Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Berlin, Germany.
Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany.
J Biol Chem. 2020 Dec 11;295(50):17158-17168. doi: 10.1074/jbc.RA120.014402. Epub 2020 Oct 6.
Cellular energy demands are met by uptake and metabolism of nutrients like glucose. The principal transcriptional regulator for adapting glycolytic flux and downstream pathways like lipogenesis to glucose availability in many cell types is carbohydrate response element-binding protein (ChREBP). ChREBP is activated by glucose metabolites and post-translational modifications, inducing nuclear accumulation and regulation of target genes. Here we report that ChREBP is modified by proline hydroxylation at several residues. Proline hydroxylation targets both ectopically expressed ChREBP in cells and endogenous ChREBP in mouse liver. Functionally, we found that specific hydroxylated prolines were dispensable for protein stability but required for the adequate activation of ChREBP upon exposure to high glucose. Accordingly, ChREBP target gene expression was rescued by re-expressing WT but not ChREBP that lacks hydroxylated prolines in ChREBP-deleted hepatocytes. Thus, proline hydroxylation of ChREBP is a novel post-translational modification that may allow for therapeutic interference in metabolic diseases.
细胞的能量需求是通过摄取和代谢营养物质来满足的，如葡萄糖。在许多细胞类型中，碳水化合物反应元件结合蛋白（ChREBP）是适应糖酵解通量和下游途径（如脂肪生成）的主要转录调节因子，这些途径的葡萄糖可用性。ChREBP 被葡萄糖代谢物和翻译后修饰激活，诱导核积累和靶基因的调节。在这里，我们报告 ChREBP 被几个残基的脯氨酸羟化修饰。脯氨酸羟化作用的靶点是细胞内异位表达的 ChREBP 和小鼠肝内的内源性 ChREBP。功能上，我们发现特定的羟脯氨酸对于蛋白质稳定性不是必需的，但对于高葡萄糖暴露时 ChREBP 的充分激活是必需的。因此，在 ChREBP 缺失的肝细胞中，通过重新表达 WT 而不是缺乏 ChREBP 羟脯氨酸的 ChREBP 可以挽救 ChREBP 靶基因的表达。因此，ChREBP 的脯氨酸羟化是一种新的翻译后修饰，可能允许在代谢性疾病中进行治疗干预。
