CARM1-mediated methylation of protein arginine methyltransferase 5 represses human -globin gene expression in erythroleukemia cells
CARM1-mediated methylation of protein arginine methyltransferase 5 represses human -globin gene expression in erythroleukemia cells
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CARM1介导的精氨酸甲基转移酶5甲基化抑制红白血病细胞中人珠蛋白基因表达
DOI：
10.1074/jbc.ra118.004028
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发表时间：
2018-11-09
影响因子：
4.8
通讯作者：
Zhao, Quan
中科院分区：
文献类型：
--
作者：
Nie, Min;Wang, Yadong;Zhao, Quan
蛋白质精氨酸甲基转移酶5（PRMT 5）是精氨酸甲基转移酶蛋白家族的成员，其关键地介导组蛋白H4（H4 R3 me 2s）处的Arg-3的对称二甲基化，并且参与许多关键细胞过程，包括造血。然而，可能影响其生物学功能的PRMT 5翻译后修饰（PTM）仍然不太清楚。在这项研究中，使用MS分析，我们发现PRMT 5本身在人红白血病Lys-562细胞中是甲基化的。生化分析表明，辅激活子相关的精氨酸甲基转移酶1（CARM 1）直接相互作用，并甲基化PRMT 5在Arg-505在体内和体外。在Arg-505的取代显着降低PRMT 5的甲基转移酶活性，减少H4 R3 me 2s富集在-珠蛋白基因启动子，并增加了在Lys-562细胞中的-珠蛋白基因的表达。此外，CARM 1敲低一致地降低PRMT 5活性和活化的β-珠蛋白基因表达。重要的是，我们表明CARM 1介导的PRMT 5甲基化对于PRMT 5的细胞内同源二聚化至其活性形式是必不可少的。因此，这些结果揭示了PRMT 5的一个关键PTM，它抑制人β-珠蛋白基因的表达。我们的结论是，CARM 1介导的不对称甲基化的PRMT 5是至关重要的二聚化和甲基转移酶活性，导致抑制珠蛋白的表达。鉴于PRMT 5在不同细胞过程中的关键作用，这些发现可能会为操纵其甲基转移酶活性以管理血红蛋白病或癌症的策略提供信息。
Protein arginine methyltransferase 5 (PRMT5) is a member of the arginine methyltransferase protein family that critically mediates the symmetric dimethylation of Arg-3 at histone H4 (H4R3me2s) and is involved in many key cellular processes, including hematopoiesis. However, the post-translational modifications (PTMs) of PRMT5 that may affect its biological functions remain less well-understood. In this study, using MS analyses, we found that PRMT5 itself is methylated in human erythroleukemia Lys-562 cells. Biochemical assays revealed that coactivator-associated arginine methyltransferase 1 (CARM1) interacts directly with and methylates PRMT5 at Arg-505 both in vivo and in vitro. Substitutions at Arg-505 significantly reduced PRMT5's methyltransferase activity, decreased H4R3me2s enrichment at the -globin gene promoter, and increased the expression of the -globin gene in Lys-562 cells. Moreover, CARM1 knockdown consistently reduced PRMT5 activity and activated -globin gene expression. Importantly, we show that CARM1-mediated methylation of PRMT5 is essential for the intracellular homodimerization of PRMT5 to its active form. These results thus reveal a critical PTM of PRMT5 that represses human -globin gene expression. We conclude that CARM1-mediated asymmetric methylation of PRMT5 is critical for its dimerization and methyltransferase activity leading to the repression of -globin expression. Given PRMT5's crucial role in diverse cellular processes, these findings may inform strategies for manipulating its methyltransferase activity for managing hemoglobinopathy or cancer.