The Amino-Terminal TPR Domain of Dia2 Tethers SCFDia2 to the Replisome Progression Complex
The Amino-Terminal TPR Domain of Dia2 Tethers SCFDia2 to the Replisome Progression Complex
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DOI：
10.1016/j.cub.2009.09.062
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发表时间：
2009-12-01
期刊：
影响因子：
9.2
通讯作者：
Labib, Karim
中科院分区：
文献类型：
--
作者：
Morohashi, Hiroko;Maculins, Timurs;Labib, Karim
真核细胞含有多种形式的E3泛素连接酶，称为SCF（Skp 1/cullin/F box），每种形式都通过不同的F box蛋白来区分，该蛋白使用羧基末端的结构域来识别底物[1，2]。F盒蛋白Dial是芽殖酵母中基因组稳定性的重要决定因素[3-5]，但其作用方式知之甚少。在这里，我们表明SCFDia 2与复制体进展复合物（RPC）相关，该复合物在DNA复制叉处组装在MCM 2 -7解旋酶周围[6]。这种相互作用需要RPC组件Mrc 1和Ctf 4，这两者都与位于Dia 2的氨基末端的一个tetratricopeptide repeat（TPR）结构域相关联。我们的数据表明，TPR域的Dial系链SCFDia 2的RPC，可能增加了本地浓度的连接酶在DNA复制叉。这种调节在蛋白质-DNA屏障处积累停滞的DNA复制叉的细胞中变得重要，可能有助于SCFDia 2与关键底物的相互作用。我们的研究结果表明，其他F盒蛋白的氨基末端结构域也可能发挥类似的调节作用，控制同源SCF复合物的定位。
Eukaryotic cells contain multiple versions of the E3 ubiquitin ligase known as the SCF (Skp1/cullin/F box), each of which is distinguished by a different F box protein that uses a domain at the carboxyl terminus to recognize substrates [1, 2]. The F box protein Dial is an important determinant of genome stability in budding yeast [3-5], but its mode of action is poorly understood. Here we show that SCFDia2 associates with the replisome progression complex (RPC) that assembles around the MCM2-7 helicase at DNA replication forks [6]. This interaction requires the RPC components Mrc1 and Ctf4, both of which associate with a tetratricopeptide repeat (TPR) domain located at the amino terminus of Dia2. Our data indicate that the TPR domain of Dial tethers SCFDia2 to the RPC, probably increasing the local concentration of the ligase at DNA replication forks. This regulation becomes important in cells that accumulate stalled DNA replication forks at protein-DNA barriers, perhaps aiding the interaction of SCFDia2 with key substrates. Our findings suggest that the amino-terminal domains of other F box proteins might also play an analogous regulatory role, controlling the localization of the cognate SCF complexes.