Kew Verity, Wills Mark, Reeves Matthew
Department of Medicine, Addenbrooke's Hospital, Cambridge, UK.
UCL Institute of Immunity & Transplantation, Royal Free Hospital, London, UK.
J Mol Biochem. 2017;6(1):13-25.
Viral binding and entry provides the first trigger of a cell death response and thus how human cytomegalovirus (HCMV) evades this - particularly during latent infection where a very limited pattern of gene expression is observed - is less well understood. It has been demonstrated that the activation of cellular signalling pathways upon virus binding promotes the survival of latently infected cells by the activation of cell encoded anti-apoptotic responses. In CD34+ cells, a major site of HCMV latency, ERK signalling is important for survival and we now show that the activation of this pathway impacts on multiple aspects of cell death pathways. The data illustrate that HCMV infection triggers activation of pro-apoptotic Bak which is then countered through multiple ERK-dependent functions. Specifically, ERK promotes ELK1 mediated transcription of the key survival molecule MCL-1, along with a concomitant decrease of the pro-apoptotic BIM and PUMA proteins. Finally, we show that the elimination of ELK-1 from CD34+ cells results in elevated Bak activation in response to viral infection, resulting in cell death. Taken together, these data begin to shed light on the poly-functional response elicited by HCMV via ERK-MAPK to promote cell survival.
病毒结合与进入是细胞死亡反应的首个触发因素,因此人们对人类巨细胞病毒(HCMV)如何逃避这一过程了解较少,尤其是在潜伏感染期间,此时观察到的基因表达模式非常有限。已经证明,病毒结合后细胞信号通路的激活通过激活细胞编码的抗凋亡反应来促进潜伏感染细胞的存活。在HCMV潜伏的主要位点CD34 +细胞中,ERK信号传导对细胞存活很重要,我们现在表明该通路的激活会影响细胞死亡通路的多个方面。数据表明,HCMV感染触发促凋亡蛋白Bak的激活,然后通过多种ERK依赖性功能来对抗。具体而言,ERK促进ELK1介导的关键存活分子MCL-1的转录,同时促凋亡蛋白BIM和PUMA的水平随之降低。最后,我们表明从CD34 +细胞中消除ELK-1会导致病毒感染后Bak激活增加,从而导致细胞死亡。综上所述,这些数据开始揭示HCMV通过ERK-MAPK引发的促进细胞存活的多功能反应。