Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA.
Neuron. 2013 Jul 10;79(1):69-81. doi: 10.1016/j.neuron.2013.05.018. Epub 2013 Jun 6.
Active force generation by outer hair cells (OHCs) underlies amplification and frequency tuning in the mammalian cochlea but whether such a process exists in nonmammals is unclear. Here, we demonstrate that hair cells of the chicken auditory papilla possess an electromechanical force generator in addition to active hair bundle motion due to mechanotransducer channel gating. The properties of the force generator, its voltage dependence and susceptibility to salicylate, as well as an associated chloride-sensitive nonlinear capacitance, suggest involvement of the chicken homolog of prestin, the OHC motor protein. The presence of chicken prestin in the hair cell lateral membrane was confirmed by immunolabeling studies. The hair bundle and prestin motors together create sufficient force to produce fast lateral displacements of the tectorial membrane. Our results imply that the first use of prestin as a motor protein occurred early in amniote evolution and was not a mammalian invention as is usually supposed.
外毛细胞（OHCs）的主动力生成是哺乳动物耳蜗放大和频率调谐的基础，但这种过程是否存在于非哺乳动物中尚不清楚。在这里，我们证明鸡听乳头的毛细胞除了由于机械换能器通道门控而产生的主动毛束运动之外，还具有机电力发生器。力发生器的特性、其电压依赖性和对水杨酸盐的敏感性，以及相关的氯离子敏感非线性电容，表明涉及鸡 prestin 的同源物，即 OHC 运动蛋白。通过免疫标记研究证实了鸡 prestin 存在于毛细胞侧膜中。毛束和 prestin 马达一起产生足够的力，以产生快速的盖膜横向位移。我们的结果表明，prestin 作为一种运动蛋白的首次使用发生在羊膜动物进化的早期，而不是像通常认为的那样是哺乳动物的发明。
