Architecture and gating of Hv1 proton channels

Voltage-gated proton channels have been described in different cells and organisms since the early '80s, but the first member of the family, Hv1, was cloned only recently. The Hv1 channel was found to contain a voltage-sensing domain (VSD), similar to those of voltage-gated sodium, potassium and calcium channels. All these other channels also contain a pore domain, which forms a central pore at the interface of the four subunits. The pore domain is missing in Hv1. This raised several questions on the location of the proton pore and on the mechanism of gating. Here, we briefly review our effort to understand the structural organization of Hv1 channels and discuss the relationship between the gating of Hv1 and the gating of ion-conducting pores recently discovered in the VSDs of mutant voltage-gated potassium and sodium channels.