细菌蛋白酶调控蛋白质降解，影响细菌代谢、应激及致病力。金葡菌金属蛋白酶Eep仅报道调节性激素分泌。申请人前期工作证实：Eep是细菌ATP依赖蛋白酶FtsH的底物蛋白，Eep促进细菌对宿主细胞粘附及中性粒细胞的杀伤，小鼠菌血症模型证实Eep明显促进细菌致病力，提示Eep在金葡菌致病中发挥重要作用。金葡菌重要毒力调控系统对Eep是否有调控作用？Eep是否通过降解某种底物蛋白，通过其底物蛋白与宿主细胞相互作用，从而影响细菌毒力？为详尽阐明Eep促进金葡菌毒力的具体分子机制，本课题拟在成功构建eep基因敲除株和互补株及获得有生物活性蛋白基础上，从转录和蛋白水平详尽分析金葡菌重要调控系统对Eep的调节及机制，蛋白质谱分析Eep的底物蛋白，细胞水平及体内实验进一步验证Eep通过降解其底物蛋白促进细菌毒力。研究成果将从新角度揭示蛋白质降解调控系统在细菌致病中的重要作用，为筛选新的抗感染药物靶标提供新思路

Bacterial membrane-associated proteases have important functions in the quality control of proteins, which are necessary for bacteria metabolism, stress response and pathogenesis. The metalloprotease Eep is involved in the secretion of Sex pheromones in Staphylococcus aureus, however, the main function is still unknown. In the previous research, we found that Eep is the possible substrate of FtsH protease. It affects bacteria adhension of host cell and neutrophil killing. Furthermore, Eep increases bacteria virulence in mouse model, showing that Eep is important for pathogenesis in S.aureus. Whether eep is regulated by the known virulence regulatory system in S.aureus? What’s the substrates for Eep in S.aureus? How does the protease affect bacteria virulence by interacting with host cells? Based on our previous study, we have constructed the eep deletion mutant and complement strains and expressed the Eep protein successfully, we intend to analyse the mechanism of how eep is regulated in S.aureus. We will identify the substrate of Eep by proteomic analysis and verify the molecular mechanism of how Eep increases bacteria virulence by degrading the substrate. Our contribution is significant because it advances our understanding of function of protein turnover and it enables us to design new molecules blocking the staphylococcal survival strategies.