scholarly journals Development of FRET-Based Indicators For Visualizing Homophilic Trans Interaction of A Clustered Protocadherin

Author(s):  
Takashi Kanadome ◽  
Natsumi Hoshino ◽  
Takeharu Nagai ◽  
Tomoki Matsuda ◽  
Takeshi Yagi

Abstract Clustered protocadherins (Pcdhs), which are cell adhesion molecules, play a fundamental role in self-recognition and non-self-discrimination by conferring diversity on the cell surface. Although systematic cell-based aggregation assays provide information regarding the binding properties of Pcdhs, direct visualization of Pcdh trans interactions across cells remains challenging. Here, we present Förster resonance energy transfer (FRET)-based indicators for directly visualizing Pcdh trans interactions. We developed the indicators by individually inserting FRET donor and acceptor fluorescent proteins (FPs) into the ectodomain of Pcdh molecules. They enabled successful visualization of specific trans interactions of Pcdh and revealed that the Pcdh trans interaction is highly sensitive to changes in extracellular Ca2+ levels. We expect that FRET-based indicators for visualizing Pcdh trans interactions will provide a new approach for investigating the roles of Pcdh in self-recognition and non-self-discrimination processes.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takashi Kanadome ◽  
Natsumi Hoshino ◽  
Takeharu Nagai ◽  
Tomoki Matsuda ◽  
Takeshi Yagi

AbstractClustered protocadherins (Pcdhs), which are cell adhesion molecules, play a fundamental role in self-recognition and non-self-discrimination by conferring diversity on the cell surface. Although systematic cell-based aggregation assays provide information regarding the binding properties of Pcdhs, direct visualization of Pcdh trans interactions across cells remains challenging. Here, we present Förster resonance energy transfer (FRET)-based indicators for directly visualizing Pcdh trans interactions. We developed the indicators by individually inserting FRET donor and acceptor fluorescent proteins (FPs) into the ectodomain of Pcdh molecules. They enabled successful visualization of specific trans interactions of Pcdh and revealed that the Pcdh trans interaction is highly sensitive to changes in extracellular Ca2+ levels. We expect that FRET-based indicators for visualizing Pcdh trans interactions will provide a new approach for investigating the roles of Pcdh in self-recognition and non-self-discrimination processes.


2004 ◽  
Vol 381 (1) ◽  
pp. 307-312 ◽  
Author(s):  
Satoshi KARASAWA ◽  
Toshio ARAKI ◽  
Takeharu NAGAI ◽  
Hideaki MIZUNO ◽  
Atsushi MIYAWAKI

GFP (green fluorescent protein)-based FRET (fluorescence resonance energy transfer) technology has facilitated the exploration of the spatio-temporal patterns of cellular signalling. While most studies have used cyan- and yellow-emitting FPs (fluorescent proteins) as FRET donors and acceptors respectively, this pair of proteins suffers from problems of pH-sensitivity and bleeding between channels. In the present paper, we demonstrate the use of an alternative additional donor/acceptor pair. We have cloned two genes encoding FPs from stony corals. We isolated a cyan-emitting FP from Acropara sp., whose tentacles exhibit cyan coloration. Similar to GFP from Renilla reniformis, the cyan FP forms a tight dimeric complex. We also discovered an orange-emitting FP from Fungia concinna. As the orange FP exists in a complex oligomeric structure, we converted this protein into a monomeric form through the introduction of three amino acid substitutions, recently reported to be effective for converting DsRed into a monomer (Clontech). We used the cyan FP and monomeric orange FP as a donor/acceptor pair to monitor the activity of caspase 3 during apoptosis. Due to the close spectral overlap of the donor emission and acceptor absorption (a large Förster distance), substantial pH-resistance of the donor fluorescence quantum yield and the acceptor absorbance, as well as good separation of the donor and acceptor signals, the new pair can be used for more effective quantitative FRET imaging.


2011 ◽  
Vol 22 (23) ◽  
pp. 4647-4656 ◽  
Author(s):  
Naoki Komatsu ◽  
Kazuhiro Aoki ◽  
Masashi Yamada ◽  
Hiroko Yukinaga ◽  
Yoshihisa Fujita ◽  
...  

Biosensors based on the principle of Förster (or fluorescence) resonance energy transfer (FRET) have shed new light on the spatiotemporal dynamics of signaling molecules. Among them, intramolecular FRET biosensors have been increasingly used due to their high sensitivity and user-friendliness. Time-consuming optimizations by trial and error, however, obstructed the development of intramolecular FRET biosensors. Here we report an optimized backbone for rapid development of highly sensitive intramolecular FRET biosensors. The key concept is to exclude the “orientation-dependent” FRET and to render the biosensors completely “distance-dependent” with a long, flexible linker. We optimized a pair of fluorescent proteins for distance-dependent biosensors, and then developed a long, flexible linker ranging from 116 to 244 amino acids in length, which reduced the basal FRET signal and thereby increased the gain of the FRET biosensors. Computational simulations provided insight into the mechanisms by which this optimized system was the rational strategy for intramolecular FRET biosensors. With this backbone system, we improved previously reported FRET biosensors of PKA, ERK, JNK, EGFR/Abl, Ras, and Rac1. Furthermore, this backbone enabled us to develop novel FRET biosensors for several kinases of RSK, S6K, Akt, and PKC and to perform quantitative evaluation of kinase inhibitors in living cells.


1998 ◽  
Vol 142 (1) ◽  
pp. 69-84 ◽  
Author(s):  
A.K. Kenworthy ◽  
M. Edidin

Membrane microdomains (“lipid rafts”) enriched in glycosylphosphatidylinositol (GPI)-anchored proteins, glycosphingolipids, and cholesterol have been implicated in events ranging from membrane trafficking to signal transduction. Although there is biochemical evidence for such membrane microdomains, they have not been visualized by light or electron microscopy. To probe for microdomains enriched in GPI- anchored proteins in intact cell membranes, we used a novel form of digital microscopy, imaging fluorescence resonance energy transfer (FRET), which extends the resolution of fluorescence microscopy to the molecular level (<100 Å). We detected significant energy transfer between donor- and acceptor-labeled antibodies against the GPI-anchored protein 5′ nucleotidase (5′ NT) at the apical membrane of MDCK cells. The efficiency of energy transfer correlated strongly with the surface density of the acceptor-labeled antibody. The FRET data conformed to theoretical predictions for two-dimensional FRET between randomly distributed molecules and were inconsistent with a model in which 5′ NT is constitutively clustered. Though we cannot completely exclude the possibility that some 5′ NT is in clusters, the data imply that most 5′ NT molecules are randomly distributed across the apical surface of MDCK cells. These findings constrain current models for lipid rafts and the membrane organization of GPI-anchored proteins.


Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3105 ◽  
Author(s):  
Henning Höfig ◽  
Michele Cerminara ◽  
Ilona Ritter ◽  
Antonie Schöne ◽  
Martina Pohl ◽  
...  

Bacterial periplasmic binding proteins (PBPs) undergo a pronounced ligand-induced conformational change which can be employed to monitor ligand concentrations. The most common strategy to take advantage of this conformational change for a biosensor design is to use a Förster resonance energy transfer (FRET) signal. This can be achieved by attaching either two fluorescent proteins (FPs) or two organic fluorescent dyes of different colors to the PBPs in order to obtain an optical readout signal which is closely related to the ligand concentration. In this study we compare a FP-equipped and a dye-labeled version of the glucose/galactose binding protein MglB at the single-molecule level. The comparison demonstrates that changes in the FRET signal upon glucose binding are more pronounced for the FP-equipped sensor construct as compared to the dye-labeled analog. Moreover, the FP-equipped sensor showed a strong increase of the FRET signal under crowding conditions whereas the dye-labeled sensor was not influenced by crowding. The choice of a labeling scheme should therefore be made depending on the application of a FRET-based sensor.


2021 ◽  
Vol 118 (25) ◽  
pp. e2101004118
Author(s):  
Julianna R. Cresti ◽  
Abramo J. Manfredonia ◽  
Christopher E. Bragança ◽  
Joseph A. Boscia ◽  
Christina M. Hurley ◽  
...  

The 26S proteasome is the macromolecular machine responsible for the bulk of protein degradation in eukaryotic cells. As it degrades a ubiquitinated protein, the proteasome transitions from a substrate-accepting conformation (s1) to a set of substrate-processing conformations (s3 like), each stabilized by different intramolecular contacts. Tools to study these conformational changes remain limited, and although several interactions have been proposed to be important for stabilizing the proteasome’s various conformations, it has been difficult to test these directly under equilibrium conditions. Here, we describe a conformationally sensitive Förster resonance energy transfer assay, in which fluorescent proteins are fused to Sem1 and Rpn6, which are nearer each other in substrate-processing conformations than in the substrate-accepting conformation. Using this assay, we find that two sets of interactions, one involving Rpn5 and another involving Rpn2, are both important for stabilizing substrate-processing conformations. Mutations that disrupt these interactions both destabilize substrate-processing conformations relative to the substrate-accepting conformation and diminish the proteasome’s ability to successfully unfold and degrade hard-to-unfold substrates, providing a link between the proteasome’s conformational state and its unfolding ability.


Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 122 ◽  
Author(s):  
Skruzny ◽  
Pohl ◽  
Abella

Förster resonance energy transfer (FRET) microscopy is a powerful fluorescence microscopy method to study the nanoscale organization of multiprotein assemblies in vivo. Moreover, many biochemical and biophysical processes can be followed by employing sophisticated FRET biosensors directly in living cells. Here, we summarize existing FRET experiments and biosensors applied in yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, two important models of fundamental biomedical research and efficient platforms for analyses of bioactive molecules. We aim to provide a practical guide on suitable FRET techniques, fluorescent proteins, and experimental setups available for successful FRET experiments in yeasts.


2020 ◽  
Vol 21 (14) ◽  
pp. 5004
Author(s):  
Ekaterina O. Serebrovskaya ◽  
Nadezda M. Podvalnaya ◽  
Varvara V. Dudenkova ◽  
Anna S. Efremova ◽  
Nadya G. Gurskaya ◽  
...  

Poly-(ADP-ribosyl)-ation (PARylation) is a reversible post-translational modification of proteins and DNA that plays an important role in various cellular processes such as DNA damage response, replication, transcription, and cell death. Here we designed a fully genetically encoded fluorescent sensor for poly-(ADP-ribose) (PAR) based on Förster resonance energy transfer (FRET). The WWE domain, which recognizes iso-ADP-ribose internal PAR-specific structural unit, was used as a PAR-targeting module. The sensor consisted of cyan Turquoise2 and yellow Venus fluorescent proteins, each in fusion with the WWE domain of RNF146 E3 ubiquitin ligase protein. This bipartite sensor named sPARroW (sensor for PAR relying on WWE) enabled monitoring of PAR accumulation and depletion in live mammalian cells in response to different stimuli, namely hydrogen peroxide treatment, UV irradiation and hyperthermia.


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