ATR kinase activation mediated by MutSalpha and MutLalpha in response to cytotoxic O6-methylguanine adducts.
ATR kinase activation mediated by MutSalpha and MutLalpha in response to cytotoxic O6-methylguanine adducts.
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发表时间：
2006
期刊：
影响因子：
16
通讯作者：
Ken‐ichi Yoshioka;Y. Yoshioka;P. Hsieh
中科院分区：
文献类型：
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作者：
Ken‐ichi Yoshioka;Y. Yoshioka;P. Hsieh
产生细胞毒性O（6）-甲基-G（O（6）-meG）DNA加合物的S（N）1型烷化剂以需要DNA错配修复（MMR）蛋白MutSalpha和MutLalpha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期，需要DNA复制，从而产生O（6）-meG/T错配。DNA结合研究表明，MutSalpha特异性识别O（6）-meG/T错配，但不识别O（6）-meG/C。在体外试验中，ATR-ATRIP而不是RPA以MutSalpha和MutLalpha依赖性方式优先募集到O（6）-meG/T错配。此外，ATR激酶在O（6）-meG/T错配和MMR蛋白存在下被激活以磷酸化Chk 1。这些结果表明，MMR蛋白可以作为甲基化损伤的直接传感器，并帮助招募ATR-ATRIP到细胞毒性O（6）-meG加合物的位点，以启动ATR检查点信号。
S(N)1-type alkylating agents that produce cytotoxic 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 MutSalpha and MutLalpha. 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 MutSalpha 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 MutSalpha- and MutLalpha-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.