Analysis of SecA2‐dependent substrates in Mycobacterium marinum identifies protein kinase G (PknG) as a virulence effector
Analysis of SecA2‐dependent substrates in Mycobacterium marinum identifies protein kinase G (PknG) as a virulence effector
复制标题
对海分枝杆菌中 SecA2 依赖性底物的分析确定蛋白激酶 G (PknG) 是毒力效应子
作者：
A. D. Woude;E. Stoop;M. Stiess;Sen Wang;R. Ummels;G. Stempvoort;S. Piersma;Alessandro Cascioferro;C. Jiménez;E. Houben;J. Luirink;J. Pieters;A. M. Sar;W. Bitter
分枝杆菌的致病性与其输出毒力因子的能力密切相关。为此，分枝杆菌具有不同的蛋白质分泌系统，包括辅助Sec易位途径SecA 2。虽然该途径与细胞内存活和毒力相关，但SecA 2依赖性效应蛋白在很大程度上仍不确定。在这项工作中，我们研究了一种海分枝杆菌secA 2突变体，该突变体启动斑马鱼胚胎肉芽肿形成的能力受损。 通过比较来自secA 2突变体与野生型海洋分枝杆菌的细胞包膜组分的蛋白质组学谱，我们鉴定了推定的SecA 2依赖性底物。免疫印迹程序证实了这些蛋白质中的几种的SecA 2依赖性膜定位，包括毒力因子蛋白激酶G（PknG）。有趣的是，secA 2突变体的表型缺陷与ΔpknG的表型缺陷相似，包括吞噬体成熟。SecA 2突变体中PknG的过表达恢复了其在细胞包膜上的定位。重要的是，PknG-过表达也部分恢复了secA 2突变体的毒力，如斑马鱼胚胎中增强的感染性和恢复对吞噬体成熟的抑制所示。这些结果表明PknG的SecA 2依赖性膜定位是海洋分枝杆菌毒力的重要决定因素。
The pathogenicity of mycobacteria is closely associated with their ability to export virulence factors. For this purpose, mycobacteria possess different protein secretion systems, including the accessory Sec translocation pathway, SecA2. Although this pathway is associated with intracellular survival and virulence, the SecA2‐dependent effector proteins remain largely undefined. In this work, we studied a Mycobacterium marinum secA2 mutant with an impaired capacity to initiate granuloma formation in zebrafish embryos. By comparing the proteomic profile of cell envelope fractions from the secA2 mutant with wild type M. marinum, we identified putative SecA2‐dependent substrates. Immunoblotting procedures confirmed SecA2‐dependent membrane localization for several of these proteins, including the virulence factor protein kinase G (PknG). Interestingly, phenotypical defects of the secA2 mutant are similar to those described for ΔpknG, including phagosomal maturation. Overexpression of PknG in the secA2 mutant restored its localization to the cell envelope. Importantly, PknG‐overexpression also partially restored the virulence of the secA2 mutant, as indicated by enhanced infectivity in zebrafish embryos and restored inhibition of phagosomal maturation. These results suggest that SecA2‐dependent membrane localization of PknG is an important determinant for M. marinum virulence.
DOI：
10.1016/j.tube.2011.11.005
发表时间：
2012-03
期刊：
Tuberculosis (Edinburgh, Scotland)
影响因子：
--
作者：
Ligon LS;Hayden JD;Braunstein M
通讯作者：
Braunstein M
影响因子：
32.4
作者：
Davis, JM;Clay, H;Ramakrishnan, L
通讯作者：
Ramakrishnan, L