ATR kinase activation mediated by MutSα and MutLα in response to cytotoxic O6-methylguanine adducts
ATR kinase activation mediated by MutSα and MutLα in response to cytotoxic O6-methylguanine adducts
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DOI：
10.1016/j.molcel.2006.04.023
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发表时间：
2006-05-19
期刊：
影响因子：
16
通讯作者：
Hsieh, Peggy
中科院分区：
文献类型：
--
作者：
Yoshioka, Ken-Ichi;Yoshioka, Yoshiko;Hsieh, Peggy
产生细胞毒素O-6-甲基-G(O-6-Meg)DNA加合物的SO型烷化剂以一种需要DNA错配修复(MMR)蛋白MutSα和MutLα的方式诱导细胞周期停滞和凋亡。在这里，我们表明，响应DNA甲基化的检查点信号发生在S时期，需要DNA复制，从而导致O-6-Meg/T错配。DNA结合研究表明，MutSA特异性识别O(6_)Meg/T错配，但不识别O-6-Meg/C。在体外实验中，ATR-Trip，而不是RPA，以MutSα和MutLα依赖的方式优先招募到O-6-Meg/T错配。此外，在O-6-Meg/T错配和MMR蛋白存在的情况下，ATR激酶被激活以磷酸化Chk1。这些结果表明，MMR蛋白可以作为甲基化损伤的直接传感器，并帮助将ATR-trip招募到细胞毒性O-6-Meg加合物的位点，以启动ATR检查点信号。
SO-type alkylating agents that produce cytotoxix O-6- methyl-G (O-6-meG) DNA adducts induce cell cycle arrest and apoptosis in a manner requiring the DNA mismatch repair (MMR) proteins MutS alpha and MutL alpha. Here, we show that checkpoint signaling in response to DNA methylation occurs during S phase and requires DNA replication that gives rise to O-6-meG/T mispairs. DNA binding studies reveal that MutSa specifically recognizes O(6_)meG/T mispairs, but not O-6-meG/C. In an in vitro assay, ATR-ATRIP, but not RPA, is preferentially recruited to O-6-meG/T mismatches in a MutS alpha and MutL alpha-dependent manner. Furthermore, ATR kinase is activated to phosphorylate Chk1 in the presence of O-6-meG/T mispairs and MMR proteins. These results suggest that MMR proteins can act as direct sensors of methylation damage and help recruit ATR-ATRIP to sites of cytotoxic O-6-meG adducts to initiate ATR checkpoint signaling.