Reciprocal and dynamic polarization of planar cell polarity core components and myosin.
Reciprocal and dynamic polarization of planar cell polarity core components and myosin.
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DOI：
10.7554/elife.05361
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发表时间：
2015-04-13
期刊：
影响因子：
7.7
通讯作者：
Smith WC
中科院分区：
文献类型：
--
作者：
Newman-Smith E;Kourakis MJ;Reeves W;Veeman M;Smith WC
脊索呈平面细胞极性(PCP)，前部有棘突(PK)和斜视(STBM)。我们报道，肌球蛋白在这些细胞的前面极化，并与STBM强烈共存。用细胞松弛素或Blebbistatin破坏肌动蛋白/肌球蛋白机制可以破坏PK和Stbm的极化，但不能破坏肌球蛋白复合体的极化，提示肌球蛋白定位的PCP不依赖于PCP。洗去细胞松弛素可恢复PK极化，但在Blebbistatin存在的情况下不能恢复PK极化，提示肌球蛋白在核心PCP蛋白定位中起积极作用。另一方面，在PK突变系中，无目的性的肌球蛋白极化在大约三分之一的细胞中被破坏，这表明核心PCP信号在肌球蛋白定位上的相互作用。我们的结果表明肌球蛋白细胞骨架与PCP核心成分之间存在复杂的关系，其中肌球蛋白不仅是PCP信号转导的下游靶标，也是PCP蛋白定位所必需的。DOI：http://dx.doi.org/10.7554/eLife.05361.001构成扁平组织层的动物细胞，如皮肤或内腔的衬里，通常定向在同一方向。同样的道理也适用于附着在皮肤上的毛发或羽毛等结构。这种现象被称为“平面细胞极性”(或简称“PCP”)。许多不同的生物体使用类似的机制来建立这种组织模式。研究最多的机制涉及所谓的“核心五氯酚途径”。这一途径中的信号蛋白协调相邻细胞的极性。其他“全局信号通路”被认为首先确保组织作为一个整体在胚胎内正确定位，为了做到这一点，全局通路被认为在细胞内以特定方向排列一个丝状结构网络。一旦定位正确，这些被称为微管的细丝被提出帮助定位核心PCP途径的组件，以便它们能够正确地定位细胞的其余部分。现在，纽曼-史密斯，库拉基斯等人。已经发现了细胞内的另一个细丝网络，它与名为Ciona savignyi的海鞘中核心PCP途径的成分相互作用。这种生物一开始是一种类似蝌蚪的幼虫，它有一个灵活的杆状结构，称为“脊索”，沿着它的身体长度运行。脊索细胞在发育过程中变得极化。当微管被破坏时，它们的平面极性保持不变。然而，当另一个细丝网络--称为肌动球蛋白网络--被化学破坏时，某些核心PCP成分的极性就会丢失。Newman-Smith，Kourakis等人的发现。揭示了五氯苯酚的核心成分和肌动球蛋白网络在这个海鞘中相互加强了极性。这代表了前面描述的平面极性模型的另一种选择，在该模型中，核心PCP成分被认为驱动肌动球蛋白网络的极化。这个模型是否扩展到其他生物，如人类和其他有脊椎的动物，仍然是未来工作的问题。DOI：http://dx.doi.org/10.7554/eLife.05361.002
The Ciona notochord displays planar cell polarity (PCP), with anterior localization of Prickle (Pk) and Strabismus (Stbm). We report that a myosin is polarized anteriorly in these cells and strongly colocalizes with Stbm. Disruption of the actin/myosin machinery with cytochalasin or blebbistatin disrupts polarization of Pk and Stbm, but not of myosin complexes, suggesting a PCP-independent aspect of myosin localization. Wash out of cytochalasin restored Pk polarization, but not if done in the presence of blebbistatin, suggesting an active role for myosin in core PCP protein localization. On the other hand, in the pk mutant line, aimless, myosin polarization is disrupted in approximately one third of the cells, indicating a reciprocal action of core PCP signaling on myosin localization. Our results indicate a complex relationship between the actomyosin cytoskeleton and core PCP components in which myosin is not simply a downstream target of PCP signaling, but also required for PCP protein localization. DOI: http://dx.doi.org/10.7554/eLife.05361.001 Animal cells that form flat layers of a tissue, such as the skin or the lining of internal cavities, are often orientated in the same direction. The same is true for structures such as hairs or feathers, which are attached to the skin. This phenomenon is known as ‘planar cell polarity’ (or ‘PCP’ for short). Many different organisms use similar mechanisms to establish this kind of tissue pattern. The best-studied mechanism involves the so-called ‘core PCP pathway’. Signaling proteins in this pathway coordinate the polarity of neighboring cells. Other ‘global signaling pathways’ are thought to first ensure that tissues are correctly orientated within the embryo as a whole, and to do this, the global pathways are thought to align a network of filament-like structures within the cells in a particular direction. Once correctly orientated, these filaments—known as microtubules—have been proposed to help position the components of the core PCP pathway such that they can correctly orientate the rest of the cell. Now Newman-Smith, Kourakis et al. have identified another network of filaments within cells that interacts with components of the core PCP pathway in a sea squirt called Ciona savignyi. This organism begins life as a tadpole-like larva that has a flexible rod-shaped structure, called a ‘notochord’, running along the length of its body. The cells of the notochord become polarized as they develop. When microtubules are disrupted, their planar polarity remains unaffected. However, when another network of filaments—called the actomyosin network––is chemically disrupted, the polarity of certain core PCP components is lost. The findings of Newman-Smith, Kourakis et al. reveal that the core PCP components and the actomyosin network in this sea squirt reinforce each other's polarity. This represents an alternative to the previously described models of planar polarity in which the core PCP components are thought to drive the polarization of the actomyosin network. Whether this model extends to planar cell polarity mechanisms in other organisms, such humans and other animals with backbones, remains a question for future work. DOI: http://dx.doi.org/10.7554/eLife.05361.002