Genetically encoded fluorescent sensors for metals in biology

Fluorescent Protein-Based Sensors for Detecting Essential Metal Ions across the Tree of Life

“…Here, alternative genetically encoded platforms have made more progress. 11 For example, chemigenetic sensors for Na + have been reported, which combine a synthetic crown ether-based Na + -binding domain with a fluorophore (synthetic or protein) and a tag protein that can be used for cellular targeting. 210,211 Applications of chemigenetic sensors have primarily focused on mammalian cell lines and primary cells, however, and efforts to expand their use to plants, bacteria, and other organisms where the synthetic component would need to be efficiently delivered have been limited.…”

“…Cell–cell communication occurs through the extracellular space, and ions like calcium and zinc can also act as extracellular signals. , Metal ions in biology can be broadly classified into those which are inaccessible (e.g., tightly bound to proteins) and those which are accessible or loosely bound (i.e., labile). Although there is no single technique that can measure both pools of metal ions simultaneously, our understanding of the dynamic processes underlying how metals are selectively trafficked and positioned within and outside cells has been greatly facilitated by the use of fluorescent sensors. − These fluorescent tools can detect, quantify, and track accessible pools of metal ions in living cells and organisms, providing insight that can be used to define the roles of metals in physiology and diseases.…”

Zinc-Induced Fluorescence Turn-On in Native and Mutant Phycoerythrobilin-Binding Orange Fluorescent Proteins

“…35−41 Fluorescent proteins can be used as sensors by attaching or embedding a metal binding site in a single fluorescent protein that modulates fluorescence in response to the metal ion. 37,40,41 Multifluorescent protein-based probes can also be prepared by employing a FRET approach where two proteins are linked by a metal site that undergoes a conformational change upon metal binding. 37,38,40,41 Given that most genetically encoded metal sensors are based on GFPs and related mFruits, 36−41 here, we sought to evaluate the PEBbinding orange fluorescent All1280g2 protein as a platform for developing a single protein or FRET-based sensor.…”

“…Fluorescent sensors are frequently used to study the roles of metals in biology given their ability to visualize real-time metal ion binding in living samples . Fluorescent protein-based sensors can be genetically encoded into living cells or organisms, allowing for species-specific, cell-specific, or subcellular imaging of metal ions. – Fluorescent proteins can be used as sensors by attaching or embedding a metal binding site in a single fluorescent protein that modulates fluorescence in response to the metal ion. ,, Multifluorescent protein-based probes can also be prepared by employing a FRET approach where two proteins are linked by a metal site that undergoes a conformational change upon metal binding. ,,, Given that most genetically encoded metal sensors are based on GFPs and related mFruits, – here, we sought to evaluate the PEB-binding orange fluorescent All1280g2 protein as a platform for developing a single protein or FRET-based sensor. Most bilin-binding fluorescent protein-based sensor development thus far has focused on designing NIR Ca 2+ sensors using bacteriophytochrome proteins. – Few examples of GAF or other bilin-binding proteins have been used as transition metal ion sensors. ,, In one example, bacteriophytochrome-derived miRFPs can be inherently quenched by Cu 2+ ions with picomolar dissociation constants .…”

“…37,40,41 Multifluorescent protein-based probes can also be prepared by employing a FRET approach where two proteins are linked by a metal site that undergoes a conformational change upon metal binding. 37,38,40,41 Given that most genetically encoded metal sensors are based on GFPs and related mFruits, 36−41 here, we sought to evaluate the PEBbinding orange fluorescent All1280g2 protein as a platform for developing a single protein or FRET-based sensor. Most bilinbinding fluorescent protein-based sensor development thus far has focused on designing NIR Ca 2+ sensors using bacteriophytochrome proteins.…”