Descending to inhibit: Antagonist-induced downward shift of VSD II in TPC2.

In this issue of Structure, Chi et al.1 report structural and functional studies that reveal the inhibition mechanism of the lysosomal two-pore channel TPC2 by the antagonist SG-094, which is of interest for drug development. Antagonist binding induces the downward displacement of the voltage-sensor domain II (VSD II), which is accompanied by asymmetric conformational rearrangements of the entire channel.