A dimerized coiled-coil domain and an adjoining part of geminin interact with two sites on Cdt1 for replication inhibition
A dimerized coiled-coil domain and an adjoining part of geminin interact with two sites on Cdt1 for replication inhibition
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DOI：
10.1016/j.molcel.2004.06.045
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发表时间：
2004-07-23
期刊：
影响因子：
16
通讯作者：
Dutta, A
中科院分区：
文献类型：
--
作者：
Saxena, S;Yuan, P;Dutta, A
Geminin是一种与Cdt 1相关的细胞蛋白质，并抑制S期期间Mcm 2 -7的负载。它阻止每个细胞周期的多个复制循环，并阻止附加体复制。它还直接抑制HoxA 11转录因子。在这里，我们报告说，双生蛋白形成一个平行的卷曲螺旋同源二聚体与非典型残基的二聚体界面。破坏二聚化的点突变可消除与Cdt 1的相互作用和复制抑制。卷曲螺旋结构域表面上的谷氨酸残基阵列与Cdt 1中间的正电荷相互作用。相邻区域独立地与Cdt 1的N-末端100个残基相互作用。这两种相互作用对于复制抑制是必不可少的。卷曲螺旋结构域上的负残基和双生蛋白的不同部分也是与HoxA 11相互作用所必需的。因此，具有负表面电荷的刚性圆柱体是双生蛋白与其细胞靶之间的二分相互作用界面的关键组成部分。
Geminin is a cellular protein that associates with Cdt1 and inhibits Mcm2-7 loading during S phase. It prevents multiple cycles of replication per cell cycle and prevents episome replication. It also directly inhibits the HoxA11 transcription factor. Here we report that geminin forms a parallel coiled-coil homodimer with atypical residues in the dimer interface. Point mutations that disrupt the dimerization abolish interaction with Cdt1 and inhibition of replication. An array of glutamic acid residues on the coiled-coil domain surface interacts with positive charges in the middle of Cdt1. An adjoining region interacts independently with the N-terminal 100 residues of Cdt1. Both interactions are essential for replication inhibition. The negative residues on the coiled-coil domain and a different part of geminin are also required for interaction with HoxA11. Therefore a rigid cylinder with negative surface charges is a critical component of a bipartite interaction interface between geminin and its cellular targets.