Interaction of mammalian end binding proteins with CAP-Gly domains of CLIP-170 and p150glued
Interaction of mammalian end binding proteins with CAP-Gly domains of CLIP-170 and p150glued
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DOI：
10.1016/j.jsb.2011.11.010
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发表时间：
2012-01-01
影响因子：
3
通讯作者：
Steinmetz, Michel O.
中科院分区：
文献类型：
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作者：
Bjelic, Sasa;De Groot, Christian O.;Steinmetz, Michel O.
末端结合蛋白（EBs）跟踪生长的微管末端，在组织动态蛋白质网络中发挥主导作用。哺乳动物细胞表达多达三种不同的EB（EB 1，EB 2和EB 3）。除了形成同源二聚体。EB 1和EB 3也组装成异二聚体。一组EB结合配偶体包括具有CAP-Gly结构域的蛋白质。不同EB对CAP-Gly蛋白的结合特性尚未进行系统研究。然而，这些信息对于比较和对比功能差异很重要。在这里，我们分析了CLIP-170和p150（胶合）CAP-Gly结构域与三种EB同源二聚体和EB 1-EB 3异源二聚体之间的相互作用。使用等温滴定量热法，我们观察到，一些EB结合到个别CAP-Gly域具有相似的亲和力，而其他相互作用与他们的目标有显着的差异。我们进一步发现，这两种类型的CAP-Gly结构域使用替代机制来靶向EB的C-末端结构域。我们成功地解决了由EB 1和EB 3 C-末端的异源二聚体与p150的CAP-Gly结构域（胶合）组成的复合物的晶体结构。总之，我们的研究结果提供了对EB相互作用特性的机制性见解，并为系统研究其在细胞中的功能差异提供了分子框架。(C)2011 Elsevier Inc. All rights reserved.
End binding proteins (EBs) track growing microtubule ends and play a master role in organizing dynamic protein networks. Mammalian cells express up to three different EBs (EB1, EB2, and EB3). Besides forming homodimers. EB1 and EB3 also assemble into heterodimers. One group of EB-binding partners encompasses proteins that harbor CAP-Gly domains. The binding properties of the different EBs towards CAP-Gly proteins have not been systematically investigated. This information is, however, important to compare and contrast functional differences. Here we analyzed the interactions between CLIP-170 and p150(glued) CAP-Gly domains with the three EB homodimers and the EB1-EB3 heterodimer. Using isothermal titration calorimetry we observed that some EBs bind to the individual CAP-Gly domains with similar affinities while others interact with their targets with pronounced differences. We further found that the two types of CAP-Gly domains use alternative mechanisms to target the C-terminal domains of EBs. We succeeded to solve the crystal structure of a complex composed of a heterodimer of EB1 and EB3 C-termini together with the CAP-Gly domain of p150(glued). Together, our results provide mechanistic insights into the interaction properties of EBs and offer a molecular framework for the systematic investigation of their functional differences in cells. (C) 2011 Elsevier Inc. All rights reserved.