Abstract: The present disclosure provides compositions comprising an opsin polypeptide and an arrestin polypeptide and their use thereof. Exemplary embodiments provide a composition including an opsin polypeptide, or an opsin polypeptide and an arrestin polypeptide, wherein at least one of the opsin or arrestin polypeptide comprises at least one mutation that increases a temporal resolution of the opsin polypeptide’s response to light. The opsin polypeptide and the arrestin polypeptide can be operably linked or separate. Additionally, use of said compositions for restoring retinal photosensitivity or treating a retinal degenerative condition is also provided.

Abstract: The present invention relates to methods of regulating G protein activity, and related methods for the treatment of therapeutic conditions, for example retinal degeneration, by transforming a cell with a bistable opsin to activate a G protein, and provide a phototransduction response.