Hv1 inhibitor HIF is a novel inhibitor of the voltage-gated proton channel Hv1 interacts with the Hv1 VSD in the up and down states.HIF rapidly inhibits proton conduction in the up state by blocking the open channel.HIF interacts with a second site that is accessible in the down state and is responsible for key features of HIF-mediated inhibition, such as the slow component of current decay and the slow recovery from inhibition.The voltage-gated proton channel Hv1 plays important roles in numerous biological processes, including pH homeostasis, the immune response, and sperm cell function.Hv1 channel belongs to the large family of proteins containing voltage-sensing domains (VSDs), which also includes Nav, Kv, and Cav channels and voltage-sensitive phosphatases.