Dcp1 links coactivators of mRNA decapping to Dcp2 by proline recognition
Dcp1 links coactivators of mRNA decapping to Dcp2 by proline recognition
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DOI：
10.1261/rna.2382011
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发表时间：
2011-02-01
期刊：
影响因子：
4.5
通讯作者：
Gross, John D.
中科院分区：
文献类型：
--
作者：
Borja, Mark S.;Piotukh, Kirill;Gross, John D.
帽水解是几种真核生物mRNA衰变途径中的关键步骤，并且通过在催化核心含有Dcp 2的进化保守的去帽复合物进行。在酵母中，Dcp 1是脱帽的重要激活剂，而辅激活剂如Edc 1和Edc 2被认为可以增强活性，尽管它们的机制仍然难以捉摸。使用动力学分析，我们表明，一个至关重要的功能Dcp 1是耦合的辅激活剂的decapping激活Dcp 2的结合。Edc 1和Edc 2通过其EVH 1脯氨酸识别位点结合Dcp 1，并刺激1000倍的脱帽，影响mRNA的K-M和催化步骤的速率。Edc 1的C-末端对于增强催化步骤是必要且足够的，而蛋白质的其余部分可能增加mRNA与去帽复合物的结合。Dcp 1 EVH 1结构域或Edc 1富含脯氨酸序列中的病变足以阻断刺激。这些结果确定了一个新的作用，Dcp 1，这是连接到底物识别和激活的Dcp 2的辅激活剂的结合。
Cap hydrolysis is a critical step in several eukaryotic mRNA decay pathways and is carried out by the evolutionarily conserved decapping complex containing Dcp2 at the catalytic core. In yeast, Dcp1 is an essential activator of decapping and coactivators such as Edc1 and Edc2 are thought to enhance activity, though their mechanism remains elusive. Using kinetic analysis we show that a crucial function of Dcp1 is to couple the binding of coactivators of decapping to activation of Dcp2. Edc1 and Edc2 bind Dcp1 via its EVH1 proline recognition site and stimulate decapping by 1000-fold, affecting both the K-M for mRNA and rate of the catalytic step. The C-terminus of Edc1 is necessary and sufficient to enhance the catalytic step, while the remainder of the protein likely increases mRNA binding to the decapping complex. Lesions in the Dcp1 EVH1 domain or the Edc1 proline-rich sequence are sufficient to block stimulation. These results identify a new role of Dcp1, which is to link the binding of coactivators to substrate recognition and activation of Dcp2.