scholarly journals A Time-Resolved Fluorescence Resonance Energy Transfer Assay for High-Throughput Screening of 14-3-3 Protein–Protein Interaction Inhibitors

2013 ◽  
Vol 11 (6) ◽  
pp. 367-381 ◽  
Author(s):  
Yuhong Du ◽  
Robert W. Fu ◽  
Bin Lou ◽  
Jing Zhao ◽  
Min Qui ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
High Throughput ◽  
Protein Interaction ◽  
High Throughput Screening ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Protein Protein Interaction

scholarly journals Comparison of Miniaturized Time-Resolved Fluorescence Resonance Energy Transfer and Enzyme-Coupled Luciferase High-Throughput Screening Assays to Discover Inhibitors of Rho-Kinase II (ROCK-II)

2007 ◽  
Vol 13 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Thomas Schröter ◽  
Dmitriy Minond ◽  
Amiee Weiser ◽  
Chinh Dao ◽  
Jeff Habel ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
High Throughput ◽  
High Throughput Screening ◽  
Resonance Energy Transfer ◽  
Rho Kinase ◽  
Resonance Energy ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescence Resonance

Kinases are important drug discovery targets for a wide variety of therapeutic indications; consequently, the measurement of kinase activity remains a common high-throughput screening (HTS) application. Recently, enzyme-coupled luciferase-kinase (LK) format assays have been introduced. This format measures luminescence resulting from metabolism of adenosine triphosphate (ATP) via a luciferin/luciferase-coupled reaction. In the research presented here, 1536-well format time-resolved fluorescence resonance energy transfer (TR-FRET) and LK assays were created to identify novel Rho-associated kinase II (ROCK-II) inhibitors. HTS campaigns for both assays were conducted in this miniaturized format. It was found that both assays were able to consistently reproduce the expected pharmacology of inhibitors known to be specific to ROCK-II (fasudil IC50: 283 ± 27 nM and 336 ± 54 nM for TR-FRET and LK assays, respectively; Y-27632 IC50: 133 ± 7.8 nM and 150 ± 22 nM for TR-FRET and LK assays, respectively). In addition, both assays proved robust for HTS efforts, demonstrating excellent plate Z′ values during the HTS campaign (0.84 ± 0.03; 0.72 ± 0.05 for LK and TR-FRET campaigns, respectively). Both formats identified scaffolds of known and novel ROCK-II inhibitors with similar sensitivity. A comparison of the performance of these 2 assay formats in an HTS campaign was enabled by the existence of a subset of 25,000 compounds found in both our institutional and the Molecular Library Screening Center Network screening files. Analysis of the HTS campaign results based on this subset of common compounds showed that both formats had comparable total hit rates, hit distributions, amount of hit clusters, and format-specific artifact. It can be concluded that both assay formats are suitable for the discovery of ROCK-II inhibitors, and the choice of assay format depends on reagents and/or screening technology available. ( Journal of Biomolecular Screening 2008:17-28)

Development of a Homogeneous Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) Assay for the Inhibition of Keap1–Nrf2 Protein–Protein Interaction

2020 ◽  
Vol 26 (1) ◽  
pp. 100-112
Author(s):  
Sumi Lee ◽  
Dhulfiqar Ali Abed ◽  
Lesa J. Beamer ◽  
Longqin Hu
Keyword(s):  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
Small Molecule ◽  
Protein Interaction ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Protein Protein Interaction ◽  
Nrf2 Protein

The transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), plays a major role in regulating the antioxidant defense system through the Kelch-like ECH-associated protein 1–Nrf2–antioxidant response element (Keap1–Nrf2–ARE) pathway. Small-molecule inhibitors targeting Keap1–Nrf2 protein–protein interaction (PPI) decrease the rate of Nrf2 degradation by the 26S proteasome and thus increase the intracellular level of Nrf2, which translocates into the nucleus, leading to upregulated expression of cytoprotective and antioxidant enzymes. Such inhibitors can be developed into potential preventive and therapeutic agents of diseases caused by oxidative damage. To more effectively identify promising Nrf2 activators through the inhibition of Keap1–Nrf2 PPI, a homogeneous time-resolved fluorescence resonance energy transfer (TR-FRET) assay was developed in this work by indirectly labeling the Keap1 Kelch domain protein with Tb-anti-His antibody as the donor and using, as the acceptor, fluorescein isothiocyanate (FITC)-labeled 9mer Nrf2 peptide amide, the same fluorescent probe that was used in an earlier fluorescence polarization (FP) assay. Assay conditions, including concentrations of the various components, buffer type, and incubation time, were optimized in the TR-FRET competition assay with known small-molecule inhibitors of Keap1–Nrf2 PPI. Under the optimized conditions, the Keap1–Nrf2 TR-FRET assay exhibited great sensitivity with a high dynamic range and considerable stability for as long as 5 h. The Z’ factor was determined to be 0.82, suggesting that the assay is suitable for high-throughput screening and lead optimization of inhibitors of Keap1–Nrf2 PPI. Furthermore, the TR-FRET assay is capable of differentiating potent inhibitors of Keap1–Nrf2 PPI down to the subnanomolar inhibition constant ( Ki) range.

scholarly journals Identification of Small Molecule Inhibitors of the Mitotic Kinase Haspin by High-Throughput Screening Using a Homogeneous Time-Resolved Fluorescence Resonance Energy Transfer Assay

2008 ◽  
Vol 13 (10) ◽  
pp. 1025-1034 ◽  
Author(s):  
Debasis Patnaik ◽  
Jun Xian ◽  
Marcie A. Glicksman ◽  
Gregory D. Cuny ◽  
Ross L. Stein ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
High Throughput ◽  
Histone H3 ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Kinase Assay ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescence Resonance

Haspin/Gsg2 is a kinase that phosphorylates histone H3 at Thr-3 (H3T3ph) during mitosis. Its depletion by RNA interference results in failure of chromosome alignment and a block in mitosis. Haspin, therefore, is a novel target for development of antimitotic agents. We report the development of a high-throughput time-resolved fluorescence resonance energy transfer (TR-FRET) kinase assay for haspin. Histone H3 peptide was used as a substrate, and a europium-labeled H3T3ph phosphospecific monoclonal antibody was used to detect phosphorylation. A library of 137632 small molecules was screened at Km concentrations of ATP and peptide to allow identification of diverse inhibitor types. Reconfirmation of hits and IC 50 determinations were carried out with the TR-FRET assay and by a radiometric assay using recombinant histone H3 as the substrate. A preliminary assessment of specificity was made by testing inhibition of 2 unrelated kinases. EC 50 values in cells were determined using a cell-based ELISA of H3T3ph. Five compounds were selected as leads based on potency and chemical structure considerations. These leads form the basis for the development of specific inhibitors of haspin that will have clear utility in basic research and possible use as starting points for development of antimitotic anticancer therapeutics. ( Journal of Biomolecular Screening 2008:1025-1034)

scholarly journals Development of a Ubiquitin Transfer Assay for High Throughput Screening by Fluorescence Resonance Energy Transfer

2000 ◽  
Vol 5 (5) ◽  
pp. 319-328 ◽  
Author(s):  
Michael D. Boisclair ◽  
Christopher McClure ◽  
Serene Josiah ◽  
Susan Glass ◽  
Steve Bottomley ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
High Throughput ◽  
High Throughput Screening ◽  
Wave Length ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved ◽  
Fluorescence Resonance ◽  
Lower Ratio

An assay based on fluorescence resonance energy transfer (FRET) has been developed to screen for ubiquitination inhibitors. The assay measures the transfer of ubiquitin from Ubc4 to HECT protein Rsc 1083. Secondary reagents (streptavidin and antibody to glutathione-S-transferase [GST]), pre-labeled with fluorophores (europium chelate, Eu3+, and allophycocyanin [APC]), are noncovalently attached via tags (biotin and GST) to the reactants (ubiquitin and Rsc). When Rsc is ubiquitinated, Eu3+ and APC are brought into close proximity, permitting energy transfer between the two fluorescent labels. FRET was measured as time-resolved fluorescence at the emission wave-length of APC, almost entirely free of nonspecific fluorescence from Eu3+ and APC. The FRET assay generated a lower ratio of signal to background (8 vs. 31) than an assay for the same ubiquitination step that was developed as a dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA). However, compared to the DELFIA method, use of FRET resulted in higher precision (4% vs. 11% intraplate coefficient of variation). Quenching of fluorescence was minimal when compounds were screened at 10 pxg/ml using FRET. Employing a quick and simple homogeneous method, the FRET assay for ubiquitin transfer is ideally suited for high throughput screening.

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