The C-Terminal Variable Region Specifies the Dynamic Properties of Arabidopsis Microtubule-Associated Protein MAP65 Isotypes[C][W]
The C-Terminal Variable Region Specifies the Dynamic Properties of Arabidopsis Microtubule-Associated Protein MAP65 Isotypes[C][W]
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DOI：
10.1105/tpc.108.063362
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发表时间：
2008-12
期刊：
影响因子：
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通讯作者：
A. Smertenko;Despina Kaloriti;Hsin-Yu Chang;J. Fišerová;Z. Opatrný;P. Hussey
中科院分区：
文献类型：
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作者：
A. Smertenko;Despina Kaloriti;Hsin-Yu Chang;J. Fišerová;Z. Opatrný;P. Hussey
微管相关蛋白MAP 65是来自不同生物体的不同微管相关蛋白家族的成员，通常参与维持有丝分裂中中央纺锤体的完整性。双子叶植物拟南芥（Arabidopsis thaliana）和单子叶植物水稻（Oryza sativa）基因组分别含有9个和11个MAP 65基因。在这项工作中，我们表明，这些蛋白质的大部分属于五个系统发育分支，分支之间的最大变化是在C-末端无规卷曲结构域。每个进化枝中至少有一个拟南芥和一个水稻同种型，这表明C末端具有功能性规范。在At MAP 65 -1中，C-末端结构域是微管结合区（MTB 2），含有控制其活性的磷酸化位点。在MAP 65同种型显示差异定位微管阵列和促进微管聚合与MTB 2依赖性的方式可变的效率。体内研究表明，不同的MAP 65同种型与微管的缔合和解离的动力学可以变化高达10倍，这与它们促进微管聚合的能力相关。我们的数据表明，C-末端可变区，MTB 2，决定了个别同种型的动态特性，并建议，更有效的微管聚合的条件，营业额较慢。
The microtubule-associated protein, MAP65, is a member of a family of divergent microtubule-associated proteins from different organisms generally involved in maintaining the integrity of the central spindle in mitosis. The dicotyledon Arabidopsis thaliana and the monocotyledon rice (Oryza sativa) genomes contain 9 and 11 MAP65 genes, respectively. In this work, we show that the majority of these proteins fall into five phylogenetic clades, with the greatest variation between clades being in the C-terminal random coil domain. At least one Arabidopsis and one rice isotype is within each clade, indicating a functional specification for the C terminus. In At MAP65-1, the C-terminal domain is a microtubule binding region (MTB2) harboring the phosphorylation sites that control its activity. The At MAP65 isotypes show differential localization to microtubule arrays and promote microtubule polymerization with variable efficiency in a MTB2-dependent manner. In vivo studies demonstrate that the dynamics of the association and dissociation of different MAP65 isotypes with microtubules can vary up to 10-fold and that this correlates with their ability to promote microtubule polymerization. Our data demonstrate that the C-terminal variable region, MTB2, determines the dynamic properties of individual isotypes and suggest that slower turnover is conditional for more efficient microtubule polymerization.