Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK.
J Cell Sci. 2013 Apr 15;126(Pt 8):1721-31. doi: 10.1242/jcs.106120. Epub 2013 May 2.
The key components of acousticolateralis systems (lateral line, hearing and balance) are sensory hair cells. At their apex, these cells have a bundle of specialized cellular protrusions, which are modified actin-containing microvilli, connected together by extracellular filaments called cross links. Stereociliary deflections open nonselective cation channels allowing ions from the extracellular environment into the cell, a process called mechanoelectrical transduction. This produces a receptor potential that causes the release of the excitatory neurotransmitter glutamate onto the terminals of the sensory nerve fibres, which connect to the cell base, causing nerve signals to be sent to the brain. Identification of the cellular mechanisms underlying mechanoelectrical transduction and of some of the proteins involved has been assisted by research into the genetics of deafness, molecular biology and mechanical measurements of function. It is thought that one type of cross link, the tip link, is composed of cadherin 23 and protocadherin 15, and gates the transduction channel when the bundle is deflected. Another type of link, called lateral (or horizontal) links, maintains optimal bundle cohesion and stiffness for transduction. This Commentary summarizes the information currently available about the structure, function and composition of the links and how they might be relevant to human hearing impairment.
听觉和平衡）的关键组成部分是感觉毛细胞。在它们的顶端，这些细胞有一束专门的细胞突起，这些突起是含有肌动蛋白的微绒毛的修饰物，通过称为交联的细胞外细丝连接在一起。纤毛的偏斜打开非选择性阳离子通道，允许细胞外环境中的离子进入细胞，这个过程称为机电转导。这会产生一种受体电位，导致兴奋性神经递质谷氨酸释放到感觉神经纤维的末端，这些纤维连接到细胞基部，从而向大脑发送神经信号。机电转导的细胞机制以及一些相关蛋白的鉴定得到了耳聋遗传学、分子生物学和功能机械测量研究的帮助。人们认为，一种交联，即尖端连接，由钙黏蛋白 23 和原钙黏蛋白 15 组成，当束被偏斜时，它可以控制转导通道。另一种类型的连接，称为侧向（或水平）连接，为转导保持最佳的束凝聚力和刚度。这篇评论总结了目前关于连接的结构、功能和组成的信息，以及它们如何与人类听力障碍相关。
