在感染过程中，食源性病原体“单核细胞增生李斯特菌”能利用宿主细胞的大量功能，包括涉及泛素化和磷酸化的、专门修饰关键蛋白活性的转录后修饰。致病细菌对被称为“SUMOylation”的泛素样修饰（真核细胞中一个重要过程）的效应在很大程度上仍不清楚。
现在，对被“单核细胞增生李斯特菌”感染的人类细胞和对一个小鼠模型所做的一项研究表明，其毒性因子listeriolysin O (LLO)通过触发Ubc9（“SUMOylation”机制中一种必要的酶）的降解诱导细胞中被SUMO化的蛋白水平下降。
这项工作说明，李斯特菌（可能还包括其他病原体）通过降低关键调控蛋白的“SUMOylation”水平来抑制宿主对感染的反应。 (生物谷Bioon.com)
生物谷推荐原文出处：
Nature doi:10.1038/nature08963
Listeria monocytogenes impairs SUMOylation for efficient infection
David Ribet1,2,3, Mélanie Hamon1,2,3, Edith Gouin1,2,3, Marie-Anne Nahori1,2,3, Francis Impens4,5, Hélène Neyret-Kahn6,7, Kris Gevaert4,5, Jo?l Vandekerckhove4,5, Anne Dejean6,7 & Pascale Cossart1,2,3
Institut Pasteur, Unité des Interactions Bactéries-Cellules, Département de Biologie Cellulaire et Infection, F-75015 Paris, France
INSERM, U604, F-75015 Paris, France
INRA, USC2020, F-75015 Paris, France
Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium
Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
Institut Pasteur, Unité Organisation Nucléaire et Oncogenèse, Département de Biologie Cellulaire et Infection, F-75015 Paris, France
INSERM, U579, F-75015 Paris, France
During infection, pathogenic bacteria manipulate the host cell in various ways to allow their own replication, propagation and escape from host immune responses. Post-translational modifications are unique mechanisms that allow cells to rapidly, locally and specifically modify activity or interactions of key proteins. Some of these modifications, including phosphorylation and ubiquitylation1, 2, can be induced by pathogens. However, the effects of pathogenic bacteria on SUMOylation, an essential post-translational modification in eukaryotic cells3, remain largely unknown. Here we show that infection with Listeria monocytogenes leads to a decrease in the levels of cellular SUMO-conjugated proteins. This event is triggered by the bacterial virulence factor listeriolysin O (LLO), which induces a proteasome-independent degradation of Ubc9, an essential enzyme of the SUMOylation machinery, and a proteasome-dependent degradation of some SUMOylated proteins. The effect of LLO on Ubc9 is dependent on the pore-forming capacity of the toxin and is shared by other bacterial pore-forming toxins like perfringolysin O (PFO) and pneumolysin (PLY). Ubc9 degradation was also observed in vivo in infected mice. Furthermore, we show that SUMO overexpression impairs bacterial infection. Together, our results reveal that Listeria, and probably other pathogens, dampen the host response by decreasing the SUMOylation level of proteins critical for infection.
