CARM1 regulates proliferation of PC12 cells by methylating HuD
CARM1 regulates proliferation of PC12 cells by methylating HuD
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DOI：
10.1128/mcb.26.6.2273-2285.2006
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发表时间：
2006-03-01
影响因子：
5.3
通讯作者：
Tohyama, M
中科院分区：
文献类型：
--
作者：
Fujiwara, T;Mori, Y;Tohyama, M
HuD是一种RNA结合蛋白，已显示其通过稳定携带富含AU的不稳定元件的不稳定mRNA来诱导神经元分化。在这里，我们显示了一种新的机制，精氨酸甲基化HuD的辅激活相关的精氨酸甲基转移酶1（CARM 1），影响mRNA周转的p21（cip 1/waf 1）mRNA在PC 12细胞。CARM 1在体外和体内特异性甲基化HuD，并与HuD共定位于细胞质中。通过CARM 1敲低抑制HuD甲基化延长了p21（cip 1/waf 1）mRNA半衰期，并导致响应于神经生长因子（NGF）的缓慢生长速率和稳健的轴突发生。甲基化抗性HuD结合更多的p21（cip 1/waf 1）mRNA比野生型，其过表达上调p21（cip 1/waf 1）蛋白的表达。这些结果表明，CARM 1-甲基化HuD通过将p21（cip 1/waf 1）mRNA提交至其衰变系统来维持PC 12细胞处于增殖状态。由于HuD的甲基化群体在NGF处理的PC 12细胞中减少，HuD甲基化的下调是NGF诱导PC 12细胞分化的可能途径。
HuD is an RNA-binding protein that has been shown to induce neuronal differentiation by stabilizing labile mRNAs carrying AU-rich instability elements. Here, we show a novel mechanism of arginine methylation of HuD by coactivator-associated arginine methyltransferase 1 (CARM1) that affected mRNA turnover of p21(cip1/waf1) mRNA in PC12 cells. CARM1 specifically methylated HuD in vitro and in vivo and colocalized with HuD in the cytoplasm. Inhibition of HuD methylation by CARM1 knockdown elongated the p21(cip1/waf1) mRNA half-life and resulted in a slow growth rate and robust neuritogenesis in response to nerve growth factor (NGF). Methylation-resistant HuD bound more p21(cip1/waf1) mRNA than did the wild type, and its overexpression upregulated p21(cip1/waf1) protein expression. These results suggested that CARM1-methylated HuD maintains PC12 cells in the proliferative state by committing p21(cip1/waf1) mRNA to its decay system. Since the methylated population of HuD was reduced in NGF-treated PC12 cells, downregulation of HuD methylation is a possible pathway through which NGF induces differentiation of PC12 cells.