赖氨酸氨基酸化的动态调控机制及其生理病理意义

The identification and characterization of metabolites-derived lysine modifications had been become the focal research topic of protein posttranslational modifications. We found that all 20 proteogenic amino acids can modify -amine of lysine and form aminoacylations (Cell Metabolism, 2017). This ground-breaking study paved new path to explore how a particular amino acid regulates various cell signaling. The current study will study dynamic regulations of aminoacylations by cell-wide identifying and confirming aminoacylases and de-aminoacylases. Moreover, substrates of a selected aminoacylations, include glutaminylation, branched chain amino acids modifications（Leucylation, isoleucylation and valinylation）and tryptophanylation, will be identified by affinity-enrichment-assisted proteomics. Signal pathways related to these aminoacylations will be studied in detail. For example, how glutaminylation regulates apoptosis and cell cycle, how Leucylation, isoleucylation and valinylation regulates mTOR pathway, and how tryptophanylation regulates insulin signaling and DNA damage repairing will be explored. Furthermore, Chemical biologic methods will be employed to screen and identify small molecules that are able to interfere diseases-related pathways through mediating aminoacylations. This study will expand the scope of protein posttranslational modifications and provide novel drugable targets for diseases such as diabetes and cancers that are associated with aminoacylations.

代谢物衍生的赖氨酸新修饰的发现和功能鉴定是蛋白质翻译后修饰研究的前沿与热点。我们发现，所有20种常规氨基酸都可以以酰胺键结合到蛋白质赖氨酸支链的伯氨基，形成氨基酸化（Cell Metabolism，2017）。这一原创性发现为阐明氨基酸调控信号通路的研究开辟了新的研究方向。本项目将系统鉴定各种氨基酸化的修饰酶和去修饰酶，阐释氨基酸化的动态调控机制；通过亲和富集修饰蛋白质组学方法建立代表氨基酸化的底物蛋白质库，深入阐明谷氨酰胺化对细胞凋亡和细胞周期的调控，支链氨基酸化对mTOR信号通路的调控，色氨酸化对胰岛素信号和DNA损伤修复通路的调控，以及揭示这些氨基酸化失调在疾病中的作用；通过化学生物学方法筛选或设计合成针对氨基酸化的小分子化合物，实现通过调控氨基酸化对信号通路和疾病表型的干预。项目的实施将拓宽蛋白质翻译后修饰的内涵，为肿瘤、糖尿病等疾病提供基于氨基酸化的干预靶标。

本项目实施过程中阐明了氨基酸修饰的功能，寻找修饰酶与去修饰酶。团队深入揭示了多种与生理和病理（肿瘤、出生缺陷）过程相关的小分子代谢物及其参与调控前述生理病理过程的分子机制，明确了相关修饰酶。其中，1）揭示肿瘤细胞中戊糖代谢异常调控细胞周期的分子机制；2）揭示高同型半胱氨酸致病新机制；3）阐明肾癌细胞脂质代谢异常机制；4）钙调神经磷酸酶的失活抑制了丙酮酸脱氢酶复合体的活性并诱导Warburg效应；5）线粒体STAT5A通过抑制丙酮酸脱氢酶复合物活性促进代谢重塑和Warburg效应。通过前述工作，深化了对氨基酸修饰的生理病理功能的理解，并为基于氨基酸修饰发展肿瘤等重大疾病的干预和预警新策略奠定了坚实基础。