Transient receptor potential (TRP) ion channels have a crucial role as cellular sensors, mediating diverse physical and chemical stimuli. The formation of heteromeric structures expands the functionality of TRP channels; however, their molecular architecture remains largely unknown. Here we present the cryo-electron microscopy structures of the human TRPC1/TRPC4 heteromer in the apo and antagonist-bound states, both consisting of one TRPC1 subunit and three TRPC4 subunits. The heteromer structure reveals a distinct ion-conduction pathway, including an asymmetrically constricted selectivity filter and an asymmetric lower gate, primarily attributed to the incorporation of TRPC1. Through a structure-guided electrophysiological assay, we show that both the selectivity filter and the lower part of the S6 helix participate in deciding overall preference for permeating monovalent cations. Moreover, we reveal that the introduction of one lysine residue of TRPC1 into the tetrameric central cavity is enough to render one of the most important functional consequences of TRPC heteromerization: reduced calcium permeability. Our results establish a framework for addressing the structure–function relationship of the heteromeric TRP channels.

瞬时受体电位 （TRP） 离子通道作为细胞传感器起着至关重要的作用，介导各种物理和化学刺激。异聚结构的形成扩展了 TRP 通道的功能;然而，它们的分子结构在很大程度上仍然未知。在这里，我们展示了人 TRPC1/TRPC4 异聚体在 apo 和拮抗剂结合状态下的冷冻电子显微镜结构，两者都由一个 TRPC1 亚基和三个 TRPC4 亚基组成。异聚体结构揭示了独特的离子传导途径，包括不对称收缩的选择性过滤器和不对称的下门，这主要归因于 TRPC1 的掺入。通过结构引导的电生理测定，我们表明选择性过滤器和 S6 螺旋的下部都参与决定渗透一价阳离子的总体偏好。此外，我们揭示了将 TRPC1 的一个赖氨酸残基引入四聚体中央腔足以使 TRPC 异构化最重要的功能后果之一：钙通透性降低。我们的结果建立了一个解决异聚 TRP 通道的结构-功能关系的框架。