KillerRed
Protein DomainKillerRed is a genetically encoded protein photosensitizer used to generate singlet oxygen upon light irradiation for photodynamic perturbation. In the cited study, plasma-membrane-targeted KillerRed activated cholecystokinin 1 receptor (CCK1R) signaling in AR4-2J cells, producing persistent calcium oscillations consistent with permanent photodynamic receptor activation.