The chloride intracellular channel protein CLIC5 is expressed at high levels in hair cell stereocilia and is essential for normal inner ear function
The chloride intracellular channel protein CLIC5 is expressed at high levels in hair cell stereocilia and is essential for normal inner ear function
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DOI：
10.1523/jneurosci.2166-06.2006
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发表时间：
2006-10-04
影响因子：
5.3
通讯作者：
Johnson, Kenneth R.
中科院分区：
文献类型：
--
作者：
Gagnon, Leona H.;Longo-Guess, Chantal M.;Johnson, Kenneth R.
虽然CLIC5是氯离子细胞内通道蛋白家族的成员，但它与基于肌动蛋白的细胞骨架结构的联系表明，它可能在细胞骨架的组装或维持中发挥重要作用。一种新的自发隐性突变Clic5基因的纯合子小鼠，被命名为jitterbug(JBG)，表现出听力和前庭功能障碍。JBG突变是一个97bp的基因内缺失，导致外显子5的跳过，从而产生翻译框架移位和过早终止密码子。Western印迹和免疫组织化学结果证实了JBG/JBG突变小鼠组织中CLIC5蛋白的预测缺失。突变内耳的组织学分析显示畸形的立体纤毛和进行性毛细胞变性。在野生型小鼠耳蜗发育过程中，CLIC5特异性免疫荧光在耳蜗毛细胞和前庭毛细胞以及Kolliker‘s器顶面均可检测到。在大鼠和鸡的前庭毛细胞中的精细免疫定位表明，CLIC5仅限于毛束的基底部区域，与Radixin的已知位置相似。在JBG突变小鼠的毛束中，放射素免疫染色减弱。质谱学和免疫印迹结果表明，CLIC5在鸡椭圆体的纤毛中有较高水平的表达，与辐射的摩尔比约为1：1。这些结果表明，CLIC5在毛细胞立体纤毛中与Radioxin结合，可能有助于形成或稳定质膜和丝状肌动蛋白核心之间的联系。
Although CLIC5 is a member of the chloride intracellular channel protein family, its association with actin-based cytoskeletal structures suggests that it may play an important role in their assembly or maintenance. Mice homozygous for a new spontaneous recessive mutation of the Clic5 gene, named jitterbug (jbg), exhibit impaired hearing and vestibular dysfunction. The jbg mutation is a 97 bp intragenic deletion that causes skipping of exon 5, which creates a translational frame shift and premature stop codon. Western blot and immunohistochemistry results confirmed the predicted absence of CLIC5 protein in tissues of jbg/jbg mutant mice. Histological analysis of mutant inner ears revealed dysmorphic stereocilia and progressive hair cell degeneration. In wild-type mice, CLIC5-specific immunofluorescence was detected in stereocilia of both cochlear and vestibular hair cells and also along the apical surface of Kolliker's organ during cochlear development. Refined immunolocalization in rat and chicken vestibular hair cells showed that CLIC5 is limited to the basal region of the hair bundle, similar to the known location of radixin. Radixin immunostaining appeared reduced in hair bundles of jbg mutant mice. By mass spectrometry and immunoblotting, CLIC5 was shown to be expressed at high levels in stereocilia of the chicken utricle, in an approximate 1:1 molar ratio with radixin. These results suggest that CLIC5 associates with radixin in hair cell stereocilia and may help form or stabilize connections between the plasma membrane and the filamentous actin core.