Zhang Xueyun, Fu Tao, He Qian, Gao Xiang, Luo Yan
Department of Biochemistry, School of Medicine, Cancer Institute of the Second Affiliated Hospital, Zhejiang University, Hangzhou, China.
Key Laboratory of Cancer Prevention and Intervention of China National Ministry of Education, Hangzhou, China.
Front Mol Biosci. 2020 Jan 9;6:147. doi: 10.3389/fmolb.2019.00147. eCollection 2019.
The major metabolic fates of glucose in cells are glycolysis and the pentose phosphate pathway, and they share the first step: converting glucose to glucose-6-phosphate (G6P). Here, we show that G6P can be sensed by the transcription factor MondoA/Mlx to modulate Txnip expression. Endogenous knockdown and EMSA (gel migration assay) analyses both confirmed that G6P is the metabolic intermediate that activates the heterocomplex MondoA/Mlx to elicit the expression of Txnip. Additionally, the three-dimensional structure of MondoA is modeled, and the binding mode of G6P to MondoA is also predicted by molecular docking and binding free energy calculation. Finally, free energy decomposition and mutational analyses suggest that certain residues in MondoA, GKL139-141 in particular, mediate its binding with G6P to activate MondoA, which signals the upregulation of the expression of Txnip.
细胞中葡萄糖的主要代谢途径是糖酵解和磷酸戊糖途径，它们共享第一步：将葡萄糖转化为6-磷酸葡萄糖（G6P）。在此，我们表明转录因子MondoA/Mlx能够感知G6P，从而调节硫氧还蛋白互作蛋白（Txnip）的表达。内源性敲低和电泳迁移率变动分析（EMSA）均证实，G6P是激活异源复合物MondoA/Mlx以引发Txnip表达的代谢中间体。此外，构建了MondoA的三维结构模型，并通过分子对接和结合自由能计算预测了G6P与MondoA的结合模式。最后，自由能分解和突变分析表明，MondoA中的某些残基，特别是GKL139-141，介导其与G6P的结合以激活MondoA，进而促使Txnip表达上调。
