Next Generation of StayGold-based Adaptable Turn-On Maturation (ATOM) Sensors Targeting PSD95, Gephyrin, and HOMER1 Proteins

Genetically encoded biosensors that have the capacity to detect intracellular molecules have proven to be invaluable tools in biology. However, development of biosensors with generalizable binding domains for detecting arbitrary targets of choice is still in its early stages. We previously introduced ATOM biosensor technology in which adaptable monobody and nanobody binding domains are employed for molecular recognition, and biosensor turn-on is achieved by coupling target binding to activation of the attached fluorescent protein by means of conformational change. In this work, we extend the ATOM mechanism to the newly identified, highly photostable fluorescent proteins mStayGold and mBaoJin. We validated the ATOM sensors using three neuronal targets: PSD95, Gephyrin, and HOMER1. The sensors exhibited turn-on ratios of over 100-fold with high specificity. Compared to existing methods for detecting these proteins, ATOM sensors demonstrated improved dynamic range, lower background, and a higher turn-on. The results highlight the adaptable nature of the ATOM mechanism and demonstrate that it allows for development of biosensors with various colors and photophysical characteristics.