Ion- and water-binding sites inside an occluded hourglass pore of a trimeric intracellular cation (TRIC) channel.

The asymmetric filter-like structure at the pore center of SsTRIC might serve as the basis for the channel to bind and select monovalent cations. A Velcro-like plug-pore interacting model has been proposed and suggests a unified framework accounting for the gating mechanisms of prokaryotic and eukaryotic TRIC channels.