Li Changqing, Debing Yannick, Jankevicius Gytis, Neyts Johan, Ahel Ivan, Coutard Bruno, Canard Bruno
CNRS, AFMB UMR 7257, Marseille, France Aix-Marseille Université, AFMB UMR 7257, Marseille, France.
Rega Institute for Medical Research, Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium.
J Virol. 2016 Sep 12;90(19):8478-86. doi: 10.1128/JVI.00705-16. Print 2016 Oct 1.
ADP-ribosylation is a posttranslational protein modification in which ADP-ribose is transferred from NAD(+) to specific acceptors to regulate a wide variety of cellular processes. The macro domain is an ancient and highly evolutionarily conserved protein domain widely distributed throughout all kingdoms of life, including viruses. The human TARG1/C6orf130, MacroD1, and MacroD2 proteins can reverse ADP-ribosylation by acting on ADP-ribosylated substrates through the hydrolytic activity of their macro domains. Here, we report that the macro domain from hepatitis E virus (HEV) serves as an ADP-ribose-protein hydrolase for mono-ADP-ribose (MAR) and poly(ADP-ribose) (PAR) chain removal (de-MARylation and de-PARylation, respectively) from mono- and poly(ADP)-ribosylated proteins, respectively. The presence of the HEV helicase in cis dramatically increases the binding of the macro domain to poly(ADP-ribose) and stimulates the de-PARylation activity. Abrogation of the latter dramatically decreases replication of an HEV subgenomic replicon. The de-MARylation activity is present in all three pathogenic positive-sense, single-stranded RNA [(+)ssRNA] virus families which carry a macro domain: Coronaviridae (severe acute respiratory syndrome coronavirus and human coronavirus 229E), Togaviridae (Venezuelan equine encephalitis virus), and Hepeviridae (HEV), indicating that it might be a significant tropism and/or pathogenic determinant.
Protein ADP-ribosylation is a covalent posttranslational modification regulating cellular protein activities in a dynamic fashion to modulate and coordinate a variety of cellular processes. Three viral families, Coronaviridae, Togaviridae, and Hepeviridae, possess macro domains embedded in their polyproteins. Here, we show that viral macro domains reverse cellular ADP-ribosylation, potentially cutting the signal of a viral infection in the cell. Various poly(ADP-ribose) polymerases which are notorious guardians of cellular integrity are demodified by macro domains from members of these virus families. In the case of hepatitis E virus, the adjacent viral helicase domain dramatically increases the binding of the macro domain to PAR and simulates the demodification activity.
ADP核糖基化是一种翻译后蛋白质修饰，其中ADP核糖从NAD(+)转移到特定受体，以调节多种细胞过程。宏结构域是一个古老且在进化上高度保守的蛋白质结构域，广泛分布于包括病毒在内的所有生命王国。人类TARG1/C6orf130、MacroD1和MacroD2蛋白可以通过其宏结构域的水解活性作用于ADP核糖基化底物，从而逆转ADP核糖基化。在这里，我们报告称，戊型肝炎病毒（HEV）的宏结构域作为一种ADP核糖-蛋白质水解酶，分别从单（ADP）核糖基化蛋白和多（ADP）核糖基化蛋白中去除单-ADP核糖（MAR）和多聚（ADP-核糖）（PAR）链（分别为去MAR化和去PAR化）。顺式存在的HEV解旋酶显著增加宏结构域与多聚（ADP-核糖）的结合，并刺激去PAR化活性。后者的缺失显著降低了HEV亚基因组复制子的复制。去MAR化活性存在于携带宏结构域的所有三个致病性正链单链RNA [(+)ssRNA]病毒家族中：冠状病毒科（严重急性呼吸综合征冠状病毒和人冠状病毒229E）、披膜病毒科（委内瑞拉马脑炎病毒）和戊型肝炎病毒科（HEV），这表明它可能是一个重要的嗜性和/或致病决定因素。
蛋白质ADP核糖基化是一种共价翻译后修饰，以动态方式调节细胞蛋白质活性，从而调节和协调多种细胞过程。冠状病毒科、披膜病毒科和戊型肝炎病毒科这三个病毒家族在其多聚蛋白中嵌入了宏结构域。在这里，我们表明病毒宏结构域逆转细胞ADP核糖基化，可能切断细胞中病毒感染的信号。各种作为细胞完整性臭名昭著守护者的多聚（ADP-核糖）聚合酶被这些病毒家族成员的宏结构域去修饰。就戊型肝炎病毒而言，相邻的病毒解旋酶结构域显著增加宏结构域与PAR的结合，并模拟去修饰活性。
