Zhang Rui, Qian Feng, Rajagopalan Lavanya, Pereira Fred A, Brownell William E, Anvari Bahman
Applied Physics Graduate Program, Rice University, Houston, Texas, USA.
Biophys J. 2007 Jul 1;93(1):L07-9. doi: 10.1529/biophysj.107.107573. Epub 2007 Apr 27.
The voltage-dependent movement, or electromotility, of cochlear outer hair cells contributes to cochlear amplification in mammalian hearing. Outer hair-cell electromotility involves a membrane-based motor in which the membrane protein prestin plays a central role. We have investigated the contribution of prestin to the mechanics and electromechanical force (EMF) generation of the membrane using membrane tethers formed from human embryonic kidney (HEK) cells. Several measures of membrane tether mechanics are greater in tethers pulled from HEK cells transfected with prestin when compared to control untransfected HEK cells. A single point mutation of alanine to tryptophan (A100W) in prestin eliminates prestin-associated charge movement and diminishes EMF but does not alter passive membrane mechanics. These results suggest that prestin-associated charge transfer is necessary for maximal EMF generation by the membrane.
耳蜗外毛细胞的电压依赖性运动，即电运动性，对哺乳动物听力中的耳蜗放大作用有贡献。外毛细胞电运动性涉及一种基于膜的马达，其中膜蛋白prestin起着核心作用。我们利用人胚肾（HEK）细胞形成的膜系绳，研究了prestin对膜的力学和机电力（EMF）产生的贡献。与未转染的对照HEK细胞相比，从转染了prestin的HEK细胞中拉出的系绳的几种膜系绳力学测量值更大。prestin中丙氨酸到色氨酸的单点突变（A100W）消除了与prestin相关的电荷移动并减少了EMF，但不改变被动膜力学。这些结果表明，与prestin相关的电荷转移对于膜产生最大EMF是必要的。
