scholarly journals cAMP Biosensors Based on Genetically Encoded Fluorescent/Luminescent Proteins

Biosensors ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 39
Author(s):  
Namdoo Kim ◽  
Seunghan Shin ◽  
Se Won Bae

Cyclic adenosine monophosphate (cAMP) plays a key role in signal transduction pathways as a second messenger. Studies on the cAMP dynamics provided useful scientific insights for drug development and treatment of cAMP-related diseases such as some cancers and prefrontal cortex disorders. For example, modulation of cAMP-mediated intracellular signaling pathways by anti-tumor drugs could reduce tumor growth. However, most early stage tools used for measuring the cAMP level in living organisms require cell disruption, which is not appropriate for live cell imaging or animal imaging. Thus, in the last decades, tools were developed for real-time monitoring of cAMP distribution or signaling dynamics in a non-invasive manner. Genetically-encoded sensors based on fluorescent proteins and luciferases could be powerful tools to overcome these drawbacks. In this review, we discuss the recent genetically-encoded cAMP sensors advances, based on single fluorescent protein (FP), Föster resonance energy transfer (FRET), single luciferase, and bioluminescence resonance energy transfer (BRET) for real-time non-invasive imaging.

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 795
Author(s):  
Hyunbin Kim ◽  
Jeongmin Ju ◽  
Hae Nim Lee ◽  
Hyeyeon Chun ◽  
Jihye Seong

Genetically encoded biosensors based on fluorescent proteins (FPs) allow for the real-time monitoring of molecular dynamics in space and time, which are crucial for the proper functioning and regulation of complex cellular processes. Depending on the types of molecular events to be monitored, different sensing strategies need to be applied for the best design of FP-based biosensors. Here, we review genetically encoded biosensors based on FPs with various sensing strategies, for example, translocation, fluorescence resonance energy transfer (FRET), reconstitution of split FP, pH sensitivity, maturation speed, and so on. We introduce general principles of each sensing strategy and discuss critical factors to be considered if available, then provide representative examples of these FP-based biosensors. These will help in designing the best sensing strategy for the successful development of new genetically encoded biosensors based on FPs.


2021 ◽  
Vol 7 (21) ◽  
pp. eabe4091
Author(s):  
Brian Tenner ◽  
Jason Z. Zhang ◽  
Yonghoon Kwon ◽  
Veronica Pessino ◽  
Siyu Feng ◽  
...  

Growing evidence suggests that many essential intracellular signaling events are compartmentalized within kinetically distinct microdomains in cells. Genetically encoded fluorescent biosensors are powerful tools to dissect compartmentalized signaling, but current approaches to probe these microdomains typically rely on biosensor fusion and overexpression of critical regulatory elements. Here, we present a novel class of biosensors named FluoSTEPs (fluorescent sensors targeted to endogenous proteins) that combine self-complementing split green fluorescent protein, CRISPR-mediated knock-in, and fluorescence resonance energy transfer biosensor technology to probe compartmentalized signaling dynamics in situ. We designed FluoSTEPs for simultaneously highlighting endogenous microdomains and reporting domain-specific, real-time signaling events including kinase activities, guanosine triphosphatase activation, and second messenger dynamics in live cells. A FluoSTEP for 3′,5′-cyclic adenosine monophosphate (cAMP) revealed distinct cAMP dynamics within clathrin microdomains in response to stimulation of G protein–coupled receptors, showcasing the utility of FluoSTEPs in probing spatiotemporal regulation within endogenous signaling architectures.


Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2927
Author(s):  
Lianmin Cui ◽  
Ling Zhang ◽  
Heping Zeng

Fluorescence resonance energy transfers (FRET) between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) on nanoporous gold (NPG) are systematically investigated by controlling the distance between NPG and fluorescent proteins with polyelectrolyte multilayers. The FRET between CFP and YFP is significantly enhanced by NPG, and the maximum enhancement is related to both ligament size of NPG and the distance between NPG and proteins. With the optimized distance, 18-fold FRET enhancement was obtained on NPG compared to that on glass, and the conversion efficiency is about 90%. The potential to tune the characteristic energy transfer distance has implications for applications in nanophotonic devices and provides a possible way to design sensors and light energy converters.


2008 ◽  
Vol 53 (2) ◽  
pp. 748-755 ◽  
Author(s):  
Meng-Tian Tsai ◽  
Yun-Hsiang Cheng ◽  
Yu-Ning Liu ◽  
Nien-Chien Liao ◽  
Wen-Wen Lu ◽  
...  

ABSTRACT A real-time assay system that allows monitoring of intracellular human enterovirus (HEV) protease activity was established using the principle of fluorescence resonance energy transfer (FRET). It was accomplished by engineering cells to constitutively express a genetically encoded FRET probe. The FRET-based probe was designed to contain an enterovirus 71 3C protease (3Cpro) cleavage motif flanked by the FRET pair composed of green fluorescent protein 2 and red fluorescent protein 2 (DsRed2). Efficient FRET from the stable line was detected in a real-time manner by fluorescence microscopy, and the disruption of FRET was readily monitored upon HEV infection. The level of the repressed FRET was proportional to the input virus titer and the infection duration as measured by the fluorometric method. The FRET biosensor cell line was also responsive to other related HEV serotypes, but not to the phylogenetically distant herpes simplex virus, which was confirmed by Western blot analysis. The FRET biosensor was then utilized to develop a format for the determination of antiviral susceptibility, as the reduced FRET appeared to reflect viral replication. Evaluations of the FRET biosensor system with representative HEV serotypes demonstrated that their susceptibilities to a 3Cpro inhibitor, rupintrivir, were all accurately determined. In summary, this novel FRET-based system is a means for rapid detection, quantification, and drug susceptibility testing for HEVs, with potential for the development of a high-throughput screening assay.


1999 ◽  
Vol 5 (S2) ◽  
pp. 508-509
Author(s):  
M. L. Ruehr ◽  
M.. Bond

The cAMP dependent-protein kinase (PKA) signaling pathway plays a key role in the sympathetic regulation of muscle contraction in adult cardiac myocytes. This pathway may be regulated via compartmentalization of its components, whereby A-kinase anchoring proteins (AKAPs) tether PKA to specific subcellular areas to give each receptor binding event specificity. The purpose of this study is to investigate the binding kinetics between Ht31, a peptide containing the PKA binding portion of an AKAP from human thyroid, and the regulatory subunit of PKA (R).Fluorescence resonance energy transfer (FRET) was used to monitor binding events between the type II regulatory subunit of PKA (RE) and Ht31 or Ht31P, a mutated form of Ht31 which does not bind RII. Each protein was fused to a derivative of the green fluorescent protein (GFP) so that the excitation-emission spectra of the two fluorescent proteins overlap.


Open Biology ◽  
2014 ◽  
Vol 4 (4) ◽  
pp. 130206 ◽  
Author(s):  
Cécile Fourrage ◽  
Karl Swann ◽  
Jose Raul Gonzalez Garcia ◽  
Anthony K. Campbell ◽  
Evelyn Houliston

Green fluorescent proteins (GFPs) and calcium-activated photoproteins of the aequorin/clytin family, now widely used as research tools, were originally isolated from the hydrozoan jellyfish Aequora victoria . It is known that bioluminescence resonance energy transfer (BRET) is possible between these proteins to generate flashes of green light, but the native function and significance of this phenomenon is unclear. Using the hydrozoan Clytia hemisphaerica , we characterized differential expression of three clytin and four GFP genes in distinct tissues at larva, medusa and polyp stages, corresponding to the major in vivo sites of bioluminescence (medusa tentacles and eggs) and fluorescence (these sites plus medusa manubrium, gonad and larval ectoderms). Potential physiological functions at these sites include UV protection of stem cells for fluorescence alone, and prey attraction and camouflaging counter-illumination for bioluminescence. Remarkably, the clytin2 and GFP2 proteins, co-expressed in eggs, show particularly efficient BRET and co-localize to mitochondria, owing to parallel acquisition by the two genes of mitochondrial targeting sequences during hydrozoan evolution. Overall, our results indicate that endogenous GFPs and photoproteins can play diverse roles even within one species and provide a striking and novel example of protein coevolution, which could have facilitated efficient or brighter BRET flashes through mitochondrial compartmentalization.


2019 ◽  
Author(s):  
Jacob R. Pope ◽  
Rachel L. Johnson ◽  
W. David Jamieson ◽  
Harley L Worthy ◽  
Senthilkumar D. Kailasam ◽  
...  

AbstractFluorescent proteins (FPs) are commonly used in pairs to monitor dynamic biomolecular events through changes in their proximity via distance dependent processes such as Förster resonance energy transfer (FRET). Many FPs have a tendency to oligomerise, which is likely to be promoted through attachment to associating proteins through increases in local FP concentration. We show here that on association of FP pairs, the inherent function of the FPs can alter. Artificial dimers were constructed using a bioorthogonal Click chemistry approach that combined a commonly used green fluorescent protein (superfolder GFP) with itself, a yellow FP (Venus) or a red FP (mCherry). In each case dimerisation changes the inherent fluorescent properties, including FRET capability. The GFP homodimer demonstrated synergistic behaviour with the dimer being brighter than the sum of the two monomers. The structure of the GFP homodimer revealed that a water-rich interface is formed between the two monomers, with the chromophores being in close proximity with favourable transition dipole alignments. Dimerisation of GFP with Venus results in a complex displaying ∼86% FRET efficiency, which is significantly below the near 100% efficiency predicted. When GFP is complexed with mCherry, FRET and mCherry fluorescence itself is essentially lost. Thus, the simple assumptions used when monitoring interactions between proteins via FP FRET may not always hold true, especially under conditions whereby the protein-protein interactions promote FP interaction.Abstract Figure


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomomi Kaku ◽  
Kazunori Sugiura ◽  
Tetsuyuki Entani ◽  
Kenji Osabe ◽  
Takeharu Nagai

AbstractUsing the lux operon (luxCDABE) of bacterial bioluminescence system as an autonomous luminous reporter has been demonstrated in bacteria, plant and mammalian cells. However, applications of bacterial bioluminescence-based imaging have been limited because of its low brightness. Here, we engineered the bacterial luciferase (heterodimer of luxA and luxB) by fusion with Venus, a bright variant of yellow fluorescent protein, to induce bioluminescence resonance energy transfer (BRET). By using decanal as an externally added substrate, color change and ten-times enhancement of brightness was achieved in Escherichia coli when circularly permuted Venus was fused to the C-terminus of luxB. Expression of the Venus-fused luciferase in human embryonic kidney cell lines (HEK293T) or in Nicotiana benthamiana leaves together with the substrate biosynthesis-related genes (luxC, luxD and luxE) enhanced the autonomous bioluminescence. We believe the improved luciferase will forge the way towards the potential development of autobioluminescent reporter system allowing spatiotemporal imaging in live cells.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3019
Author(s):  
Heejung Kim ◽  
Jihye Seong

Autophagy is an essential cellular process of self-degradation for dysfunctional or unnecessary cytosolic constituents and organelles. Dysregulation of autophagy is thus involved in various diseases such as neurodegenerative diseases. To investigate the complex process of autophagy, various biochemical, chemical assays, and imaging methods have been developed. Here we introduce various methods to study autophagy, in particular focusing on the review of designs, principles, and limitations of the fluorescent protein (FP)-based autophagy biosensors. Different physicochemical properties of FPs, such as pH-sensitivity, stability, brightness, spectral profile, and fluorescence resonance energy transfer (FRET), are considered to design autophagy biosensors. These FP-based biosensors allow for sensitive detection and real-time monitoring of autophagy progression in live cells with high spatiotemporal resolution. We also discuss future directions utilizing an optobiochemical strategy to investigate the in-depth mechanisms of autophagy. These cutting-edge technologies will further help us to develop the treatment strategies of autophagy-related diseases.


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