Truncation of the otoferlin transmembrane domain alters the development of hair cells and reduces membrane docking.
Truncation of the otoferlin transmembrane domain alters the development of hair cells and reduces membrane docking.
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DOI：
10.1091/mbc.e20-10-0657
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发表时间：
2021-07-01
影响因子：
3.3
通讯作者：
Johnson CP
中科院分区：
文献类型：
--
作者：
Manchanda A;Bonventre JA;Bugel SM;Chatterjee P;Tanguay R;Johnson CP
从感觉毛细胞释放神经递质是由otoferlin调节。尽管otoferlin在听觉和前庭通路中的重要性，但该蛋白的结构域的功能贡献尚未完全表征。使用斑马鱼模型，我们研究了突变otoferlin与终止密码子在跨膜结构域的开始。我们发现，无论是表型的严重程度和突变otoferlin的表达水平的变化与年龄的斑马鱼。在受精后72小时的早期发育时间点，低表达的otoferlin突变体符合突触带缺陷，减少内吞作用，和异常转录的几个毛细胞基因。随着发育的进行，突变体otoferlin的表达增加，突触带和毛细胞转录水平与野生型相似。然而，毛细胞内吞赤字和异常的GABA受体的表达仍然存在，即使上调突变otoferlin。膜重构otoferlin测量的分析表明脂质体对接中跨膜结构域的功能。我们的结论是，跨膜结构域的删除减少膜对接，减弱内吞作用，并导致毛细胞发育迟缓。
Release of neurotransmitter from sensory hair cells is regulated by otoferlin. Despite the importance of otoferlin in the auditory and vestibular pathways, the functional contributions of the domains of the protein have not been fully characterized. Using a zebrafish model, we investigated a mutant otoferlin with a stop codon at the start of the transmembrane domain. We found that both the phenotype severity and the expression level of mutant otoferlin changed with the age of the zebrafish. At the early developmental time point of 72 h post fertilization, low expression of the otoferlin mutant coincided with synaptic ribbon deficiencies, reduced endocytosis, and abnormal transcription of several hair cell genes. As development proceeded, expression of the mutant otoferlin increased, and both synaptic ribbons and hair cell transcript levels resembled wild type. However, hair cell endocytosis deficits and abnormalities in the expression of GABA receptors persisted even after up-regulation of mutant otoferlin. Analysis of membrane-reconstituted otoferlin measurements suggests a function for the transmembrane domain in liposome docking. We conclude that deletion of the transmembrane domain reduces membrane docking, attenuates endocytosis, and results in developmental delay of the hair cell.