Symmetry-driven gating of TRPM8 by PIP2 and menthol

TRPM8, a cold-activated ion channel, enables mammals to sense cooling agents such as menthol. While PIP2 is essential for menthol-induced activation of TRPM8, the precise cooperative mechanism and the specific binding mode of menthol have remained elusive. Here, we present cryo-EM structures of mouse TRPM8 in diverse conformations, including a PIP2-induced two-fold symmetric intermediate and an icilin-bound open state. Our results reveal that PIP2 binding initiates a symmetry-breaking event, priming the channel for activation through a noncanonical intermediate states. The subsequent binding of cooling agonists promotes a transition back to four-fold symmetry. Notably, we find that menthol stabilizes the PIP2-bound state, thereby overcoming channel desensitization, while icilin, in concert with calcium, stabilizes a fully open conformation. Together, these structures illuminate a stepwise activation pathway involving distinct symmetry transitions and define the cooperative allosteric mechanism by which PIP2 and cooling agonists gate the channel. TRPM8 ion channels are central to cold and menthol sensation. Here, the authors present various cryo-EM structures of TRPM8, including a two-fold symmetric intermediate and a menthol-bound sensitized conformation, revealing how PIP2 and cooling agonists allosterically activate TRPM8.