scholarly journals Cholesterol as a modulator of cannabinoid receptor CB2 signaling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexei Yeliseev ◽  
Malliga R. Iyer ◽  
Thomas T. Joseph ◽  
Nathan J. Coffey ◽  
Resat Cinar ◽  
...  
Keyword(s):  
G Protein ◽  
Md Simulation ◽  
Cannabinoid Receptor ◽  
Partial Agonist ◽  
G Protein Coupled Receptors ◽  
Affinity Ligands ◽  
Drug Candidates ◽  
Different Types ◽  
G Protein Coupled ◽  
Specific Ligand

AbstractSignaling through integral membrane G protein-coupled receptors (GPCRs) is influenced by lipid composition of cell membranes. By using novel high affinity ligands of human cannabinoid receptor CB2, we demonstrate that cholesterol increases basal activation levels of the receptor and alters the pharmacological categorization of these ligands. Our results revealed that (2-(6-chloro-2-((2,2,3,3-tetramethylcyclopropane-1-carbonyl)imino)benzo[d]thiazol-3(2H)-yl)ethyl acetate ligand (MRI-2646) acts as a partial agonist of CB2 in membranes devoid of cholesterol and as a neutral antagonist or a partial inverse agonist in cholesterol-containing membranes. The differential effects of a specific ligand on activation of CB2 in different types of membranes may have implications for screening of drug candidates in a search of modulators of GPCR activity. MD simulation suggests that cholesterol exerts an allosteric effect on the intracellular regions of the receptor that interact with the G-protein complex thereby altering the recruitment of G protein.

scholarly journals Organized cannabinoid receptor distribution in neurons revealed by super-resolution fluorescence imaging

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hui Li ◽  
Jie Yang ◽  
Cuiping Tian ◽  
Min Diao ◽  
Quan Wang ◽  
...  
Keyword(s):  
G Protein ◽  
Fluorescence Imaging ◽  
Cannabinoid Receptor ◽  
Super Resolution ◽  
G Protein Coupled Receptors ◽  
Cellular Functions ◽  
Cannabinoid Receptor 1 ◽  
Intracellular Organization ◽  
Dynamic Movement ◽  
G Protein Coupled

Abstract G-protein-coupled receptors (GPCRs) play important roles in cellular functions. However, their intracellular organization is largely unknown. Through investigation of the cannabinoid receptor 1 (CB1), we discovered periodically repeating clusters of CB1 hotspots within the axons of neurons. We observed these CB1 hotspots interact with the membrane-associated periodic skeleton (MPS) forming a complex crucial in the regulation of CB1 signaling. Furthermore, we found that CB1 hotspot periodicity increased upon CB1 agonist application, and these activated CB1 displayed less dynamic movement compared to non-activated CB1. Our results suggest that CB1 forms periodic hotspots organized by the MPS as a mechanism to increase signaling efficacy upon activation.

New small molecule fluorescent probes for G protein-coupled receptors: valuable tools for drug discovery

2021 ◽  
Vol 13 (1) ◽  
pp. 63-90
Author(s):  
Joshua W Conner ◽  
Daniel P Poole ◽  
Manuela Jörg ◽  
Nicholas A Veldhuis
Keyword(s):  
Drug Discovery ◽  
Ligand Binding ◽  
G Protein ◽  
Small Molecule ◽  
G Protein Coupled Receptors ◽  
Signaling Proteins ◽  
Drug Candidates ◽  
Compound Screening ◽  
G Protein Coupled ◽  
Single Approach

G protein-coupled receptors (GPCRs) are essential signaling proteins and tractable therapeutic targets. To develop new drug candidates, GPCR drug discovery programs require versatile, sensitive pharmacological tools for ligand binding and compound screening. With the availability of new imaging modalities and proximity-based ligand binding technologies, fluorescent ligands offer many advantages and are increasingly being used, yet labeling small molecules remains considerably more challenging relative to peptides. Focusing on recent fluorescent small molecule studies for family A GPCRs, this review addresses some of the key challenges, synthesis approaches and structure–activity relationship considerations, and discusses advantages of using high-resolution GPCR structures to inform conjugation strategies. While no single approach guarantees successful labeling without loss of affinity or selectivity, the choice of fluorophore, linker type and site of attachment have proved to be critical factors that can significantly affect their utility in drug discovery programs, and as discussed, can sometimes lead to very unexpected results.

Heterodimers and Receptor Mosaics of Different Types of G-Protein-Coupled Receptors

Physiology ◽  
2008 ◽  
Vol 23 (6) ◽  
pp. 322-332 ◽  
Author(s):  
Kjell Fuxe ◽  
Daniel Marcellino ◽  
Diego Guidolin ◽  
Amina S. Woods ◽  
Luigi F. Agnati
Keyword(s):  
Drug Development ◽  
G Protein ◽  
Research Area ◽  
G Protein Coupled Receptors ◽  
Major Research ◽  
Receptor Mosaics ◽  
Different Types ◽  
Allosteric Mechanisms ◽  
Novel Drug ◽  
G Protein Coupled

Through an assembly of interacting GPCRs, heterodimers and high-order heteromers (termed receptor mosaics) are formed and lead to changes in the agonist recognition, signaling, and trafficking of participating receptors via allosteric mechanisms, sometimes involving the appearance of cooperativity. This field has now become a major research area, and this review deals with their physiology being integrators of receptor signaling in the CNS and their use as targets for novel drug development based on their unique pharmacology.

scholarly journals Comparative Analysis of Functional Assays for Characterization of Agonist Ligands at G Protein-Coupled Receptors

2003 ◽  
Vol 8 (5) ◽  
pp. 500-510 ◽  
Author(s):  
Anke Niedernberg ◽  
Sorin Tunaru ◽  
Andree Blaukat ◽  
Bruce Harris ◽  
Evi Kostenis
Keyword(s):  
G Protein ◽  
Partial Agonist ◽  
A Priori ◽  
G Protein Coupled Receptors ◽  
Binding Assays ◽  
Functional Assays ◽  
Gtpγs Binding ◽  
Sphingosine 1 Phosphate ◽  
Intracellular Ca ◽  
G Protein Coupled

A variety of functional assays are available for agonist or antagonist screening of G protein-coupled receptors (GPCRs), but it is a priori not predictable which assay is the most suitable to identify agonists or antagonists of GPCRs with therapeutic value in humans. More specifically, it is not known how a given set of GPCR agonists compares in different functional assays with respect to potency and efficacy and whether the level of the signaling cascade that is analyzed has any impact on the detection of agonistic responses. To address this question, the authors used the recently cloned human S1P5 receptor as a model and compared a set of 3 lipid ligands (sphingosine 1-phosphate [S1P], dihydro sphingosine 1-phosphate [dhS1P], and sphingosine) in 5 different functional assays: GTPγS binding, inhibition of adenylyl cyclase activity, mobilization of intracellular Ca2+ via the FLIPR and aequorin technology, and MAP kinase (ERK1/2) activation. S1P induced agonistic responses in all except the ERK1/2 assays with EC50 values varying by a factor of 10. Whereas dhS1P was identified as a partial agonist in the GTPγS assay, it behaved as a full agonist in all other settings. Sphingosine displayed partial agonistic activity exclusively in GTPγS binding assays. The findings suggest that assays in a given cellular background may vary significantly with respect to suitability for agonist finding and that ligands producing a response may not readily be detectable in all agonist assays. ( Journal of Biomolecular Screening 2003:500-510)

GPCR Screening via ERK 1/2: A Novel Platform for Screening G Protein–Coupled Receptors

2005 ◽  
Vol 10 (7) ◽  
pp. 730-737 ◽  
Author(s):  
Ronald I. W. Osmond ◽  
Antony Sheehan ◽  
Romana Borowicz ◽  
Emma Barnett ◽  
Georgina Harvey ◽  
...  
Keyword(s):  
G Protein ◽  
High Throughput ◽  
Measurement Techniques ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
G Protein Coupled Receptors ◽  
Drug Candidates ◽  
Gpcr Activation ◽  
Intracellular Ca ◽  
G Protein Coupled

Discovery of novel agonists and antagonists for G protein–coupled receptors (GPCRs) relies heavily on cell-based assays because determination of functional consequences of receptor engagement is often desirable. Currently, there are several key parameters measured to achieve this, including mobilization of intracellular Ca2+ and formation of cyclic adenosine monophosphate or inositol triphosphate. However, no single assay platform is suitable for all situations, and all of the assays have limitations. The authors have developed a new high-throughput homogeneous assay platform for GPCR discovery as an alternative to current assays, which employs detection of phosphorylation of the key signaling molecule p42/44 MAP kinase (ERK 1/2). The authors show that ERK 1/2 is consistently activated in cells stimulated by Gq-coupled GPCRs and provides a new high-throughput platform for screening GPCR drug candidates. The activation of ERK 1/2 in Gq-coupled GPCR systems generates comparable pharmacological data for receptor agonist and antagonist data obtained by other GPCR activation measurement techniques.

G protein-coupled receptors, an unexploited animal toxin targets: Exploration of green mamba venom for novel drug candidates active against adrenoceptors

Toxicon ◽  
2012 ◽  
Vol 59 (4) ◽  
pp. 487-496 ◽  
Author(s):  
Arhamatoulaye Maïga ◽  
Gilles Mourier ◽  
Loïc Quinton ◽  
Céline Rouget ◽  
Céline Gales ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Drug Candidates ◽  
Novel Drug ◽  
G Protein Coupled

Cannabinoid Receptor-Related Orphan G Protein-Coupled Receptors

2017 ◽  
pp. 223-247 ◽  
Author(s):  
Andrew Irving ◽  
Ghayth Abdulrazzaq ◽  
Sue L.F. Chan ◽  
June Penman ◽  
Jenni Harvey ◽  
...  
Keyword(s):  
G Protein ◽  
Cannabinoid Receptor ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled
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