Identification of Potential Modulators of the RGS7/Gβ5/R7BP Complex

2021 ◽  
pp. 247255522110206
Author(s):  
Hannah M. Stoveken ◽  
Virneliz Fernandez-Vega ◽  
Brian S. Muntean ◽  
Dipak N. Patil ◽  
Justin Shumate ◽  
...  
Keyword(s):  
G Protein ◽  
Protein Complex ◽  
High Throughput Screening ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Opioid Analgesics ◽  
Rgs Proteins ◽  
Time Resolved ◽  
Binding Partners

Regulators of G protein signaling (RGS) proteins serve as critical regulatory nodes to limit the lifetime and extent of signaling via G protein–coupled receptors (GPCRs). Previously, approaches to pharmacologically inhibit RGS activity have mostly focused on the inhibition of GTPase activity by interrupting the interaction of RGS proteins with the G proteins they regulate. However, several RGS proteins are also regulated by association with binding partners. A notable example is the mammalian RGS7 protein, which has prominent roles in metabolic control, vision, reward, and actions of opioid analgesics. In vivo, RGS7 exists in complex with the binding partners type 5 G protein β subunit (Gβ5) and R7 binding protein (R7BP), which control its stability and activity, respectively. Targeting the whole RGS7/Gβ5/R7BP protein complex affords the opportunity to allosterically tune opioid receptor signaling following opioid engagement while potentially bypassing undesirable side effects. Hence, we implemented a novel strategy to pharmacologically target the interaction between RGS7/Gβ5 and R7BP. To do so, we searched for protein complex inhibitors using a time-resolved fluorescence resonance energy transfer (FRET)–based high-throughput screening (HTS) assay that measures compound-mediated alterations in the FRET signal between RGS7/Gβ5 and R7BP. We performed two HTS campaigns, each screening ~100,000 compounds from the Scripps Drug Discovery Library (SDDL). Each screen yielded more than 100 inhibitors, which will be described herein.

scholarly journals Role of metAB in Methionine Metabolism and Optimal Chicken Colonization in Campylobacter jejuni

2020 ◽  
Vol 89 (1) ◽  
pp. e00542-20
Author(s):  
Brandon Ruddell ◽  
Alan Hassall ◽  
Orhan Sahin ◽  
Qijing Zhang ◽  
Paul J. Plummer ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Differential Distribution ◽  
Time Resolved ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Adenosyl Methionine ◽  
Strain Type

ABSTRACTCampylobacter jejuni is a zoonotic pathogen and is one of the leading causes of human gastroenteritis worldwide. C. jejuni IA3902 (representative of the sheep abortion clone) is genetically similar to C. jejuni W7 (representative of strain type NCTC 11168); however, there are significant differences in the ability of luxS mutants of these strains to colonize chickens. LuxS is essential for the activated methyl cycle and generates homocysteine for conversion to l-methionine. Comparative genomics identified differential distribution of the genes metA and metB, which function to convert homoserine for downstream production of l-methionine, between IA3902 and W7, which could enable a secondary pathway for l-methionine biosynthesis in a W7 ΔluxS but not in an IA3902 ΔluxS strain. To test the hypothesis that the genes metA and metB contribute to l-methionine production and chicken colonization by Campylobacter, we constructed two mutants for phenotypic comparison, the W7 ΔmetAB ΔluxS and IA3902 ΔluxS::metAB mutants. Quantitative reverse transcription-PCR and tandem mass spectrometry protein analysis were used to validate MetAB transcription and translation as present in the IA3902 ΔluxS::metAB mutant and absent in the W7 ΔmetAB ΔluxS mutant. Time-resolved fluorescence resonance energy transfer fluorescence assays demonstrated that l-methionine and S-adenosyl methionine concentrations decreased in the W7 ΔmetAB ΔluxS mutant and increased in the IA3902 ΔluxS::metAB mutant. Assessment of chicken colonization revealed that the IA3902 ΔluxS::metAB strain partially rescued the colonization defect of the IA3902 ΔluxS strain, while the W7 ΔmetAB ΔluxS strain showed significantly decreased colonization compared to that of the wild-type and the W7 ΔluxS strain. These results indicate that the ability to maintain l-methionine production in vivo, conferred by metA and metB in the absence of luxS, is critical for normal chicken colonization by C. jejuni.

scholarly journals Repurposing a Histamine Detection Platform for High-Throughput Screening of Histidine Decarboxylase

2018 ◽  
Vol 23 (9) ◽  
pp. 974-981
Author(s):  
Yu-Chi Juang ◽  
Xavier Fradera ◽  
Yongxin Han ◽  
Anthony William Partridge
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Large Scale ◽  
Histidine Decarboxylase ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Gastric Ulcers ◽  
Statistical Parameters ◽  
Time Resolved ◽  
Neurological Response

Histidine decarboxylase (HDC) is the primary enzyme that catalyzes the conversion of histidine to histamine. HDC contributes to many physiological responses as histamine plays important roles in allergic reaction, neurological response, gastric acid secretion, and cell proliferation and differentiation. Small-molecule modulation of HDC represents a potential therapeutic strategy for a range of histamine-associated diseases, including inflammatory disease, neurological disorders, gastric ulcers, and select cancers. High-throughput screening (HTS) methods for measuring HDC activity are currently limited. Here, we report the development of a time-resolved fluorescence resonance energy transfer (TR-FRET) assay for monitoring HDC activity. The assay is based on competition between HDC-generated histamine and fluorophore-labeled histamine for binding to a Europium cryptate (EuK)-labeled anti-histamine antibody. We demonstrated that the assay is highly sensitive and simple to develop. Assay validation experiments were performed using low-volume 384-well plates and resulted in good statistical parameters. A pilot HTS screen gave a Z′ score > 0.5 and a hit rate of 1.1%, and led to the identification of a validated hit series. Overall, the presented assay should facilitate the discovery of therapeutic HDC inhibitors by acting as a novel tool suitable for large-scale HTS and subsequent interrogation of compound structure–activity relationships.

scholarly journals G-protein-coupled receptor 30 interacts with receptor activity-modifying protein 3 and confers sex-dependent cardioprotection

2013 ◽  
Vol 51 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Patricia M Lenhart ◽  
Stefan Broselid ◽  
Cordelia J Barrick ◽  
L M Fredrik Leeb-Lundberg ◽  
Kathleen M Caron
Keyword(s):  
G Protein ◽  
Transmembrane Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Cardiac Cells ◽  
Receptor Activity ◽  
Hek293 Cells ◽  
G Protein Coupled

Receptor activity-modifying protein 3 (RAMP3) is a single-pass transmembrane protein known to interact with and affect the trafficking of several G-protein-coupled receptors (GPCRs). We sought to determine whether RAMP3 interacts with GPR30, also known as G-protein-coupled estrogen receptor 1. GPR30 is a GPCR that binds estradiol and has important roles in cardiovascular and endocrine physiology. Using bioluminescence resonance energy transfer titration studies, co-immunoprecipitation, and confocal microscopy, we show that GPR30 and RAMP3 interact. Furthermore, the presence of GPR30 leads to increased expression of RAMP3 at the plasma membrane in HEK293 cells. In vivo, there are marked sex differences in the subcellular localization of GPR30 in cardiac cells, and the hearts of Ramp3−/− mice also show signs of GPR30 mislocalization. To determine whether this interaction might play a role in cardiovascular disease, we treated Ramp3+/+ and Ramp3−/− mice on a heart disease-prone genetic background with G-1, a specific agonist for GPR30. Importantly, this in vivo activation of GPR30 resulted in a significant reduction in cardiac hypertrophy and perivascular fibrosis that is both RAMP3 and sex dependent. Our results demonstrate that GPR30–RAMP3 interaction has functional consequences on the localization of these proteins both in vitro and in vivo and that RAMP3 is required for GPR30-mediated cardioprotection.

scholarly journals Assay Concordance between SPA and TR-FRET in High-Throughput Screening

2006 ◽  
Vol 11 (6) ◽  
pp. 606-616 ◽  
Author(s):  
Oliver Von Ahsen ◽  
Anne Schmidt ◽  
Monika Klotz ◽  
Karsten Parczyk
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Statistical Significance ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved ◽  
Detection Technology ◽  
Significant Difference ◽  
Set Up ◽  
Detection Technologies

High-throughput screening (HTS) of large chemical libraries has become the main source of new lead compounds for drug development. Several specialized detection technologies have been developed to facilitate the cost- and time-efficient screening of millions of compounds. However, concerns have been raised, claiming that different HTS technologies may produce different hits, thus limiting trust in the reliability of HTS data. This study was aimed to investigate the reliability of the authors most frequently used assay techniques: scintillation proximity assay (SPA) and homogeneous time-resolved fluorescence resonance energy transfer (TR-FRET). To investigate the data concordance between these 2 detection technologies, the authors screened a large subset of the Schering compound library consisting of 300,000 compounds for inhibitors of a nonreceptor tyrosine kinase. They chose to set up this study in realistic HTS scale to ensure statistical significance of the results. The findings clearly demonstrate that the choice of detection technology has no significant impact on hit finding, provided that assays are biochemically equivalent. Data concordance is up to 90%. The little differences in hit findings are caused by threshold setting but not by systematic differences between the technologies. The most significant difference between the compared techniques is that in the SPA format, more false-positive primary hits were obtained.

scholarly journals Alteration of RNA Splicing by Small-Molecule Inhibitors of the Interaction between NHP2L1 and U4

2017 ◽  
Vol 23 (2) ◽  
pp. 164-173 ◽  
Author(s):  
Barthelemy Diouf ◽  
Wenwei Lin ◽  
Asli Goktug ◽  
Christy R. R. Grace ◽  
Michael Brett Waddell ◽  
...  
Keyword(s):  
Small Molecules ◽  
Rna Splicing ◽  
High Throughput Screening ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Therapeutic Strategies ◽  
Biological Processes ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
U4 Rna

Splicing is an important eukaryotic mechanism for expanding the transcriptome and proteome, influencing a number of biological processes. Understanding its regulation and identifying small molecules that modulate this process remain a challenge. We developed an assay based on time-resolved fluorescence resonance energy transfer (TR-FRET) to detect the interaction between the protein NHP2L1 and U4 RNA, which are two key components of the spliceosome. We used this assay to identify small molecules that interfere with this interaction in a high-throughput screening (HTS) campaign. Topotecan and other camptothecin derivatives were among the top hits. We confirmed that topotecan disrupts the interaction between NHP2L1 and U4 by binding to U4 and inhibits RNA splicing. Our data reveal new functions of known drugs that could facilitate the development of therapeutic strategies to modify splicing and alter gene function.

scholarly journals Thermally Denatured BSA, a Surrogate Additive to Replace BSA in Buffers for High-Throughput Screening

2010 ◽  
Vol 15 (10) ◽  
pp. 1281-1286 ◽  
Author(s):  
Imanol Peña ◽  
Juan Manuel Domínguez
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Negative Impact ◽  
Specific Binding ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Masking Effect ◽  
Binding Properties ◽  
Time Resolved ◽  
Beneficial Effects

The use of thermally denatured bovine serum albumin (tdBSA) as an additive in high-throughput screening (HTS) buffers has been studied with the aim of finding a surrogate to native albumin devoid of its inconveniences, in particular its compound masking effect. The presence of aggregates in the thermally denatured material did not have any negative impact on common readout technologies used in HTS such as fluorescence intensity (FLINT), fluorescence polarization, time-resolved fluorescence resonance energy transfer (TR-FRET) and luminescence. tdBSA rendered the same beneficial effects as native albumin in several assays or even improved its performance due to the lack of specific binding properties. Although tdBSA still binds compounds nonspecifically as any other protein does, it mitigates the compound masking effect observed with native albumin and can be postulated as a convenient surrogate to BSA for HTS purposes.

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