Superiority of SpiroZin2 Versus FluoZin-3 for monitoring vesicular Zn²⁺ allows tracking of lysosomal Zn²⁺ pools
Author(s)Han, Yu; Goldberg, Jacob Michael; Lippard, Stephen J.; Palmer, Amy E.
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Small-molecule fluorescent probes are powerful and ubiquitous tools for measuring the concentration and distribution of analytes in living cells. However, accurate characterization of these analytes requires rigorous evaluation of cell-to-cell heterogeneity in fluorescence intensities and intracellular distribution of probes. In this study, we perform a parallel and systematic comparison of two small-molecule fluorescent vesicular Zn²⁺ probes, FluoZin-3 AM and SpiroZin2, to evaluate each probe for measurement of vesicular Zn²⁺ pools. Our results reveal that SpiroZin2 is a specific lysosomal vesicular Zn²⁺ probe and affords uniform measurement of resting Zn²⁺ levels at the single cell level with proper calibration. In contrast, FluoZin-3 AM produces highly variable fluorescence intensities and non-specifically localizes in the cytosol and multiple vesicular compartments. We further applied SpiroZin2 to lactating mouse mammary epithelial cells and detected a transient increase of lysosomal free Zn²⁺ at 24-hour after lactation hormone treatment, which implies that lysosomes play a role in the regulation of Zn²⁺ homeostasis during lactation. This study demonstrates the need for critical characterization of small-molecule fluorescent probes to define the concentration and localization of analytes in different cell populations, and reveals SpiroZin2 to be capable of reporting diverse perturbations to lysosomal Zn²⁺.
DepartmentMassachusetts Institute of Technology. Department of Chemistry
Han, Yu, Jacob M. Goldberg, Stephen J. Lippard, and Amy E. Palmer. “Superiority of SpiroZin2 Versus FluoZin-3 for monitoring vesicular Zn²⁺ allows tracking of lysosomal Zn²⁺ pools.” Scientific Reports 8, 1 (October 2018): 15034 © 2018 The Author(s)
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