Mdt1, a novel Rad53 FHA1 domain-interacting protein, modulates DNA damage tolerance and G2/M cell cycle progression in Saccharomyces cerevisiae
Mdt1, a novel Rad53 FHA1 domain-interacting protein, modulates DNA damage tolerance and G2/M cell cycle progression in Saccharomyces cerevisiae
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DOI：
10.1128/mcb.24.7.2779-2788.2004
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发表时间：
2004-04-01
影响因子：
5.3
通讯作者：
Heierhorst, J
中科院分区：
文献类型：
--
作者：
Pike, BL;Yongkiettrakul, S;Heierhorst, J
Rad 53激酶在酵母DNA损伤检查点中起核心作用。Rad 53含有两个FRA磷酸苏氨酸结合结构域，其是Rad 53激活和可能的下游信号传导所需的。在这里，我们表明，N-末端Rad 53 FHA 1结构域与RNA识别基序，卷曲螺旋，和SQ/TQ簇结构域含有蛋白Mdt 1（YB 1051 C）相互作用。Rad 53和Mdt 1的相互作用取决于Mdt 1的FRA 1磷酸苏氨酸结合位点以及苏氨酸-305的结构完整性。mdt 1是组成型苏氨酸磷酸化和超磷酸化，在体内DNA损伤的反应。DNA损伤依赖性Mdt 1过度磷酸化依赖于Mec 1和Tel 1检查点激酶，Mec 1可以直接磷酸化重组Mdt 1 SQ/TQ结构域片段。MDT 1过表达是合成致死的rad 53缺失，而mdt 1缺失部分抑制检查点受损菌株的DNA损伤超敏反应，并通常提高DNA损伤耐受性。在没有DNA损伤的情况下，mdt 1缺失导致后期完成延迟，细胞形态延长，使人联想到G（2）/M细胞周期突变体。mdt 1依赖性和DNA损伤依赖性细胞周期延迟不是相加的，这表明它们在相同的途径中起作用。这些数据表明，Mdt 1参与正常的G（2）/M细胞周期进程，是检查点依赖性细胞周期阻滞途径的新靶点。
The Rad53 kinase plays a central role in yeast DNA damage checkpoints. Rad53 contains two FRA phosphothreonine-binding domains that are required for Rad53 activation and possibly downstream signaling. Here we show that the N-terminal Rad53 FHA1 domain interacts with the RNA recognition motif, coiled-coil, and SQ/TQ cluster domain-containing protein Mdt1 (YB1051C). The interaction of Rad53 and Mdt1 depends on the structural integrity of the FRA1 phosphothreonine-binding site as well as threonine-305 of Mdt1. Mdt1 is constitutively threonine phosphorylated and hyperphosphorylated in response to DNA damage in vivo. DNA damage-dependent Mdt1 hyperphosphorylation depends on the Mec1 and Tel1 checkpoint kinases, and Mec1 can directly phosphorylate a recombinant Mdt1 SQ/TQ domain fragment. MDT1 overexpression is synthetically lethal with a rad53 deletion, whereas mdt1 deletion partially suppresses the DNA damage hypersensitivity of checkpoint-compromised strains and generally improves DNA damage tolerance. In the absence of DNA damage, mdt1 deletion leads to delayed anaphase completion, with an elongated cell morphology reminiscent of that of G(2)/M cell cycle mutants. mdt1-dependent and DNA damage-dependent cell cycle delays are not additive, suggesting that they act in the same pathway. The data indicate that Mdt1 is involved in normal G(2)/M cell cycle progression and is a novel target of checkpoint-dependent cell cycle arrest pathways.