Department of Advanced Technology Fusion, Konkuk University, Seoul, Korea.
BMB Rep. 2011 May;44(5):352-7. doi: 10.5483/BMBRep.2011.44.5.352.
The effect of human MutY homolog (hMYH) on the activation of checkpoint proteins in response to hydroxyurea (HU) and ultraviolet (UV) treatment was investigated in hMYH-disrupted HEK293 cells. hMYH-disrupted cells decreased the phosphorylation of Chk1 upon HU or UV treatment and increased the phosphorylation of Cdk2 and the amount of Cdc25A, but not Cdc25C. In siMYH-transfected cells, the increased rate of phosphorylated Chk1 upon HU or UV treatment was lower than that in siGFP-transfected cells, meaning that hMYH was involved in the activation mechanism of Chk1 upon DNA damage. The phosphorylation of ataxia telangiectasia and Rad3- related protein (ATR) upon HU or UV treatment was decreased in hMYH-disrupted HEK293 and HaCaT cells. Co-immunoprecipitation experiments showed that hMYH was immunoprecipitated by anti-ATR. These results suggest that hMYH may interact with ATR and function as a mediator of Chk1 phosphorylation in response to DNA damage.
研究了人 MutY 同源物（hMYH）对羟脲（HU）和紫外线（UV）处理引发的检查点蛋白激活的影响，该研究在 hMYH 敲除的 HEK293 细胞中进行。hMYH 敲除细胞降低了 HU 或 UV 处理后 Chk1 的磷酸化水平，并增加了 Cdk2 的磷酸化和 Cdc25A 的含量，但不增加 Cdc25C 的含量。在 siMYH 转染的细胞中，HU 或 UV 处理后磷酸化 Chk1 的增加速度低于 siGFP 转染的细胞，这意味着 hMYH 参与了 DNA 损伤时 Chk1 的激活机制。hMYH 敲除的 HEK293 和 HaCaT 细胞中，HU 或 UV 处理后 ataxia telangiectasia 和 Rad3-相关蛋白（ATR）的磷酸化水平降低。免疫共沉淀实验表明，hMYH 可被抗 ATR 免疫沉淀。这些结果表明，hMYH 可能与 ATR 相互作用，并作为 DNA 损伤时 Chk1 磷酸化的介质发挥作用。
