State Key Laboratory of Genetic Engineering, School of Life Science, Fudan University, Shanghai, China.
NPFPC Key Laboratory of Contraceptives and Devices, Shanghai Institute of Planned Parenthood Research, Institutes of Reproduction and Development, Shanghai, China.
Sci Rep. 2017 Mar 21;7:44826. doi: 10.1038/srep44826.
Several enzymes involved in central carbon metabolism such as isocitrate lyase and phosphoenolpyruvate carboxykinase are key determinants of pathogenesis of Mycobacterium tuberculosis (M. tb). In this study, we found that lysine acetylation plays an important role in the modulation of central carbon metabolism in M. tb. Mutant of M. tb defective in sirtuin deacetylase exhibited improved growth in fatty acid-containing media. Global analysis of lysine acetylome of M. tb identified three acetylated lysine residues (K322, K331, and K392) of isocitrate lyase (ICL1). Using a genetically encoding system, we demonstrated that acetylation of K392 increased the enzyme activity of ICL1, whereas acetylation of K322 decreased its activity. Antibodies that specifically recognized acetyllysine at 392 and 322 of ICL1 were used to monitor the levels of ICL1 acetylation in M. tb cultures. The physiological significance of ICL1 acetylation was demonstrated by the observation that M. tb altered the levels of acetylated K392 in response to changes of carbon sources, and that acetylation of K392 affected the abundance of ICL1 protein. Our study has uncovered another regulatory mechanism of ICL1.
几种参与中央碳代谢的酶，如异柠檬酸裂解酶和磷酸烯醇丙酮酸羧激酶，是结核分枝杆菌（M. tb）发病机制的关键决定因素。在这项研究中，我们发现赖氨酸乙酰化在结核分枝杆菌中央碳代谢的调节中起着重要作用。缺乏组蛋白去乙酰化酶的结核分枝杆菌突变体在含脂肪酸的培养基中生长良好。结核分枝杆菌赖氨酸乙酰组的全局分析鉴定出异柠檬酸裂解酶（ICL1）的三个乙酰化赖氨酸残基（K322、K331 和 K392）。使用遗传编码系统，我们证明了 K392 的乙酰化增加了 ICL1 的酶活性，而 K322 的乙酰化降低了其活性。特异性识别 ICL1 中的 392 和 322 位乙酰赖氨酸的抗体被用于监测结核分枝杆菌培养物中 ICL1 乙酰化的水平。ICL1 乙酰化的生理意义表现在结核分枝杆菌根据碳源的变化改变 K392 的乙酰化水平，并且 K392 的乙酰化影响 ICL1 蛋白的丰度。我们的研究揭示了 ICL1 的另一种调节机制。
