分枝菌酸小杆菌不同生长周期的磷酸化蛋白质定量表达比较

Quantitative comparison of phospho-proteins of Mycolicibacterium smegmatis at different growing phases

摘要:

蛋白质磷酸化修饰在结核病致病菌—结核分枝杆菌中扮演重要角色，有望成为抗结核药的新靶点。本研究以结核分枝杆菌近源菌—分枝菌酸小杆菌为研究对象，分析其在不同生长时期的磷酸化蛋白质。从分枝菌酸小杆菌对数期和平台期样品中共鉴定并定量了来自385个蛋白质的573个磷酸化肽段和816个磷酸化位点，构建了分枝菌酸小杆菌不同生长期的磷酸化蛋白质组数据集。之后定量比较了该菌在对数期和平台期显著差异表达的磷酸化蛋白质，经选择性离子检测(selected ion monitoring, SIM)验证了68个磷酸化水平上调的蛋白质，主要参与细胞增殖和蛋白质翻译等通路；69个磷酸化水平下调的蛋白质，主要参与三羧酸循环的通路。差异磷酸化蛋白质在细菌生长、增殖等重要生命活动过程显著富集，为分枝菌酸小杆菌和结核分枝杆菌蛋白质磷酸化功能的揭示提供了蛋白质组学数据支撑。

Abstract:

Protein phosphorylation plays a key role in Mycobacterium tuberculosis, the pathogen of tuberculosis, holding promise as a new target of anti-tuberculosis drugs. We used M. smegmatis, a close relative of M. tuberculosis, as a model organism to study the protein phosphorylation at different growth phases. We identified 573 phosphorylated peptides and 816 phosphorylated sites of 385 proteins in the M. smegmatis samples at both logarithmic and stationary phases, and then established a comprehensive dataset of phosphorylated proteins in M. smegmatis. By comparing the expression levels of phosphorylated proteins between the logarithmic and the stationary phase with the selected ion monitoring (SIM) strategy, we verified 68 upregulated proteins involved in cell division and protein translation, and 69 downregulated proteins mainly involved in the tricarboxylic acid cycle pathway. The differentially expressed phosphorylated proteins were significantly enriched in important cellular cycle events such as cell elongation and division. The findings of this study provide proteome evidence for elucidating the phosphorylation in both M. smegmatis and M. tuberculosis.