Investigating the Molecular Basis of Mechanotransduction Channel Gating

描述(由Candiate提供)：在细胞和分子水平上，人们对人类感觉触摸的确切方式知之甚少。即使是轻微的微风也会对皮肤施加足够的压力，启动快速的信号级联反应，立即将感觉传递到大脑。这种将机械刺激转化为神经信号的过程被称为机械感觉，它对触觉、听觉、平衡、肾脏调节等方面至关重要。机械感觉的组成部分是嵌入在细胞表面的蛋白质，称为离子通道，在拉伸或拉伸时打开。在哺乳动物中，上皮钠通道(ENaCs)和酸敏离子通道(ASIC)与机械感觉有关，但人们对它们在这一过程中的作用知之甚少。线虫是一种常用于研究机械感觉的模式生物。这项提案的重点是线虫的两种蛋白质，MEC-4和MEC-10，它们构成了感知温柔触摸的通道，与ENaCs和ASIC属于同一超级家族。因此，在它们的自然环境中研究MEC-4和MEC-10所获得的信息将与哺乳动物的触觉相关。在这个超级家族中，许多排列在通道毛孔中的残基是高度保守的，它们长期以来一直与通道功能有关。在这项建议中，将突变由MEC-4和MEC-10形成的通道孔隙中高度保守的残基，以利用缝隙蠕虫全细胞膜片钳技术确定特定的变化如何改变体内的通道功能。确定这些残基的作用将在分子蛋白质水平上加强对通道门控的理解。首先，将研究表型已知的突变。然后，我们将对许多内孔甘氨酸进行研究，以探讨GxxxG螺旋填充基序在通道门控途径中的重要性。这项工作将是第一次对这一重要区域进行深入的在体电生理研究。机械敏感蛋白通道参与许多重要的过程，如解释触觉和听觉、调节肾脏功能、控制血压、平衡细胞间的盐水比例等。了解这些渠道是如何发挥作用的，可以为干预打开大门，以防止或减缓它们控制的重要人类功能的衰退。

DESCRIPTION (provided by candidate): On the cellular and molecular level, exactly how humans sense touch is poorly understood. Even a slight breeze exerts enough pressure against the skin to start a rapid signaling cascade that immediately transmits the sensation to the brain. This process of translating mechanical stimuli into neuronal signals is called mechanosensation, and it is critical for the sense of touch, hearing, balance, kidney regulation, and more. Integral components of mechanosensation are proteins embedded within the surface of a cell called ion channels that open upon tension or stretch. In mammals epithelial sodium channels (ENaCs) and acid- sensing ion channels (ASICs) are linked to mechanosensation, but little is known about how they function in this process. C. elegans is a model organism often used for studying mechanosensation. The two C. elegans proteins that are the focus of this proposal, MEC-4 and MEC-10, constitute the channel that senses gentle touch and are in the same super family as ENaCs and ASICs. Thus, information gained from studying MEC-4 and MEC-10 in their native environment will be relevant to mammalian touch sensation. Many of the residues that line the pore of the channels in this super family are highly conserved, and they have long been implicated in channel function. In this proposal highly conserved residues found in the pore of the channel formed by MEC-4 and MEC-10 will be mutated in order to determine how specific changes alter channel function in vivo using the slit-worm whole-cell patch clamp technique. Determining the roles of these residues will enhance the understanding of channel gating at the molecular protein level. First, mutations with known phenotypes will be studied. Then, the many pore-lining glycines will be investigated to probe the importance of the GxxxG helix-packing motif in the gating pathway of the channel. This work will be the first thorough in vivo electrophysiological investigation of this important region. Mechanosensitive protein channels are involved in many vital processes such as interpreting the sensations of touch and hearing, regulating kidney function, controling blood pressure, and balancing the ratio of salt and water across cells. Understanding how these channels function could open the door to interventions that prevent or slow the decline of the important human functions that they control.