Transient receptor potential canonical (TRPC) channels TRPC3, TRPC6 and TRPC7 are able to sense the lipid messenger diacylglycerol (DAG). The DAG-sensing and lipid-gating processes in these ion channels are still unknown. To gain insights into the lipid-sensing principle, we generated a DAG photoswitch, OptoDArG, that enabled efficient control of TRPC3 by light. A structure-guided mutagenesis screen of the TRPC3 pore domain unveiled a single glycine residue behind the selectivity filter (G652) that is exposed to lipid through a subunit-joining fenestration. Exchange of G652 with larger residues altered the ability of TRPC3 to discriminate between different DAG molecules. Light-controlled activation–deactivation cycling of TRPC3 channels by an OptoDArG-mediated optical ‘lipid clamp’ identified pore domain fenestrations as pivotal elements of the channel´s lipid-sensing machinery. We provide evidence for a novel concept of lipid sensing by TRPC channels based on a lateral fenestration in the pore domain that accommodates lipid mediators to control gating.

瞬时受体电位规范 (TRPC) 通道 TRPC3、TRPC6 和 TRPC7 能够感知脂质信使甘油二酯 (DAG)。这些离子通道中的 DAG 感应和脂质门控过程仍然未知。为了深入了解脂质传感原理，我们生成了 DAG 光开关 OptoDArG，它可以通过光有效控制 TRPC3。TRPC3 孔结构域的结构引导诱变筛选揭示了选择性过滤器 (G652) 后面的单个甘氨酸残基，该残基通过亚基连接开窗暴露于脂质。G652 与较大残基的交换改变了 TRPC3 区分不同 DAG 分子的能力。通过 OptoDArG 介导的光学“脂质钳”对 TRPC3 通道进行光控激活-失活循环，将孔域开窗确定为通道脂质传感机制的关键要素。我们为 TRPC 通道的脂质传感新概念提供了证据，该通道基于孔域中的横向开窗，可容纳脂质介质以控制门控。