Localizable Fluorescent Metal Ion Indicators With Tunable Colors
Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine
ABSTRACT Elucidating the role of metal ion homeostasis in physiological and pathological processes requires detection tools with high sensitivity and selectivity, spectral versatility, and precise subcellular localization. Here, we introduce a modular strategy for generating fluorescent metal ion indicators that are comprised of a sulfonamide‐functionalized chelator, a rhodamine derivative, and a ligand for bioconjugation to self‐labeling proteins. With a concise three‐step synthesis, the design allows tuning of both the emission color and ligand specificity of the resulting indicators. Specifically, we developed a family of bright, color‐tunable potassium indicators that can be selectively coupled to intra‐ or extracellular HaloTag and SNAP‐tag fusion proteins. The increase in fluorescence upon binding to HaloTag or SNAP‐tag enabled wash‐free live‐cell imaging. The localized potassium indicators enabled the detection of dynamic potassium efflux in rat hippocampal neurons upon glutamate stimulation. Our work thus establishes a versatile platform for the generation of localizable fluorescent metal ion indicators and opens up new avenues for live‐cell potassium sensing. A modular platform enables the generation of fluorescent metal ion indicators with tunable emission colors and precise subcellular localization. Conjugation to self‐labeling proteins yields bright, color‐tunable potassium probes that permit wash‐free live‐cell imaging, revealing dynamic potassium efflux in stimu
Abstract
ABSTRACT Elucidating the role of metal ion homeostasis in physiological and pathological processes requires detection tools with high sensitivity and selectivity, spectral versatility, and precise subcellular localization. Here, we introduce a modular strategy for generating fluorescent metal ion indicators that are comprised of a sulfonamide‐functionalized chelator, a rhodamine derivative, and a ligand for bioconjugation to self‐labeling proteins. With a concise three‐step synthesis, the design allows tuning of both the emission color and ligand specificity of the resulting indicators. Specifically, we developed a family of bright, color‐tunable potassium indicators that can be selectively coupled to intra‐ or extracellular HaloTag and SNAP‐tag fusion proteins. The increase in fluorescence upon binding to HaloTag or SNAP‐tag enabled wash‐free live‐cell imaging. The localized potassium indicators enabled the detection of dynamic potassium efflux in rat hippocampal neurons upon glutamate stimulation. Our work thus establishes a versatile platform for the generation of localizable fluorescent metal ion indicators and opens up new avenues for live‐cell potassium sensing. A modular platform enables the generation of fluorescent metal ion indicators with tunable emission colors and precise subcellular localization. Conjugation to self‐labeling proteins yields bright, color‐tunable potassium probes that permit wash‐free live‐cell imaging, revealing dynamic potassium efflux in stimulated neurons. advs75402-abs-0001 graphical