Context-specific requirements of functional domains of the Spectraplakin Short stop in vivo
Context-specific requirements of functional domains of the Spectraplakin Short stop in vivo
复制标题
DOI：
10.1016/j.mod.2009.04.004
复制
发表时间：
2009-07-01
影响因子：
2.6
通讯作者：
Prokop, Andreas
中科院分区：
文献类型：
--
作者：
Bottenberg, Wolfgang;Sanchez-Soriano, Natalia;Prokop, Andreas
光谱蛋白是一种大型的多功能细胞骨架相互作用分子，涉及多种过程，包括原肠胚形成、伤口愈合、皮肤起泡和神经元变性。据推测，在Spectraplakins中发现的各种功能域和区域以特定于上下文的方式使用，这一模型将为Spectraplakins的多功能性质提供重要解释。在这里，我们通过在三种不同的细胞环境下研究果蝇光谱plakin Short stop （Shot）的结构域需求来测试这种可能性：(1)神经元生长，这需要动态的肌动蛋白-微管相互作用；(2)肌腱细胞的形成和维持，这取决于高度稳定的肌动蛋白细丝和微管阵列；(3)神经元的区隔化，这可能涉及皮质f -肌动蛋白网络。利用这些细胞背景对Shot突变背景下的Shot删除构建体进行拯救实验，发现了许多不同的结构域要求。首先，通过第一个钙钙蛋白结构域将Shot与f -肌动蛋白结合在神经元环境中是必不可少的，但在肌腱细胞中是必不可少的。我们对短粒（kakP2）突变胚胎的分析支持了这一发现，kakP2突变胚胎只产生缺乏第一钙钙蛋白结构域的内源性同种异构体。因此，我们的数据证明了这些同工异构体在体内的功能相关性。其次，我们提供了Shot的Plakin结构域的第一个功能作用，它在神经元和轴突生长中对区隔化有很强的要求，证明了长谱Plakin异构体的Plakin结构域具有功能相关性。与钙钙蛋白结构域一样，Plakin结构域在肌腱细胞中也是不可缺少的，目前认为Shot作为微管连接肌腱细胞表面的作用可能需要重新考虑。第三，我们证明了Shot在树突生长中作为肌动蛋白-微管连接体的功能，从而为这种神经突类型的主要生长机制提供了新的视角。综上所述，我们的数据清楚地支持了这样一种观点，即在体内，Spectraplakins以组织特异性模式起作用，甚至在特定情况下，被认为对Spectraplakin功能至关重要的结构域也可能是可有可无的。2009爱思唯尔爱尔兰有限公司版权所有。
Spectraplakins are large multifunctional cytoskeletal interacting molecules implicated in various processes, including gastrulation, wound healing, skin blistering and neuronal degeneration. It has been speculated that the various functional domains and regions found in Spectraplakins are used in context-specific manners, a model which would provide a crucial explanation for the multifunctional nature of Spectraplakins. Here we tested this possibility by studying domain requirements of the Drosophila Spectraplakin Short stop (Shot) in three different cellular contexts in vivo: (1) neuronal growth, which requires dynamic actin-microtubule interaction; (2) formation and maintenance of tendon cells, which depends on highly stabilised arrays of actin filaments and microtubules, and (3) compartmentalisation in neurons, which is likely to involve cortical F-actin networks. Using these cellular contexts for rescue experiments with Shot deletion constructs in shot mutant background, a number of differential domain requirements were uncovered. First, binding of Shot to F-actin through the first Calponin domain is essential in neuronal contexts but dispensable in tendon cells. This finding is supported by our analyses of shot(kakP2) mutant embryos, which produce only endogenous isoforms lacking the first Calponin domain. Thus, our data demonstrate a functional relevance for these isoforms in vivo. Second, we provide the first functional role for the Plakin domain of Shot, which has a strong requirement for compartmentalisation in neurons and axonal growth, demonstrating that Plakin domains of long Spectraplakin isoforms are of functional relevance. Like the Calponin domain, also the Plakin domain is dispensable in tendon cells, and the currently assumed role of Shot as a linker of microtubules to the tendon cell surface may have to be reconsidered. Third, we demonstrate a function of Shot as an actin-microtubule linker in dendritic growth, thus shedding new light into principal growth mechanisms of this neurite type. Taken together, our data clearly support the view that Spectraplakins function in tissue-specific modes in vivo, and even domains believed to be crucial for Spectraplakin function can be dispensable in specific contexts. (C) 2009 Elsevier Ireland Ltd. All rights reserved.