Summary
A bioRxiv preprint reports cryo-EM structures of human THIK1 bound to two chemically related inhibitors. Both occupy the same pore site, but structural and electrophysiological results indicate that they affect a second channel gate differently.
A bioRxiv preprint reports cryo-electron microscopy (cryo-EM) structures of human THIK1 bound to two inhibitors, alongside electrophysiological analyses of how the compounds affect the channel. The researchers found that C101248 and CVN293 bind at a similar site but differ in how a second gate contributes to inhibition.
THIK1 is a two-pore domain potassium channel expressed at high levels in microglia, immune cells in the brain and spinal cord. The channel contributes to microglial homeostasis and neuroinflammatory responses. Its inhibition has been linked to reduced tonic potassium currents and less NLRP3-dependent release of the inflammatory signalling molecule IL-1β, making THIK1 a target of interest in research on neuroinflammatory disorders.
Both compounds occupy the channel’s inner pore
The structures show C101248 and CVN293 bound in the inner vestibule of full-length human THIK1. This part of the channel is formed by the transmembrane segments TM2 and TM4, below the selectivity filter—the narrow region that helps determine which ions pass through a channel.
The compounds have closely related chemical scaffolds and bind in a similar location. Both also remodel the Y273 inner gate, a structural feature involved in controlling ion flow through the pore. But the researchers found a difference at the channel’s C-terminal gate: electrophysiological analyses indicate that this gate contributes differently to inhibition by the two compounds.
C101248 is described as a commercially available tool compound. CVN293 is described as a clinical-stage inhibitor that has completed Phase I evaluation. The structural comparison therefore concerns two related inhibitors with different development contexts, while the reported channel experiments focus on how each interacts with THIK1.
A more detailed picture of channel inhibition
A shared binding site does not necessarily mean that two inhibitors control a channel in exactly the same way. These findings point to a distinction between where a compound binds and how that binding affects multiple gates in the channel. The authors’ results suggest the C-terminal gate helps explain why chemically related inhibitors can produce different inhibitory effects despite occupying a common pore site.
That distinction may help researchers interpret THIK1 experiments and guide studies of compounds targeting the channel. The work is a preprint reporting structural and electrophysiological evidence; it is not a clinical study of whether THIK1 inhibition treats neuroinflammatory disease. CVN293’s Phase I status is separate from the experiments reported here.