Curated Optogenetic Publication Database

Abstract: A comprehensive understanding of signaling mechanisms helps interpret fundamental biological processes and restore cell behavior from pathological conditions. Signaling outcome depends not only on the activity of each signaling component but also on their dynamic interaction in time and space, which remains challenging to probe by biochemical and cell-based assays. Opsin-based optogenetics has transformed neural science research with its spatiotemporal modulation of the activity of excitable cells. Motivated by this advantage, opsin-free optogenetics extends the power of light to a larger spectrum of signaling molecules. This review summarizes commonly used opsin-free optogenetic strategies, presents a historical overview of split protein complementation, and highlights the adaptation of split protein recombination as optogenetic sensors and actuators.

Abstract: Plant-based photosensors, such as the light-oxygen-voltage sensing domain 2 (LOV2) from oat phototropin 1, can be modularly wired into cell signaling networks to remotely control protein activity and physiological processes. However, the applicability of LOV2 is hampered by the limited choice of available caging surfaces and its preference to accommodate the effector domains downstream of the C-terminal Jα helix. Here, we engineered a set of LOV2 circular permutants (cpLOV2) with additional caging capabilities, thereby expanding the repertoire of genetically encoded photoswitches to accelerate the design of optogenetic devices. We demonstrate the use of cpLOV2-based optogenetic tools to reversibly gate ion channels, antagonize CRISPR-Cas9-mediated genome engineering, control protein subcellular localization, reprogram transcriptional outputs, elicit cell suicide and generate photoactivatable chimeric antigen receptor T cells for inducible tumor cell killing. Our approach is widely applicable for engineering other photoreceptors to meet the growing need of optogenetic tools tailored for biomedical and biotechnological applications.