Wasilko David J, Mao Yuxin
Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
Curr Genet. 2016 Feb;62(1):105-8. doi: 10.1007/s00294-015-0521-y. Epub 2015 Oct 3.
Intracellular bacterial pathogens use secreted effector proteins to alter host cellular processes, with the goal of subverting host defenses and allowing the infection to progress. One such pathogen, Legionella pneumophila, secretes ~300 proteins into its host to alter a number of pathways including intracellular trafficking, phosphoinositide metabolism, and cell signaling. The Legionella effector SidC was previously found to bind to PI(4)P and was responsible for the enrichment of ER proteins and ubiquitinated species on the Legionella-containing vacuoles. Through our recent work, we have discovered that SidC contains a unique N-terminal E3 ubiquitin ligase domain and a C-terminal novel PI(4)P-binding domain. Our results demonstrate that SidC serves to link two distinct cellular pathways, ubiquitin and phosphoinositide. However, how the ubiquitin ligase activity regulates host membrane trafficking events remains to be investigated.
细胞内细菌病原体利用分泌的效应蛋白来改变宿主细胞过程，目的是颠覆宿主防御并使感染得以进展。嗜肺军团菌就是这样一种病原体，它向宿主分泌约300种蛋白质，以改变包括细胞内运输、磷酸肌醇代谢和细胞信号传导在内的多种途径。军团菌效应蛋白SidC先前被发现可与PI(4)P结合，并负责含军团菌液泡上内质网蛋白和泛素化物种的富集。通过我们最近的研究工作，我们发现SidC含有一个独特的N端E3泛素连接酶结构域和一个C端新型PI(4)P结合结构域。我们的结果表明，SidC起到连接泛素和磷酸肌醇这两种不同细胞途径的作用。然而，泛素连接酶活性如何调节宿主膜运输事件仍有待研究。
