Endoplasmic reticulum targeting fluorescent probes to image mobile Zn.

Zn plays an important role in the normal function of the endoplasmic reticulum (ER) and its deficiency can cause ER stress, which is related to a wide range of diseases. In order to provide tools to better understand the role of mobile Zn in ER processes, the first custom designed ER-localised fluorescent Zn probes have been developed through the introduction of a cyclohexyl sulfonylurea as an ER-targeting unit with different Zn receptors. Experiments and show that both probes have a good fluorescence switch on response to Zn, high selectivity over other cations, low toxicity, ER-specific targeting ability and are efficacious imaging agents for mobile Zn in four different cell lines. Probe has been used to detect mobile Zn changes under ER stress induced by both tunicamycin or thapsigargin, which indicates that the new probes should allow a better understanding of the mechanisms cells use to respond to dysfunction of zinc homeostasis in the ER and its role in the initiation and progression of diseases to be developed.