The stable actin core of mechanosensory stereocilia features continuous turnover of actin cross-linkers.
The stable actin core of mechanosensory stereocilia features continuous turnover of actin cross-linkers.
复制标题
机械感觉静纤毛的稳定肌动蛋白核心具有肌动蛋白交联剂的连续周转的特征。
DOI：
10.1091/mbc.e18-03-0196
复制
发表时间：
2018
影响因子：
3.3
通讯作者：
Perrin,BenjaminJ
中科院分区：
文献类型：
--
作者：
Roy,Pallabi;Perrin,BenjaminJ
静纤毛是内耳感觉毛细胞表面上的机械敏感突起，其检测声音、重力和头部运动。它们的核心由平行的肌动蛋白丝组成，这些肌动蛋白丝通过几种肌动蛋白结合蛋白交联和稳定，包括肌成束蛋白-2，plastin-1，espin和XIRP 2。肌动蛋白丝是已知的最稳定的，肌动蛋白周转主要发生在静纤毛尖端。虽然静纤毛肌动蛋白动力学已经得到了很好的研究，但对肌动蛋白交联蛋白的行为知之甚少，肌动蛋白交联蛋白是静纤毛中肌动蛋白之后最丰富的蛋白质类型，并且对于静纤毛形态发生和维持至关重要。在这里，我们开发了一种新的转基因小鼠来监测EGFP-fascin-2的掺入。我们还比较了EGFP-fascin-2表达对静纤毛发育和成熟的影响。当它在毛细胞发育过程中被诱导时，我们观察到静纤毛的长度和宽度都增加。有趣的是，静纤毛的大小不受影响时，EGFP-fascin-2诱导成人静纤毛。无论诱导的时间，EGFP-fascin-2从静纤毛置换espin和plastin-1。改变肌动蛋白交联剂的组成，即使肌动蛋白丝表现出很少或没有营业额，提供了一个机制，持续重塑和修复静纤毛稳态的重要。
Stereocilia are mechanosensitive protrusions on the surfaces of sensory hair cells in the inner ear that detect sound, gravity, and head movement. Their cores are composed of parallel actin filaments that are cross-linked and stabilized by several actin-binding proteins, including fascin-2, plastin-1, espin, and XIRP2. The actin filaments are the most stable known, with actin turnover primarily occurring at the stereocilia tips. While stereocilia actin dynamics has been well studied, little is known about the behavior of the actin cross-linking proteins, which are the most abundant type of protein in stereocilia after actin and are critical for stereocilia morphogenesis and maintenance. Here, we developed a novel transgenic mouse to monitor EGFP-fascin-2 incorporation.In contrast to actin, EGFP-fascin-2 readily enters the stereocilia core. We also compared the effect of EGFP-fascin-2 expression on developing and mature stereocilia. When it was induced during hair cell development, we observed increases in both stereocilia length and width. Interestingly, stereocilia size was not affected when EGFP-fascin-2 was induced in adult stereocilia. Regardless of the time of induction, EGFP-fascin-2 displaced both espin and plastin-1 from stereocilia. Altering the actin cross-linker composition, even as the actin filaments exhibit little to no turnover, provides a mechanism for ongoing remodeling and repair important for stereocilia homeostasis.