Wang Huiping, Zhu Xinxing, Zhu Ying, Liu Jiangfang, Hu Xiangming, Wang Yu, Peng Sijia, Chen Yanheng, Chen Ruichuan, Ding Feng, Liu Runzhong
State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, China ; Department of Neurobiology, Xuzhou Medical College, Xuzhou, Jiangsu 221009, China.
State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, China.
Biomed Res Int. 2014;2014:968027. doi: 10.1155/2014/968027. Epub 2014 Jul 21.
Prostratin has been proposed as a promising reagent for eradicating the latent HIV-1 provirus by inducing HIV-1 transcription activation. The molecular mechanism of this activation, however, is far from clear. Here, we show that the protein kinase D3 (PKD3) is essential for prostratin-induced transcription activation of latent HIV-1 provirus. First, silencing PKD3, but not the other members of PKD family, blocked prostratin-induced transcription of HIV-1. Second, overexpressing the constitutively active form of PKD3, but not the wild-type or kinase-dead form of PKD3, augmented the expression of HIV-1. Consistent with this observation, we found that prostratin could trigger PKD3 activation by inducing the phosphorylation of its activation loop. In addition, we identified PKCε of the novel PKC subfamily as the upstream kinase for this phosphorylation. Finally, the activation effect of PKD3 on HIV-1 transcription was shown to depend on the presence of κB element and the prostratin-induced activation of NF-κB, as indicated by the fact that silencing PKD3 blocked prostratin-induced NF-κB activation and NF-κB-dependent HIV-1 transcription. Therefore, for the first time, PKD3 is implicated in the transcription activation of latent HIV-1 provirus, and our results revealed a molecular mechanism of prostratin-induced HIV-1 transcription via PKCε/PKD3/NF-κB signaling pathway.
原卟啉被认为是一种有前景的试剂，可通过诱导HIV-1转录激活来根除潜伏的HIV-1前病毒。然而，这种激活的分子机制尚不清楚。在此，我们表明蛋白激酶D3（PKD3）对于原卟啉诱导的潜伏HIV-1前病毒转录激活至关重要。首先，沉默PKD3而非PKD家族的其他成员，可阻断原卟啉诱导的HIV-1转录。其次，过表达PKD3的组成型活性形式而非野生型或激酶失活形式的PKD3，可增强HIV-1的表达。与这一观察结果一致，我们发现原卟啉可通过诱导其激活环的磷酸化来触发PKD3激活。此外，我们确定新型PKC亚家族的PKCε为这种磷酸化的上游激酶。最后，PKD3对HIV-1转录的激活作用显示取决于κB元件的存在以及原卟啉诱导的NF-κB激活，这一事实表明沉默PKD3可阻断原卟啉诱导的NF-κB激活和NF-κB依赖性HIV-1转录。因此，PKD3首次被证明与潜伏HIV-1前病毒的转录激活有关，我们的结果揭示了原卟啉通过PKCε/PKD3/NF-κB信号通路诱导HIV-1转录的分子机制。
