The actin-microtubule cross-linking activity of Drosophila Short stop is regulated by intramolecular inhibition.
The actin-microtubule cross-linking activity of Drosophila Short stop is regulated by intramolecular inhibition.
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DOI：
10.1091/mbc.e12-11-0798
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发表时间：
2013-09
影响因子：
3.3
通讯作者：
Rogers SL
中科院分区：
文献类型：
--
作者：
Applewhite DA;Grode KD;Duncan MC;Rogers SL
作者研究了果蝇肌动蛋白-微管交联剂Short stop （Shot）的调控，发现Shot发生分子内构象变化，调节其交联活性。这种分子内相互作用依赖于Shot的nh2末端肌动蛋白结合结构域和EF-hand-GAS2结构域。在细胞迁移、有丝分裂和形态发生过程中，肌动蛋白和微管动力学必须精确协调，这种协调大部分是由连接两个细胞骨架网络的蛋白质介导的。我们研究了果蝇肌动蛋白-微管交联剂Short stop （Shot）的调控，它是光谱蛋白家族的一员。我们的数据表明，Shot的细胞骨架交联活性受到分子内抑制机制的调节。在非活性构象中，Shot通过nh2端肌动蛋白结合域与cooh端EF-hand-GAS2结构域相互作用，形成“封闭”构象。这种非活性构象被EB1靶向于生长中的微管+端。在激活时，Shot通过其cooh末端GAS2结构域沿微管结合，并通过其nh2末端串联CH结构域与肌动蛋白结合。我们提出这种机制允许Shot快速交联动态微管，以响应细胞皮层的局部激活信号。
The authors investigated the regulation of the Drosophila actin-microtubule cross-linker Short stop (Shot) and found that Shot undergoes an intramolecular conformational change that regulates its cross-linking activity. This intramolecular interaction depends on Shot's NH2-terminal actin-binding domain and EF-hand-GAS2 domain. Actin and microtubule dynamics must be precisely coordinated during cell migration, mitosis, and morphogenesis—much of this coordination is mediated by proteins that physically bridge the two cytoskeletal networks. We have investigated the regulation of the Drosophila actin-microtubule cross-linker Short stop (Shot), a member of the spectraplakin family. Our data suggest that Shot's cytoskeletal cross-linking activity is regulated by an intramolecular inhibitory mechanism. In its inactive conformation, Shot adopts a “closed” conformation through interactions between its NH2-terminal actin-binding domain and COOH-terminal EF-hand-GAS2 domain. This inactive conformation is targeted to the growing microtubule plus end by EB1. On activation, Shot binds along the microtubule through its COOH-terminal GAS2 domain and binds to actin with its NH2-terminal tandem CH domains. We propose that this mechanism allows Shot to rapidly cross-link dynamic microtubules in response to localized activating signals at the cell cortex.