UCBerkeley
Home
People
Contact
Publications
Berkeley
Research
Ion Channels
Optical
Bottom
Top

LIGHT-ACTIVATED ION CHANNELS

Constructing "light-switchable" ion channels
Ion channels can be regulated by voltage, chemical transmitters, and mechanical forces. We are trying to engineer the first ion channel that can be directly activated with light. An ion channel protein is coupled through an introduced cysteine to a specially designed light-sensitive molecule that contains a tetraethylammonium group (TEA), which blocks the pore of the channel.

Light Activated Ion Channel

Blockage of the channel pore depends on the conformation of the photoswitchable molecule.
The extended form (trans) of the molecule is long enough to allow the TEA to reach the pore, but after photoisomerization the bent form (cis) is too short. Different wavelengths switch the molecule back and forth between cis and trans, so both channel opening and closing should be controllable with light. Expression of these channels in neurons will allow their electrical activity to be regulated with flashes of light. Light-activated channels may have applications in neural computing and as an alternative to invasive methods of neural stimulation in the intact nervous system.