scholarly journals Semisynthetic pH-sensitive fluorophores for imaging exocytosis and endocytosis

2017 ◽  
Author(s):  
Magalie Martineau ◽  
Agila Somasundaram ◽  
Jonathan B. Grimm ◽  
Todd D. Gruber ◽  
Daniel Choquet ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Fluorescent Protein ◽  
Ph Sensitive ◽  
Protein Scaffolds ◽  
Red Fluorescent Protein ◽  
Protein Conjugates ◽  
Key Steps

AbstractThe GFP-based superecliptic pHluorin (SEP) enables detection of exocytosis and endocytosis, but its performance has not been duplicated in red fluorescent protein scaffolds. Here we describe ‘semisynthetic’ pH-sensitive protein conjugates that match the properties of SEP. Conjugation to genetically encoded self-labeling tags or antibodies allows visualization of both exocytosis and endocytosis, constituting new bright sensors for these key steps of synaptic transmission.

A pH-sensitive red fluorescent protein compatible with hydrophobic resin embedding

2017 ◽  
Author(s):  
Wenyan Guo ◽  
Yadong Gang ◽  
Xiuli Liu ◽  
Hongfu Zhou ◽  
Shaoqun Zeng
Keyword(s):  
Fluorescent Protein ◽  
Ph Sensitive ◽  
Red Fluorescent Protein

pHuji, a pH-sensitive red fluorescent protein for imaging of exo- and endocytosis

2014 ◽  
Vol 144 (6) ◽  
pp. 1446OIA52
Author(s):  
Yi Shen ◽  
Morgane Rosendale ◽  
Robert E. Campbell ◽  
David Perrais
Keyword(s):  
Fluorescent Protein ◽  
Ph Sensitive ◽  
Red Fluorescent Protein

scholarly journals pHuji, a pH-sensitive red fluorescent protein for imaging of exo- and endocytosis

2014 ◽  
Vol 207 (3) ◽  
pp. 419-432 ◽  
Author(s):  
Yi Shen ◽  
Morgane Rosendale ◽  
Robert E. Campbell ◽  
David Perrais
Keyword(s):  
Transferrin Receptor ◽  
Adrenergic Receptor ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Ph Sensitive ◽  
Vesicle Formation ◽  
Red Fluorescent Protein ◽  
Endocytic Vesicle ◽  
Β2 Adrenergic Receptor ◽  
Green Fluorescent

Fluorescent proteins with pH-sensitive fluorescence are valuable tools for the imaging of exocytosis and endocytosis. The Aequorea green fluorescent protein mutant superecliptic pHluorin (SEP) is particularly well suited to these applications. Here we describe pHuji, a red fluorescent protein with a pH sensitivity that approaches that of SEP, making it amenable for detection of single exocytosis and endocytosis events. To demonstrate the utility of the pHuji plus SEP pair, we perform simultaneous two-color imaging of clathrin-mediated internalization of both the transferrin receptor and the β2 adrenergic receptor. These experiments reveal that the two receptors are differentially sorted at the time of endocytic vesicle formation.

Fluorescent proteins for in vivo imaging, where's the biliverdin?

2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez
Keyword(s):  
Hydrogen Peroxide ◽  
In Vivo Imaging ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Fluorescent Imaging ◽  
Infrared Light ◽  
Red Fluorescent Protein ◽  
Color Palette

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

scholarly journals Novel Regeneration Approach for Creating Reusable FO-SPR Probes with NTA Surface Chemistry

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 186
Author(s):  
Jia-Huan Qu ◽  
Karen Leirs ◽  
Remei Escudero ◽  
Žiga Strmšek ◽  
Roman Jerala ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Fluorescent Protein ◽  
Cost Effective ◽  
Nitrilotriacetic Acid ◽  
Antibody Fragments ◽  
Rapid Screening ◽  
Red Fluorescent Protein ◽  
Effective Manner ◽  
Surface Regeneration ◽  
Sensitivity Specificity

To date, surface plasmon resonance (SPR) biosensors have been exploited in numerous different contexts while continuously pushing boundaries in terms of improved sensitivity, specificity, portability and reusability. The latter has attracted attention as a viable alternative to disposable biosensors, also offering prospects for rapid screening of biomolecules or biomolecular interactions. In this context here, we developed an approach to successfully regenerate a fiber-optic (FO)-SPR surface when utilizing cobalt (II)-nitrilotriacetic acid (NTA) surface chemistry. To achieve this, we tested multiple regeneration conditions that can disrupt the NTA chelate on a surface fully saturated with His6-tagged antibody fragments (scFv-33H1F7) over ten regeneration cycles. The best surface regeneration was obtained when combining 100 mM EDTA, 500 mM imidazole and 0.5% SDS at pH 8.0 for 1 min with shaking at 150 rpm followed by washing with 0.5 M NaOH for 3 min. The true versatility of the established approach was proven by regenerating the NTA surface for ten cycles with three other model system bioreceptors, different in their size and structure: His6-tagged SARS-CoV-2 spike fragment (receptor binding domain, RBD), a red fluorescent protein (RFP) and protein origami carrying 4 RFPs (Tet12SN-RRRR). Enabling the removal of His6-tagged bioreceptors from NTA surfaces in a fast and cost-effective manner can have broad applications, spanning from the development of biosensors and various biopharmaceutical analyses to the synthesis of novel biomaterials.

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