Biophysics and Biomechanics of the Semicircular Canals

总结。本工作旨在促进对角运动感觉的定量理解 通过半规管，特别注意转导和信号转导的生物物理学。 发束。实验将使用我们开发的一种新的转基因小鼠品系进行 实验室对立体纤毛中的发束偏转和钙瞬变进行成像，在某些情况下通过 在不破坏膜迷路的情况下保持完整的壶腹。具体目标的动机是 初步数据显示刺激诱发的钙点几乎完全位于Tall的尾部 立体纤毛，数据显示随着刺激强度的增加，钙点向上移动 增加，数据表明超快的钙信号从转导位置到细胞体。 特定目标1将使用生理学方法定位束中的机电转导通道 刺激，当刺激强度增加时，检查通道的招募，并绘制空间图 转导蛋白在上皮细胞表面的分布。特定目标2将测量轴向 刺激运动诱发立体纤毛内钙点状突起，并检测电位微机械 以及化学动力学起源。特指目标3将研究超快钙信号从部位 毛束顶端的转导作用距离细胞体40微米。

Summary. The present work seeks to advance quantitative understanding of angular motion sensation by the semicircular canals, with specific attention to biophysics of transduction and signaling in crista hair bundles. Experiments will be done using a new transgenic mouse strain developed in our laboratory to image hair bundle deflection and calcium transients in stereocilia, in some cases through the intact ampulla without disrupting the membranous labyrinth. The specific aims are motivated by preliminary data localizing stimulus-evoked calcium puncta almost exclusively at the tipse of tall stereocilia, data demonstrating upward movement of calcium puncta as the stimulus strength is increased, and data suggesting ultrafast calcium signaling from the transduction site to the cell body. Specific Aim 1 will localize mechano-electrical transduction channels in the bundle using physiological stimulation, examine recruitment of channels as the stimulus strength is increased, and map the spatial distribution of transduction across the surface of the epithelium. Specific Aim 2 will measure axial movements of stimulus evoked calcium puncta in stereocilia, and examine potential micromechanical and chemical-kinetic origins. Specific Aim 3 will investigate ultrafast calcium signaling from the site of transduction at tips of hair bundles over a distance >40µm to the cell body.