Suppression of PRMT6-mediated arginine methylation of p16 protein potentiates its ability to arrest A549 cell proliferation.
Suppression of PRMT6-mediated arginine methylation of p16 protein potentiates its ability to arrest A549 cell proliferation.
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DOI：
10.1016/j.biocel.2012.09.015
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发表时间：
2012-12
期刊：
影响因子：
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通讯作者：
Xiuli Wang;Ying Huang;Jing Zhao-;Yu Zhang;Jun Lu;Baiqu Huang
中科院分区：
文献类型：
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作者：
Xiuli Wang;Ying Huang;Jing Zhao-;Yu Zhang;Jun Lu;Baiqu Huang
肿瘤抑制因子p16 INK 4A（p16）通过抑制视网膜母细胞瘤蛋白的磷酸化来阻断细胞周期进程。在这里，我们描述了一个新的方面的翻译后控制，有一个重要的功能后果p16蛋白。我们首次发现p16蛋白在不同的细胞系中被甲基化。然后我们确定p16的精氨酸22、131和138是主要的甲基化位点。Western blotting和TUNEL分析显示，携带这些点突变的p16蛋白在A549细胞中诱导了比野生型p16更高的凋亡率。此外，免疫共沉淀分析表明，p16精氨酸甲基化水平的降低促进了p16与CDK 4的结合。此外，我们确定蛋白质精氨酸甲基转移酶6（PRMT 6）负责p16精氨酸甲基化。流式细胞仪分析结果表明，PRMT 6过表达抵消了野生型p16诱导的A549细胞G1期细胞周期阻滞。我们还提供了PRMT 6能够与p16相互作用的证据，并且在PRMT 6过表达时p16-CDK 4缔合的强度降低。总之，本报告中提供的数据表明，PRMT 6对p16蛋白特定精氨酸残基的甲基化可能对p16的活性至关重要。
The tumor suppressor p16INK4A(p16) blocks the cell cycle progression by inhibiting phosphorylation of the retinoblastoma protein. We describe here a novel aspect of the posttranslational control that has an important functional consequence on p16 protein. We first discovered that the p16 protein was methylated in various cell lineages. We then determined that the arginine 22, 131 and 138 of p16 were the main methylation sites. Western blotting and TUNEL analyses revealed that the p16 protein bearing these point mutations induced a higher apoptosis ratio than wild-type p16 in A549 cells. Furthermore, co-immunoprecipitation assays suggested that decrease of p16 arginine methylation level promoted the association of p16 with CDK4. Additionally, we determined that the protein arginine methyltransferase 6 (PRMT6) was responsible for the p16 arginine methylation. Results from flow cytometric analysis demonstrated that PRMT6 overexpression counteracted the cell cycle arrest at G1 phase induced by wild-type p16 in A549 cells. We also provided evidence that PRMT6 was able to interact with p16, and that the intensity of p16-CDK4 association was reduced upon PRMT6 overexpression. Together, data presented in this report establish that methylation at specific arginine residues of p16 protein by PRMT6 may be critical for the activity of p16.