Edwards Megan R, Basler Christopher F
Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York.
J Infect Dis. 2015 Oct 1;212 Suppl 2(Suppl 2):S154-9. doi: 10.1093/infdis/jiv050. Epub 2015 Apr 29.
Marburg virus (MARV) is an emerging zoonotic pathogen that causes hemorrhagic fever. MARV VP24 (mVP24) protein interacts with the host cell protein Kelch-like-ECH-associated protein 1 (Keap1). Keap1 interacts with and promotes the degradation of IκB kinase β (IKKβ), a component of the IκB kinase (IKK) complex that regulates nuclear factor-κB (NF-κB) activity. We studied whether mVP24 could relieve Keap1 repression of the NF-κB pathway.
Coimmunoprecipitation assays were used to examine the interaction between Keap1 and IKKβ in the presence of wild-type mVP24 and mutants of mVP24 defective for binding to Keap1. Western blotting was used to determine levels of IKKβ expression in the presence of Keap1 and mVP24. NF-κB promoter-luciferase assays were used to determine the effect of mVP24 on Keap1-induced repression of activity.
Expression of wild-type mVP24 disrupted the interaction of IKKβ and Keap1, whereas weakly interacting and noninteracting mVP24 mutants did not disrupt the interaction between Keap1 and IKKβ. The interaction of mVP24 with Keap1 enhanced IKKβ levels in the presence of Keap1. The interaction of mVP24 with Keap1 also relieved Keap1 repression of NF-κB reporter activity.
mVP24 can relieve Keap1 repression of the NF-κB pathway through its interaction with Keap1.
马尔堡病毒（MARV）是一种新兴的人畜共患病原体，可引起出血热。MARV的VP24（mVP24）蛋白与宿主细胞蛋白kelch样ECH相关蛋白1（Keap1）相互作用。Keap1与IκB激酶β（IKKβ）相互作用并促进其降解，IKKβ是调节核因子κB（NF-κB）活性的IκB激酶（IKK）复合物的一个组成部分。我们研究了mVP24是否能解除Keap1对NF-κB途径的抑制。
采用免疫共沉淀试验检测野生型mVP24和与Keap1结合缺陷的mVP24突变体存在时Keap1与IKKβ之间的相互作用。采用蛋白质免疫印迹法测定Keap1和mVP24存在时IKKβ的表达水平。采用NF-κB启动子荧光素酶试验测定mVP24对Keap1诱导的活性抑制的影响。
野生型mVP24的表达破坏了IKKβ与Keap1的相互作用，而弱相互作用和非相互作用的mVP24突变体则没有破坏Keap1与IKKβ之间的相互作用。在有Keap1存在的情况下，mVP24与Keap1的相互作用提高了IKKβ的水平。mVP24与Keap1的相互作用也解除了Keap1对NF-κB报告基因活性的抑制。
mVP24可通过与Keap1相互作用解除Keap1对NF-κB途径的抑制。
