Balanced levels of espin are critical for stereociliary growth and length maintenance
Balanced levels of espin are critical for stereociliary growth and length maintenance
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DOI：
10.1002/cm.20094
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发表时间：
2005-11-01
影响因子：
--
通讯作者：
Kachar, B
中科院分区：
文献类型：
--
作者：
Rzadzinska, A;Schneider, M;Kachar, B
听力和平衡依赖于以微绒毛样肌动蛋白为基础的感觉毛细胞的投射，这种细胞被称为立体纤毛。它们对纳米尺度的机械位移的敏感性需要高度组织的发束，其中每个立体纤毛的物理尺寸都受到严格控制。每个立体纤毛的长度和直径是在毛束成熟的过程中确定的，并由终生持续的动态调节来维持。在这里，我们研究了肌动蛋白捆绑蛋白ESPIN在立体纤毛生长中的作用，通过检测ESPN(JE)缺陷的抽动小鼠(ESPN(JE))的毛细胞立体纤毛，以及在培养的Corti器官的神经上皮细胞中瞬时过表达ESPIN的影响。利用荧光扫描共聚焦和电子显微镜，我们发现缺乏ESpin会导致立体纤毛生长受到抑制，继而导致毛束的进行性退化。相反，ESpin的过表达诱导了体纤毛和微绒毛的延长，这反映了肌动蛋白细丝束在其核心的伸长。有趣的是，ESpin缺陷似乎也影响了肌球蛋白XVA的定位，这是一种非传统的肌球蛋白，通常存在于立体纤毛尖端，水平与立体纤毛长度成正比。这些结果表明，ESpin对于内耳神经上皮细胞肌动蛋白突起的生长和维持是重要的。细胞运动。
Hearing and balance depend on microvilli-like actin-based projections of sensory hair cells called stereocilia. Their sensitivity to mechanical displacements on the nanometer scale requires a highly organized hair bundle in which the physical dimension of each stereocilium is tightly controlled. The length and diameter of each stereocilium are established during hair bundle maturation and maintained by life-long continuing dynamic regulation. Here, we studied the role of the actin-bundling protein Espin in stereociliary growth by examining the hair cell stereocilia of Espin-deficient jerker mice (EspN(je)), and the effects of transiently over-expressing Espin in the neuroepithelial cells of the organ of Corti cultures. Using fluorescence scanning confocal and electron microscopy, we found that a lack of Espin results in inhibition of stereociliary growth followed by progressive degeneration of the hair bundle. In contrast, overexpression of Espin induced lengthening of stereocilia and microvilli that mirrored the elongation of the actin filament bundle at their core. Interestingly, Espin deficiency also appeared to influence the localization of Myosin XVa, an unconventional myosin that is normally present at the stereocilia tip at levels proportional to stereocilia length. These results indicate that Espin is important for the growth and maintenance of the actin-based protrusions of inner ear neuroepithelial cells. Cell Motil.