Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France.
Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier, France.
J Lipid Res. 2020 Aug;61(8):1180-1191. doi: 10.1194/jlr.RA120000747. Epub 2020 Jun 2.
is the causative agent of tuberculosis and remains one of the most widespread and deadliest bacterial pathogens in the world. A distinguishing feature of mycobacteria that sets them apart from other bacteria is the unique architecture of their cell wall, characterized by various species-specific lipids, most notably mycolic acids (MAs). Therefore, targeted inhibition of enzymes involved in MA biosynthesis, transport, and assembly has been extensively explored in drug discovery. Additionally, more recent evidence suggests that many enzymes in the MA biosynthesis pathway are regulated by kinase-mediated phosphorylation, thus opening additional drug-development opportunities. However, how phosphorylation regulates MA production remains unclear. Here, we used genetic strategies combined with lipidomics and phosphoproteomics approaches to investigate the role of protein phosphorylation in The results of this analysis revealed that the Ser/Thr protein kinase PknB regulates the export of MAs and promotes the remodeling of the mycobacterial cell envelope. In particular, we identified the essential MmpL3 as a substrate negatively regulated by PknB. Taken together, our findings add to the understanding of how PknB activity affects the mycobacterial MA biosynthesis pathway and reveal the essential role of protein phosphorylation/dephosphorylation in governing lipid metabolism, paving the way for novel antimycobacterial strategies.
结核分枝杆菌是结核病的病原体，也是世界上分布最广、致死率最高的细菌病原体之一。分枝杆菌的一个显著特征是其细胞壁的独特结构，由各种特定于物种的脂质组成，其中最显著的是分枝菌酸（MAs）。因此，针对参与 MA 生物合成、运输和组装的酶的靶向抑制在药物发现中得到了广泛的探索。此外，最近的证据表明，MA 生物合成途径中的许多酶受到激酶介导的磷酸化调节，从而为药物开发提供了更多机会。然而，磷酸化如何调节 MA 产生仍不清楚。在这里，我们使用遗传策略结合脂质组学和磷酸化蛋白质组学方法，研究了蛋白质磷酸化在分枝杆菌中的作用。
分析结果表明，Ser/Thr 蛋白激酶 PknB 调节 MA 的外排并促进分枝杆菌细胞膜的重塑。特别是，我们鉴定出必需的 MmpL3 作为 PknB 负调控的底物。总之，我们的研究结果增加了对 PknB 活性如何影响分枝杆菌 MA 生物合成途径的理解，并揭示了蛋白质磷酸化/去磷酸化在调节脂质代谢中的重要作用，为新型抗分枝杆菌策略铺平了道路。
