K-BiPOLES: The next generation of bidirectional optogenetic actuators

The spatio-temporal precision of Optogenetics is one of the main reasons for its versatile utilization within Neurosciences. Recently developed tools like BiPOLES allow bidirectional optogenetic control regarding activation and inhibition. But while the current mode of inhibition, using anion-selective channelrhodopsins proved effective when targeted to the soma of the neuron, it is yet insufficient in terminals and smaller compartments. Building upon the recent discovery of light gated potassium channels, K-BIPOLES could constitute a promising alternative with the light controlled outflow of potassium ions as a more physiological form of inhibition. WiChR, a Channelrhodopsin from Wobblia lunata, features so far unmatched K+-selective, large currents. In combination with a selection of kinetic mutations it proves to be a game changer regarding bidirectional constructs and opens up the next geneation of BiPOLES.