Voltage-gated ion channel

Each of the four homologous domains makes up one subunit of the ion channel. The S4 voltage-sensing segments (marked with + symbols) are shown as charged.
Identifiers
SymbolVIC
Pfam clanCL0030
TCDB1.A.1
OPM superfamily8
OPM protein2a79
Ions are depicted by the red circles. A gradient is represented by the different concentration of ions on either side of the membrane. The open conformation of the ion channel allows for the translocation of ions across the cell membrane, while the closed conformation does not.

Voltage-gated ion channels are a class of transmembrane proteins that form ion channels that are activated by changes in a cell's electrical membrane potential near the channel. The membrane potential alters the conformation of the channel proteins, regulating their opening and closing. Cell membranes are generally impermeable to ions, thus they must diffuse through the membrane through transmembrane protein channels.

Voltage-gated ion channels have a crucial role in excitable cells such as neuronal and muscle tissues, allowing a rapid and co-ordinated depolarization in response to triggering voltage change. Found along the axon and at the synapse, voltage-gated ion channels directionally propagate electrical signals.

Voltage-gated ion-channels are usually ion-specific, and channels specific to sodium (Na+), potassium (K+), calcium (Ca2+), and chloride (Cl−) ions have been identified.[1] The opening and closing of the channels are triggered by changing ion concentration, and hence charge gradient, between the sides of the cell membrane.[2]

  1. ^ Purves D, Augustine GJ, Fitzpatrick D, Katz LC, LaMantia AS, McNamara JO, Williams SM (2001). "Voltage-Gated Ion Channels". Neuroscience (2nd ed.). Sunderland, Mass: Sinauer Associates. ISBN 978-0-87893-742-4.
  2. ^ Catterall WA (April 2000). "From ionic currents to molecular mechanisms: the structure and function of voltage-gated sodium channels". Neuron. 26 (1): 13–25. doi:10.1016/S0896-6273(00)81133-2. PMID 10798388.