PDF(Pubmed)
Abstract：
An interaction between human papillomavirus 16 (HPV16) E2 and the cellular proteins TopBP1 and BRD4 is required for E2 plasmid segregation function. The E2-TopBP1 interaction promotes increased mitotic E2 protein levels in U2OS and N/Tert-1 cells, as well as in human foreskin keratinocytes immortalized by HPV16 (HFK + HPV16). SIRT1 deacetylation reduces E2 protein stability and here we demonstrate that increased E2 acetylation occurs during mitosis in a TopBP1 interacting-dependent manner, promoting E2 mitotic stabilization. p300 mediates E2 acetylation and acetylation is increased due to E2 switching off SIRT1 function during mitosis in a TopBP1 interacting-dependent manner, confirmed by increased p53 stability and acetylation on lysine 382, a known target for SIRT1 deacetylation. SIRT1 can complex with E2 in growing cells but is unable to do so during mitosis due to the E2-TopBP1 interaction; SIRT1 is also unable to complex with p53 in mitotic E2 wild-type cells but can complex with p53 outside of mitosis. E2 lysines 111 and 112 are highly conserved residues across all E2 proteins and we demonstrate that K111 hyper-acetylation occurs during mitosis, promoting E2 interaction with Topoisomerase 1 (Top1). We demonstrate that K112 ubiquitination promotes E2 proteasomal degradation during mitosis. E2-TopBP1 interaction promotes mitotic acetylation of CHK2, promoting phosphorylation and activation of the DNA damage response (DDR). The results present a new model in which the E2-TopBP1 complex inactivates SIRT1 during mitosis, and activates the DDR. This is a novel mechanism of HPV16 activation of the DDR, a requirement for the viral life cycle.
OBJECTIVE: Human papillomaviruses (HPVs) are causative agents in around 5% of all human cancers. While there are prophylactic vaccines that will significantly alleviate HPV disease burden on future generations, there are currently no anti-viral strategies available for the treatment of HPV cancers. To generate such reagents, we must understand more about the HPV life cycle, and in particular about viral-host interactions. Here, we describe a novel mitotic complex generated by the HPV16 E2 protein interacting with the host protein TopBP1 that controls the function of the deacetylase SIRT1. The E2-TopBP1 interaction disrupts SIRT1 function during mitosis in order to enhance acetylation and stability of viral and host proteins. We also demonstrate that the E2-TopBP1 interaction activates the DDR. This novel complex is essential for the HPV16 life cycle and represents a novel anti-viral therapeutic target.
OBJECTIVE: Human papillomaviruses (HPVs) are causative agents in around 5% of all human cancers. While there are prophylactic vaccines that will significantly alleviate HPV disease burden on future generations, there are currently no anti-viral strategies available for the treatment of HPV cancers. To generate such reagents, we must understand more about the HPV life cycle, and in particular about viral-host interactions. Here, we describe a novel mitotic complex generated by the HPV16 E2 protein interacting with the host protein TopBP1 that controls the function of the deacetylase SIRT1. The E2-TopBP1 interaction disrupts SIRT1 function during mitosis in order to enhance acetylation and stability of viral and host proteins. We also demonstrate that the E2-TopBP1 interaction activates the DDR. This novel complex is essential for the HPV16 life cycle and represents a novel anti-viral therapeutic target.
摘要：
人乳头瘤病毒16（HPV16）E2与细胞蛋白TopBP1和BRD4之间的相互作用是E2质粒分离功能所必需的。E2-TopBP1相互作用促进U2OS和N/Tert-1细胞中有丝分裂E2蛋白水平增加，以及通过HPV16（HFKHPV16）永生化的人包皮角质形成细胞。SIRT1脱乙酰化降低E2蛋白的稳定性，在这里我们证明了在有丝分裂过程中E2乙酰化的增加以TopBP1相互作用依赖性方式发生。促进E2有丝分裂稳定。p300介导E2乙酰化和乙酰化增加，由于E2在有丝分裂过程中以TopBP1相互作用依赖性方式关闭SIRT1功能，通过增加的p53稳定性和赖氨酸382的乙酰化，SIRT1去乙酰化的已知目标证实。SIRT1可以在生长中的细胞中与E2复合，但由于E2-TopBP1相互作用，在有丝分裂期间无法这样做；SIRT1也无法在有丝分裂E2野生型细胞中与p53复合，但可以在有丝分裂之外与p53复合。E2赖氨酸111和112是所有E2蛋白中高度保守的残基，我们证明了K111在有丝分裂过程中发生过度乙酰化，促进E2与拓扑异构酶1（Top1）的相互作用。我们证明K112泛素化促进有丝分裂过程中的E2蛋白酶体降解。E2-TopBP1相互作用促进CHK2的有丝分裂乙酰化，促进DNA损伤反应（DDR）的磷酸化和激活。结果提出了一种新的模型，其中E2-TopBP1复合物在有丝分裂期间使SIRT1失活，并激活DDR。这是一种新的HPV16激活DDR的机制，病毒生命周期的要求。
目的：人类乳头瘤病毒（HPV）是所有人类癌症中约5％的病原体。虽然有预防性疫苗可以显著减轻后代的HPV疾病负担，目前尚无抗病毒策略可用于治疗HPV癌症.为了产生这样的试剂，我们必须更多地了解HPV的生命周期，特别是关于病毒与宿主的相互作用。这里,我们描述了由HPV16E2蛋白与控制脱乙酰酶SIRT1功能的宿主蛋白TopBP1相互作用产生的新型有丝分裂复合物。E2-TopBP1相互作用在有丝分裂期间破坏SIRT1功能,以增强病毒和宿主蛋白的乙酰化和稳定性。我们还证明E2-TopBP1相互作用激活DDR。这种新型复合物对于HPV16生命周期是必不可少的，并且代表了一种新型的抗病毒治疗靶标。
目的：人类乳头瘤病毒（HPV）是所有人类癌症中约5％的病原体。虽然有预防性疫苗可以显著减轻后代的HPV疾病负担，目前尚无抗病毒策略可用于治疗HPV癌症.为了产生这样的试剂，我们必须更多地了解HPV的生命周期，特别是关于病毒与宿主的相互作用。这里,我们描述了由HPV16E2蛋白与控制脱乙酰酶SIRT1功能的宿主蛋白TopBP1相互作用产生的新型有丝分裂复合物。E2-TopBP1相互作用在有丝分裂期间破坏SIRT1功能,以增强病毒和宿主蛋白的乙酰化和稳定性。我们还证明E2-TopBP1相互作用激活DDR。这种新型复合物对于HPV16生命周期是必不可少的，并且代表了一种新型的抗病毒治疗靶标。
