MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systematic Biology, School of Life Sciences, MOE Key Laboratory of Bioinformatics, Beijing, China.
Tsinghua University-Peking University Joint Center for Life Sciences, Beijing, China.
Mol Cell Proteomics. 2020 Nov;19(11):1910-1920. doi: 10.1074/mcp.RA120.002132. Epub 2020 Aug 31.
Glutathionylation is an important posttranslational modification that protects proteins from further oxidative damage as well as influencing protein structure and activity. In the present study, we demonstrate that the cysteine-42 residue in protein arginine N-methyltransferase 5 (PRMT5) is glutathionylated in aged mice or in cells that have been exposed to oxidative stress. Deglutathionylation of this protein is catalyzed by glutaredoxin-1 (Grx1). Using mutagenesis and subsequent biochemical analyses, we show that glutathionylation decreased the binding affinity of PRMT5 with methylosome protein-50 (MEP50) and reduced the methyltransferase activity of PRMT5. Furthermore, overexpression of PRMT5-C42A mutant caused a significant increase in histone methylation in HEK293T and A549 cells and promoted cell growth, whereas overexpression of the PRMT5-C42D mutant, a mimic of glutathionylated PRMT5, inhibited cell proliferation. Taken together, our results demonstrate a new mechanism of regulation of PRMT5 methyltransferases activity and suggest that PRMT5 glutathionylation is partly responsible for reactive oxygen species-mediated cell growth inhibition.
谷胱甘肽化是一种重要的翻译后修饰，可保护蛋白质免受进一步的氧化损伤，同时影响蛋白质的结构和活性。在本研究中，我们证明了蛋白质精氨酸 N-甲基转移酶 5（PRMT5）中的半胱氨酸 42 残基在衰老的小鼠或暴露于氧化应激的细胞中被谷胱甘肽化。谷胱甘肽的去修饰由谷胱甘肽过氧化物酶 1（Grx1）催化。通过突变和随后的生化分析，我们表明谷胱甘肽化降低了 PRMT5 与甲基体蛋白 50（MEP50）的结合亲和力，并降低了 PRMT5 的甲基转移酶活性。此外，PRMT5-C42A 突变体的过表达导致 HEK293T 和 A549 细胞中组蛋白甲基化的显著增加，并促进细胞生长，而 PRMT5-C42D 突变体（谷胱甘肽化 PRMT5 的模拟物）的过表达则抑制细胞增殖。总之，我们的研究结果表明了 PRMT5 甲基转移酶活性的一种新的调节机制，并表明 PRMT5 谷胱甘肽化部分负责活性氧介导的细胞生长抑制。
