A highly specific Golgi-targetable fluorescent probe for tracking cysteine generation during the Golgi stress response

In the appropriate Golgi stress response, adaptive repair will occur by changing or triggering the expression of related pathways. Furthermore, it also can inhibit the cytotoxicity of cells in the altered redox homeostasis. Elevated biosynthesis and transport of cysteine (Cys) will be induced to restore the abnormal redox state, and more evidences are needed to confirm this process in the Golgi stress response. Herein, we developed a novel Golgi-targetable Cys-specific fluorescent probe GT-Cys for sensitively detecting Cys generation during the Golgi stress response. In probe GT-Cys, thiobenzoate moiety was chosen as recognition group of Cys, and 4-CF3-7-aminoquinoline dye was selected as fluorophore and Golgi targetable unit. Probe GT-Cys can selectively and sensitively respond to Cys. Additionally, it has good targetable properties, facilitating the study of complicated stress response of Golgi apparatus. Importantly, the applications of probe GT-Cys in biological imaging showed that it is sensitive enough to basal Cys, especially to endogenous Cys during the Golgi stress response.