活细胞中低温激活TRPM8离子通道的分子机制

对温度的感受是生命体维持的重要基础，对于个体的生存与延续有着至关重要的意义。作为经典的低温感受器，细胞膜上的TRPM8离子通道在低于28℃时开放，控制离子的跨细胞膜流动，将环境低温信号转化为神经电信号。然而，低温激活该通道的分子机制尚未阐明。随着TRPM8通道高分辨率三维结构的解析，本项目以其三维结构为基础，以比较冷敏感性各异的来自不同物种的TRPM8通道为切入点，围绕在物理机制上低温是如何被通道蛋白感受以及在结构机制上通道感受冷刺激后如何开放等关键科学问题，在活细胞中应用电生理、荧光非天然氨基酸等技术并结合计算建模，检验位于孔区的氨基酸发生包埋/暴露三维构象变化引起通道激活这一科学假设。本项目将从物理与结构两个方面理解冷激活TRPM8的分子机制，故有着重要的基础科学意义。同时，由于TRPM8通道在前列腺癌等疾病中起关键作用，理解其激活机制将为以该通道为靶点的创新药物研发提供理论指导。

Sensing temperature is crucial for the surviving and thriving of all living creatures. As a classic sensor for coldness, the Transient Receptor Potential Melastatin 8（TRPM8）ion channel on the cell membrane is activated by cold temperature below 28℃, which controls the transmembrane movements of cations to convert the temperature information into neuronal signals. However, how TRPM8 channel is activated by low temperature remains largely unknown. With the high-resolution structure of TRPM8 channel determined by cryo-EM, this project aims to understand the molecular mechanism of cold activation of this channel by testing the hypothesis that sidechains of residues within the pore of TRPM8 channel undergo conformational changes between the buried/exposed states during cold activation, which cause changes in heat capacity to drive the channel activation. We will first compare the cold sensitivities of homologous TRPM8 channels, and then use fluorescent unnatural amino acids like ANAP to probe conformational changes. As TRPM8 channel is also critically involved in diseases like prostate cancer, understanding of its activation mechanism will not only be of great scientific significance but also lay a solid foundation for drug development targeting this channel in future.