Localization of septin proteins in the mouse cochlea.
Localization of septin proteins in the mouse cochlea.
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DOI：
10.1016/j.heares.2012.04.015
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发表时间：
2012-07
期刊：
影响因子：
2.8
通讯作者：
Ito J
中科院分区：
文献类型：
--
作者：
Yoshida A;Yamamoto N;Kinoshita M;Hiroi N;Hiramoto T;Kang G;Trimble WS;Tanigaki K;Nakagawa T;Ito J
Septins是GTP结合蛋白的一个家族，在除植物外的真核生物中非常保守。间隔蛋白通过与膜脂质、肌动蛋白和微管结合，促进膜的横向区室化、皮质刚性和膜运输的调节。耳蜗中的Corti器在听觉感知中起着关键作用，包括两种高度极化的细胞，毛细胞和支持细胞，两者都富含肌动蛋白和微管。为了确定septins在耳蜗中的作用，我们分析了在脑组织中大量表达的三种septin蛋白，septin 4（SEPT4），septin 5（SEPT5）和septin 7（SEPT7）的定位，并且还检查了Sept4和Sept5无效小鼠的听觉功能。SEPT4、SEPT5和SEPT7在内柱细胞、外柱细胞和Deiters细胞中均有表达，但各蛋白在Deiters细胞中的分布模式不同。SEPT4和SEPT7在未检测到SEPT5的指骨突中表达。除了这些细胞，SEPT5和SEPT7与传出神经末梢的突触前囊泡共定位。胚胎期耳蜗中仅表达SEPT7。虽然Septin蛋白的表达模式表明其在耳蜗功能中的重要作用，但Sept4和Sept5无效小鼠与其野生型同窝小鼠具有相似的听觉功能。Sept4基因敲除小鼠的免疫组织化学分析表明，SEPT5在Deiters细胞的指突中的代偿性表达可能引起Sept4基因敲除小鼠听力的功能性代偿。
Septins are a family of GTP binding proteins that are well conserved in eukaryotic species except plants. Septins contribute to the lateral compartmentalization of membranes, cortical rigidity, and the regulation of membrane trafficking by associating with membrane lipids, actin, and microtubules. The organ of Corti in the cochlea has pivotal roles in auditory perception and includes two kinds of highly polarized cells, hair and supporting cells, both of which are rich in actin and microtubules. To identify the roles of septins in the cochlea, we analyzed the localization of three septin proteins, septin 4 (SEPT4), septin 5 (SEPT5), and septin 7 (SEPT7) that are abundantly expressed in brain tissues, and also examined auditory functions of Sept4 and Sept5 null mice. SEPT4, SEPT5, and SEPT7 were expressed in inner and outer pillar cells and Deiters’ cells but the distribution patterns of each protein in Deiters’ cells were different. SEPT4 and SEPT7 were expressed in the phalangeal process where SEPT5 was not detected. In addition to these cells SEPT5 and SEPT7 were co-localized with presynaptic vesicles of efferent nerve terminals. Only SEPT7 was expressed in the cochlea at embryonic stages. Although expression patterns of septin proteins suggested their important roles in the function of the cochlea, both Sept4 and Sept5 null mice had similar auditory functions to their wild type littermates. Immunohistochemical analysis of Sept4 null mice showed that compensatory expression of SEPT5 in the phalangeal process of Deiters’ cells may have caused functional compensation of hearing ability in Sept4 null mice.