We have developed methods to spatially confine GPCR activation to selected regions of a single cell. This is based on color opsins from the human retina and non-rhodopsin opsins from other species. This approach allows immune cell migration and neuron differentiation to be optically directed. The spectral selectivity allows intracellular molecules to be quantitatively imaged simultaneously while orchestrating cell behavior.
In another approach we have used the optically directed translocation of the cryptochrome domain, CRY2 to selected regions of a cell to create gradients of activated G protein subunits in a single immune cell. These internal gradients evoke directional cell migration.