Identification and functional characterization of Piezo2-multiprotein complexes involved in mechanotransduction

我们的感官世界是丰富的。从母亲温柔的抚摸到踩到钉子的痛苦感觉，我们感知和编码这些不同输入的能力对于生存至关重要。然而，机械感觉，感知机械刺激的能力，仍然是脊椎动物中最不了解的感觉。在脊椎动物躯体感觉系统的水平上，我们的触觉和疼痛的检测依赖于支配皮肤和内部器官的专门的机械敏感神经元的激活。这些神经元能够检测机械刺激，这是由于不同的机械敏感蛋白的表达，其中包括机械激活的离子通道。机械刺激介导离子通道门控，其导致跨膜的离子通量，因此代表机械刺激转化为电代码的第一步。尽管深入的研究工作，这些机械门控离子通道在脊椎动物的躯体感觉系统的分子身份是在很大程度上是未知的。在少数考虑的候选人中，最近发现的Piezo1和Piezo2通道代表了一类新的真正的机械敏感离子通道。在小鼠中，Piezo2在躯体感觉神经元中大量表达，在那里它介导快速适应的机械电流。因此，体内敲低Piezo2影响小鼠的触摸反应。Piezo2激活的后果可能主要取决于调节Piezo2活性的相关蛋白质，这些蛋白质表达的神经元类型以及它们所在的亚细胞微区。所有这些方面目前都是未知的。我们建议识别和研究Piezo2相关蛋白复合物参与小鼠感觉神经元的机械感觉。为此，我们将结合联合收割机定量质谱技术，小鼠行为疼痛范例，电生理学和蛋白质表达水平的体内操纵。我们希望确定新的分子组件的机械感觉器在体感神经元，从而有助于我们了解脊椎动物的体感机械感觉。

Our sensory universe is rich. From a gentle touch of a mother to the painful perception of stepping on a nail, our ability to perceive and encode such different inputs is critical for survival. However, mechanosensation, the ability to perceive mechanical stimuli, remains the least understood sense in vertebrates. At the level of the vertebrate somatosensory system our sense of touch and the detection of pain rely on the activation of specialized mechanosensitive neurons which innervate the skin and internal organs. These neurons are able to detect mechanical stimuli due to the expression of distinct mechanosensitive proteins, among them mechanically activated ion channels. Mechanical stimulation mediates ion channel gating which results in ion flux across membranes, thus representing the first step in the conversion of mechanical stimuli into an electrical code. Despite intensive research efforts the molecular identity of these mechanically gated ion channels in the vertebrate somatosensory system is largely unknown. Among the few considered candidates, the very recently discovered Piezo1 and Piezo2 channels represent a novel bona fide class of mechanosensitive ion channels. In mice Piezo2 is abundantly expressed in somatosensory neurons where it mediates rapidly adapting mechanocurrents. Accordingly, in vivo knock down of Piezo2 affects touch responses in mice. The consequences of Piezo2 activation are likely to depend critically on associated proteins that regulate Piezo2 activity, on the type of neuron where these proteins are expressed and also on the subcellular microdomains where they are located. All these aspects are currently unknown. We propose to identify and study Piezo2 associated protein complexes involved in mechanosensation in sensory neurons of mice. To this end, we will combine quantitative mass spectrometry techniques, mouse behavioral pain paradigms, electrophysiology and in vivo manipulation of protein expression levels. We expect to identify novel molecular components of the mechanosensitive apparatus in somatosensory neurons and thereby contribute to our understanding of somatosensory mechanosensation in vertebrates.