Myosin-X functions in polarized epithelial cells.
Myosin-X functions in polarized epithelial cells.
复制标题
肌球蛋白-X在极化上皮细胞中起作用。
DOI：
10.1091/mbc.e11-04-0358
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发表时间：
2012-05
影响因子：
3.3
通讯作者：
Cheney RE
中科院分区：
文献类型：
--
作者：
Liu KC;Jacobs DT;Dunn BD;Fanning AS;Cheney RE
肌球蛋白-X是一种主要在成纤维细胞样细胞中研究的非常规肌球蛋白，已被证明在极化上皮细胞连接形成、细胞旁通透性调节和上皮形态发生中具有重要功能。肌球蛋白-X（Myo 10）是一种非传统的肌球蛋白，定位于丝状伪足的尖端，并在丝状伪足中具有关键功能。虽然Myo 10主要在非极化的成纤维细胞样细胞中进行研究，但Myo 10在许多富含上皮的组织（如肾脏）中体内表达。在这项研究中，我们调查的定位和极化上皮细胞Myo 10的功能，使用Madin-Darby犬肾II细胞作为模型系统。钙开关实验表明，在连接组件，绿色荧光蛋白Myo 10定位到侧膜细胞-细胞接触和丝状伪足样结构的基底表面上的全内反射荧光成像。Myo 10的敲低导致E-钙粘蛋白和ZO-1向连接的延迟募集，以及紧密连接屏障形成的延迟，如通过峰值跨上皮电阻（TER）的发展的延迟所指示的。虽然Myo 10敲低细胞最终成熟为具有正常TER的单层，但这些单层确实表现出对荧光葡聚糖的细胞旁渗透性增加。重要的是，Myo 10的敲低导致有丝分裂纺锤体的错误取向，并且在三维培养中，Myo 10敲低的囊肿表现出管腔形成的缺陷。总之，这些结果表明，Myo 10在极化上皮细胞中的连接形成，调节细胞旁通透性和上皮形态发生中起作用。
Myosin-X, an unconventional myosin that has been studied primarily in fibroblast-like cells, has been shown to have important functions in polarized epithelial cell junction formation, regulation of paracellular permeability, and epithelial morphogenesis. Myosin-X (Myo10) is an unconventional myosin that localizes to the tips of filopodia and has critical functions in filopodia. Although Myo10 has been studied primarily in nonpolarized, fibroblast-like cells, Myo10 is expressed in vivo in many epithelia-rich tissues, such as kidney. In this study, we investigate the localization and functions of Myo10 in polarized epithelial cells, using Madin-Darby canine kidney II cells as a model system. Calcium-switch experiments demonstrate that, during junction assembly, green fluorescent protein–Myo10 localizes to lateral membrane cell–cell contacts and to filopodia-like structures imaged by total internal reflection fluorescence on the basal surface. Knockdown of Myo10 leads to delayed recruitment of E-cadherin and ZO-1 to junctions, as well as a delay in tight junction barrier formation, as indicated by a delay in the development of peak transepithelial electrical resistance (TER). Although Myo10 knockdown cells eventually mature into monolayers with normal TER, these monolayers do exhibit increased paracellular permeability to fluorescent dextrans. Importantly, knockdown of Myo10 leads to mitotic spindle misorientation, and in three-dimensional culture, Myo10 knockdown cysts exhibit defects in lumen formation. Together these results reveal that Myo10 functions in polarized epithelial cells in junction formation, regulation of paracellular permeability, and epithelial morphogenesis.