On September, 28, 2015, Geng Jing and Sun Xiufeng, PhD students of School of Life Sciences, Xiamen University published a cover paper on Nature Immunology entitled “Kinases Mst1 and Mst2 positively regulate phagocytic induction of reactive oxygen species and bactericidal activity”.

　　Mitochondria need to be juxtaposed to phagosomes for the synergistic production of ample reactive oxygen species (ROS) in phagocytes to kill pathogens. However, how phagosomes transmit signals to recruit mitochondria has remained unclear. Here we found that the kinases Mst1 and Mst2 functioned to control ROS production by regulating mitochondrial trafficking and mitochondrion-phagosome juxtaposition. Mst1 and Mst2 activated the GTPase Rac to promote Toll-like receptor (TLR)-triggered assembly of the TRAF6-ECSIT complex that is required for the recruitment of mitochondria to phagosomes. Inactive forms of Rac, including the human Rac2^D57N mutant, disrupted the TRAF6-ECSIT complex by sequestering TRAF6 and substantially diminished ROS production and enhanced susceptibility to bacterial infection. Our findings demonstrate that the TLR-Mst1-Mst2-Rac signaling axis is critical for effective phagosome-mitochondrion function and bactericidal activity.

        The research is undertaken by Gen Jing of PhD Class 2012, Sun Xiufeng of PhD Class 2013 and Wang Ping, Zhang Shihao and Wang Xiaozhen, who are now in a research team led by Prof. Zhou Dawang and Chen Lanfen, collaborating with Xiamen First Hopital, Changgeng University of Taiwan andUniversityofScienceand Technology of China. The research is funded by "Thousand Youth Talents Plan", Chinese National Natural Science Foundation and Ministry of Science and Technology.

　     Article Website: http://www.nature.com/ni/journal/vaop/ncurrent/full/ni.3268.html