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Annu Rev Biochem. 2015;84:685-709. doi: 10.1146/annurev-biochem-060614-034307.

Gating mechanisms of voltage-gated proton channels.

Author information

1
Department of Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan; email: yokamura@phys2.med.osaka-u.ac.jp , fujiwara@phys2.med.osaka-u.ac.jp , sakata@phys2.med.osaka-u.ac.jp.

Abstract

Hv1 is a voltage-gated proton-selective channel that plays critical parts in host defense, sperm motility, and cancer progression. Hv1 contains a conserved voltage-sensor domain (VSD) that is shared by a large family of voltage-gated ion channels, but it lacks a pore domain. Voltage sensitivity and proton conductivity are conferred by a unitary VSD that consists of four transmembrane helices. The architecture of Hv1 differs from that of cation channels that form a pore in the center among multiple subunits (as in most cation channels) or homologous repeats (as in voltage-gated sodium and calcium channels). Hv1 forms a dimer in which a cytoplasmic coiled coil underpins the two protomers and forms a single, long helix that is contiguous with S4, the transmembrane voltage-sensing segment. The closed-state structure of Hv1 was recently solved using X-ray crystallography. In this article, we discuss the gating mechanism of Hv1 and focus on cooperativity within dimers and their sensitivity to metal ions.

KEYWORDS:

arginine residue; membrane potential; reactive oxygen species; salt bridge; zinc binding

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