A common pathway for charge transport through voltage-sensing domains.
Voltage-gated ion channels derive their voltage sensitivity from the movement of specific charged residues in response to a change in transmembrane potential. Several studies on mechanisms of voltage sensing in ion channels support the idea that these gating charges move through a well-defined permeation pathway. This gating pathway in a voltage-gated ion channel can also be mutated to transport free cations, including protons. The recent discovery of proton channels with sequence homology to the voltage-sensing domains suggests that evolution has perhaps exploited the same gating pathway to generate a bona fide voltage-dependent proton transporter. Here we will discuss implications of these findings on the mechanisms underlying charge (and ion) transport by voltage-sensing domains.
Chanda
Baron
B
Department of Physiology, University of Wisconsin, Madison, WI 53706, USA.
Bezanilla
Francisco
F
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D015640:Ion Channel Gating / Q000502:physiology*; D007473:Ion Channels / Q000737:chemistry / Q000502:physiology*; D017136:Ion Transport; D008954:Models, Biological; D008958:Models, Molecular; D017434:Protein Structure, Tertiary / Q000502:physiology*
D007473:Ion Channels