Mdp3 is a novel microtubule-binding protein that regulates microtubule assembly and stability
Mdp3 is a novel microtubule-binding protein that regulates microtubule assembly and stability
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DOI：
10.4161/cc.10.22.18106
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发表时间：
2011-11-15
期刊：
影响因子：
4.3
通讯作者：
Zhou, Jun
中科院分区：
文献类型：
--
作者：
Sun, Xiaoou;Shi, Xingjuan;Zhou, Jun
微管结合蛋白是一组与微管结合，调控微管结构特性，从而参与多种微管介导的细胞活动的分子。最近一项基于质谱的蛋白质组学研究发现，微管相关蛋白7 （MAP 7）结构域3 （Mdp3）是一种潜在的微管结合蛋白。然而，其亚细胞定位和功能重要性尚不清楚。在这项研究中，通过gst -pull - down实验，我们发现Mdp3在细胞内和体外都与微管蛋白相互作用。免疫荧光显微镜和微管共沉淀法显示Mdp3也与微管相关。序列缺失实验表明，Mdp3的两个卷曲线圈基序对其与微管蛋白和微管的相互作用至关重要。冷恢复和nocodazole洗脱实验进一步证明了mp3在调节细胞微管组装中的重要作用。我们的数据还表明，Mdp3显著增强了细胞微管的稳定性。通过微管蛋白浊度测定，我们发现Mdp3可以促进微管在纯化系统中的组装和稳定性。此外，我们发现Mdp3的表达随细胞周期和原代组织的变化而变化。这些发现表明，Mdp3是一种新型的微管结合蛋白，可以调节微管的组装和稳定性。
Microtubule-binding proteins are a group of molecules that associate with microtubules, regulate the structural properties of microtubules, and thereby participate in diverse microtubule-mediated cellular activities. A recent mass spectrometry-based proteomic study has identified microtubule-associated protein 7 (MAP 7) domain-containing 3 (Mdp3) as a potential microtubule-binding protein. However, its subcellular localization and functional importance are not characterized. In this study, by GST-pulldown assays, we found that Mdp3 interacted with tubulin both in cells and in vitro. Immunofluorescence microscopy and microtubule cosedimentation assays revealed that Mdp3 also associated with microtubules. Serial deletion experiments showed that the two coiled coil motifs of Mdp3 were critical for its interaction with tubulin and microtubules. Cold recovery and nocodazole washout assays further demonstrated an important role for Mdp3 in regulating cellular microtubule assembly. Our data also showed that Mdp3 significantly enhanced the stability of cellular microtubules. By tubulin turbidity assay, we found that Mdp3 could promote microtubule assembly and stability in the purified system. In addition, we found that Mdp3 expression varied during the cell cycle and in primary tissues. These findings thus establish Mdp3 as a novel microtubule-binding protein that regulates microtubule assembly and stability.