Light-gated ion channel

In the specific case of light-gated ion channels, the transmembrane proteins are usually coupled with a smaller molecule that acts as a photoswitch, whereby photons bind to the switching molecule, to then alter the conformation of the proteins, so that the pore changes from a closed state to an open state, or vice versa, thereby increasing or decreasing ion conductance.

[5] Other types of gated ion channels, ligand-gated and voltage-gated, have been synthesized with a light-gated component in an attempt to better understand their nature and properties.

For example, the addition of a light-gated component allows for the introduction of many highly similar ligands to be introduced to the binding site of a ligand-gated ion channel to assist in the determination of the mechanism.

[6][7] Azobenzene is a common choice for the functional portion of a tether for synthetically-developed light-gated ion channels because of its well documented length change as either cis or trans isomers, as well as the excitation wavelength needed to induce photoisomerization.

[10][4] They have an advantage over other types of ion channel regulation in that they provide non-invasive, reversible membrane potential changes with fine temporal and spatial control granted by induction through laser stimuli.

[3][6] They reliably stimulate single action potentials with rapid depolarization and can be utilized in vivo because they do not require high intensity illumination to maintain function, unlike other techniques like light-activated proton pumps and photoactivatable probes.