Direct comparison of a genetically encoded sensor and small molecule indicator: implications for quantification of cytosolic Zn(2+)

• Published in: ACS chemical biology 2013-11, Vol.8 (11), p.2366-2371
• Main Authors: Qin, Yan, Miranda, Jose G, Stoddard, Caitlin I, Dean, Kevin M, Galati, Domenico F, Palmer, Amy E
• Format: Article
• Language: English
• Subjects: Cells, Cultured; Cytosol - chemistry; Fluorescent Dyes - chemistry; HeLa Cells; Humans; Luminescent Proteins - chemistry; Luminescent Proteins - genetics; Polycyclic Compounds - chemistry; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Zinc - analysis; Zinc - chemistry
• ISSN: 1554-8937
• DOI: 10.1021/cb4003859

Fluorescent sensors are powerful tools for visualizing and quantifying molecules and ions in living cells. A variety of small molecule and genetically encoded sensors have been developed for studying intracellular Zn(2+) homeostasis and signaling, but no direct comparisons exist, making it challenging for researchers to identify the appropriate sensor for a given application. Here we directly compare the widely used small molecule probe FluoZin-3 and a genetically encoded sensor, ZapCY2. We demonstrate that, in contrast to FluoZin-3, ZapCY2 exhibits a well-defined cytosolic localization, provides estimates of Zn(2+) concentration with little variability, does not perturb cytosolic Zn(2+) levels, and exhibits rapid Zn(2+) response dynamics. ZapCY2 was used to measure Zn(2+) concentrations in 5 different cell types, revealing higher cytosolic Zn(2+) levels in prostate cancer cells compared to normal prostate cells (although the total zinc is reduced in prostate cancer cells), suggesting distinct regulatory mechanisms.