Organelle-Level Labile Zn2+Mapping Based on TargetableFluorescent Sensors

Although many Zn2+fluorescent probes have beendeveloped, there remains a lack of consensus on the labile Zn2+concentrations ([Zn2+]) in several cellular compartments, as thefluorescence properties and zinc affinity of thefluorescent probesare greatly affected by the pH and redox environments specifictoorganelles. In this study, we developed two turn-on-type Zn2+fluorescent probes, namely, ZnDA-2H and ZnDA-3H, with low pHsensitivity and suitable affinity (Kd= 5.0 and 0.16 nM) fordetecting physiological labile Zn2+in various cellular compart-ments, such as the cytosol, nucleus, ER, and mitochondria. Due totheir sufficient membrane permeability, both probes were preciselylocalized to the target organelles in HeLa cells using HaloTaglabeling technology. Using anin situstandard quantificationmethod, we identified the [Zn2+] in the tested organelles, resulting in the subcellular [Zn2+] distribution as [Zn2+]ER< [Zn2+]mito<[Zn2+]cyto similar to[Zn2+]nuc

Automated summary

Although many Zn2+ fluorescent probes have been developed, there is still a lack of consensus on the labile Zn2+ concentrations in different cellular compartments. In this study, two highly sensitive Zn2+ fluorescent probes were developed and successfully used to determine the subcellular distribution of labile Zn2+.