Meng Yunzhu, Wei Tiantian, Zhang Chenlin, Yu Anqi, Liu Yuan, Xiao Junyu, Wang Chu
Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University Beijing 100871 China
Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China.
Chem Sci. 2025 Jul 2. doi: 10.1039/d5sc02378e.
Itaconate (ITA) is an upregulated immunometabolite in macrophages during pathogen infection. It is known to influence oxidation stress, cellular metabolism, programmed cell death and many other biological processes to regulate the immune response interaction with proteins. Previous studies capture covalently ITA-modified proteins by activity-based proteome profiling with bioorthogonal chemical probes; however, how itaconate interacts non-covalently with other proteins at the proteome level remains unexplored. Here we applied thermal proteome profiling (TPP) to globally identify a large number of ITA-interacting proteins in macrophage proteomes. Among these targets, we verified mitochondrial branched-chain aminotransferase (BCAT2) as a novel non-covalent binding target of itaconate biochemical and structural experiments. The binding of itaconate could inhibit transamination activity of BCAT and regulate the metabolism of branched-chain amino acids (BCAAs) in lipopolysaccharide (LPS)-activated inflammatory macrophages. This study offers a valuable resource that helps decipher novel and comprehensive functions of ITA in macrophages during the immune response and other related biological processes.
衣康酸（ITA）是病原体感染期间巨噬细胞中上调的免疫代谢物。已知它会影响氧化应激、细胞代谢、程序性细胞死亡以及许多其他生物过程，以调节免疫反应与蛋白质的相互作用。先前的研究通过基于活性的蛋白质组分析和生物正交化学探针共价捕获衣康酸修饰的蛋白质；然而，衣康酸在蛋白质组水平上如何与其他蛋白质非共价相互作用仍未得到探索。在这里，我们应用热蛋白质组分析（TPP）来全面鉴定巨噬细胞蛋白质组中大量与衣康酸相互作用的蛋白质。在这些靶点中，我们通过生化和结构实验验证了线粒体支链氨基转移酶（BCAT2）是衣康酸的一种新型非共价结合靶点。衣康酸的结合可以抑制BCAT的转氨活性，并调节脂多糖（LPS）激活的炎性巨噬细胞中支链氨基酸（BCAAs）的代谢。这项研究提供了宝贵的资源，有助于解读衣康酸在免疫反应及其他相关生物过程中在巨噬细胞中的新的和全面的功能。
