhibits Tat translocation into the nucleus, (ii) accumulation of Tat phosphorylation abolishes Tat–Tat-responsive region (TAR) binding, and (iii) Tat phosphorylation at T23 and/or T40 obliterates the Tat-cyclin T1 interaction. These five Ser/Thr sites on Tat were highly conserved in HIV-1 strains prevalent in Europe and the United States. Taken together, our findings indicate that p53-derived host restriction of HIV-1 replication is likely attributable, at least in part, to a noncanonical p53/PKR/Tat phosphorylation and inactivation pathway in HIV-1 infection and AIDS pathogenesis. IMPORTANCE HIV-1-mediated disease progression to AIDS lasts for years to decades after primary infection. Host restriction and associated viral latency have been studied for several decades. p53 has been suggested as an important host restriction factor against HIV-1 replication. However, the detailed molecular mechanism is still unclear. In the present study, we found that the p53-mediated HIV-1 restriction is attributed to a p53/PKR/Tat-inactivation pathway. HIV-1 infection activated p53, which subsequently induced PKR expression and activation. PKR directly phosphorylated Tat exclusively at five specific Ser/Thr residues, which was accompanied by significant suppression of HIV-1 replication. Accumulation of Tat phosphorylation at these sites inhibited Tat function by blocking Tat nuclear localization, Tat binding to TAR, and Tat-cyclin T1 interaction. Our findings provide a better understanding of the p53-derived host restriction mechanism against HIV-1 replication in AIDS pathogenesis and may contribute to further research focusing on the investigation of potential therapeutic targets for HIV-1.
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影响因子：
32.4
作者：
Blanco-Melo D;Venkatesh S;Bieniasz PD
通讯作者：
Bieniasz PD
DOI：
10.1073/pnas.89.20.9734
发表时间：
1992-10-15
影响因子：
11.1
作者：
LORET, EP;GEORGEL, P;HO, PS
通讯作者：
HO, PS
影响因子：
16.8
作者：
Shaw MH;Kamada N;Warner N;Kim YG;Nuñez G
通讯作者：
Nuñez G
影响因子：
32.4
作者：
Kim YG;Kamada N;Shaw MH;Warner N;Chen GY;Franchi L;Núñez G
通讯作者：
Núñez G
影响因子：
16
作者：
Kaehlcke, K;Dorr, A;Ott, M
通讯作者：
Ott, M